EP3755408A1 - Catheter inflatable cuff pressure stabilizers - Google Patents

Catheter inflatable cuff pressure stabilizers

Info

Publication number
EP3755408A1
EP3755408A1 EP19758270.3A EP19758270A EP3755408A1 EP 3755408 A1 EP3755408 A1 EP 3755408A1 EP 19758270 A EP19758270 A EP 19758270A EP 3755408 A1 EP3755408 A1 EP 3755408A1
Authority
EP
European Patent Office
Prior art keywords
pressure
balloon
inflatable portion
volume
inflatable
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19758270.3A
Other languages
German (de)
French (fr)
Other versions
EP3755408A4 (en
Inventor
Yair Ramot
Eizik Amar
Oron Zachar
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Airway Medix Sp zoo
Original Assignee
Airway Medix Sp zoo
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US16/160,668 external-priority patent/US10286170B1/en
Application filed by Airway Medix Sp zoo filed Critical Airway Medix Sp zoo
Publication of EP3755408A1 publication Critical patent/EP3755408A1/en
Publication of EP3755408A4 publication Critical patent/EP3755408A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/04—Tracheal tubes
    • A61M16/0434—Cuffs
    • A61M16/044—External cuff pressure control or supply, e.g. synchronisation with respiration
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/0051—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes with alarm devices
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/01—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes specially adapted for anaesthetising
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/04—Tracheal tubes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/04—Tracheal tubes
    • A61M16/0463—Tracheal tubes combined with suction tubes, catheters or the like; Outside connections
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/06—Respiratory or anaesthetic masks
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/20—Valves specially adapted to medical respiratory devices
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/0003—Accessories therefor, e.g. sensors, vibrators, negative pressure
    • A61M2016/0027—Accessories therefor, e.g. sensors, vibrators, negative pressure pressure meter
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2202/00—Special media to be introduced, removed or treated
    • A61M2202/02—Gases
    • A61M2202/0266—Nitrogen (N)
    • A61M2202/0283—Nitrous oxide (N2O)
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/33—Controlling, regulating or measuring
    • A61M2205/3331—Pressure; Flow
    • A61M2205/3341—Pressure; Flow stabilising pressure or flow to avoid excessive variation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/50—General characteristics of the apparatus with microprocessors or computers
    • A61M2205/502—User interfaces, e.g. screens or keyboards
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/58—Means for facilitating use, e.g. by people with impaired vision
    • A61M2205/581—Means for facilitating use, e.g. by people with impaired vision by audible feedback
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/58—Means for facilitating use, e.g. by people with impaired vision
    • A61M2205/583—Means for facilitating use, e.g. by people with impaired vision by visual feedback
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/82—Internal energy supply devices
    • A61M2205/8206—Internal energy supply devices battery-operated
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2210/00—Anatomical parts of the body
    • A61M2210/10—Trunk
    • A61M2210/1025—Respiratory system
    • A61M2210/1028—Larynx
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2210/00—Anatomical parts of the body
    • A61M2210/10—Trunk
    • A61M2210/1025—Respiratory system
    • A61M2210/1032—Trachea

Definitions

  • the inflatable portion of the balloon contains a second-medium-pressure volume of air, (a) the inflatable portion of the balloon has a second-medium pressure of 30 cm H20, and (b) at least 20% of the outer surface of the inflatable portion of the balloon touches a portion of the inner surface of the protective housing; the second-medium-pressure volume of air equals the sum of (a) the base low-pressure volume of air and (b) a second incremental quantity of air that is between 10 cc and 50 cc.
  • a pressure display which is configured to display the pressure sensed by the pressure sensor
  • Inventive concept 120 The cuff pressure stabilizer according to Inventive concept 119, wherein the first and the second inflatable portions include a same material, and wherein the first and the second inflatable portions have first and second average wall thicknesses, respectively, that equal each other.
  • an average rate of change of the aggregate pressure-volume curve over a first pressure interval between 25 and 30 cm H20 is between 0.3 and 2 cm H20 / cc.
  • the cuff pressure stabilizer is characterized by an aggregate pressure-volume curve that represents the pressure in the first and the second inflatable portions when inflated, in aggregate, with different aggregate incremental volumes of air beyond the base low- pressure volume of air,
  • each of the first and the second inflatable portions contains, in aggregate, a base aggregate low-pressure volume of air, each of the first and the second inflatable portions has a base low pressure of 10 cm H20,
  • Inventive concept 131 A system including the cuff pressure stabilizer according to any one of Inventive concepts 29-55, wherein the system further includes the airway ventilation device.
  • a cuff pressure stabilizer for use (a) in contact with the atmosphere and (b) with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the cuff pressure stabilizer including:
  • Fig. 8A includes "confined” and “free” pressure-volume curves of a first inflatable portion of a first elastic balloon of the cuff pressure stabilizer of Fig. 5, in accordance with an application of the present invention
  • airway ventilation device 10 is a laryngeal mask airway (LMA) device 24, and inflatable cuff 11 is an inflatable cuff 28 (which is typically annular) that is insertable through a mouth of a patient to an inserted location within the patient, such that an anterior side of the cuff forms a seal around a laryngeal inlet of the patient upon inflation of the cuff.
  • LMA laryngeal mask airway
  • the LMA device is suitable for facilitating lung ventilation.
  • the working medium pressure may be between 15 and 60 cm H20, such as between 20 and 60 cm H20, e.g., between 25 and 55 cm H20, such as between 40 and 50 cm H20.
  • inflatable cuff 28 typically has a volume of between 25 and 50 cc, depending on the size of LMA device 24.
  • First and second frustoconical portions 160A and 160B geometrically define respective cones 170A and 170B (portions of which are labeled in Fig. 3B).
  • cones 170A and 170B intersect each other at one or more angles a (alpha), at least one of which is greater than 45 degrees.
  • at least one of the angles is less than 90 degrees.
  • all of the angles are greater than 45 degrees, and/or all of the angles are less than 90 degrees.
  • a "rising point of inflection” is a point of inflection at which the third derivative is positive, i.e., the curve is upward- flowing about the point and the curve changes from concave to convex from lower to higher pressures across the inflection point.
  • concave means concave downward
  • convex means concave upward, in accordance with the common definitions in calculus.
  • the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that the first volume equals at least 50% of the second volume when each of first and second inflatable portions 350 and 351 is inflated at the first-medium pressure of 15 cm H20, such as, for example, could be the pressure illustrated in Fig. 7B.
  • second inflatable portion 351 of second elastic balloon 349 of cuff pressure stabilizer 300 would be characterized by "free" pressure-volume curve 412 if second inflatable portion 351 were not disposed within second portion 357 or otherwise confined, i.e., unlike the configuration of cuff pressure stabilizer 300 described herein with reference to Figs. 5-7C, but like the configuration of cuff pressure stabilizer 600, described hereinbelow with reference to Fig. 11.
  • "free" pressure-volume curve 412 reflects physical, structural properties of second inflatable portion 351.
  • Figs. 12A-C are schematic cross-sectional illustrations of a cuff pressure stabilizer 800 with an elastic balloon 848 thereof inflated at different pressures, in accordance with an application of the present invention.
  • cuff pressure stabilizer 800 is similar cuff pressure stabilizer 300 described hereinabove with reference to Figs. 5-9, may implement any of the features thereof, and is for use with airway ventilation device 10 (e.g., tracheal ventilation tube 22 or laryngeal mask airway (LMA) device 24).
  • airway ventilation device 10 e.g., tracheal ventilation tube 22 or laryngeal mask airway (LMA) device 24.
  • LMA laryngeal mask airway
  • cuff pressure stabilizer 100 further comprises an inflation valve 191, which may, for example, comprise an on/off "push-valve” (e.g., conventional ETT inlet valve), or a one-way valve, or another kind of valve.
  • Cuff pressure stabilizer 100 further comprises a switchable pre-inflate valve 193, disposed along a fluid-communication path between stabilizer port 122 and inflation lumen proximal port connector 124, such as along connector tube 125, described hereinabove with reference to Figs. 1A-C.
  • inflation lumen proximal port connector 124 that is shaped to form an air-tight seal with inflation lumen proximal port 15 of airway ventilation device 10.
  • Switchable pre-inflate valve 193 is configured to be switchable between a close configuration, in which the valve blocks fluid flow therethrough, and an open configuration, in which the valve allows fluid flow therethrough.
  • cuff pressure stabilizer 100 further comprises a flow limiter 194, which is configured to slow the pressure-regulation response time of cuff pressure stabilizer 100.
  • This flow regulation prevents the cuff pressure stabilizer from responding erratically to changes of pressure in inflatable cuff 11 of airway ventilation device within a single ventilation cycle, but rather to regulate only pressure changes that continue over an extended period of time.
  • the above- mentioned second-medium incremental quantity Q2 of air may be at least 10 cc (e.g., at least 20 cc), no more than 50 cc (e.g., no more than 40 cc), and/or between 10 and 50 cc, such as between 20 and 40 cc.
  • inner surface 954 of protective housing 910 is shaped so as to include one or more cylindrical portions 960.
  • Balloon 948 is arranged such that inflatable portion 950 of balloon 948 is disposed inside protective housing 910, typically such that:
  • the at least a portion of the one or more cylindrical portions 960 touched by inflatable portion 950 has a length of at least 0.5 cm, such as at least 1 cm, measured along a central longitudinal axis of the one or more cylindrical portions 960.
  • Protective housing 910 is configured such that inflation of inflatable portion 950 of balloon 948 to beyond the threshold volume causes:
  • moveable portion 962 of protective housing 910 includes an accordion-pleated surface that allows for moving of moveable portion with respect to base portion 964 and expansion of the internal volume of protective housing 910 without necessarily increasing the inner surface area of protective housing 910 (configuration not shown).

Landscapes

  • Health & Medical Sciences (AREA)
  • Pulmonology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Anesthesiology (AREA)
  • Biomedical Technology (AREA)
  • Emergency Medicine (AREA)
  • Hematology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Media Introduction/Drainage Providing Device (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)

Abstract

A cuff pressure stabilizer (100, 900) includes a protective housing (110, 910) and a balloon (148, 948) disposed therein. The balloon (148, 948) has a base low pressure of 10 cm H20 when containing a base low-pressure volume of air. When the balloon (148, 948) contains a first medium-pressure volume of air, the balloon (148, 948) has a first medium pressure of 15 cm H20, and less than 15% of an outer surface (152, 952) of the balloon (148, 948) touches an inner surface (154, 954) of the housing (110, 910). When the balloon (148, 948) contains a second medium-pressure volume of air, the balloon (148, 948) has a second medium pressure of 30 cm H20, and at least 20% of the outer surface (152, 952) of the balloon (148, 948) touches a portion of the inner surface (154, 954) of the housing (110, 910). Other embodiments are also described.

Description

CATHETER INFLATABLE CUFF PRESSURE STABILIZERS
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application:
(a) claims priority from (i) US Provisional Application 62/632,668, filed February 20, 2018, (ii) US Provisional Application 62/758,007, filed November 9, 2018, and (iii) US Provisional Application 62/774,588, filed December 3, 2018, and
(b) claims priority from and is a continuation-in-part of US Application 16/160,668, filed October 15, 2018.
All of the above-mentioned applications are assigned to the assignee of the present application and are incorporated herein by reference.
FIELD OF THE APPLICATION
The present invention relates generally to medical suction catheter systems, and specifically to airway ventilation device cuff systems.
BACKGROUND OF THE APPLICATION
Some endotracheal tubes (ETTs) comprise an inflatable cuff, which forms a seal against the tracheal wall. This seal prevents gases from leaking past the cuff and allows positive pressure ventilation. Desired safe inflatable cuff pressure is in the range of 23 - 27 cm H20, with an optimal pressure of about 25 cm H20. Pressure above 30 cm H20 can cause irritation to the surrounding tracheal tissue. Extended duration of such high cuff pressure can interfere with oxygen flow to the tissue, causing tissue necrosis and a substantial wound. Low cuff pressure, typically below 20 cm H20, compromises the cuff sealing performance, and allows leakage into the lungs of subglottic fluids descending from above the cuff.
The external surface of inflatable cuffs is in communication with the ventilation pressure of the lungs. The pressure of the inflatable cuff cycles with the ventilation cycle. When an artificially- ventilated patient is also anesthetized, the plastic of the inflatable cuff absorbs the nitrous oxide (N20) gas used in anesthesia, which increases pressure in the cuff.
In current clinical settings of intensive care patients, changes of body positioning lead to significant changes in cuff pressure in the range of 10 - 50 cm H20, i.e., out of the safe range of 20-30 cm H20, and certainly out of the desired range of 23-27 cm H20. See, for example, Lizy C et ah, "Cuff pressure of endotracheal tubes after changes in body position in critically ill patients treated with mechanical ventilation," Am J Crit Care. 2014 Jan;23(l):el-8.
Therefore, there is a need to safely maintain the inflatable cuff pressure is in the range of 23 - 27 cm H20, optimally about 25 cm H20, and to avoid extended periods of pressure above 30 cm H20. In particular, there is a need to suppress the fluctuations of pressure in clinical settings caused by patient change of body positions.
Currently, the most common practiced approach for ETT cuff pressure management is manual monitoring (using a manometer) and adjustment of cuff pressure, which contributes to ICU staff workload. It has been shown that up to eight manual adjustments of cuff pressure are required daily to maintain recommended cuff pressure ranges. Even so, the cuff pressure is uncontrolled during the long time periods between manual cuff adjustments. In addition, the manometer must be connected to and disconnected from the ETT cuff for each pressure measurement, which allows a small amount of air to escape from the ETT cuff. Still further, many conventional ETT manometers lose calibration relatively quickly.
Prior art cuff pressure regulators can be divided into two groups: (a) large bedside non-disposable expensive electric pump and electronic pressure monitors; and (b) small and light disposable non-electric limited-pressure reservoir compartments that must be filled manually. Use of disposable devices both prevents cross-contamination between patients and obviates the need for costly sterilization processes between patients. Moreover, the compactness of the disposable devices allows them to be attached on the ETT circuit and not occupy bedside space and an electric power cable connection.
Laryngeal mask airway (LMA) devices are useful in facilitating lung ventilation by forming a low-pressure seal around the patient's laryngeal inlet, thereby avoiding the known harmful effects of ETT devices, which form a seal within the trachea. LMA devices have become standard medical devices, instead of ETT devices, for rapidly and reliably establishing an unobstructed airway in a patient in emergency situations and in the administration of anesthetic gases.
During general anesthesia, pulmonary ventilation is secured with an ETT device or by an LMA device, and attention to the risk of complications related to a high intracuff pressure is important. When the cuff-to-tracheal wall pressure exceeds the tracheal capillary pressure (130-140 cm H20) for approximately 15 minutes, the tracheal mucous membrane becomes ischemic. The intracuff pressure approximates the cuff-to-tracheal wall pressures in high volume/low pressure cuffs, and a cuff pressure below 120 cm H20 is recommended to prevent ischemic injury. In addition, recurrent laryngeal nerve palsy has been demonstrated in up to 5% of patients after intubation, and a high cuff pressure is suspected as contributing to this complication. Similarly, in patients provided with a laryngeal mask, a high cuff pressure may lead to palsy of the lingual, hypoglossal, and recurrent laryngeal nerves, and postoperative sore throat.
US Patent Application Publication 2015/0283343 to Schnell et al. describes a pressure-equalizing device with a pressure equalizing balloon, the volume of which is connected to a further volume, the pressure of which is intended to be kept at as constant a value as possible even in the event of an enforced change in volume. In order therefore to keep the cuff pressure within the pressure range that is generally considered to be useful and optimal of between approximately 20 mbar and 30 mbar, but also make possible, if required, to increase the pressure in a controlled manner, according to the invention the equalizing balloon keeping the pressure generally constant is accommodated in a protective sleeve which has radial bulges deviating from a uniformly concave form matched to the outer contour of the balloon, which bulges are designed such that the equalizing balloon first abuts against the wall areas of the protective sleeve matched to the contour of the balloon and then, when pressure is increased, extends only into the bulges, whereby the pressure in the equalizing balloon gradually increases as the volume in the bulges increases.
PCT Publication WO 2017/153988 to Zachar et al., which is incorporated herein by reference, describes a cuff pressure stabilizer that includes an inflation lumen proximal port connector, which is shaped to form an air-tight seal with an inflation lumen proximal port of a catheter additionally having an inflatable cuff and an inflation lumen; a fluid reservoir; a liquid column container, which is (a) open to the atmosphere at at least one site along the liquid column container, (b) in fluid communication with the fluid reservoir, and (c) in communication with the inflation lumen proximal port connector via the fluid reservoir; and a liquid, which is contained (a) in the fluid reservoir, (b) in the liquid column container, or (c) partially in the fluid reservoir and partially in the liquid column container, and which has a density of between 1.5 and 5 g/cm3 at 4 degrees Celsius at 1 atm. US Patent 4,134,407 to Elam describes a monitoring system that is comprised of an elastomer balloon housed in a rigid cage having a plurality of windows which is designed to continuously indicate the state of collapse or expansion of the internal cuff or cuffs of an endotracheal tube. This balloon monitor is interconnected in series with the pneumatic channel through which the cuff or cuffs are inflated. The volume of the balloon may be observed visually with reference to its filling the cage enclosure denoting thereby its state of inflation and therefore, also that of the endotracheal cuff. Calibration of the balloon monitor provides means for accurately observing both the volume and pressure of air in the system. Therefore, visual inspection of the balloon monitor indicates by reason of the calibration the prevailing level of pressure in the patient's endotracheal cuff. Since the maintenance of safe cuff pressures results in a normal position of the balloon, in contact with the cage, electrical and electronic means may be arranged appropriately between the balloon and the inner surface of the cage to produce a warning signal in the event of cuff overdistension and an alarm signal in the event of cuff collapse.
SUMMARY OF THE APPLICATION
Applications of the present invention provide cuff pressure stabilizers for use with an airway ventilation device having an inflatable cuff. The same cuff pressure stabilizer, without requiring adjustment, calibration, or other configuration, is able to provide pressure stabilization to inflatable cuffs of both tracheal ventilation tubes and laryngeal mask airway (LMA) devices, even though the cuffs of these devices are inflated to substantially different pressures. Typically, cuffs of tracheal ventilation tubes are inflated to 25-30 cm H20, while cuffs of LMA devices are inflated to 40-60 cm H20.
In some applications of the present invention, in order to provide this pressure stabilization over such a wide range of pressures, a cuff pressure stabilizer is provided that comprises an elastic balloon, which is in fluid communication with the inflatable cuff, and which is disposed inside a protective housing that is configured to provide a pressure- volume curve with certain characteristics.
Typically, the protective housing is shaped and an inflatable portion of the balloon is configured such that:
• when the inflatable portion of the balloon contains a base low-pressure volume of air, (a) the inflatable portion of the balloon has a base low pressure of 10 cm H20, and (b) none of or less than 10% of an outer surface of the inflatable portion of the balloon touches (i.e., comes in direct physical contact with) an inner surface of the protective housing,
• when the inflatable portion of the balloon contains a first-medium-pressure volume of air, (a) the inflatable portion of the balloon has a first- medium pressure of 15 cm H20, and (b) none or less than 15% of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing; the first-medium- pressure volume of air equals the sum of (a) the base low-pressure volume of air and (b) a first incremental quantity of air of less than 10 cc, and
• when the inflatable portion of the balloon contains a second-medium-pressure volume of air, (a) the inflatable portion of the balloon has a second-medium pressure of 30 cm H20, and (b) at least 20% of the outer surface of the inflatable portion of the balloon touches a portion of the inner surface of the protective housing; the second-medium-pressure volume of air equals the sum of (a) the base low-pressure volume of air and (b) a second incremental quantity of air that is between 10 cc and 50 cc.
The inflatable portion of the balloon is characterized by a pres sure- volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the above-mentioned base low-pressure volume of air. The area of physical contact between the outer surface of the balloon and the inner surface of the protective housing at different pressures/volumes has a strong influence on the shape of the pressure-volume curve, because the contact affects the minimum radius of curvature of the balloon, and the pressure in a balloon is approximately proportional to the ratio of the surface tension to the minimum radius of curvature of the balloon. At a first stage, when the balloon is inflated at low pressure, its radius of curvature increases with increased inflation volume. In contrast, after contact with the shaped protective housing, the balloon's radius of curvature decreases upon further increased inflation volume, while the surface tension of the balloon continues to increase with inflation. The shape of the inner surface of the protective housing thus affects the shape of the pressure-volume curve of the balloon, including the presence and locations of local maximums and minimums and points of inflection.
In some applications of the present invention, in order to provide the above- mentioned pressure stabilization over such a wide range of pressures, a cuff pressure stabilizer is provided that comprises first and second elastic balloons, which are in fluid communication with each other and with the inflatable cuff. The cuff pressure stabilizer further comprises a housing, which comprises one or more internal protective surfaces.
Typically, the one or more internal protective surfaces are shaped and first and second inflatable portions of the first and second elastic balloons, respectively, are configured such that:
• when each of the first and the second inflatable portions is inflated at a first-medium pressure of 15 cm H20: (i) none or less than 15% of a first entire outer surface of the first inflatable portion touches the one or more internal protective surfaces, i.e., the first inflatable portion is not meaningfully confined by the first portion of the one or more internal protective surfaces, and (ii) none or less than 15% of a second entire outer surface of the second inflatable portion touches the one or more internal protective surfaces, i.e., the second inflatable portion is not meaningfully confined by the one or more internal protective surfaces, and
• when each of the first and the second inflatable portions is inflated at a second- medium pressure of 30 cm H20: (i) at least 20% of the first entire outer surface touches a first portion of the one or more internal protective surfaces, i.e., the first inflatable portion is at least somewhat confined by first portion of the one or more internal protective surfaces, and (ii) none or less than 15% of the second entire outer surface touches the one or more internal protective surfaces, i.e., the second inflatable portion is not meaningfully confined by the one or more internal protective surfaces.
As a result of this configuration, the cuff pressure stabilizer is characterized by an aggregate pres sure- volume curve, which represents the pressure in the first and the second inflatable portions when inflated, in aggregate, with different aggregate incremental volumes of air beyond a base low-pressure volume of air corresponding to the base low pressure of 10 cm H20 described hereinabove. As the pressure in the inflatable portions increases from the base low pressure of 10 cm H20, the properties of the first and the second inflatable portions together result in the aggregate pressure-volume curve. As the first inflatable portion comes into meaningful contact with the first portion of the one or more internal protective surfaces, the first portion confines the first inflatable portion to some extent and inhibits further expansion of the first inflatable portion to some extent. As a result, as the contact of the first inflatable portion with the first portion of the one or more internal protective surfaces increases, the first inflatable portion makes a diminishing contribution to the pressure-volume curve, such that the properties of the second inflatable make an increasing relative contribution to the aggregate pres sure- volume curve.
Since the first inflatable portion and the second inflatable portion contribute to different pressure intervals of the aggregate pres sure- volume curve, the properties of the two inflatable portions can be configured to produce desired different slopes of the curve at different pressure intervals that are appropriate for tracheal ventilation tubes and LMA devices, respectively. For example, the cuff pressure stabilizer may be configured to result in an aggregate pressure-volume curve having:
• an average rate of change over a first pressure interval between 25 and 30 cm H20 is between 0.3 and 2 cm H20 / cc, which may provide pressure stabilization for a cuff of a tracheal ventilation tube, and
• an average rate of change over a second pressure interval between 40 and 50 cm H20 is between 0.2 and 2 cm H20 / cc, which may provide pressure stabilization for a cuff of an LMA device.
For some applications, the protective housing is configured so as to define an internal volume that is expandable from a base internal volume to a greater, expanded internal volume. Typically, the protective housing is configured such that inflation of the inflatable portion of the balloon to below a threshold volume does not cause the internal volume of the protective housing to expand from the base internal volume, and to beyond the threshold volume causes the internal volume of the protective housing to expand from the base internal volume to the greater, expanded internal volume.
For some applications, the cuff pressure stabilizer comprises a base portion, and the protective housing comprises a moveable portion that is moveably coupled to the base portion such that the internal volume of the protective housing varies based on a relative position of the moveable portion with respect to the base portion. For some applications, the cuff pressure stabilizer is configured to assume locked and unlocked states; when in the locked state, to prevent the moveable portion from moving with respect to the base portion; and when in the unlocked state, to allow the moveable portion to move with respect to the base portion. During use of the cuff pressure stabilizers described above, a healthcare worker inflates the inflatable cuff of the airway ventilation device to an initial desired pressure. The cuff pressure stabilizer is configured to automatically mechanically and non- electrically stabilize the pressure in the inflatable cuff to within a clinically-acceptable range above and below the initial desired pressure, so long as the initial desired pressure is within the normal clinically-acceptable range for cuffs of tracheal ventilation tubes or LMA devices.
There is therefore provided, in accordance with an Inventive concept 1 of the present invention, a cuff pressure stabilizer for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the cuff pressure stabilizer including:
a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port;
a protective housing; and
an elastic balloon, which is in fluid communication with the stabilizer port, and which is arranged such that an inflatable portion of the balloon is disposed inside the protective housing,
wherein the protective housing is more rigid than the elastic balloon,
wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
when the inflatable portion of the balloon contains a base low-pressure volume of air, (a) the inflatable portion of the balloon has a base low pressure of 10 cm H20, and (b) none of or less than 10% of an outer surface of the inflatable portion of the balloon touches an inner surface of the protective housing,
when the inflatable portion of the balloon contains a first-medium-pressure volume of air, (a) the inflatable portion of the balloon has a first-medium pressure of 15 cm H20, and (b) none or less than 15% of an outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, wherein the first- medium-pressure volume of air equals the sum of (a) the base low-pressure volume of air and (b) a first incremental quantity of air of less than 10 cc, and
when the inflatable portion of the balloon contains a second-medium- pressure volume of air, (a) the inflatable portion of the balloon has a second-medium pressure of 30 cm H20, and (b) at least 20% of the outer surface of the inflatable portion of the balloon touches a portion of the inner surface of the protective housing, wherein the second-medium-pressure volume of air equals the sum of (a) the base low-pressure volume of air and (b) a second incremental quantity of air that is between 10 cc and 50 cc.
Inventive concept 2. The cuff pressure stabilizer according to Inventive concept 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
when the inflatable portion of the balloon contains the second-medium-pressure volume of air, no more than 50% of the outer surface of the inflatable portion of the balloon touches a portion of the inner surface of the protective housing.
Inventive concept 3. The cuff pressure stabilizer according to Inventive concept 1, wherein the second incremental quantity of air is less than 40 cc.
Inventive concept 4. The cuff pressure stabilizer according to Inventive concept 3, wherein the second incremental quantity of air is less than 30 cc.
Inventive concept 5. The cuff pressure stabilizer according to Inventive concept 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
the pressure-volume curve does not include a local maximum pressure at any pressure between 20 and 50 cm H20.
Inventive concept 6. The cuff pressure stabilizer according to Inventive concept 1, wherein the inflatable portion of the balloon is configured such that, if the protective housing were to be removed:
the inflatable portion of the balloon would be characterized by a removed- protective-housing pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
the removed-protective-housing pressure-volume curve includes a local maximum pressure at a pressure between 20 and 30 cm H20. Inventive concept 7. The cuff pressure stabilizer according to Inventive concept 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air,
the pressure-volume curve includes a local maximum pressure and a local minimum pressure at a greater incremental volume than the local maximum pressure, and
a pressure difference between the local maximum pressure and the local minimum pressure is less than 3 cm H20.
Inventive concept 8. The cuff pressure stabilizer according to Inventive concept 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air,
the pressure-volume curve includes a local maximum pressure and a local minimum pressure at a greater incremental volume than the local maximum pressure, and
a volume difference between the local maximum pressure and the local minimum pressure is less than 40 cc.
Inventive concept 9. The cuff pressure stabilizer according to Inventive concept 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
an average rate of change of the pressure-volume curve over a pressure interval between 40 and 50 cm H20 is between 0.5 and 3 cm H20 / cc.
Inventive concept 10. The cuff pressure stabilizer according to Inventive concept 9, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the pres sure- volume curve includes a rising point of inflection at an inflection-point pressure of between 15 and 35 cm H20.
Inventive concept 11. The cuff pressure stabilizer according to Inventive concept 10, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
an average rate of change of the pressure-volume curve over a pressure interval between 20 and 30 cm H20 is between 0.3 and 5 cm H20 / cc.
Inventive concept 12. The cuff pressure stabilizer according to Inventive concept 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
an average rate of change of the pressure-volume curve over a pressure interval between 50 and 60 cm H20 is between 0.5 and 3 cm H20 / cc.
Inventive concept 13. The cuff pressure stabilizer according to Inventive concept 12, wherein the average rate of change of the pressure-volume curve over the pressure interval between 50 and 60 cm H20 is less than 2 cm H20 / cc.
Inventive concept 14. The cuff pressure stabilizer according to Inventive concept 13, wherein the average rate of change of the pressure-volume curve over the pressure interval between 50 and 60 cm H20 is less than 1 cm H20 / cc.
Inventive concept 15. The cuff pressure stabilizer according to Inventive concept 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
an average rate of change of the pressure-volume curve over a pressure interval between 20 and 30 cm H20 is between 0.3 and 5 cm H20 / cc.
Inventive concept 16. The cuff pressure stabilizer according to Inventive concept 15, wherein the average rate of change of the pressure-volume curve over the pressure interval between 20 and 30 cm H20 is less than 4 cm H20 / cc. Inventive concept 17. The cuff pressure stabilizer according to Inventive concept 16, wherein the average rate of change of the pressure-volume curve over the pressure interval between 20 and 30 cm H20 is less than 3 cm H20 / cc.
Inventive concept 18. The cuff pressure stabilizer according to Inventive concept 15, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the pres sure- volume curve includes a rising point of inflection at an inflection-point pressure of between 15 and 35 cm H20.
Inventive concept 19. The cuff pressure stabilizer according to Inventive concept 18, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
an average rate of change of the pressure-volume curve over a pressure interval between 40 and 50 cm H20 is between 0.5 and 3 cm H20 / cc.
Inventive concept 20. The cuff pressure stabilizer according to Inventive concept 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is shaped so as to define an inflation inlet that is in fluid communication with the stabilizer port,
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond a base low-pressure volume of air,
when the inflatable portion of the balloon contains the base low-pressure volume of air, the inflatable portion of the balloon has a base low pressure of 10 cm H20 and at least a base-low-pressure portion of the outer surface of the inflatable portion of the balloon does not touch the inner surface of the protective housing, wherein the base-low-pressure portion excludes all portions of the outer surface of the inflatable portion within 5 mm of the inflation inlet of the inflatable portion of the balloon when the inflatable portion of the balloon has the base low pressure of 10 cm H20,
at all pressures greater than 10 cm H20 and less than a touching -point pressure, less than none of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, wherein the touching -point pressure is less than 30 cm H20, at all pressures at and greater than the touching-point pressure, the base-low- pressure portion of the outer surface of the inflatable portion of the balloon at least partially touches the inner surface of the protective housing, and
at all pressures at and greater than the touching-point pressure and less than 60 cm H20, the pressure-volume curve is convex.
Inventive concept 21. The cuff pressure stabilizer according to Inventive concept 20, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that the touching-point pressure is greater than 15 cm H20 and less than 25 cm H20.
Inventive concept 22. The cuff pressure stabilizer according to Inventive concept 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is shaped so as to define an inflation inlet that is in fluid communication with the stabilizer port,
when the inflatable portion of the balloon contains the base low-pressure volume of air, the inflatable portion of the balloon has a base low pressure of 10 cm H20 and at least a base-low-pressure portion of the outer surface of the inflatable portion of the balloon does not touch the inner surface of the protective housing, wherein the base-low-pressure portion excludes all portions of the outer surface of the inflatable portion within 5 mm of the inflation inlet of the inflatable portion of the balloon when the inflatable portion of the balloon has the base low pressure of 10 cm H20,
at all pressures greater than 10 cm H20 and less than a touching-point pressure, none of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, wherein the touching -point pressure is less than 30 cm H20,
at all pressures at and greater than the touching-point pressure, the base-low- pressure portion of the outer surface of the inflatable portion of the balloon at least partially touches the inner surface of the protective housing,
at a pressure of 20 cm H20, a first area of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing,
at a pressure of 30 cm H20, a second area of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, and
the second area equals at least 3 times the first area.
Inventive concept 23. The cuff pressure stabilizer according to any one of Inventive concepts 1-22,
wherein the protective housing is shaped so as to define an inner surface that includes a cylindrical portion, and
wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
when the inflatable portion of the balloon contains the first-medium- pressure volume of air, none or less than 15% of the outer surface of the inflatable portion of the balloon touches the cylindrical portion, and
when the inflatable portion of the balloon contains the second-medium- pressure volume of air, at least 20% of the outer surface of the inflatable portion of the balloon touches at least a portion of the cylindrical portion.
Inventive concept 24. The cuff pressure stabilizer according to Inventive concept 23, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
when the inflatable portion of the balloon contains the second-medium-pressure volume of air, the at least a portion of the cylindrical portion touched by the inflatable portion has a length of at least 0.5 cm, measured along a central longitudinal axis of the cylindrical portion.
Inventive concept 25. The cuff pressure stabilizer according to Inventive concept 1,
wherein the protective housing is shaped so as to define an inner surface that includes a frustoconical portion, and
wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
when the inflatable portion of the balloon contains the first-medium- pressure volume of air, none or less than 15% of the outer surface of the inflatable portion of the balloon touches the frustoconical portion, and
when the inflatable portion of the balloon contains the second-medium- pressure volume of air, at least 20% of the outer surface of the inflatable portion of the balloon touches at least a portion of the frustoconical portion. Inventive concept 26. The cuff pressure stabilizer according to Inventive concept 25, wherein the frustoconical portion of the inner surface of the protective housing that comes into contact with the balloon when the balloon is inflated to a medium pressure of 50 cm H20 has an area of between 10 and 60 cm2.
Inventive concept 27. The cuff pressure stabilizer according to Inventive concept 25, wherein the protective housing is shaped such that the frustoconical portion is part of a conical portion of the inner surface.
Inventive concept 28. The cuff pressure stabilizer according to Inventive concept 25, wherein the protective housing is cylindrically symmetric about a central longitudinal axis defined by the frustoconical portion.
Inventive concept 29. The cuff pressure stabilizer according to Inventive concept 25, wherein the frustoconical portion is a first frustoconical portion, and wherein the protective housing is shaped such that the inner surface includes a second frustoconical portion, and wherein the first and the second frustoconical portions geometrically define different respective apices.
Inventive concept 30. The cuff pressure stabilizer according to Inventive concept 29, wherein the first and the second frustoconical portions share a common central longitudinal axis.
Inventive concept 31. The cuff pressure stabilizer according to Inventive concept 29, wherein respective cones geometrically defined by the first and the second frustoconical portions intersect each other at one or more angles, at least one of which is greater than 45 degrees.
Inventive concept 32. The cuff pressure stabilizer according to Inventive concept 31, wherein at least one of the angles is less than 90 degrees.
Inventive concept 33. The cuff pressure stabilizer according to Inventive concept 31, wherein all of the angles are greater than 45 degrees.
Inventive concept 34. The cuff pressure stabilizer according to Inventive concept 31, wherein all of the angles are less than 90 degrees.
Inventive concept 35. The cuff pressure stabilizer according to Inventive concept 31, wherein the respective cones geometrically defined by the first and the second frustoconical portions intersect each other at exactly one angle. Inventive concept 36. The cuff pressure stabilizer according to Inventive concept 29, wherein the balloon is arranged such that the inflatable portion of the balloon is disposed inside the protective housing such that as the inflatable portion of the balloon is inflated from the first-medium pressure toward the second-medium pressure, the outer surface of the inflatable portion of the balloon increases contact with the second frustoconical portion before increasing contact with the first frustoconical portion.
Inventive concept 37. The cuff pressure stabilizer according to Inventive concept 25, wherein the balloon is shaped so as to define an inflation inlet, and wherein a proximal surface of the protective housing is shaped so as to define an inflation opening aligned with the inflation inlet, such that the inflatable portion of the balloon is inflatable via the inflation opening of the protective housing,
wherein the inner surface of the protective housing includes a proximal portion that faces generally distally, and a distal portion that faces generally proximally toward the proximal portion, and
wherein one of the proximal and the distal portions of the inner surface includes the frustoconical portion.
Inventive concept 38. The cuff pressure stabilizer according to Inventive concept 37, wherein a cone geometrically defined by the frustoconical portion intersects the other one of the proximal and the distal portions of the inner surface at one or more angles, at least one of which is greater than 45 degrees.
Inventive concept 39. The cuff pressure stabilizer according to Inventive concept 37, wherein the other one of the proximal and the distal portions of the inner surface is generally flat.
Inventive concept 40. The cuff pressure stabilizer according to Inventive concept 39, wherein a cone geometrically defined by the frustoconical portion intersects the other one of the proximal and the distal portions of the inner surface at one or more angles, at least one of which is greater than 45 degrees.
Inventive concept 41. The cuff pressure stabilizer according to Inventive concept 37, wherein the frustoconical portion is a first frustoconical portion, and wherein the other one of the proximal and the distal portions of the inner surface defines a second frustoconical portion. Inventive concept 42. The cuff pressure stabilizer according to any one of Inventive concepts 1-22, further including:
a pressure sensor, which is configured to sense a pressure in the inflatable portion of the balloon; and
a pressure display, which is configured to display the pressure sensed by the pressure sensor,
wherein the cuff pressure stabilizer is configured to automatically mechanically and non-electrically stabilize the pressure in the inflatable cuff without input from the pressure sensor.
Inventive concept 43. The cuff pressure stabilizer according to Inventive concept 42, wherein the pressure display is digital.
Inventive concept 44. The cuff pressure stabilizer according to Inventive concept 42, further including an external casing, wherein the pressure display is integrated with the external casing.
Inventive concept 45. The cuff pressure stabilizer according to Inventive concept 42, further including a battery power supply and a tum-ON switch that cannot be turned off to stop battery drain after initial turn-ON.
Inventive concept 46. The cuff pressure stabilizer according to Inventive concept 42, further including:
an alarm output, which is configured to generate a visual and/or audible signal; a user input interface; and
an electronic pressure measurement circuit, which includes the pressure sensor, and which is configured to:
set a pressure threshold responsively to an input received from the user input interface, and
activate the alarm output whenever the pressure sensed by the pressure sensor exceeds the pressure threshold by at least a deviation value.
Inventive concept 47. The cuff pressure stabilizer according to Inventive concept 46, wherein the electronic pressure measurement circuit is configured such that the deviation value equals at least 2 cm H20.
Inventive concept 48. The cuff pressure stabilizer according to Inventive concept 47, wherein the electronic pressure measurement circuit is configured such that the deviation value equals at least 4 cm H20.
Inventive concept 49. The cuff pressure stabilizer according to Inventive concept 46, wherein the electronic pressure measurement circuit is configured, upon receiving a set- pressure input from the user input interface, to set the pressure threshold equal to a current pressure sensed by the pressure sensor at a time of receipt of the set-pressure input.
Inventive concept 50. The cuff pressure stabilizer according to any one of Inventive concepts 1-22, wherein the protective housing is configured so as to define an internal volume that is expandable from a base internal volume to a greater, expanded internal volume.
Inventive concept 51. The cuff pressure stabilizer according to any one of Inventive concepts 1-22,
wherein the cuff pressure stabilizer includes a base portion,
wherein the protective housing includes a moveable portion that is moveably coupled to the base portion, and
wherein the protective housing is configured such that inflation of the inflatable portion of the balloon to below a threshold volume does not cause the moveable portion to move with respect to the base portion, and to beyond the threshold volume causes the moveable portion to move with respect to the base portion.
Inventive concept 52. The cuff pressure stabilizer according to any one of Inventive concepts 1-22, further including:
an inflation lumen proximal port connector that is shaped to form an air-tight seal with the inflation lumen proximal port of the airway ventilation device; and
a switchable pre-inflate valve, which is (a) disposed along a fluid-communication path between the stabilizer port and the inflation lumen proximal port connector, and (b) configured to be switchable between a close configuration, in which the valve blocks fluid flow therethrough, and an open configuration, in which the valve allows fluid flow therethrough.
Inventive concept 53. The cuff pressure stabilizer according to any one of Inventive concepts 1-22, further including a flow limiter, which is configured to slow a pressure- regulation response time of the cuff pressure stabilizer. Inventive concept 54. A system including the cuff pressure stabilizer according to any one of Inventive concepts l-dl, wherein the system further includes the airway ventilation device.
Inventive concept 55. The system according to Inventive concept 54, wherein the airway ventilation device includes a tracheal ventilation tube.
Inventive concept 56. The system according to Inventive concept 54, wherein the airway ventilation device includes a laryngeal mask airway (LMA) device.
There is further provided, in accordance with an Inventive concept 57 of the present invention, a method for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the method including:
providing a cuff pressure stabilizer, which includes (a) a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port, (b) a protective housing, and (c) an elastic balloon, which is in fluid communication with the stabilizer port, and which is arranged such that an inflatable portion of the balloon is disposed inside the protective housing, wherein the protective housing is more rigid than the elastic balloon; and
coupling the stabilizer port in fluid communication with the inflation lumen proximal port of the airway ventilation device,
wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
when the inflatable portion of the balloon contains a base low-pressure volume of air, (a) the inflatable portion of the balloon has a base low pressure of 10 cm H20, and (b) none of or less than 10% of an outer surface of the inflatable portion of the balloon touches an inner surface of the protective housing,
when the inflatable portion of the balloon contains a first-medium-pressure volume of air, (a) the inflatable portion of the balloon has a first-medium pressure of 15 cm H20, and (b) none of or less than 15% of an outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, wherein the first- medium-pressure volume of air equals the sum of (a) the base low-pressure volume of air and (b) a first incremental quantity of air of less than 10 cc, and
when the inflatable portion of the balloon contains a second-medium- pressure volume of air, (a) the inflatable portion of the balloon has a second-medium pressure of 30 cm H20, and (b) at least 20% of the outer surface of the inflatable portion of the balloon touches a portion of the inner surface of the protective housing, wherein the second-medium-pressure volume of air equals the sum of (a) the base low-pressure volume of air and (b) a second incremental quantity of air that is between 10 cc and 50 cc.
There is still further provided, in accordance with an Inventive concept 58 of the present invention, a cuff pressure stabilizer for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the cuff pressure stabilizer including:
a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port;
a protective housing; and
an elastic balloon, which is in fluid communication with the stabilizer port, and which is arranged such that an inflatable portion of the balloon is disposed inside the protective housing,
wherein the protective housing is more rigid than the elastic balloon,
wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond a base low-pressure volume of air,
when the inflatable portion of the balloon contains the base low-pressure volume of air, the inflatable portion of the balloon has a base low pressure of 10 cm H20,
the pressure-volume curve includes a rising point of inflection at an inflection-point pressure of between 15 and 35 cm H20,
an average rate of change of the pressure-volume curve over a pressure interval between 20 and 30 cm H20 is between 0.3 and 5 cm H20 / cc, and
an average rate of change of the pressure-volume curve over a pressure interval between 40 and 50 cm H20 is between 0.5 and 3 cm H20 / cc.
Inventive concept 59. The cuff pressure stabilizer according to Inventive concept 58, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that the inflection-point pressure is between 15 and 25 cm H20.
Inventive concept 60. The cuff pressure stabilizer according to Inventive concept 58, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that an average rate of change of the pressure-volume curve over a pressure interval between 50 and 60 cm H20 is between 0.5 and 3 cm H20 / cc.
Inventive concept 61. The cuff pressure stabilizer according to Inventive concept 58, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is shaped so as to define an inflation inlet that is in fluid communication with the stabilizer port,
when the inflatable portion of the balloon is inflated at the base low pressure of 10 cm H20, at least a base-low-pressure portion of an outer surface of the inflatable portion of the balloon does not touch an inner surface of the protective housing, wherein the base-low- pressure portion excludes all portions of the outer surface of the inflatable portion within 5 mm of the inflation inlet of the inflatable portion of the balloon when the inflatable portion of the balloon has the base low pressure of 10 cm H20,
when the inflatable portion of the balloon is inflated at all pressures greater than 10 cm H20 and less than the inflection-point pressure, none of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, and
when the inflatable portion of the balloon is inflated at all pressures at and greater than the inflection-point pressure, the base-low-pressure portion of the outer surface of the inflatable portion of the balloon at least partially touches the inner surface of the protective housing.
Inventive concept 62. The cuff pressure stabilizer according to Inventive concept 61, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
when the inflatable portion of the balloon is inflated at a pressure of 20 cm H20, a first area of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing,
when the inflatable portion of the balloon is inflated at a pressure of 30 cm H20, a second area of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, and
the second area equals at least 3 times the first area.
Inventive concept 63. The cuff pressure stabilizer according to Inventive concept 61, wherein the protective housing is configured so as to define an internal volume that is expandable from a base internal volume to a greater, expanded internal volume.
Inventive concept 64. The cuff pressure stabilizer according to Inventive concept 61, wherein the cuff pressure stabilizer includes a base portion,
wherein the protective housing includes a moveable portion that is moveably coupled to the base portion, and
wherein the protective housing is configured such that inflation of the inflatable portion of the balloon to below a threshold volume does not cause the moveable portion to move with respect to the base portion, and to beyond the threshold volume causes the moveable portion to move with respect to the base portion.
Inventive concept 65. The cuff pressure stabilizer according to Inventive concept 58, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that the pressure-volume curve is concave at at least all pressures between 10 cm H20 and the inflection-point pressure.
Inventive concept 66. The cuff pressure stabilizer according to Inventive concept 58, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that the pressure-volume curve is convex at at least all pressures between the inflection-point pressure and 60 cm H20.
Inventive concept 67. The cuff pressure stabilizer according to any one of Inventive concepts 58-66, further including:
a pressure sensor, which is configured to sense a pressure in the inflatable portion of the balloon; and
a pressure display, which is configured to display the pressure sensed by the pressure sensor,
wherein the cuff pressure stabilizer is configured to automatically mechanically and non-electrically stabilize the pressure in the inflatable cuff without input from the pressure sensor. Inventive concept 68. The cuff pressure stabilizer according to any one of Inventive concepts 58-66, further including:
an inflation lumen proximal port connector that is shaped to form an air-tight seal with the inflation lumen proximal port of the airway ventilation device; and
a switchable pre-inflate valve, which is (a) disposed along a fluid-communication path between the stabilizer port and the inflation lumen proximal port connector, and (b) configured to be switchable between a close configuration, in which the valve blocks fluid flow therethrough, and an open configuration, in which the valve allows fluid flow therethrough.
Inventive concept 69. The cuff pressure stabilizer according to any one of Inventive concepts 58-66, further including a flow limiter, which is configured to slow a pressure- regulation response time of the cuff pressure stabilizer.
Inventive concept 70. A system comprising the cuff pressure stabilizer according to any one of Inventive concepts 58-66, wherein the system further includes the airway ventilation device.
Inventive concept 71. The system according to Inventive concept 70, wherein the airway ventilation device includes a tracheal ventilation tube.
Inventive concept 72. The system according to Inventive concept 70, wherein the airway ventilation device includes a laryngeal mask airway (LMA) device.
There is additionally provided, in accordance with an Inventive concept 73 of the present invention, a method for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the method including: providing a cuff pressure stabilizer, which includes (a) a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port, (b) a protective housing, and (c) an elastic balloon, which is in fluid communication with the stabilizer port, and which is arranged such that an inflatable portion of the balloon is disposed inside the protective housing, wherein the protective housing is more rigid than the elastic balloon; and
coupling the stabilizer port in fluid communication with the inflation lumen proximal port of the airway ventilation device,
wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond a base low-pressure volume of air,
when the inflatable portion of the balloon contains the base low-pressure volume of air, the inflatable portion of the balloon has a base low pressure of 10 cm H20,
the pressure-volume curve includes a rising point of inflection at an inflection-point pressure of between 15 and 35 cm H20,
an average rate of change of the pressure-volume curve over a pressure interval between 20 and 30 cm H20 is between 0.3 and 5 cm H20 / cc, and
an average rate of change of the pressure-volume curve over a pressure interval between 40 and 50 cm H20 is between 0.5 and 3 cm H20 / cc.
There is yet additionally provided, in accordance with an Inventive concept 74 of the present invention, a cuff pressure stabilizer for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the cuff pressure stabilizer including:
a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port;
a protective housing; and
an elastic balloon, which is in fluid communication with the stabilizer port, and which is arranged such that an inflatable portion of the balloon is disposed inside the protective housing,
wherein the protective housing is more rigid than the elastic balloon,
wherein the protective housing is configured so as to define an internal volume that is expandable from a base internal volume to a greater, expanded internal volume.
Inventive concept 75. The cuff pressure stabilizer according to Inventive concept 74, wherein the protective housing is configured so as to define an inner surface area that is expandable from a base inner surface area to a greater, expanded inner surface area.
Inventive concept 76. The cuff pressure stabilizer according to Inventive concept 74, wherein the cuff pressure stabilizer includes a base portion, and wherein the protective housing includes a moveable portion that is moveably coupled to the base portion such that the internal volume of the protective housing varies based on a relative position of the moveable portion with respect to the base portion.
Inventive concept 77. The cuff pressure stabilizer according to Inventive concept 76, wherein the moveable portion is axially-slidably coupled to the base portion such that the internal volume of the protective housing varies based on the relative axial position of the moveable portion with respect to the base portion.
Inventive concept 78. The cuff pressure stabilizer according to Inventive concept 76, wherein the cuff pressure stabilizer is configured:
to assume locked and unlocked states,
when in the locked state, to prevent the moveable portion from moving with respect to the base portion, and
when in the unlocked state, to allow the moveable portion to move with respect to the base portion.
Inventive concept 79. The cuff pressure stabilizer according to Inventive concept 78, wherein the cuff pressure stabilizer is configured such that a transition between the locked and unlocked states is effected by rotation of the moveable portion with respect to the base portion.
Inventive concept 80. The cuff pressure stabilizer according to Inventive concept 74, wherein the protective housing is configured such that inflation of the inflatable portion of the balloon to below a threshold volume does not cause the internal volume of the protective housing to expand from the base internal volume, and to beyond the threshold volume causes the internal volume of the protective housing to expand from the base internal volume to the greater, expanded internal volume.
Inventive concept 81. The cuff pressure stabilizer according to Inventive concept 80, wherein the protective housing is configured such that the threshold volume corresponds to a pressure in the inflatable portion of the balloon of at least 20 cm H20 and no more than 40 cm H20.
Inventive concept 82. The cuff pressure stabilizer according to any one of Inventive concepts 74-81, further including a flow limiter, which is configured to slow a pressure- regulation response time of the cuff pressure stabilizer. Inventive concept 83. The cuff pressure stabilizer according to any one of Inventive concepts 74-81, further including:
a pressure sensor, which is configured to sense a pressure in the inflatable portion of the balloon; and
a pressure display, which is configured to display the pressure sensed by the pressure sensor,
wherein the cuff pressure stabilizer is configured to automatically mechanically and non-electrically stabilize the pressure in the inflatable cuff without input from the pressure sensor.
Inventive concept 84. A system including the cuff pressure stabilizer according to any one of Inventive concepts C-g3, wherein the system further includes the airway ventilation device.
Inventive concept 85. The system according to Inventive concept 84, wherein the airway ventilation device includes a tracheal ventilation tube.
Inventive concept 86. The system according to Inventive concept 84, wherein the airway ventilation device includes a laryngeal mask airway (LMA) device.
There is also provided, in accordance with an Inventive concept 87 of the present invention, a method for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the method including:
providing a cuff pressure stabilizer, which includes (a) a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port, (b) a protective housing, and (c) an elastic balloon, which is in fluid communication with the stabilizer port, and which is arranged such that an inflatable portion of the balloon is disposed inside the protective housing, wherein the protective housing is more rigid than the elastic balloon, and wherein the protective housing is configured so as to define an internal volume that is expandable from a base internal volume to a greater, expanded internal volume; and
coupling the stabilizer port in fluid communication with the inflation lumen proximal port of the airway ventilation device.
There is further provided, in accordance with an Inventive concept 88 of the present invention, a cuff pressure stabilizer for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the cuff pressure stabilizer including:
a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port;
a protective housing;
a base portion; and
an elastic balloon, which is in fluid communication with the stabilizer port, and which is arranged such that an inflatable portion of the balloon is disposed inside the protective housing,
wherein the protective housing is more rigid than the elastic balloon,
wherein the protective housing includes a moveable portion that is moveably coupled to the base portion, and
wherein the protective housing is configured such that inflation of the inflatable portion of the balloon to below a threshold volume does not cause the moveable portion to move with respect to the base portion, and to beyond the threshold volume causes the moveable portion to move with respect to the base portion.
Inventive concept 89. The cuff pressure stabilizer according to Inventive concept 88, wherein the protective housing is configured such that the threshold volume corresponds to a pressure in the inflatable portion of the balloon of at least 20 cm H20 and no more than 40 cm H20.
Inventive concept 90. The cuff pressure stabilizer according to Inventive concept 88, wherein the protective housing is configured so as to define an internal volume that is expandable from a base internal volume to a greater, expanded internal volume in response to the relative position of the moveable portion with respect to the base portion.
Inventive concept 91. The cuff pressure stabilizer according to Inventive concept 88, wherein the protective housing is configured so as to define an inner surface area that is expandable from a base inner surface area to a greater, expanded inner surface area.
Inventive concept 92. The cuff pressure stabilizer according to Inventive concept 88, wherein the moveable portion is axially- slidably coupled to the base portion.
Inventive concept 93. The cuff pressure stabilizer according to Inventive concept 88, wherein the cuff pressure stabilizer is configured:
to assume locked and unlocked states, when in the locked state, to prevent the moveable portion from moving with respect to the base portion, and
when in the unlocked state, to allow the moveable portion to move with respect to the base portion.
Inventive concept 94. The cuff pressure stabilizer according to Inventive concept 93, wherein the cuff pressure stabilizer is configured such that a transition between the locked and unlocked states is effected by rotation of the moveable portion with respect to the base portion.
Inventive concept 95. The cuff pressure stabilizer according to any one of Inventive concepts 88-94, further including a flow limiter, which is configured to slow a pressure- regulation response time of the cuff pressure stabilizer.
Inventive concept 96. The cuff pressure stabilizer according to any one of Inventive concepts 88-94, further including:
a pressure sensor, which is configured to sense a pressure in the inflatable portion of the balloon; and
a pressure display, which is configured to display the pressure sensed by the pressure sensor,
wherein the cuff pressure stabilizer is configured to automatically mechanically and non-electrically stabilize the pressure in the inflatable cuff without input from the pressure sensor.
Inventive concept 97. A system including the cuff pressure stabilizer according to any one of Inventive concepts C2-g3b, wherein the system further includes the airway ventilation device.
Inventive concept 98. The system according to Inventive concept 97, wherein the airway ventilation device includes a tracheal ventilation tube.
Inventive concept 99. The system according to Inventive concept 97, wherein the airway ventilation device includes a laryngeal mask airway (LMA) device.
There is still further provided, in accordance with an Inventive concept 100 of the present invention, a method for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the method including: providing a cuff pressure stabilizer, which includes (a) a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port, (b) a protective housing, (c) a base portion, and (d) an elastic balloon, which is in fluid communication with the stabilizer port, and which is arranged such that an inflatable portion of the balloon is disposed inside the protective housing, wherein the protective housing is more rigid than the elastic balloon, wherein the protective housing includes a moveable portion that is moveably coupled to the base portion, and wherein the protective housing is configured such that inflation of the inflatable portion of the balloon (i) to below a threshold volume does not cause the moveable portion to move with respect to the base portion, and (ii) to beyond the threshold volume causes the moveable portion to move with respect to the base portion; and
coupling the stabilizer port in fluid communication with the inflation lumen proximal port of the airway ventilation device.
There is additionally provided, in accordance with an Inventive concept 101 of the present invention, a cuff pressure stabilizer for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the cuff pressure stabilizer including:
a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port;
a housing, which includes one or more internal protective surfaces; and
first and second elastic balloons, which include respective first and second inflatable portions that are in fluid communication with each other and with the stabilizer port,
wherein the one or more internal protective surfaces are more rigid than the first and the second elastic balloons,
wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
(a) when each of the first and the second inflatable portions is inflated at a first- medium pressure of 15 cm H20:
(i) none of or less than 15% of a first entire outer surface of the first inflatable portion touches the one or more internal protective surfaces, and
(ii) none of or less than 15% of a second entire outer surface of the second inflatable portion touches the one or more internal protective surfaces, and
(b) when each of the first and the second inflatable portions is inflated at a second-medium pressure of 30 cm H20: (i) at least 20% of the first entire outer surface touches a first portion of the one or more internal protective surfaces, and
(ii) none or less than 15% of the second entire outer surface touches the one or more internal protective surfaces.
Inventive concept 102. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
when each of the first and the second inflatable portions is inflated at a second- medium pressure of 30 cm H20:
(i) at least 50% of the first entire outer surface touches the first portion of the one or more internal protective surfaces, and
(ii) none or less than 20% of the second entire outer surface touches the one or more internal protective surfaces.
Inventive concept 103. The cuff pressure stabilizer according to Inventive concept 102, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
when each of the first and the second inflatable portions is inflated at the second- medium pressure of 50 cm H20:
(i) at least 75% of the first entire outer surface touches the first portion of the one or more internal protective surfaces, and
(ii) none or less than 20% of the second entire outer surface touches the one or more internal protective surfaces.
Inventive concept 104. The cuff pressure stabilizer according to Inventive concept 101, wherein the first portion of the one or more internal protective surfaces surrounds at least 50% of the first entire outer surface when the first inflatable portion is inflated at the first- medium pressure of 15 cm H20.
Inventive concept 105. The cuff pressure stabilizer according to Inventive concept 104, wherein the first portion of the one or more internal protective surfaces is generally spherical.
Inventive concept 106. The cuff pressure stabilizer according to Inventive concept 104, wherein the first portion of the one or more internal protective surfaces is generally ellipsoidal. Inventive concept 107. The cuff pressure stabilizer according to Inventive concept 104, wherein a second portion of the one or more internal protective surfaces, which is entirely distinct from the first portion of the one or more internal protective surfaces, surrounds at least 50% of the second entire outer surface when the second inflatable portion is inflated at the first- medium pressure of 15 cm H20.
Inventive concept 108. The cuff pressure stabilizer according to Inventive concept 107, wherein the second portion of the one or more internal protective surfaces is generally spherical.
Inventive concept 109. The cuff pressure stabilizer according to Inventive concept 107, wherein the first and the second portions of the one or more internal protective surfaces are shaped so as to define first and second chambers, respectively, and wherein the first and the second chambers are not in fluid communication with each other via the housing.
Inventive concept 110. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that no portion of the first entire outer surface touches the second entire outer surface when each of the first and the second inflatable portions is inflated at any pressure.
Inventive concept 111. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
(a) each of the first and the second inflatable portions has a base low pressure of 10 cm H20 when the first and the second inflatable portions contain, in aggregate, a base aggregate low-pressure volume of air,
(b) each of the first and the second inflatable portions has the first- medium pressure of 15 cm H20 when the first and the second inflatable portions contain, in aggregate, a first aggregate medium-pressure volume of air, and
(c) the first aggregate medium-pressure volume of air equals the sum of (a) the base aggregate low-pressure volume of air and (b) a first aggregate incremental quantity of air of less than 10 cc.
Inventive concept 112. The cuff pressure stabilizer according to Inventive concept 111, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that: each of the first and the second inflatable portions has the second-medium pressure of 30 cm H20 when the first and the second inflatable portions contain, in aggregate, a second aggregate medium-pressure volume of air equal to the sum of (a) the base aggregate low-pressure volume of air and (b) a second aggregate incremental quantity of air that is between 10 cc and 60 cc.
Inventive concept 113. The cuff pressure stabilizer according to Inventive concept 112, wherein the second aggregate incremental quantity of air is less than 30 cc.
Inventive concept 114. The cuff pressure stabilizer according to Inventive concept 113, wherein the second aggregate incremental quantity of air is less than 15 cc.
Inventive concept 115. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
a second volume of the second inflatable portion equals between 80% and 120% of a first volume of the first inflatable portion when each of the first and the second inflatable portions is inflated at a base low pressure of 10 cm H20.
Inventive concept 116. The cuff pressure stabilizer according to Inventive concept 115, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
the first volume equals at least 50% of the second volume when each of the first and the second inflatable portions is inflated at the first- medium pressure of 15 cm H20.
Inventive concept 117. The cuff pressure stabilizer according to Inventive concept 115, wherein the first and the second inflatable portions include respective different materials.
Inventive concept 118. The cuff pressure stabilizer according to Inventive concept 115, wherein the first and the second inflatable portions include a same material, wherein the first and the second inflatable portions have first and second average wall thicknesses, respectively, and
wherein the second average wall thickness equals between 110% and 180% of the first average wall thickness.
Inventive concept 119. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that: a second volume of the second inflatable portion equals between 50% and 75% of a first volume of the first inflatable portion when each of the first and the second inflatable portions has a base low pressure of 10 cm H20.
Inventive concept 120. The cuff pressure stabilizer according to Inventive concept 119, wherein the first and the second inflatable portions include a same material, and wherein the first and the second inflatable portions have first and second average wall thicknesses, respectively, that equal each other.
Inventive concept 121. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
when the first and the second inflatable portions contain, in aggregate, a base aggregate low-pressure volume of air, each of the first and the second inflatable portions has a base low pressure of 10 cm H20,
the cuff pressure stabilizer is characterized by an aggregate pressure-volume curve that represents the pressure in the first and the second inflatable portions when inflated, in aggregate, with different aggregate incremental volumes of air beyond the base low- pressure volume of air, and
an average rate of change of the aggregate pressure-volume curve over a first pressure interval between 25 and 30 cm H20 is between 0.3 and 2 cm H20 / cc.
Inventive concept 122. The cuff pressure stabilizer according to Inventive concept 121, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that an average rate of change of the aggregate pres sure- volume curve over a second pressure interval between 40 and 50 cm H20 is between 0.2 and 2 cm H20 / cc.
Inventive concept 123. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
when the first and the second inflatable portions contain, in aggregate, a base aggregate low-pressure volume of air, each of the first and the second inflatable portions has a base low pressure of 10 cm H20,
the cuff pressure stabilizer is characterized by an aggregate pressure-volume curve that represents the pressure in the first and the second inflatable portions when inflated, in aggregate, with different aggregate incremental volumes of air beyond the base aggregate low-pressure volume of air, and
an average rate of change of the aggregate pressure-volume curve over a second pressure interval between 40 and 50 cm H20 is between 0.2 and 2 cm H20 / cc.
Inventive concept 124. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
(a) when the first inflatable portion contains a first base low-pressure volume of air, the first inflatable portion has a first base low pressure of 10 cm H20, (b) the first inflatable portion is characterized by a first pressure-volume curve that represents the pressure in the first inflatable portion when inflated with different incremental volumes of air beyond the first base low-pressure volume of air, and (c) an average rate of change of the first pressure- volume curve over a first pressure interval between 25 and 30 cm H20 is between 0.3 and 2 cm H20 / cc, and
(a) when the second inflatable portion contains a second base low-pressure volume of air, the second inflatable portion has a second base low pressure of 10 cm H20, (b) the second inflatable portion is characterized by a second pres sure- volume curve that represents the pressure in the second inflatable portion when inflated with different incremental volumes of air beyond the second base low-pressure volume of air, and (c) an average rate of change of the second pressure-volume curve over a second pressure interval between 40 and 50 cm H20 is between 0.2 and 2 cm H20 / cc.
Inventive concept 125. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
when the first and the second inflatable portions contain, in aggregate, a base aggregate low-pressure volume of air, each of the first and the second inflatable portions has a base low pressure of 10 cm H20,
the cuff pressure stabilizer is characterized by an aggregate pressure-volume curve that represents the pressure in the first and the second inflatable portions when inflated, in aggregate, with different aggregate incremental volumes of air beyond the base low- pressure volume of air, and
the aggregate pressure-volume curve does not include a local maximum pressure at any pressure between 20 and 50 cm H20. Inventive concept 126. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
when the first and the second inflatable portions contain, in aggregate, a base aggregate low-pressure volume of air, each of the first and the second inflatable portions has a base low pressure of 10 cm H20,
the cuff pressure stabilizer is characterized by an aggregate pressure-volume curve that represents the pressure in the first and the second inflatable portions when inflated, in aggregate, with different aggregate incremental volumes of air beyond the base low- pressure volume of air,
the aggregate pressure- volume curve includes a local maximum pressure and a local minimum pressure at a greater incremental volume than the local maximum pressure, and a pressure difference between the local maximum pressure and the local minimum pressure is less than 3 cm H20.
Inventive concept 127. The cuff pressure stabilizer according to Inventive concept 101, wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
when the first and the second inflatable portions contain, in aggregate, a base aggregate low-pressure volume of air, each of the first and the second inflatable portions has a base low pressure of 10 cm H20,
the cuff pressure stabilizer is characterized by an aggregate pressure-volume curve that represents the pressure in the first and the second inflatable portions when inflated, in aggregate, with different aggregate incremental volumes of air beyond the base low- pressure volume of air,
the aggregate pressure- volume curve includes a local maximum pressure and a local minimum pressure at a greater incremental volume than the local maximum pressure, and a volume difference between the local maximum pressure and the local minimum pressure is less than 40 cc.
Inventive concept 128. The cuff pressure stabilizer according to any one of Inventive concepts 101-127, further including:
a pressure sensor, which is configured to sense a pressure in the first and the second inflatable portions; and
a pressure display, which is configured to display the pressure sensed by the pressure sensor,
wherein the cuff pressure stabilizer is configured to automatically mechanically and non-electrically stabilize the pressure in the inflatable cuff without input from the pressure sensor.
Inventive concept 129. The cuff pressure stabilizer according to any one of Inventive concepts 101-127, further including:
an inflation lumen proximal port connector that is shaped to form an air-tight seal with the inflation lumen proximal port of the airway ventilation device; and
a switchable pre-inflate valve, which is (a) disposed along a fluid-communication path between the stabilizer port and the inflation lumen proximal port connector, and (b) configured to be switchable between a close configuration, in which the valve blocks fluid flow therethrough, and an open configuration, in which the valve allows fluid flow therethrough.
Inventive concept 130. The cuff pressure stabilizer according to any one of Inventive concepts 101-127, further including a flow limiter, which is configured to slow a pressure- regulation response time of the cuff pressure stabilizer.
Inventive concept 131. A system including the cuff pressure stabilizer according to any one of Inventive concepts 29-55, wherein the system further includes the airway ventilation device.
Inventive concept 132. The system according to Inventive concept 131, wherein the airway ventilation device includes a tracheal ventilation tube.
Inventive concept 133. The system according to Inventive concept 131, wherein the airway ventilation device includes a laryngeal mask airway (LMA) device.
There is yet additionally provided, in accordance with an Inventive concept 134 of the present invention, a method for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the method including:
providing a cuff pressure stabilizer, which includes (a) a housing, which includes one or more internal protective surfaces, and (b) first and second elastic balloons, which include respective first and second inflatable portions that are in fluid communication with each other and with the stabilizer port, wherein the one or more internal protective surfaces are more rigid than the first and the second elastic balloons; and
coupling the stabilizer port in fluid communication with the inflation lumen proximal port of the airway ventilation device,
wherein the one or more internal protective surfaces are shaped and the first and the second inflatable portions are configured such that:
(a) when each of the first and the second inflatable portions is inflated at a first- medium pressure of 15 cm H20:
(i) none or less than 15% of a first entire outer surface of the first inflatable portion touches the one or more internal protective surfaces, and
(ii) none or less than 15% of a second entire outer surface touches the one or more internal protective surfaces, and
(b) when each of the first and the second inflatable portions is inflated at a second-medium pressure of 30 cm H20:
(i) at least 20% of the first entire outer surface touches a first portion of the one or more internal protective surfaces, and
(ii) none or less than 15% of the second entire outer surface touches the one or more internal protective surfaces.
There is also provided, in accordance with an Inventive concept 135 of the present invention, a cuff pressure stabilizer for use (a) in contact with the atmosphere and (b) with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the cuff pressure stabilizer including:
a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port;
an expandable wall membrane, which is not in fluid communication with the stabilizer port and is in fluid communication with the atmosphere; and
an elastic balloon, which includes an inflatable portion that is in fluid communication with the stabilizer port and is disposed within the expandable wall membrane.
Inventive concept 136. The cuff pressure stabilizer according to Inventive concept 135, wherein the inflatable portion and the expandable wall membrane are configured such that:
(a) when the inflatable portion is inflated at a first-medium pressure of 15 cm H20:
(i) none or less than 15% of an entire inflatable -portion outer surface of the inflatable portion touches a wall-membrane internal surface of the expandable wall membrane, and
(ii) the wall-membrane internal surface has a first-medium-pressure area, and
(b) when the inflatable portion is inflated at a second-medium pressure of 30 cm
H20:
(i) at least 50% of the entire inflatable-portion outer surface touches the wall-membrane internal surface, and
(ii) the wall-membrane internal surface has a second-medium-pressure area that equals at least 120% of the first-medium-pressure area.
Inventive concept 137. The cuff pressure stabilizer according to Inventive concept 136, further including a substantially rigid chamber,
wherein the expandable wall membrane is disposed within the chamber, and wherein the chamber is shaped and the inflatable portion and the expandable wall membrane are configured such that when the inflatable portion is inflated at the second- medium pressure of 30 cm H20, none or less than 20% of an entire wall-membrane outer surface of the expandable wall membrane touches a chamber internal surface of the chamber.
Inventive concept 138. The cuff pressure stabilizer according to Inventive concept 135, wherein the inflatable portion and the expandable wall membrane are configured such that: when the inflatable portion contains a base low-pressure volume of air, the inflatable portion has a base low pressure of 10 cm H20,
the cuff pressure stabilizer is characterized by a pressure-volume curve that represents the pressure in the inflatable portion when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
an average rate of change of the pressure- volume curve over a first pressure interval between 25 and 30 cm H20 is between 0.3 and 1 cm H20 / cc.
Inventive concept 139. The cuff pressure stabilizer according to Inventive concept 138, wherein the inflatable portion and the expandable wall membrane are configured such that that an average rate of change of the pressure-volume curve over a second pressure interval between 40 and 50 cm H20 is between 0.2 and 2 cm H20 / cc.
Inventive concept 140. The cuff pressure stabilizer according to Inventive concept 135, wherein the inflatable portion and the expandable wall membrane are configured such that: when the inflatable portion contains a base low-pressure volume of air, the inflatable portion has a base low pressure of 10 cm H20,
the cuff pressure stabilizer is characterized by a pressure-volume curve that represents the pressure in the inflatable portion when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
an average rate of change of the pressure-volume curve over a second pressure interval between 40 and 50 cm H20 is between 0.2 and 2 cm H20 / cc.
There is further provided, in accordance with an Inventive concept 141 of the present invention, a method for use (a) in contact with the atmosphere and (b) with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the method including:
providing a cuff pressure stabilizer, which includes (a) a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port, (b) an expandable wall membrane, which is not in fluid communication with the stabilizer port and is in fluid communication with the atmosphere, (c) and an elastic balloon, which includes an inflatable portion that is in fluid communication with the stabilizer port and is disposed within the expandable wall membrane; and
coupling the stabilizer port in fluid communication with the inflation lumen proximal port of the airway ventilation device.
Inventive concept 142. The method according to Inventive concept 141, wherein the inflatable portion and the expandable wall membrane are configured such that:
(a) when the inflatable portion is inflated at a first-medium pressure of 15 cm
H20:
(i) none or less than 15% of an entire inflatable -portion outer surface of the inflatable portion touches a wall-membrane internal surface of the expandable wall membrane, and
(ii) the wall-membrane internal surface has a first-medium-pressure area, and
(b) when the inflatable portion is inflated at a second-medium pressure of 30 cm H20:
(i) at least 50% of the entire inflatable-portion outer surface touches the wall-membrane internal surface, and
(ii) the wall-membrane internal surface has a second-medium-pressure area that equals at least 120% of the first-medium-pressure area.
There is still further provided, in accordance with an Inventive concept 143 of the present invention, a cuff pressure stabilizer for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the cuff pressure stabilizer including:
a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port;
a substantially rigid protective housing, which is shaped so as to define an inner surface that includes a frustoconical portion; and
an elastic balloon, which is in fluid communication with the stabilizer port, and which is arranged such that an inflatable portion of the balloon is disposed inside the protective housing, such that (a) none or less than 10% of an outer surface of the inflatable portion of the balloon touches the frustoconical portion when the inflatable portion of the balloon is inflated to a first-medium pressure of 25 cm H20, and (b) at least 20% of the outer surface of the inflatable portion of the balloon touches at least a portion of the frustoconical portion when the inflatable portion of the balloon is inflated to a second- medium pressure greater than the first-medium pressure.
Inventive concept 144. The cuff pressure stabilizer according to Inventive concept 143, wherein the frustoconical portion of the inner surface of the protective housing that comes into contact with the balloon when the balloon is inflated to a medium pressure of 50 cm H20 has an area of between 10 and 60 cm2.
Inventive concept 145. The cuff pressure stabilizer according to Inventive concept 143, wherein the protective housing is shaped such that the frustoconical portion is part of a conical portion of the inner surface.
Inventive concept 146. The cuff pressure stabilizer according to Inventive concept 143, wherein the protective housing is cylindrically symmetric about a central longitudinal axis defined by the frustoconical portion. Inventive concept 147. The cuff pressure stabilizer according to Inventive concept 143, wherein the frustoconical portion is a first frustoconical portion, and wherein the protective housing is shaped such that the inner surface includes a second frustoconical portion, and wherein the first and the second frustoconical portions geometrically define different respective apices.
Inventive concept 148. The cuff pressure stabilizer according to Inventive concept 147, wherein the first and the second frustoconical portions share a common central longitudinal axis.
Inventive concept 149. The cuff pressure stabilizer according to Inventive concept 147, wherein respective cones geometrically defined by the first and the second frustoconical portions intersect each other at one or more angles, at least one of which is greater than 45 degrees.
Inventive concept 150. The cuff pressure stabilizer according to Inventive concept 149, wherein at least one of the angles is less than 90 degrees.
Inventive concept 151. The cuff pressure stabilizer according to Inventive concept 149, wherein all of the angles are greater than 45 degrees.
Inventive concept 152. The cuff pressure stabilizer according to Inventive concept 149, wherein all of the angles are less than 90 degrees.
Inventive concept 153. The cuff pressure stabilizer according to Inventive concept 149, wherein the respective cones geometrically defined by the first and the second frustoconical portions intersect each other at exactly one angle.
Inventive concept 154. The cuff pressure stabilizer according to Inventive concept 147, wherein the balloon is arranged such that the inflatable portion of the balloon is disposed inside the protective housing such that as the inflatable portion of the balloon is inflated from the first-medium pressure toward the second-medium pressure, the outer surface of the inflatable portion of the balloon increases contact with the second frustoconical portion before increasing contact with the first frustoconical portion.
Inventive concept 155. The cuff pressure stabilizer according to Inventive concept 143, wherein the balloon is shaped so as to define an inflation inlet, and wherein a proximal surface of the protective housing is shaped so as to define an inflation opening aligned with the inflation inlet, such that the inflatable portion of the balloon is inflatable via the inflation opening of the protective housing,
wherein the inner surface of the protective housing includes a proximal portion that faces generally distally, and a distal portion that faces generally proximally toward the proximal portion, and
wherein one of the proximal and the distal portions of the inner surface includes the frustoconical portion.
Inventive concept 156. The cuff pressure stabilizer according to Inventive concept 155, wherein a cone geometrically defined by the frustoconical portion intersects the other one of the proximal and the distal portions of the inner surface at one or more angles, at least one of which is greater than 45 degrees.
Inventive concept 157. The cuff pressure stabilizer according to Inventive concept 155, wherein the other one of the proximal and the distal portions of the inner surface is generally flat.
Inventive concept 158. The cuff pressure stabilizer according to Inventive concept 157, wherein a cone geometrically defined by the frustoconical portion intersects the other one of the proximal and the distal portions of the inner surface at one or more angles, at least one of which is greater than 45 degrees.
Inventive concept 159. The cuff pressure stabilizer according to Inventive concept 155, wherein the frustoconical portion is a first frustoconical portion, and wherein the other one of the proximal and the distal portions of the inner surface defines a second frustoconical portion.
Inventive concept 160. The cuff pressure stabilizer according to Inventive concept 159, wherein respective cones geometrically defined by the first and the second frustoconical portions intersect each other at one or more angles, at least one of which is greater than 45 degrees.
Inventive concept 161. A system including the cuff pressure stabilizer according to any one of Inventive concepts 143-154, wherein the system further includes the airway ventilation device.
Inventive concept 162. The system according to Inventive concept 161, wherein the airway ventilation device includes a tracheal ventilation tube. Inventive concept 163. The system according to Inventive concept 161, wherein the airway ventilation device includes a laryngeal mask airway (LMA) device.
The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figs. 1A-C are schematic illustrations of a cuff pressure stabilizer for use with an airway ventilation device, in accordance with respective applications of the present invention;
Figs. 2A-B are additional schematic illustrations of the cuff pressure stabilizer of Fig. 1A, in accordance with an application of the present invention;
Figs. 3A-D are schematic illustrations of the cuff pressure stabilizer of Fig. 1A with an inflatable portion of a balloon thereof inflated with different respective volumes, in accordance with an application of the present invention;
Fig. 4 includes a pressure-volume curve, in accordance with an application of the present invention;
Fig. 5 is a schematic illustration of another cuff pressure stabilizer for use with an airway ventilation device, in accordance with an application of the present invention;
Fig. 6 is a cross-sectional view of the cuff pressure stabilizer of Fig. 5, in accordance with an application of the present invention;
Figs. 7A-C are schematic cross-sectional illustrations of the cuff pressure stabilizer of Fig. 5 with two elastic balloons thereof inflated at different pressures, in accordance with an application of the present invention;
Fig. 8A includes "confined" and "free" pressure-volume curves of a first inflatable portion of a first elastic balloon of the cuff pressure stabilizer of Fig. 5, in accordance with an application of the present invention;
Fig. 8B includes "confined" and "free" pressure-volume curves of a second inflatable portion of a second elastic balloon of the cuff pressure stabilizer of Fig. 5, in accordance with an application of the present invention;
Fig. 9 includes an aggregate pres sure- volume curve of the cuff pressure stabilizer of Fig. 5, in accordance with an application of the present invention;
Fig. 10 is a schematic cross-sectional illustration of yet another cuff pressure stabilizer for use with an airway ventilation device, in accordance with respective applications of the present invention;
Fig. 11 is a schematic cross-sectional illustration of still another cuff pressure stabilizer for use with an airway ventilation device, in accordance with respective applications of the present invention;
Figs. 12A-C are schematic cross-sectional illustrations of another pressure stabilizer with an elastic balloon thereof inflated at different pressures, in accordance with an application of the present invention;
Figs. 13A-B are schematic illustrations of an alternative configuration of the cuff pressure stabilizer of Figs. 1A-3D, in accordance with an application of the present invention;
Fig. 13C is a schematic illustration of another alternative configuration of the cuff pressure stabilizer of Figs. 1A-3D, in accordance with an application of the present invention;
Figs. 14 are schematic illustrations of another cuff pressure stabilizer, in accordance with an application of the present invention;
Figs. 15A-B are cross-sectional views of Fig. 14 taken along lines XV— XV, in accordance with an application of the present invention;
Figs. 16A-C are schematic illustrations of the cuff pressure stabilizer of Figs. 14- 15B with an inflatable portion of a balloon thereof inflated with different respective volumes, in accordance with an application of the present invention;
Figs. 17A-B are schematic illustrations of a protective housing of the cuff pressure stabilizer of Figs. 14-15B in locked and unlocked states, in accordance with an application of the present invention; and
Fig. 18 includes three pres sure- volume curves, in accordance with respective applications of the present invention. DETAILED DESCRIPTION OF APPLICATIONS
Figs. 1A-C are schematic illustrations of a cuff pressure stabilizer 100 for use with an airway ventilation device 10, in accordance with respective applications of the present invention. For example, airway ventilation device 10 may be a tracheal ventilation tube 22, such as shown in Figs. 1A-B, or a laryngeal mask airway (LMA) device 24, such as shown in Fig. 1C. Cuff pressure stabilizer 100 is for use in contact with the atmosphere 99 (i.e., ambient air) of the Earth.
Figs. 1A-C also show (a) airway ventilation device 10, which is not a component of cuff pressure stabilizer 100, (b) an external inflation source 20, such as a syringe, which is typically not a component of cuff pressure stabilizer 100, and (c) one or more connector tubes, described hereinbelow, which are optionally a component of cuff pressure stabilizer 100 (and may be removably or permanently coupled to cuff pressure stabilizer 100). Cuff pressure stabilizer 100 typically comprises a stabilizer port 122, which is in fluid communication with elastic balloon 148, described hereinbelow with reference to Figs. 2A- B, and is configured to be coupled to the one or more connector tubes. The one or more connector tubes typically comprise a connector tube 125, which comprises an inflation lumen proximal port connector 124 that is shaped to form an air-tight seal with inflation lumen proximal port 15 of airway ventilation device 10, described immediately below. For some applications, inflation lumen proximal port connector 124 comprises a male conical fitting with a taper. For some applications, the taper is at least a 5% taper. For some applications, the taper is a 6% taper, and the male conical fitting with the 6% taper complies with International Standard ISO 594-1: 1986, which is the standard for connections to conventional inflation lumen proximal ports of tracheal ventilation tubes and LMA masks.
Airway ventilation device 10 comprises an inflatable cuff 11, an inflation lumen 13, and an inflation lumen proximal port 15. Inflatable cuff 11 may comprise, for example, a balloon. Airway ventilation device 10 typically further comprises a cuff inflation lumen distal port 12, an airway ventilation tube ventilation port 16, an airway ventilation tube ventilation lumen 17, and an airway ventilation tube ventilator connection 19. For some applications, airway ventilation device 10 further comprises an inflating tube 14, which couples inflation lumen 13 in fluid communication with inflation lumen proximal port 15.
Reference is made to Figs. 1A-B. In these configurations, airway ventilation device 10 is a tracheal ventilation tube 22, and inflatable cuff 11 is an inflatable cuff 26 mounted on tracheal ventilation tube 22, typically near a distal end of the tracheal ventilation tube, e.g., within 3 cm, such as within 1 cm, of the distal end. In these configurations, inflatable cuff 26 typically comprises a nearly non-compliant material, and/or typically has a volume of between 5 and 20 cc, depending on the size of airway ventilation device 10. Tracheal ventilation tube 22 is schematically shown inserted into a trachea 18, and inflatable cuff 26 is inflatable into sealing contact with the inner surface of trachea 18. As used in the present application, including in the claims, a "tracheal ventilation tube" comprises an endotracheal tube (ETT) or a tracheostomy tube.
Reference is made to Fig. 1C. In this configuration, airway ventilation device 10 is a laryngeal mask airway (LMA) device 24, and inflatable cuff 11 is an inflatable cuff 28 (which is typically annular) that is insertable through a mouth of a patient to an inserted location within the patient, such that an anterior side of the cuff forms a seal around a laryngeal inlet of the patient upon inflation of the cuff. When cuff 28 is inflated to a working medium pressure, the LMA device is suitable for facilitating lung ventilation. For example, the working medium pressure may be between 15 and 60 cm H20, such as between 20 and 60 cm H20, e.g., between 25 and 55 cm H20, such as between 40 and 50 cm H20. In this configuration, inflatable cuff 28 typically has a volume of between 25 and 50 cc, depending on the size of LMA device 24.
Reference is made to Figs. 1A and 1C. In these configurations, cuff pressure stabilizer 100 further comprises an inflation inlet port 130, which is in fluid communication with elastic balloon 148, described hereinbelow with reference to Figs. 2A-B. Inflation inlet port 130 is configured to be coupled in fluid communication with external inflation source 20. In these configurations, connector tube 125 typically further comprises a stabilizer-port connector 123, which is configured to be coupled in fluid communication with stabilizer port 122.
Reference is made to Fig. IB. In this configuration, cuff pressure stabilizer 100 further comprises an inlet junction 131, which couples in fluid communication: connector tube 125, an inflation inlet port 132, first connector tube 133, and stabilizer port 122. Inflation inlet port 132 is configured to be coupled in fluid communication with external inflation source 20. In this configuration, cuff pressure stabilizer 100 typically does not comprise inflation inlet port 130, described hereinabove with reference to Figs. 1A and 1C. Alternatively, inlet junction 131 is provided, but is not a component of cuff pressure stabilizer 100. In an alternative configuration (not shown), the configuration described with reference to Fig. 1B is combined with LMA device 24, described with reference to in Fig. 1C, mutatis mutandis.
Reference is still made to Fig. 1A-C, and is additionally made to Figs. 2A-B, which are additional schematic illustrations of cuff pressure stabilizer 100, in accordance with an application of the present invention. Fig. 2B is a cross-section of Fig. 2A. Figs. 2A-B show the configuration of cuff pressure stabilizer 100 shown in Fig. 1A.
Cuff pressure stabilizer 100 comprises:
• stabilizer port 122, described hereinabove, which is configured to be coupled in fluid communication with inflation lumen proximal port 15 of airway ventilation device 10;
• a protective housing 110; and
• an elastic balloon 148, which is in fluid communication with stabilizer port 122, and which is arranged such that an inflatable portion 150 of balloon 148 is disposed inside protective housing 110 (balloon 148 may include other portions, such as the neck thereof, that are not inflatable because they are constrained from inflating, e.g., by the casing of cuff pressure stabilizer 100).
Protective housing 110 is typically more rigid than elastic balloon 148. For example, protective housing 110 may have a durometer hardness that is at least 3 times (e.g., at least 5 times) greater than a durometer hardness of elastic balloon 148. For example, the durometer hardness may be measured in Shore, such as Shore A, or another scale.
For some applications, protective housing 110 is substantially rigid. As used in the present application, including in the claims, "substantially rigid," when referring to protective housing 110, means that the protective housing, when disposed in atmosphere 99, does not materially deform at least when the pressure in balloon 148 is between 0 and 120 cm H20. For some applications, the volume of the protective housing does not change by more than 1% when the pressure in the balloon increases from 0 cm H20 to 120 cm H20.
For some applications, protective housing 110 is opaque. Inflatable portion 150 of balloon 148 is shaped so as to define an inflation inlet 114 that is in fluid communication with stabilizer port 122, such as shown in Figs. 3B-D, and a proximal surface of protective housing 110 is typically shaped so as to define an inflation opening 112 aligned with inflation inlet 114, such that inflatable portion 150 of balloon 148 is inflatable via inflation opening 112 of protective housing 110.
Reference is still made to Figs. 1A-C and 2A-B, and is additionally made to Figs. 3A-D, which are schematic illustrations of cuff pressure stabilizer 100 with inflatable portion 150 of balloon 148 inflated with different respective volumes, in accordance with an application of the present invention. Figs. 3A-D show the configuration of cuff pressure stabilizer 100 shown in Fig. 1A. For some applications, protective housing 110 is shaped and inflatable portion 150 of balloon 148 is configured such that:
• when inflatable portion 150 of balloon 148 contains a base low-pressure volume Vg of air, (a) inflatable portion 150 of balloon 148 has a base low pressure of 10 cm H20, and (b) none of or less than 10% of an outer surface 152 of inflatable portion 150 of balloon 148 touches (i.e., comes in direct physical contact with) an inner surface 154 of protective housing 110, such as schematically illustrated in Fig. 3A,
• when inflatable portion 150 of balloon 148 contains a first-medium-pressure volume Y of air, (a) inflatable portion 150 of balloon 148 has a first-medium pressure of 15 cm H20, and (b) none of or less than 15% of outer surface 152 of inflatable portion 150 of balloon 148 touches (i.e., comes in direct physical contact with) inner surface 154 of protective housing 110, such as schematically illustrated in Fig. 3B; the first-medium-pressure volume Y of air equals the sum of (a) the base low- pressure volume Vg of air and (b) a first incremental quantity Q ] of air of less than 10 cc, and
• when inflatable portion 150 of balloon 148 contains a second-medium-pressure volume V2 of air, (a) inflatable portion 150 of balloon 148 has a second-medium pressure of 30 cm H20, and (b) at least 20% of outer surface 152 of inflatable portion 150 of balloon 148 touches a portion of inner surface 154 of protective housing 110, such as schematically illustrated in Fig. 3D; the second-medium- pressure volume V2 of air equals the sum of (a) the base low-pressure volume Vg of air and (b) a second incremental quantity Q2 of air that is between 10 cc and 50 cc, e.g., between 10 and 40 cc, such as between 10 and 30 cc.
For some applications, when inflatable portion 150 of balloon 148 contains the second-medium-pressure volume V2 of air, no more than 50% of outer surface 152 of inflatable portion 150 of balloon 148 touches a portion of inner surface 154 of the protective housing 110.
Fig. 3C schematically illustrates inflatable portion 150 of balloon 148 containing another medium-pressure volume of air (greater than first-medium-pressure volume V ] and less than second-medium-pressure volume V2), such that inflatable portion 150 of balloon
148 has a medium pressure of 20 cm H20, and less than 15% of outer surface 152 of inflatable portion 150 of balloon 148 touches inner surface 154 of protective housing 110.
For example, the above-mentioned base low-pressure volume Vg of air may be at least 2 cc, no more than 6 cc, and/or between 2 and 6 cc. For example, the above-mentioned first incremental quantity Q ] of air may be at least 2 cc, no more than 10 cc (e.g., no more than 7 cc), and/or between 2 and 10 cc, such as between 2 and 7 cc. For example, the above- mentioned second-medium incremental quantity Q2 of air may be at least 10 cc (e.g., at least 20 cc), no more than 50 cc (e.g., no more than 40 cc), and/or between 10 and 50 cc, such as between 20 and 40 cc.
Alternatively or additionally, for some applications, protective housing 110 is shaped and inflatable portion 150 of balloon 148 is configured such that:
• when inflatable portion 150 of balloon 148 contains a base low-pressure volume Vg of air, inflatable portion 150 of balloon 148 has a base low pressure of 10 cm H20, such as schematically illustrated in Fig. 3A,
• when inflatable portion 150 of balloon 148 contains a first-medium-pressure volume Y of air, (a) inflatable portion 150 of balloon 148 has a first-medium pressure of 15 cm H20, and (b) none of or less than 15% of outer surface 152 of inflatable portion 150 of balloon 148 touches (i.e., comes in direct physical contact with) inner surface 154 of protective housing 110, such as schematically illustrated in Fig. 3B; the first-medium-pressure volume Y of air equals the sum of (a) the base low- pressure volume Vg of air and (b) a first incremental quantity of air, typically less than 10 cc, and • when inflatable portion 150 of balloon 148 contains a second-medium-pressure volume V2 of air, (a) inflatable portion 150 of balloon 148 has a second-medium pressure, and (b) at least 20% of outer surface 152 of inflatable portion 150 of balloon 148 touches a portion of inner surface 154 of protective housing 110, such as schematically illustrated in Fig. 3D; the second-medium-pressure volume V2 of air equals the sum of (a) the base low-pressure volume Vg of air and (b) a second incremental quantity of air that is between 1.1 and 3 times the first incremental quantity of air.
Protective housing 110 is shaped so as to define at least one opening 111 therethrough to the atmosphere 99 (labeled in Fig. 2B), in order to maintain air pressure within protective housing 110 but outside balloon 148 at approximately atmospheric pressure. For some applications, protective housing 110 has a volume of at least 20 cc (e.g., at least 30 cc), no more than 80 cc (e.g., no more than 60 cc), and/or between 20 and 80 cc, such as between 30 and 60 cc.
Reference is again made to Figs. 2A-B and 3A-D. For some applications, inner surface 154 of protective housing 110 is shaped so as to include a frustoconical portion 160 (labeled in Figs. 2A and 3A). Balloon 148 is arranged such that inflatable portion 150 of balloon 148 is disposed inside protective housing 110, typically such that:
• none or less than 15% of outer surface 152 of inflatable portion 150 of balloon 148 touches frustoconical portion 160 when inflatable portion 150 of balloon 148 is inflated to a first-medium pressure of 15 cm H20, such as schematically illustrated in Fig. 3B, and
• at least 20% of outer surface 152 of inflatable portion 150 of balloon 148 touches at least a portion of frustoconical portion 160 when inflatable portion 150 of balloon 148 is inflated to a second-medium pressure greater than the first-medium pressure, such as schematically illustrated in Fig. 3D.
For some applications, frustoconical portion 160 of inner surface 154 of protective housing 110 that comes into contact with balloon 148 when balloon 148 is inflated to a medium pressure of 50 cm H20 has an area of at least 10 cm2, no more than 60 cm2, and/or between 10 and 60 cm2. For some applications, protective housing 110 is cylindrically symmetric about a central longitudinal axis 166 defined by frustoconical portion 160. For some applications, frustoconical portion 160 is a first frustoconical portion 160A, and protective housing 110 is shaped such that inner surface 154 includes a second frustoconical portion 160B. First and second frustoconical portions 160A and 160B geometrically define different respective apices 168 A and 168B. (It is to be understood that for a frustoconical portion that is not conical, the apex is the geometric apex of the portion of the cone cut off to produce the frustum that defines the frustoconical portion.) Optionally, first and second frustoconical portions 160A and 160B share a common central longitudinal axis 166, such as shown. Alternatively, first and second frustoconical portions 160A and 160B do not share a common central longitudinal axis (configuration not shown).
First and second frustoconical portions 160A and 160B geometrically define respective cones 170A and 170B (portions of which are labeled in Fig. 3B). For some applications, cones 170A and 170B intersect each other at one or more angles a (alpha), at least one of which is greater than 45 degrees. Typically, at least one of the angles is less than 90 degrees. For some applications, all of the angles are greater than 45 degrees, and/or all of the angles are less than 90 degrees. For applications in which first and second frustoconical portions 160A and 160B share common central longitudinal axis 166, such as shown, the respective cones 170A and 170B geometrically defined by first and second frustoconical portions 160A and 160B intersect each other at exactly one angle a (alpha). As used in the present application, including in the claims, "geometrically defined" means that the shape is defined abstractly in geometry, but not necessarily as a structural element of the device; for example, cones 170A and 170B are not necessarily structural elements of protective housing 110, although they could be. As used in the present application, including in the claims, the angle between two geometrical shapes is the smaller of the two supplementary angles between the two geometrical shapes, or equals 90 degrees if the two geometrical shapes are perpendicular.
For some applications, balloon 148 is arranged such that inflatable portion 150 of balloon 148 is disposed inside protective housing 110 such that as inflatable portion 150 of balloon 148 is inflated from the first-medium pressure toward the second-medium pressure, outer surface 152 of inflatable portion 150 of balloon 148 increases contact with second frustoconical portion 160B before increasing contact with first frustoconical portion 160A.
For some applications, protective housing 110 is shaped such that frustoconical portion 160 is part of a conical portion of inner surface 154. For example, first frustoconical portion 160A is illustrated as part of a conical portion of inner surface 154.
For some applications, inner surface 154 of protective housing 110 includes a proximal portion 182A that faces generally distally, and a distal portion 182B that faces generally proximally toward proximal portion 182A (labeled in Fig. 3C). One of proximal and distal portions 182A and 182B of inner surface 154 includes frustoconical portion 160. For some applications, a cone geometrically defined by frustoconical portion 160 intersects the other one of proximal and distal portions 182A and 182B of inner surface 154 at one or more angles, at least one of which is greater than 45 degrees.
For some applications, the other one of proximal and distal portions 182A and 182B of inner surface 154 is generally flat (configuration not shown). Frustoconical portion 160 geometrically defines a cone, which, for some of these applications, intersects the other one of proximal and distal portions 182A and 182B of inner surface 154 at one or more angles, e.g., at exactly one angle. At least one (e.g., all) of the one or more angles is greater than 45 degrees.
For some applications, frustoconical portion 160 is a first frustoconical portion 160A, and the other one of proximal and distal portions 182 A and 182B of inner surface 154 defines a second frustoconical portion 160B. For some of these applications, respective cones geometrically defined by first and second frustoconical portions 160A and 160B intersect each other at one or more angles, e.g., at exactly one angle. At least one (e.g., all) of the one or more angles is greater than 45 degrees.
Reference is made to Figs. 1A-C, 2A-B, and 3A-D. For some applications, cuff pressure stabilizer 100 further comprises an electronic pressure measurement circuit 141 (labeled in Fig. 2B), comprising a pressure sensor 143 (labeled in Fig. 2B), which is configured to sense a pressure in inflatable portion 150 of balloon 148 (e.g., via an air inlet 142 for fluid communication between the pressure sensor and the balloon). The pressure sensor is disposed in balloon 148 or in a volume that is in fluid communication with balloon 148. Cuff pressure stabilizer 100 further comprises a pressure display 140, which is configured to display the pressure sensed by the pressure sensor, and is typically integrated with an external casing 149 of cuff pressure stabilizer 100, such as shown in Fig. 2A. Pressure display 140 may be digital or analog. It is noted that pressure sensor 143 and pressure display 140 only sense and display the pressure, respectively, but are not involved in setting or otherwise regulating the pressure in balloon 148 or inflatable cuff 11; in other words, the cuff pressure stabilizer 100 automatically mechanically and non-electrically stabilizes the pressure in inflatable cuff 11 without input from pressure sensor 143.
Electronic pressure measurement circuit 141 and display 140 comprise: pressure sensor 143 (labeled in Fig. 2B), a battery power supply 144 (labeled in Fig. 2B), an electronic controller 145 (labeled in Fig. 2B), a tum-ON switch 146 (labeled in Fig. 2A), and display 140 (labeled in Fig. 2A). For some applications, electronic pressure measurement circuit 141 takes a pressure measurement at time intervals greater than 10 seconds and less than 5 minutes (such as once per 30 seconds, or once per 60 seconds). For some applications, battery power supply 144 drains within less than 30 days of use (such as less than 14 days, or less than 7 days). This feature ensures the disposability of the device within the intended time limit of single-patient residence in hospital intensive care. For some applications, turn-ON switch 146 cannot be turned off to stop the battery drain after initial turn-ON.
For some applications, cuff pressure stabilizer 100 further comprises an alarm output 151 (shown in Fig. 2A), which is configured to generate a visual and/or audible signal (e.g., comprising a light source, such as an FED, for generating the visual signal, and/or a sound generator for generating the audible signal). For example, alarm output 151 may comprise a light source that is configured to emit green light when the pressure sensed by pressure sensor 143 is within a deviation value of a pressure threshold, and to emit a red light when the pressure sensed by pressure sensor 143 exceeds the pressure threshold by at least the deviation value. For some of these applications, cuff pressure stabilizer 100 further comprises a user input interface 153, and electronic pressure measurement circuit 141 is configured to set a pressure threshold responsively to an input received from user input interface 153 (for example, the input may be activation, e.g., by depressing, of user input interface 153, when the current pressure is at a certain value, and the pressure threshold may be set to the current pressure value), and activate alarm output 151 whenever the pressure sensed by pressure sensor 143 exceeds the pressure threshold by at least a deviation value. Typically, the deviation value equals at least 2 cm H20, such as at least 4 cm H20, e.g., 5 cm H20. The deviation value is typically not adjustable by the user, and may be preset as an absolute value, or calculated by electronic pressure measurement circuit 141, for example as a percentage of the pressure threshold.
For some applications electronic pressure measurement circuit 141 is configured, upon receiving a set-pressure input from user input interface 153, to set the pressure threshold equal to a current pressure sensed by pressure sensor 143 at a time of receipt of the set-pressure input. For example, user input interface 153 may comprise a single button, which generates the set-pressure input upon being depressed by the user. The user may inflate inflatable cuff 11 of airway ventilation device 10 to a desired pressure and then actuate user input interface 153 to generate the set-pressure input (e.g., by depressing the button). Alternatively, user input interface 153 may comprise one or more buttons (e.g., two buttons) that allow the user to increase or decrease the desired pressure threshold.
The pressure-sensing techniques described above with reference to Figs. 1 A-C, 2A- B, and 3A-D may optionally be implemented by cuff pressure stabilizer 300, described hereinbelow with reference to Figs. 5-9; cuff pressure stabilizer 600, described hereinbelow with reference to Figs. 10; or cuff pressure stabilizer 700, described hereinbelow with reference to Fig. 11, mutatis mutandis (e.g., pressure sensor 143 is configured to sense a pressure in first and second inflatable portions 350 and 351 of first and second elastic balloons 348 and 349, respectively, of cuff pressure stabilizer 300, 600, or 700). In addition, the pressure-sensing techniques described above with reference to Figs. 1A-C, 2A-B, and 3A-D may optionally be implemented by cuff pressure stabilizer 800, described hereinbelow with reference to Figs. 12A-C, mutatis mutandis (e.g., pressure sensor 143 is configured to sense a pressure in inflatable portion 850 of elastic balloon 848 of cuff pressure stabilizer 800). In addition, the pressure-sensing techniques described above with reference to Figs. 1A-C, 2A-B, and 3A-D may optionally be implemented by cuff pressure stabilizer 900, described hereinbelow with reference to Figs. 14-17B, mutatis mutandis.
Reference is now made to Fig. 4, which includes a pressure-volume curve 200, in accordance with an application of the present invention. Fig. 4 also includes a known pres sure- volume curve 202, measured in an experiment conducted on behalf of the inventors using the TRACOE® smart Cuff Manager (TRACOE medical GmbH, Nieder- Olm, Germany), which was similar to the pressure-equalizing device described in the above-mentioned US Patent Application Publication 2015/0283343 to Schnell et al. Inflatable portion 150 of balloon 148 of cuff pressure stabilizer 100 is characterized by pres sure- volume curve 200, which represents the pressure in inflatable portion 150 of balloon 148 when inflated with different incremental volumes of air (AV) beyond the base low-pressure volume Vg of air corresponding to the base low pressure of 10 cm H20 described hereinabove with reference to Figs. 3A-B. Pressure-volume curve 200 illustrated in Fig. 4 is an exemplary pressure-volume curve; a large number of additional pressure- volume curves having the general properties of pres sure- volume curve 200 are possible, and are within the scope of the present invention.
For some applications, such as shown in Fig. 4, pressure-volume curve 200 does not include a local maximum pressure at any pressure between 20 and 50 cm H20. By contrast, known pres sure- volume curve 202 includes a local maximum pressure at about 32 cm H20 (at about 10 cc of incremental air). Alternatively, for other applications (not shown), pres sure- volume curve 200 includes a local maximum pressure and a local minimum pressure at a greater incremental volume than the local maximum pressure, and (a) a pressure difference between the local maximum pressure and the local minimum pressure is less than 3 cm H20, e.g., less than 2 cm H20, and/or (b) a volume difference between the local maximum pressure and the local minimum pressure is less than 40 cc, e.g., less than 30 cc.
For some applications, an average rate of change of pressure-volume curve 200 over a first pressure interval 210 between 40 and 50 cm H20 is between 0.5 and 3 cm H20 / cc, such as between 0.5 and 2 cm H20 / cc, e.g., between 0.5 and 1 cm H20 / cc. By contrast, an average rate of change of known pressure- volume curve 202 over first pressure interval 210 is about 4 cm H20 / cc. Alternatively or additionally, for some applications, an average rate of change of pressure-volume curve 200 over a second pressure interval 212 between 50 and 60 cm H20 is between 0.5 and 3 cm H20 / cc, such as between 0.5 and 2 cm H20 / cc, e.g., between 0.5 and 1 cm H20 / cc. By contrast, an average rate of change of known pres sure- volume curve 202 over second pressure interval 212 is about 6 cm H20 / cc. As is known in the mathematical arts, the "average rate of change" is the slope of the secant line joining respective points on the curve at the endpoints of the relevant interval.
Providing these relatively low average rates of change has the effect of stabilizing the pressure in inflatable cuff 28 of LMA device 24. Relatively small increases or decreases in the volume of inflatable cuff 28, for example caused by movement of cuff 28 against the patient's laryngeal inlet, result in corresponding decreases or increases in the volume of inflatable portion 150 of balloon 148. In the relevant typically desired pressure range of LMA cuffs of between 40 and 60 cm H20, these changes in the volume of inflatable portion 150 have only minimal effect on the pressure in inflatable portion 150, and thus in inflatable cuff 28, because of the elasticity of balloon 148.
Alternatively or additionally, for some applications, an average rate of change of pres sure- volume curve 200 over a pressure interval 214 between 20 and 30 cm H20 is between 0.3 and 5 cm H20 / cc, such as between 1 and 4 cm H20 / cc, e.g., between 1 and 3 cm H20 / cc. Providing these relatively low average rates of change has the effect of stabilizing the pressure in inflatable cuff 26 of tracheal ventilation tube 22. Relatively small increases or decreases in the volume of inflatable cuff 26, for example caused by movement of cuff 26 in trachea 18, result in corresponding decreases or increases in the volume of inflatable portion 150 of balloon 148. In the relevant typically desired pressure range of tracheal ventilation tube cuffs of between 20 and 30 cm H20, these changes in the volume of inflatable portion 150 have only minimal effect on the pressure in inflatable portion 150, and thus in inflatable cuff 26, because of the elasticity of balloon 148.
Further alternatively or additionally, for some applications, pres sure- volume curve 200 includes a rising point of inflection 220 at an inflection-point pressure of between 15 and 40 cm H20, such as between 15 and 35 cm H20 or between 25 and 40 cm H20, and/or at an incremental volume between 5 and 60 cc, such as between 10 and 30 cc. For these applications, pressure-volume curve 200 typically does not include a local maximum pressure at any pressure between 20 and 50 cm H20. By contrast, known pres sure- volume curve 202 does not include a rising point of inflection, and does include local maximum and minimum pressures. As is known in the mathematical arts, a "rising point of inflection" is a point of inflection at which the third derivative is positive, i.e., the curve is upward- flowing about the point and the curve changes from concave to convex from lower to higher pressures across the inflection point. As used in the present application, including in the claims, when referring to a pres sure- volume curve, "concave" means concave downward, and "convex" means concave upward, in accordance with the common definitions in calculus.
For some applications, protective housing 110 is shaped and inflatable portion 150 of balloon 148 is configured such that:
• when inflatable portion 150 of balloon 148 is inflated at the base low pressure of 10 cm H20, at least a base-low-pressure portion 180 of outer surface 152 of inflatable portion 150 of balloon 148 does not touch inner surface 154 of protective housing 110; base-low-pressure portion 180 excludes all portions of outer surface 152 of inflatable portion 150 within 5 mm of inflation inlet 114 of inflatable portion 150 of balloon 148 when inflatable portion 150 has the base low pressure of 10 cm H20,
• when inflatable portion 150 of balloon 148 is inflated at all pressures greater than 10 cm H20 and less than the inflection-point pressure, none of base-low-pressure portion 180 of outer surface 152 of the inflatable portion of the balloon touches inner surface 154 of protective housing 110, and
• when inflatable portion 150 of balloon 148 is inflated at all pressures at and greater than the inflection-point pressure, base-low-pressure portion 180 of outer surface 152 of inflatable portion 150 of balloon 148 at least partially touches inner surface 154 of protective housing 110.
When inflatable portion 150 of balloon 148 contains the base low-pressure volume Vg of air, at least base-low-pressure portion 180 of outer surface 152 of inflatable portion 150 of balloon 148 does not touch inner surface 154 of protective housing 110. At all pressures greater than 10 cm H20 and less than a touching -point pressure, none of base- low-pressure portion 180 of outer surface 152 of inflatable portion 150 of balloon 148 touches inner surface 154 of protective housing 110. Typically, the touching-point pressure is less than 60 cm H20; for example, the touching -point pressure may be greater than 15 cm H20 and less than 40 cm H20, such as less than 30 cm H20, or less than 25 cm H20. For some applications, the touching-point pressure corresponds to the inflection-point pressure described above. At all pressures at and greater than the touching -point pressure, base-low-pressure portion 180 of outer surface 152 of inflatable portion 150 of balloon 148 at least partially touches inner surface 154 of protective housing 110.
For some applications, when inflatable portion 150 of balloon 148 is inflated at at all pressures at and greater than the touching -point pressure and less than 60 cm H20, pres sure- volume curve 200 is convex.
For some applications:
• when inflatable portion 150 of balloon 148 is inflated at a pressure of 20 cm H20, a first area of base-low-pressure portion 180 of outer surface 152 of inflatable portion 150 of balloon 148 touches inner surface 154 of protective housing 110,
• when inflatable portion 150 of balloon 148 is inflated at a pressure of 30 cm H20, a second area of base-low-pressure portion 180 of outer surface 152 of inflatable portion 150 of balloon 148 touches inner surface 154 of protective housing 110, and • the second area equals at least 3 times the first area.
For some applications, pressure-volume curve 200 does not include any plateaus (i.e., horizontal portions where the pressure-volume curve has a constant value).
Reference is now made to Fig. 5, which is a schematic illustration of a cuff pressure stabilizer 300 for use with airway ventilation device 10, in accordance with an application of the present invention. For example, airway ventilation device 10 may be tracheal ventilation tube 22, such as shown in Fig. 5, or laryngeal mask airway (LMA) device 24, such as shown in Fig. 1C, described hereinabove for cuff pressure stabilizer 100. Cuff pressure stabilizer 300 is for use in contact with the atmosphere 99 (i.e., ambient air) of the Earth.
Fig. 5 also shows (a) airway ventilation device 10, which is not a component of cuff pressure stabilizer 300, (b) external inflation source 20, such as a syringe, which is typically not a component of cuff pressure stabilizer 300, and (c) one or more connector tubes, described hereinbelow, which are optionally a component of cuff pressure stabilizer 300 (and may be removably or permanently coupled to cuff pressure stabilizer 300). Airway ventilation device 10 is described hereinabove with reference to Figs. 1A-C. Cuff pressure stabilizer 300 typically comprises a stabilizer port 322, which is in fluid communication with first and second elastic balloons 348 and 349, described hereinbelow with reference to Figs. 5, 6, and 7A-C, and is configured to be coupled to the one or more connector tubes. The one or more connector tubes typically comprise connector tube 125, which comprises inflation lumen proximal port connector 124 that is shaped to form an air-tight seal with inflation lumen proximal port 15 of airway ventilation device 10, described immediately below. Inflation lumen proximal port connector 124 is described hereinabove with reference to Figs. 1A-C.
For some applications, such as shown in Fig. 5, cuff pressure stabilizer 300 further comprises an inflation inlet port 330, which is in fluid communication with first and second elastic balloons 348 and 349, described hereinbelow with reference to Figs. 5-7C. Inflation inlet port 330 is configured to be coupled in fluid communication with external inflation source 20. In these configurations, connector tube 125 typically further comprises stabilizer-port connector 123, which is configured to be coupled in fluid communication with stabilizer port 322. For other applications, such as shown in Fig. IB for cuff pressure stabilizer 100, cuff pressure stabilizer 300 further comprises inlet junction 131, which couples in fluid communication: connector tube 125, an inflation inlet port 132, first connector tube 133, and stabilizer port 122. Inflation inlet port 132 is configured to be coupled in fluid communication with external inflation source 20. In this configuration, cuff pressure stabilizer 300 typically does not comprise inflation inlet port 330, described hereinabove with reference to Fig. 2. Alternatively, inlet junction 131 is provided, but is not a component of cuff pressure stabilizer 300. In an alternative configuration (not shown), the configuration described with reference to Fig. 1B is combined with LMA device 24, described with reference to in Fig. 1C, mutatis mutandis.
Reference is still made to Fig. 5, and is additionally made to Fig. 6, which is a cross- sectional view of cuff pressure stabilizer 300, in accordance with an application of the present invention. Cuff pressure stabilizer 300 comprises:
• stabilizer port 322, described hereinabove, which is configured to be coupled in fluid communication with inflation lumen proximal port 15 of airway ventilation device 10;
• housing 310, which comprises one or more internal protective surfaces 354 and 355; and
• first and second elastic balloons 348 and 349, which comprise respective first and second inflatable portions 350 and 351 that are in fluid communication with each other and with stabilizer port 322 (balloons 348 and 349 may include other portions, such as necks thereof, that are not inflatable because they are constrained from inflating, e.g., by housing 310 of cuff pressure stabilizer 300).
The one or more internal protective surfaces 354 and 355 are typically more rigid than first and second elastic balloons 348 and 349. For example, the one or more internal protective surfaces 354 and 355 may have a durometer hardness that is at least 3 times (e.g., at least 5 times) greater than a durometer hardness of first and second elastic balloons 348 and 349. For example, the durometer hardness may be measured in Shore, such as Shore A, or another scale.
For some applications, the one or more internal protective surfaces 354 and 355 are substantially rigid. As used in the present application, including in the claims, first and second inflatable portions 350 and 351 include the entireties of respective inflatable portions of first and second elastic balloons 348 and 349, and not arbitrary sub-portions thereof. As used in the present application, including in the claims, "substantially rigid," when referring to internal protective surfaces 354 and 355 of housing 310, means that the internal protective surfaces, when disposed in atmosphere 99, does no materially deform at least when the pressure in balloons 348 and 349 is between 0 and 120 cm H20, i.e., the volume of housing 310 does not change by more than 1% when the pressure in balloon 348 and 349 increases from 0 cm H20 to 120 H20.
For some applications, housing 310 is opaque.
Reference is made to Figs. 7A-C, which are schematic cross-sectional illustrations of cuff pressure stabilizer 300 with balloons 348 and 349 inflated at different pressures, in accordance with an application of the present invention. Typically, the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that:
(a) when each of first and second inflatable portions 350 and 351 is inflated at a first- medium pressure of 15 cm H20, such as, for example, could be the pressure illustrated in Fig. 7B:
(i) none of or less than 15% of a first entire outer surface 352 of first inflatable portion 350 touches the one or more internal protective surfaces 354 and 355, i.e., first inflatable portion 350 is not meaningfully confined by the one or more internal protective surfaces 354 and 355, and
(ii) none of or less than 15% of a second entire outer surface 353 of second inflatable portion 351 touches the one or more internal protective surfaces 354 and 355, i.e., second inflatable portion 351 is not meaningfully confined by the one or more internal protective surfaces 354 and 355, and
(b) when each of first and second inflatable portions 350 and 351 is inflated at a second-medium pressure of 30 cm H20:
(i) at least 20% of first entire outer surface 352 touches a first portion 356 (labeled in Fig. 7B) of the one or more internal protective surfaces 354 and 355, i.e., first inflatable portion 350 is at least somewhat confined by first portion 356 of the one or more internal protective surfaces 354 and 355, and
(ii) none of or less than 15% of second entire outer surface 353 touches the one or more internal protective surfaces 354 and 355, i.e., second inflatable portion 351 is not meaningfully confined by the one or more internal protective surfaces 354 and 355.
For some applications, the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that when each of first and second inflatable portions 350 and 351 is inflated at a second-medium pressure of 50 cm H20, such as, for example, could be the pressure illustrated in Fig. 7C:
(i) at least 50% (such as at least 75%) of first entire outer surface 352 touches first portion 356 of the one or more internal protective surfaces 354 and 355, i.e., first inflatable portion 350 is highly confined by first portion 356 of the one or more internal protective surfaces 354 and 355, and
(ii) none of or less than 20% of second entire outer surface 353 touches the one or more internal protective surfaces 354 and 355, i.e., second inflatable portion 351 is not meaningfully confined by the one or more internal protective surfaces 354 and 355.
For some applications, such as shown in Figs. 5-7C, first portion 356 of the one or more internal protective surfaces 354 and 355 surrounds at least 50% (such as least 75%, e.g., least 90%, such as at least 99%) of first entire outer surface 352 when first inflatable portion 350 is inflated at the first-medium pressure of 15 cm H20. Alternatively, first portion 356 of the one or more internal protective surfaces 354 and 355 surrounds less than 50% of first entire outer surface 352 when first inflatable portion 350 is inflated at the first- medium pressure of 15 cm H20 (configuration not shown).
For some applications, such as shown in Figs. 5-7C, first portion 356 of the one or more internal protective surfaces 354 and 355 is generally spherical. Alternatively, first portion 356 has another shape, e.g., is generally ellipsoidal (configuration not shown).
For some applications, such as shown in Figs. 5-7C, a second portion 357 (labeled in Fig. 7B) of the one or more internal protective surfaces 354 and 355, which is entirely distinct from first portion 356 of the one or more internal protective surfaces 354 and 355, surrounds at least 50% (such as least 75%, e.g., least 90%, such as at least 99%) of second entire outer surface 353 when second inflatable portion 351 is inflated at the first-medium pressure of 15 cm H20. Second portion 357 may protect second elastic balloon 349. Typically, second portion 357 does not meaningfully constrain or confine the expansion of second inflatable portion 351 of second elastic balloon 349 during normal use of cuff pressure stabilizer 300 at normal pressures. Alternatively, second portion 357 of the one or more internal protective surfaces 354 and 355, surrounds less than 50% of second entire outer surface 353 when second inflatable portion 351 is inflated at the first-medium pressure of 15 cm H20.
For some applications, such as shown in Figs. 5-7C, second portion 357 of the one or more internal protective surfaces 354 and 355 is generally spherical. Alternatively, second portion 357 has another shape, e.g., is generally ellipsoidal (configuration not shown).
For some applications, such as shown in Figs. 5-7C, first portion 356 and second portion 357 of the one or more internal protective surfaces 354 and 355 are shaped so as to define first and second chambers 358 and 359 (labeled in Fig. 7A), respectively, and first and second chambers 358 and 359 are not in fluid communication with each other via housing 310. Alternatively, first and second inflatable portions 350 and 351 are disposed in a single chamber, such as described hereinbelow with reference to Fig. 11.
Typically, first portion 356 (e.g., first chamber 358) is shaped so as to define at least one opening 311 therethrough to the atmosphere 99, in order to maintain air pressure within first portion 356 (e.g., first chamber 358) but outside first elastic balloon 348 at approximately atmospheric pressure. Similarly, for configuration in which second portion 357 is provided, second portion 357 (e.g., second chamber 359) is shaped so as to define at least one opening 313 therethrough to the atmosphere 99, in order to maintain air pressure within second portion 357 (e.g., second chamber 359) but outside second elastic balloon 349 at approximately atmospheric pressure.
Typically, such as shown in Figs. 5-7C, the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that no portion of first entire outer surface 352 touches second entire outer surface 353 when each of first and second inflatable portions 350 and 351 is inflated at any pressure. For some applications, the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that a second volume of second inflatable portion 351 equals between 80% and 120% (e.g., between 90% and 110%, such as between 95% and 105%, e.g., 100%) of a first volume of first inflatable portion 350 when each of first and second inflatable portions 350 and 351 is inflated at a base low pressure of 10 cm H20, such as, for example, could be the pressure illustrated in Fig. 7A. For some of these applications, the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that the first volume equals at least 50% of the second volume when each of first and second inflatable portions 350 and 351 is inflated at the first-medium pressure of 15 cm H20, such as, for example, could be the pressure illustrated in Fig. 7B.
For some of these applications, first and second inflatable portions 350 and 351 comprise respective different materials in order to provide the above-mentioned first and second volumes. Alternatively, (a) first and second inflatable portions 350 and 351 comprise a same material (i.e., the same exact material, not just the same type of material or class of materials), (b) first and second inflatable portions 350 and 351 have first and second average wall thicknesses, respectively, and (c) the second average wall thickness equals between 110% and 180% of the first average wall thickness.
For some applications, cuff pressure stabilizer 300 comprises electronic pressure measurement circuit 141, described hereinabove with reference to Figs. 1A-C, 2A-B, and 3A-D. The pressure sensor of electronic pressure measurement circuit 141 is configured to sense a pressure in first and second inflatable portions 350 and 351, and is disposed in first elastic balloon 348, second elastic balloon 349, or in a volume that is in fluid communication with first and second elastic balloons 348 and 349.
Reference is now made to Fig. 8A, which includes "confined" and "free" pressure- volume curves 400 and 402 of first inflatable portion 350 of first elastic balloon 348, in accordance with an application of the present invention. "Confined" and "free" pressure- volume curves 400 and 402 represent the pressure in first inflatable portion 350 of first elastic balloon 348 when inflated with different incremental volumes of air (AV) beyond a first base low-pressure volume Vg ] of air corresponding to the base low pressure of 10 cm
H20 described hereinabove with reference to Figs. 5-7C. Pressure-volume curves 400 and 402 illustrated in Fig. 8A are exemplary pressure-volume curves; a large number of additional pressure-volume curves having the general properties of pres sure- volume curves 400 and 402 are possible, and are within the scope of the present invention.
First inflatable portion 350 of first elastic balloon 348 of cuff pressure stabilizer 300 is characterized by "confined" pressure-volume curve 400 when first inflatable portion 350 is disposed within first portion 356 of the one or more internal protective surfaces 354 and 355 and configured such that at least certain percentages of first entire outer surface 352 touches first portion 356 at certain pressures, as described hereinabove with reference to Figs. 7A-C.
By contrast, first inflatable portion 350 of first elastic balloon 348 of cuff pressure stabilizer 300 would be characterized by "free" pressure- volume curve 402 if first inflatable portion 350 were not disposed within first portion 356 or otherwise confined, i.e., unlike the configuration of cuff pressure stabilizer 300 described herein with reference to Figs. 5- 7C. Thus, "free" pressure-volume curve 402 reflects physical, structural properties of first inflatable portion 350.
First inflatable portion 350 of first elastic balloon 348 of cuff pressure stabilizer 300 is characterized by a first pressure-volume curve 404 at all pressures up to 30 cm H20 whether or not first inflatable portion 350 is confined by first portion 356 of the one or more internal protective surfaces 354 and 355 at pressures greater than 30 cm H20.
Reference is now made to Fig. 8B, which includes "confined" and "free" pressure- volume curves 410 and 412 of second inflatable portion 351 of second elastic balloon 349, in accordance with an application of the present invention. "Confined" and "free" pressure- volume curves 410 and 412 represent the pressure in second inflatable portion 351 of second elastic balloon 349 when inflated with different incremental volumes of air (AV) beyond a second base low-pressure volume Vg2 °f air corresponding to the base low pressure of 10 cm H20 described hereinabove with reference to Figs. 5-7C. Pres sure- volume curves 410 and 412 illustrated in Fig. 8B are exemplary pressure-volume curves; a large number of additional pressure-volume curves having the general properties of pressure-volume curves 410 and 412 are possible, and are within the scope of the present invention.
Second inflatable portion 351 of second elastic balloon 349 of cuff pressure stabilizer 300 is characterized by "confined" pres sure- volume curve 410 when second inflatable portion 351 is disposed within second portion 357 of the one or more internal protective surfaces 354 and 355 and configured such that at least certain percentages of second entire outer surface 353 touches second portion 357 at certain pressures. As mentioned above with reference to Figs. 7A-C, second portion 357 typically does not meaningfully constrain or confine the expansion of second inflatable portion 351 of second elastic balloon 349 during normal use of cuff pressure stabilizer 300 at normal pressures.
By contrast, second inflatable portion 351 of second elastic balloon 349 of cuff pressure stabilizer 300 would be characterized by "free" pressure-volume curve 412 if second inflatable portion 351 were not disposed within second portion 357 or otherwise confined, i.e., unlike the configuration of cuff pressure stabilizer 300 described herein with reference to Figs. 5-7C, but like the configuration of cuff pressure stabilizer 600, described hereinbelow with reference to Fig. 11. Thus, "free" pressure-volume curve 412 reflects physical, structural properties of second inflatable portion 351.
Second inflatable portion 351 of second elastic balloon 349 of cuff pressure stabilizer 300 is characterized by a first pressure- volume curve 414 at all pressures up to 50 cm H20 whether or not second inflatable portion 351 is confined by second portion 357 of the one or more internal protective surfaces 354 and 355 at pressures greater than 50 cm H20.
Reference is made to both Figs. 8A and 8B. For some applications, the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that:
• (a) when first inflatable portion 350 contains first base low-pressure volume V g ] of air, first inflatable portion 350 has the base low pressure of 10 cm H20, (b) first inflatable portion 350 is characterized by first pressure-volume curve 404 that represents the pressure in first inflatable portion 350 when inflated with different incremental volumes of air beyond the first base low-pressure volume Vg i of air, and (c) an average rate of change of the first pres sure- volume curve over a first pressure interval 406 between 25 and 30 cm H20 is between 0.3 and 2 cm H20 / cc, and
• (a) when second inflatable portion 351 contains second base low-pressure volume Vj32 °f aii\ second inflatable portion 351 has the base low pressure of 10 cm H20, (b) second inflatable portion 351 is characterized by second pressure-volume curve 414 that represents the pressure in second inflatable portion 351 when inflated with different incremental volumes of air beyond the second base low-pressure volume Vj32 °f air, and (c) an average rate of change of the second pressure-volume curve over a second pressure interval 416 between 40 and 50 cm H20 is between 0.2 and 2 cm H20 / cc.
Reference is now made to Fig. 9, which includes an aggregate pressure-volume curve 420, in accordance with an application of the present invention. Cuff pressure stabilizer 300 is characterized by aggregate pressure-volume curve 420, which represents the pressure in first and second inflatable portions 350 and 351 when inflated, in aggregate, with different aggregate incremental volumes of air beyond a base aggregate low-pressure volume VBA °f a>r corresponding to the base low pressure of 10 cm H20 described hereinabove with reference to Figs. 5-7C. Aggregate pressure-volume curve 420 illustrated in Fig. 9 is an exemplary pressure-volume curve; a large number of additional pressure- volume curves having the general properties of aggregate pres sure- volume curve 420 are possible, and are within the scope of the present invention.
For some applications, the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that:
• when first and second inflatable portions 350 and 351 contain, in aggregate, the base aggregate low-pressure volume VgA °f a>r ' each °f first and second inflatable portions 350 and 351 has the base low pressure of 10 cm H20,
• cuff pressure stabilizer 300 is characterized by aggregate pressure-volume curve 420 that represents the pressure in first and second inflatable portions 350 and 351 when inflated, in aggregate, with different aggregate incremental volumes of air beyond the base aggregate low-pressure volume VgA °f a·1 - and
• an average rate of change of the aggregate pressure-volume curve over first pressure interval 406 between 25 and 30 cm H20 is between 0.3 and 2 cm H20 / cc.
For some applications, the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that an average rate of change of the aggregate pressure-volume curve over second pressure interval 416 between 40 and 50 cm H20 is between 0.2 and 2 cm H20 / cc.
For some applications the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that aggregate pressure-volume curve 420 does not include a local maximum pressure at any pressure between 20 and 50 cm H20, such as shown in Fig. 9. Alternatively, for some applications, the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that aggregate pressure- volume curve 420 includes a local maximum pressure and a local minimum pressure at a greater incremental volume than the local maximum pressure, and a pressure difference between the local maximum pressure and the local minimum pressure is less than 3 cm H20 (configuration not shown). Alternatively or additionally, for some applications, aggregate pres sure- volume curve 420 includes a local maximum pressure and a local minimum pressure at a greater incremental volume than the local maximum pressure, and a volume difference between the local maximum pressure and the local minimum pressure is less than 40 cc (configuration not shown).
For some applications, the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that:
• each of first and second inflatable portions 350 and 351 has the base low pressure of 10 cm H20 when first and second inflatable portions 350 and 351 contain, in aggregate, the base aggregate low-pressure volume VgA °f ai>\ and
• each of first and second inflatable portions 350 and 351 has the first-medium pressure of 15 cm H20 when first and second inflatable portions 350 and 351 contain, in aggregate, a first aggregate medium-pressure volume of air, and
• the first-medium-pressure volume of air equals the sum of (a) the base aggregate low-pressure volume VgA °f a>r and (b) a first aggregate incremental quantity of air of less than 10 cc.
For some applications the one or more internal protective surfaces 354 and 355 are shaped and first and second inflatable portions 350 and 351 are configured such that each of first and second inflatable portions 350 and 351 has the second-medium pressure of 30 cm H20 when first and second inflatable portions 350 and 351 contain, in aggregate, a second aggregate medium-pressure volume of air equal to the sum of (a) the base aggregate low-pressure volume Vg A °f air ar|d (b) a second aggregate incremental quantity of air that is between 10 cc and 60 cc, such as less than 30 cc, e.g., less than 15 cc. In an application of the present invention, a cuff pressure stabilizer is provided that is identical to cuff pressure stabilizer 300 described hereinabove with reference to Figs. 5- 9, except as follows. This cuff pressure stabilizer may implement any of the features of cuff pressure stabilizer 300 described hereinabove with reference to Figs. 5-9. This cuff pressure stabilizer comprises first and second elastic balloons, which comprise respective first and second inflatable portions that are in fluid communication with each other and with stabilizer port 322.
The one or more internal protective surfaces 354 and 355 of this cuff pressure stabilizer are shaped and the first and the second inflatable portions are configured such that a second volume of the second inflatable portion equals between 50% and 75% of a first volume of the first inflatable portion when each of the first and the second inflatable portions has a base low pressure of 10 cm H20. For some applications, the first and the second inflatable portions comprise a same material, and the first and the second inflatable portions have first and second average wall thicknesses, respectively, that equal each other.
Reference is now made to Fig. 10, which is a schematic cross-sectional illustration of a cuff pressure stabilizer 600 for use with airway ventilation device 10, in accordance with respective applications of the present invention. Except as described hereinbelow, cuff pressure stabilizer 600 is identical to cuff pressure stabilizer 300 described hereinabove with reference to Figs. 5-9, and may implement any of the features thereof, and/or of the cuff pressure stabilizer described immediately hereinabove. Like reference numerals refer to like elements.
Cuff pressure stabilizer 600, unlike the configuration of cuff pressure stabilizer 300 illustrated in Figs. 5-7C, does not include second portion 357 of the one or more internal protective surfaces 354 and 355. Therefore, second entire outer surface 353 of second inflatable portion 351 is not surrounded by the one or more internal protective surfaces 354 and 355. This modification to cuff pressure stabilizer 300 typically does not affect the pres sure- volume curves thereof because, as mentioned above with reference to Figs. 5-7C, second portion 357 of the one or more internal protective surfaces 354 and 355 typically in any event does not meaningfully constrain or confine the expansion of second inflatable portion 351 of second elastic balloon 349 during normal use of cuff pressure stabilizer 300 at normal pressures.
Reference is now made to Fig. 11, which is a schematic cross-sectional illustration of a cuff pressure stabilizer 700 for use with airway ventilation device 10, in accordance with respective applications of the present invention. Except as described hereinbelow, cuff pressure stabilizer 700 is identical to cuff pressure stabilizer 300 described hereinabove with reference to Figs. 5-9, and may implement any of the features thereof, and/or of the cuff pressure stabilizer described hereinabove immediately before the description of Fig. 10. Like reference numerals refer to like elements. Cuff pressure stabilizer 700 comprises a housing 710, which comprises one or more internal protective surfaces 754 and 755. Internal protective surfaces 754 and 755 are shaped so as to define first and second portions 756 and 757 that are similar to first and second portions 356 and 357 of cuff pressure stabilizer 300.
For some applications, housing 710 is opaque.
In cuff pressure stabilizer 700, unlike in the configuration of cuff pressure stabilizer 300 illustrated in Figs. 5-7C, first and second inflatable portions 350 and 351 are disposed in a single chamber 760 defined by internal protective surfaces 754 and 755. This modification to cuff pressure stabilizer 300 typically does not affect the pressure-volume curves thereof because the shape of first portion 756 of cuff pressure stabilizer 700 is similar to the shape of first portion 356 of cuff pressure stabilizer 300.
Reference is made to Figs. 12A-C, which are schematic cross-sectional illustrations of a cuff pressure stabilizer 800 with an elastic balloon 848 thereof inflated at different pressures, in accordance with an application of the present invention. Except as described hereinbelow, cuff pressure stabilizer 800 is similar cuff pressure stabilizer 300 described hereinabove with reference to Figs. 5-9, may implement any of the features thereof, and is for use with airway ventilation device 10 (e.g., tracheal ventilation tube 22 or laryngeal mask airway (LMA) device 24). Like reference numerals refer to like elements.
Cuff pressure stabilizer 800 comprises:
• a stabilizer port 322, which is configured to be coupled in fluid communication with inflation lumen proximal port 15 of airway ventilation device 10;
• an expandable wall membrane 834, which is not in fluid communication with stabilizer port 322 and is in fluid communication with the atmosphere 99; and
• elastic balloon 848, which comprises an inflatable portion 850 that is in fluid communication with stabilizer port 322 and is disposed within expandable wall membrane 834.
For some applications, inflatable portion 850 and expandable wall membrane 834 are configured such that:
(a) when inflatable portion 850 is inflated at a first-medium pressure of 15 cm
H20, such as, for example, could be the pressure illustrated in Fig. 12B:
(i) none of or less than 15% of an entire inflatable-portion outer surface 852 of inflatable portion 850 touches a wall-membrane internal surface 861 of expandable wall membrane 834, and
(ii) wall-membrane internal surface 861 has a first-medium-pressure area, and
(b) when inflatable portion 850 is inflated at a second-medium pressure of 30 cm H20, such as, for example, could be the pressure illustrated in Fig. 12C:
(i) at least 50% of entire inflatable-portion outer surface 852 touches wall-membrane internal surface 861, and
(ii) wall-membrane internal surface 861 has a second-medium-pressure area that equals at least 120% of the first-medium-pressure area.
For some applications, cuff pressure stabilizer 800 further comprises a substantially rigid chamber 860. For example, substantially rigid chamber 860 may be defined by a housing 810 of cuff pressure stabilizer 800. Expandable wall membrane 834 is disposed within chamber 860. Chamber 860 is shaped and inflatable portion 850 and expandable wall membrane 834 are configured such that when inflatable portion 850 is inflated at the second-medium pressure of 30 cm H20, none of or less than 20% of an entire wall- membrane outer surface of expandable wall membrane 834 touches a chamber internal surface 854 of chamber 860, such as, for example, could be the pressure illustrated in Fig. 12C.
For some applications, housing 810 is opaque.
For some applications inflatable portion 850 and expandable wall membrane 834 are configured such that:
• when inflatable portion 850 contains a base low-pressure volume Vg of air, inflatable portion 850 has a base low pressure of 10 cm H20, such as, for example, could be the pressure illustrated in Fig. 12A,
• cuff pressure stabilizer 800 is characterized by a pressure-volume curve that represents the pressure in inflatable portion 850 when inflated with different incremental volumes of air beyond the base low-pressure volume Vg of air, and
• an average rate of change of the pressure- volume curve over a first pressure interval between 25 and 30 cm H20 is between 0.3 and 1 cm H20 / cc.
For some applications inflatable portion 850 and expandable wall membrane 834 are configured such that that an average rate of change of the pres sure- volume curve over a second pressure interval between 40 and 50 cm H20 is between 0.2 and 2 cm H20 / cc.
Typically, chamber 860 is shaped so as to define at least one opening 811 therethrough to the atmosphere 99, in order to maintain air pressure within chamber 860 but outside elastic balloon 848 and expandable wall membrane 834 at approximately atmospheric pressure. In addition, expandable wall membrane 834 is typically shaped so as to define at least one opening 813 therethrough to chamber 860, and via chamber 860 to the atmosphere 99, in order to maintain air pressure within expandable wall membrane 834 but outside elastic balloon 848 at approximately atmospheric pressure, until expandable wall membrane 834 become confined by chamber 860.
Reference is now made to Figs. 13A-B, which are schematic illustrations of an alternative configuration of cuff pressure stabilizer 100, in accordance with an application of the present invention. Although these features are illustrated with respect to cuff pressure stabilizer 100, they are equally applicable to and may be implemented in combination with the other cuff pressure stabilizers described herein.
In this configuration, cuff pressure stabilizer 100 further comprises an inflation valve 191, which may, for example, comprise an on/off "push-valve" (e.g., conventional ETT inlet valve), or a one-way valve, or another kind of valve. Cuff pressure stabilizer 100 further comprises a switchable pre-inflate valve 193, disposed along a fluid-communication path between stabilizer port 122 and inflation lumen proximal port connector 124, such as along connector tube 125, described hereinabove with reference to Figs. 1A-C. As described hereinabove, inflation lumen proximal port connector 124 that is shaped to form an air-tight seal with inflation lumen proximal port 15 of airway ventilation device 10. Switchable pre-inflate valve 193 is configured to be switchable between a close configuration, in which the valve blocks fluid flow therethrough, and an open configuration, in which the valve allows fluid flow therethrough.
Switchable pre-inflate valve 193 enables a user to choose to inflate and maintain inflatable portion 150 of balloon 148 to a desired pressure before connecting cuff pressure stabilizer 100 (e.g., inflation lumen proximal port connector 124 thereof) to inflation lumen proximal port 15 of airway ventilation device 10.
As shown in Fig. 13 A, when switchable pre-inflate valve 193 is in the closed configuration, valve 193 blocks out-flow between balloon 148 and inflation lumen proximal port connector 124. Thus, as indicated in Fig 13A, balloon 148 can be inflated to pressures above 10 cm H20 even when not connected to airway ventilation device 10.
As shown in Fig. 13B, after such inflation and subsequent coupling of inflation lumen proximal port connector 124 to inflation lumen proximal port 15 of airway ventilation device 10, switchable pre-inflate valve 193 is set in the open configuration, in which there is fluid communication between the balloon 148 and inflation lumen proximal port 15 of airway ventilation device 10, and thus with inflatable cuff 11 of airway ventilation device 10.
Reference is still made to Fig. 13B, and is additionally made to Fig. 13C. Figs. 13B and 13C are schematic illustrations of additional alternative configurations of cuff pressure stabilizer 100, in accordance with respective applications of the present invention. Although these features are illustrated with respect to cuff pressure stabilizer 100, they are equally applicable to and may be implemented in combination with the other cuff pressure stabilizers described herein.
In these configurations, cuff pressure stabilizer 100 further comprises a flow limiter 194, which is configured to slow the pressure-regulation response time of cuff pressure stabilizer 100. This flow regulation prevents the cuff pressure stabilizer from responding erratically to changes of pressure in inflatable cuff 11 of airway ventilation device within a single ventilation cycle, but rather to regulate only pressure changes that continue over an extended period of time.
For some applications, flow limiter 194 is configured, when exposed to a pressure difference of 5 cm H20 thereacross, to allow air flow therethrough of less than 0.5 cc (e.g., less than 0.3 cc) over a period of 3 seconds (which is the typical half-time of a single breathing cycle), and/or less than 0.167 cc per second (e.g., less than 0.1 cc per second, or less than 0.05 cc per second).
For some applications, in order to provide the flow limitation, flow limiter 194 comprises a tube having a diameter of 0.3 mm and a length of 3 cm.
Flow limiter 194 may be disposed anywhere in the fluid communication path between balloon 148 and inflation lumen proximal port connector 124. For example, flow limiter 194 may be disposed along connector tube 125, as shown in Fig. 13B, or between balloon 148 and stabilizer port 122, such as shown in Fig. 13C.
Reference is made to Figs. 14 and 15A-B, which are schematic illustrations of a cuff pressure stabilizer 900, in accordance with an application of the present invention. Figs. 15A-B are cross-sectional views of Fig. 14 taken along lines XV— XV. Other than as described hereinbelow, cuff pressure stabilizer 900 is generally similar to cuff pressure stabilizer 100, described hereinabove with reference to Figs. 1A-4, and may implement any of the features thereof. Like reference numerals refer to like parts.
Although not shown in Figs. 14 and 15A-B, cuff pressure stabilizer 900 is configured to be used with (a) airway ventilation device 10, which is not a component of cuff pressure stabilizer 900, (b) external inflation source 20, such as a syringe, which is typically not a component of cuff pressure stabilizer 900, and (c) one or more connector tubes, such as described hereinabove with reference to Figs. 1A-C, which are optionally a component of cuff pressure stabilizer 900 (and may be removably or permanently coupled to cuff pressure stabilizer 900). Cuff pressure stabilizer 900 typically comprises stabilizer port 122, which is in fluid communication with an elastic balloon 948, and is configured to be coupled to the one or more connector tubes, such as described hereinabove with reference to Figs. 1A-C. For some applications, cuff pressure stabilizer 900 comprises inflation inlet port 130, which is in fluid communication with elastic balloon 948, such as described hereinabove with reference to Figs. 1A and 1C; for other applications, cuff pressure stabilizer 900 further comprises inlet junction 131, which couples in fluid communication: connector tube 125, an inflation inlet port 132, first connector tube 133, and stabilizer port 122, such as described hereinabove with reference to Fig. IB.
Cuff pressure stabilizer 900 comprises:
• stabilizer port 122, described hereinabove, which is configured to be coupled in fluid communication with inflation lumen proximal port 15 of airway ventilation device 10;
• a protective housing 910; and
• elastic balloon 948, which is in fluid communication with stabilizer port 122, and which is arranged such that an inflatable portion 950 of balloon 948 is disposed inside protective housing 910 (balloon 948 may include other portions, such as the neck thereof, that are not inflatable because they are constrained from inflating, e.g., by the casing of cuff pressure stabilizer 900).
Protective housing 910 is typically more rigid than elastic balloon 948. For example, protective housing 910 may have a durometer hardness that is at least 3 times (e.g., at least 5 times) greater than a durometer hardness of elastic balloon 948. For example, the durometer hardness may be measured in Shore, such as Shore A, or another scale.
For some applications, protective housing 910 is substantially rigid. As used in the present application, including in the claims, "substantially rigid," when referring to protective housing 910, means that the protective housing, when disposed in atmosphere 99, does not materially deform at least when the pressure in balloon 948 is between 0 and 120 cm H20.
Although protective housing 910 is shown as generally right cylindrical, it may alternatively have another tubular shape, such as an elliptical cylinder or a rectangular tube.
For some applications, protective housing 910 is opaque.
Inflatable portion 950 of balloon 948 is shaped so as to define an inflation inlet 914 that is in fluid communication with stabilizer port 122, such as shown in Fig. 15A, and a proximal surface of protective housing 910 is typically shaped so as to define an inflation opening 912 aligned with inflation inlet 914, such that inflatable portion 950 of balloon 948 is inflatable via inflation opening 912 of protective housing 910.
Reference is still made to Figs. 14 and 15A-B, and is additionally made to Figs. 16A-C, which are schematic illustrations of cuff pressure stabilizer 900 with inflatable portion 950 of balloon 948 inflated with different respective volumes, in accordance with an application of the present invention. For some applications, protective housing 910 is shaped and inflatable portion 950 of balloon 948 is configured such that: • when inflatable portion 950 of balloon 948 contains a base low-pressure volume Vg of air, (a) inflatable portion 950 of balloon 948 has a base low pressure of 10 cm H20, and (b) none of or less than 10% of an outer surface 952 of inflatable portion 950 of balloon 948 touches (i.e., comes in direct physical contact with) an inner surface 954 of protective housing 910 (inflation level not illustrated),
• when inflatable portion 950 of balloon 948 contains a first-medium-pressure volume Y of air, (a) inflatable portion 950 of balloon 948 has a first-medium pressure of
15 cm H20, and (b) none of or less than 15% of an outer surface 952 of inflatable portion 950 of balloon 948 touches (i.e., comes in direct physical contact with) an inner surface 954 of protective housing 910, such as schematically illustrated in Fig. 16A; the first- medium-pressure volume Y of air equals the sum of (a) the base low- pressure volume Vg of air and (b) a first incremental quantity Q ] of air of less than 10 cc, and
• when inflatable portion 950 of balloon 948 contains a second-medium-pressure volume V2 of air, (a) inflatable portion 950 of balloon 948 has a second-medium pressure of 30 cm H20, and (b) at least 20% of outer surface 952 of inflatable portion 950 of balloon 948 touches a portion of inner surface 954 of protective housing 910, such as schematically illustrated in Fig. 16C; the second-medium- pressure volume V2 of air equals the sum of (a) the base low-pressure volume Vg of air and (b) a second incremental quantity Q2 of air that is between 10 cc and 50 cc, e.g., between 10 and 40 cc, such as between 10 and 30 cc.
For some applications, when inflatable portion 950 of balloon 848 contains the second-medium-pressure volume V2 of air, no more than 50% of outer surface 952 of inflatable portion 950 of balloon 948 touches a portion of inner surface 954 of the protective housing 910.
Fig. 16B schematically illustrates inflatable portion 950 of balloon 948 containing another medium-pressure volume of air (greater than first-medium-pressure volume V ] and less than second-medium-pressure volume V2), such that inflatable portion 950 of balloon
948 has a medium pressure of 22 cm H20, and less than 15% of an outer surface 952 of inflatable portion 950 of balloon 948 touches inner surface 954 of protective housing 910. For example, the above-mentioned base low-pressure volume Vg of air may be at least 2 cc, no more than 6 cc, and/or between 2 and 6 cc. For example, the above-mentioned first incremental quantity Q ] of air may be at least 2 cc, no more than 10 cc (e.g., no more than 7 cc), and/or between 2 and 10 cc, such as between 2 and 7 cc. For example, the above- mentioned second-medium incremental quantity Q2 of air may be at least 10 cc (e.g., at least 20 cc), no more than 50 cc (e.g., no more than 40 cc), and/or between 10 and 50 cc, such as between 20 and 40 cc.
Alternatively or additionally, for some applications, protective housing 910 is shaped and inflatable portion 950 of balloon 948 is configured such that:
• when inflatable portion 950 of balloon 948 contains a base low-pressure volume Vg of air, inflatable portion 950 of balloon 948 has a base low pressure of 10 cm H20 (inflation level not illustrated),
• when inflatable portion 950 of balloon 948 contains a first-medium-pressure volume Vj of air, (a) inflatable portion 950 of balloon 948 has a first-medium pressure of
15 cm H20, and (b) none of or less than 15% of an outer surface 952 of inflatable portion 950 of balloon 948 touches (i.e., comes in direct physical contact with) an inner surface 954 of protective housing 910, such as schematically illustrated in Fig. 16A; the first- medium-pressure volume Y of air equals the sum of (a) the base low- pressure volume Vg of air and (b) a first incremental quantity of air, typically less than 10 cc, and
• when inflatable portion 950 of balloon 948 contains a second-medium-pressure volume V2 of air, (a) inflatable portion 950 of balloon 948 has a second-medium pressure, and (b) at least 20% of outer surface 952 of inflatable portion 950 of balloon 948 touches a portion of inner surface 954 of protective housing 910, such as schematically illustrated in Fig. 16C; the second-medium-pressure volume V2 of air equals the sum of (a) the base low-pressure volume Vg of air and (b) a second incremental quantity of air that is between 1.1 and 3 times the first incremental quantity of air.
Protective housing 910 is shaped so as to define at least one opening 911 therethrough to the atmosphere 99 (labeled in Fig. 15B), in order to maintain air pressure within protective housing 910 but outside balloon 948 at approximately atmospheric pressure. For some applications in which protective housing 910 comprises moveable portion 962 that is moveably coupled to base portion 964, such as described hereinbelow with reference to Figs. 16A-C, the at least one opening 911 is defined by a small gap (e.g., less than 1 mm in width) between moveable portion 962 and base portion 964; the gap also allows moveable portion 962 to move with respect to base portion 964 with minimal friction. Alternatively or additionally, the at least one opening 911 may be similar to the at least one opening 111 through protective housing 110, described hereinabove with reference to Fig. 2B.
For some applications, protective housing 910 has a volume of at least 20 cc (e.g., at least 30 cc), no more than 100 cc (e.g., no more than 80 cc, such as no more than 60 cc), and/or between 20 and 100 cc, such as between 30 and 80 cc, e.g., between 30 and 60 cc.
Reference is still made to Figs. 15A-B and 16A-C. For some applications, inner surface 954 of protective housing 910 is shaped so as to include one or more cylindrical portions 960. Balloon 948 is arranged such that inflatable portion 950 of balloon 948 is disposed inside protective housing 910, typically such that:
• none or less than 15% of outer surface 952 of inflatable portion 950 of balloon 948 touches the one or more cylindrical portions 960 when inflatable portion 950 of balloon 948 is inflated to a first-medium pressure of 15 cm H20, such as schematically illustrated in Fig. 16A, and
• at least 20% of outer surface 952 of inflatable portion 950 of balloon 948 touches at least a portion of the one or more cylindrical portions 960 when inflatable portion 950 of balloon 948 is inflated to a second-medium pressure greater than the first- medium pressure, such as schematically illustrated in Fig. 16C.
For some applications, the one or more cylindrical portions 960 of inner surface 954 of protective housing 910 that come into contact with balloon 948 when inflatable portion 950 of balloon 948 is inflated to a medium pressure of 50 cm H20 have an area of at least 10 cm2, no more than 60 cm2, and/or between 10 and 60 cm2.
For some applications, when inflatable portion 950 of balloon 948 contains the second-medium-pressure volume of air, the at least a portion of the one or more cylindrical portions 960 touched by inflatable portion 950 has a length of at least 0.5 cm, such as at least 1 cm, measured along a central longitudinal axis of the one or more cylindrical portions 960.
For some applications, an external surface of protective housing 910 is shaped so as to define one or more loops 961 that protrude outwardly from the external surfaces, for enabling coupling of cuff pressure stabilizer 900 to a conventional pole, rail, hospital wall, or other surface or object. For some applications, cuff pressure stabilizer 900 comprises an attachment strip 963, which passes through the one or more loops 961, and which is configured to be coupleable to a conventional pole, rail, hospital wall, or other surface or object.
Reference is made to Figs. 14, 15A-B, and 16A-C. For some applications, cuff pressure stabilizer 900 may implement some or all of the pressure-sensor-based pressure sensing, pres sure- setting, pressure-display, and/or other user-interface techniques described hereinabove with reference to Figs. 1A-C, 2A-B, and 3A-D.
Reference is still made to Figs. 16A-C. For some applications, protective housing 910 is configured so as to define an internal volume that is expandable from a base internal volume, as shown in Figs. 16A-B, to a greater, expanded internal volume, as shown in Fig. 16C. As used in the present application, including in the claims, the "internal volume" of protective housing 910 is the space enclosed by protective housing 910, including the volume of inflatable portion 950 of balloon 948, which is within protective housing 910 (the volume of inflatable portion 950 of balloon 948 varies based on pressure, as described herein).
For some applications, protective housing 910 is configured so as to define an inner surface area of inner surface 954 that is expandable from a base inner surface area to a greater, expanded inner surface area, as shown in the transition from Fig. 16B to Fig. 16C.
For some applications, protective housing 910 is configured such that a balloon- exposed portion 956 of inner surface 954 of protective housing 910 is in fluid communication with (but not necessarily touching) outer surface 952 of inflatable portion 950 of balloon 948. (A non-balloon-exposed portion 958 of inner surface 954 of protective housing 910 is not in fluid communication with outer surface 952 of inflatable portion 950 of balloon 948.)
For some applications, protective housing 910 comprises a moveable portion 962 that is moveably coupled to a base portion 964 of cuff pressure stabilizer 900. (Optionally, moveable portion 962 is the entirety of protective housing 910.)
For some applications, protective housing 910 is configured such that balloon- exposed portion 956 of inner surface 954 has a variable surface area. For some applications, the surface area of balloon-exposed portion 956 of inner surface 954 varies based on a relative position of moveable portion 962 with respect to base portion 964.
For some applications, moveable portion 962 of protective housing 910 is moveably coupled to base portion 964 such that the internal volume of the protective housing varies based on a relative position of moveable portion 962 with respect to base portion 964. For some of these applications, moveable portion 962 is axially-slidably coupled to base portion 964 such that the internal volume of protective housing 910 varies based on the relative axial position of moveable portion 962 with respect to base portion 964.
Alternatively or additionally, for some applications, moveable portion 962 of protective housing 910 is moveably coupled to base portion 964 such that the inner surface area of protective housing 910 varies based on a relative position of moveable portion 962 with respect to base portion 964. For some of these applications, moveable portion 962 is axially-slidably coupled to base portion 964 such that the inner surface area of protective housing 910 varies based on the relative axial position of moveable portion 962 with respect to base portion 964.
For some applications, moveable portion 962 is axially-slidably coupled to base portion 964, which may be axially fixed. For example, moveable portion 962 may be disposed radially outward from base portion 964, as shown in the figures. The surface area of balloon-exposed portion 956 of inner surface 954 varies based on the relative axial position of moveable portion 962 with respect to base portion 964.
For some of these applications, protective housing 910 is configured such that inflation of inflatable portion 950 of balloon 948 to below a threshold volume does not cause:
• internal volume of protective housing 910 to expand,
• the inner surface area of protective housing 910 to expand, or
• the surface area of balloon-exposed portion 956 of inner surface 954 to increase. Protective housing 910 is configured such that inflation of inflatable portion 950 of balloon 948 to beyond the threshold volume causes:
• internal volume of protective housing 910 to expand from the base internal volume to the greater, expanded volume,
• the inner surface area of protective housing 910 to expand from the base inner surface area to the greater, expanded inner surface area, and/or
• the surface area of balloon-exposed portion 956 of inner surface 954 to increase.
For example, inflation of inflatable portion 950 of balloon 948 to beyond the threshold volume may cause outer surface 952 of inflatable portion 950 to push moveable portion 962 with respect to base portion 964, thereby increasing the internal volume of protective housing 910, the inner surface area of protective housing 910, and/or balloon- exposed portion 956 of inner surface 954.
Typically, protective housing 910 is configured such that the surface area of balloon-exposed portion 956 of inner surface 954 is adjustable between minimum and maximum values, and protective housing 910 is provided with balloon-exposed portion 956 of inner surface 954 having the minimum surface area, in order to provide cuff pressure stabilizer 900 with a small form-factor, which increases only as necessary to accommodate higher inflation volumes of inflatable portion 950 of balloon 948 beyond the threshold volume.
For some applications, moveable portion 962 of protective housing 910 includes an accordion-pleated surface that allows for moving of moveable portion with respect to base portion 964 and expansion of the internal volume of protective housing 910 without necessarily increasing the inner surface area of protective housing 910 (configuration not shown).
For some applications, protective housing 910 is configured such that the threshold volume corresponds to a pressure in inflatable portion 950 of balloon 948 of at least 20 cm H20 and/or no more than 40 cm H20 (e.g., no more than 30 cm H20), such as 25 cm H20. For some applications, as a result of the value of the threshold volume, balloon-exposed portion 956 of inner surface 954 only increases at pressures that commonly occur when cuff pressure stabilizer 900 is used with an LMA device. As mentioned above, cuffs of tracheal ventilation tubes are typically inflated to 25-30 cm H20, while cuffs of LMA devices are inflated to 40-60 cm H20. Thus, at volumes corresponding to pressures less than about 40 cm H20, such as for use with tracheal ventilation tubes, protective housing 910 has a small form-factor, which may be more convenient for the user.
Alternatively, for some applications, balloon-exposed portion 956 of inner surface 954 has a fixed surface area that is large enough to allow inflation of inflatable portion 950 of balloon 948 to at least a volume of 40 cc and/or the volumes shown in pressure-volume curve 1000, described hereinbelow with reference to Fig. 18.
For some applications, protective housing 910 is not shaped so as to define, therethrough to balloon-exposed portion 956 of inner surface 954, an opening having an area of more than 0.5 cm2. Thus, protective housing 910 is not shaped so as to allow access to balloon 948 by a human finger.
Reference is now made to Figs. 17A-B, which are schematic illustrations of protective housing 910 of cuff pressure stabilizer 900 in locked and unlocked states, in accordance with an application of the present invention. For some applications, cuff pressure stabilizer 900 is configured to assume these locked and unlocked states. For other applications, cuff pressure stabilizer 900 is not configured to assume these locked and unlocked states; for such applications in which balloon-exposed portion 956 of inner surface 954 has the above-described variable surface area, cuff pressure stabilizer 900 is always in the equivalent of the unlocked state.
Cuff pressure stabilizer 900 is configured, when in the locked state, such as shown in Fig. 17A, to prevent moveable portion 962 (and typically the external surface of protective housing 910) from moving (e.g., axially sliding) with respect to base portion 964. As a result, balloon-exposed portion 956 of inner surface 954 has a fixed surface area. This locked state is typically appropriate when cuff pressure stabilizer 900 is used with a tracheal ventilation tube, in which case expansion of the surface area of balloon-exposed portion 956 of inner surface 954 is unnecessary, and it may be desirable to ensure that protective housing 910 retains its small form-factor. Typically, cuff pressure stabilizer 900 will also function in the locked state when coupled to the inflatable cuff of an LMA mask, albeit with less volume available for regulation, but still better than if cuff pressure stabilizer 900 were not coupled to the inflatable cuff of the LMA mask.
Cuff pressure stabilizer 900 is configured, when in the unlocked state, such as shown in Fig. 17B, to allow moveable portion 962 (and typically the external surface of protective housing 910) to move (e.g., axially slide) with respect to base portion 964. As a result, balloon-exposed portion 956 of inner surface 954 has a variable surface area, such as described hereinabove with reference to Figs. 16A-C.
For some applications, a transition between the locked and unlocked states is effected by rotation of moveable portion 962 (and typically the external surface of protective housing 910) with respect to base portion 964. In the locked state, a tab 968 may prevent moving (e.g., axially sliding) of moveable portion 962 with respect to base portion 964. For example, moveable portion 962 (and typically the external surface of protective housing 910) may be shaped so as define an L-shaped slot 970 in which tab 968 may slide both upon rotation of moveable portion 962 (and typically the external surface of protective housing 910) and axially sliding of moveable portion 962 (and typically the external surface of protective housing 910) with respect to base portion 964.
Reference is now made to Fig. 18, which includes pressure-volume curves 1000, 1010, and 1020, in accordance with respective applications of the present invention. Inflatable portion 950 of balloon 948 of cuff pressure stabilizer 900 is characterized by pres sure- volume curves 1000 and 1010, which represent the pressure in inflatable portion 950 of balloon 948 when inflated with different incremental volumes of air (AV) beyond the base low-pressure volume Vg of air corresponding to the base low pressure of 10 cm
H20 described hereinabove with reference to Figs. 16A-C. Pres sure- volume curves 1000 and 1010 illustrated in Fig. 18 are exemplary pressure-volume curves; a large number of additional pressure-volume curves having the general properties of pressure-volume curves 1000 and 1010 are possible, and are within the scope of the present invention.
For applications in which (a) balloon-exposed portion 956 of inner surface 954 has a variable surface area, such as described hereinabove with reference to Figs. 16A-C, and (b) protective housing 910 has locked and unlocked states, such as described hereinabove with reference to Figs. 17A-B, cuff pressure stabilizer 900 is configured to be characterized by pres sure- volume curve 1000 when in the unlocked state described hereinabove with reference to Fig. 17B.
Alternatively, for applications in which (a) balloon-exposed portion 956 of inner surface 954 has a variable surface area, such as described hereinabove with reference to Figs. 16A-C, and (b) protective housing 910 does not have locked and unlocked states, but instead is always in the equivalent of the unlocked state, cuff pressure stabilizer 900 is configured to be characterized by pres sure- volume curve 1000.
Further alternatively, for some applications in which balloon-exposed portion 956 of inner surface 954 has a fixed surface area, the surface area is large enough to allow inflation of inflatable portion 950 of balloon 948 to the volumes shown in pressure-volume curve 1000. Cuff pressure stabilizer 900 is thus configured to be characterized by pressure- volume curve 1000.
Still further alternatively, for applications in which (a) balloon-exposed portion 956 of inner surface 954 has a variable surface area, such as described hereinabove with reference to Figs. 16A-C, and (b) protective housing 910 has locked and unlocked states, such as described hereinabove with reference to Figs. 17A-B, cuff pressure stabilizer 900 is configured to be characterized by pres sure- volume curve 1010 when in the locked state described hereinabove with reference to Fig. 17A. As mentioned above, this locked state is typically appropriate when cuff pressure stabilizer 900 is used with a tracheal ventilation tube. Typically, cuff pressure stabilizer 900 will also function in the locked state when coupled to the inflatable cuff of an LMA mask, albeit with less volume available for regulation, but still better than if cuff pressure stabilizer 900 were not coupled to the inflatable cuff of the LMA mask.
For some applications, such as shown in Fig. 18, pres sure- volume curves 1000 and 1010 do not include a local maximum pressure at any pressure between 20 and 50 cm H20. By contrast, known pressure-volume curve 202, described hereinabove with reference to Fig. 4, includes a local maximum pressure at about 31 cm H20 (at about 10 cc of incremental air). Alternatively, for other applications (not shown), pressure-volume curves 1000 and 1010 include a local maximum pressure and a local minimum pressure at a greater incremental volume than the local maximum pressure, and (a) a pressure difference between the local maximum pressure and the local minimum pressure is less than 3 cm H20, e.g., less than 2 cm H20, and/or (b) a volume difference between the local maximum pressure and the local minimum pressure is less than 40 cc, e.g., less than 30 cc.
For some applications, an average rate of change of pressure-volume curve 1000 over a first pressure interval 1210 between 40 and 50 cm H20 is between 0.5 and 3 cm H20 / cc, such as between 0.5 and 2 cm H20 / cc, e.g., between 0.5 and 1 cm H20 / cc. By contrast, an average rate of change of known pressure-volume curve 202, described hereinabove with reference to Fig. 4, over first pressure interval 210 is about 4 cm H20 / cc.
Alternatively or additionally, for some applications, an average rate of change of pres sure- volume curve 1000 over a second pressure interval 1212 between 50 and 60 cm H20 is between 0.5 and 3 cm H20 / cc, such as between 0.5 and 2 cm H20 / cc, e.g., between 0.5 and 1 cm H20 / cc. By contrast, an average rate of change of known pressure- volume curve 202, described hereinabove with reference to Fig. 4, over second pressure interval 212 is about 6 cm H20 / cc. As is known in the mathematical arts, the "average rate of change" is the slope of the secant line joining respective points on the curve at the endpoints of the relevant interval.
Providing these relatively low average rates of change has the effect of stabilizing the pressure in inflatable cuff 28 of LMA device 24. Relatively small increases or decreases in the volume of inflatable cuff 28, for example caused by movement of cuff 28 against the patient's laryngeal inlet, result in corresponding decreases or increases in the volume of inflatable portion 950 of balloon 948. In the relevant typically desired pressure range of LMA cuffs of between 40 and 60 cm H20, these changes in the volume of inflatable portion 950 have only minimal effect on the pressure in inflatable portion 950, and thus in inflatable cuff 28, because of the elasticity of balloon 948.
Alternatively or additionally, for some applications, an average rate of change of pres sure- volume curves 1000 and 1010 over a pressure interval 1214 between 20 and 30 cm H20 is between 0.3 and 5 cm H20 / cc, such as between 0.3 and 3 cm H20 / cc, e.g., between 0.5 and 2 cm H20 / cc, such as between 0.3 and 1 cm H20. Alternatively or additionally, for some applications, a rate of change of pres sure- volume curves 1000 and 1010 at each given pressure over a pressure interval between 22 and 30 cm H20 is between 0.3 and 1 cm H20 / cc. Providing these relatively low average rates of change has the effect of stabilizing the pressure in inflatable cuff 26 of tracheal ventilation tube 22. Relatively small increases or decreases in the volume of inflatable cuff 26, for example caused by movement of cuff 26 in trachea 18, result in corresponding decreases or increases in the volume of inflatable portion 950 of balloon 948. In the relevant typically desired pressure range of tracheal ventilation tube cuffs of between 20 and 30 cm H20, these changes in the volume of inflatable portion 950 have only minimal effect on the pressure in inflatable portion 950, and thus in inflatable cuff 26, because of the elasticity of balloon 948.
Further alternatively or additionally, for some applications, pres sure- volume curve 1000 includes a rising point of inflection 1220 at an inflection-point pressure of between 15 and 30 cm H20, such as between 15 and 25 cm H20 (e.g., 22 cm H20), and/or at an incremental volume between 5 and 30 cc, such as between 10 and 20 cc (e.g., 10 cc). For these applications, pressure-volume curve 1000 typically does not include a local maximum pressure at any pressure between 20 and 50 cm H20. By contrast, known pres sure- volume curve 202, described hereinabove with reference to Fig. 4, does not include a rising point of inflection, and does include local maximum and minimum pressures. Still further alternatively or additionally, for some applications, pres sure- volume curve 1010 includes a rising point of inflection 1222 at a pressure of between 15 and 30 cm H20, such as between 15 and 25 cm H20 (e.g., 22 cm H20), and/or at an incremental volume between 5 and 30 cc, such as between 10 and 20 cc (e.g., 10 cc). For these applications, pressure-volume curve 1010 typically does not include a local maximum pressure at any pressure between 20 and 50 cm H20.
For some applications, protective housing 910 is shaped and inflatable portion 950 of balloon 948 is configured such that:
• when inflatable portion 950 of balloon 948 is inflated at the base low pressure of 10 cm H20, at least a base-low-pressure portion 980 of outer surface 952 of inflatable portion 950 of balloon 948 does not touch inner surface 954 of protective housing 910; base-low-pressure portion 980 excludes all portions of outer surface 952 of inflatable portion 950 within 5 mm of inflation inlet 914 of inflatable portion 950 of balloon 948 when inflatable portion 950 has the base low pressure of 10 cm H20,
• when inflatable portion 950 of balloon 948 is inflated at all pressures greater than 10 cm H20 and less than the inflection-point pressure, none of base-low-pressure portion 980 of outer surface 952 of the inflatable portion of the balloon touches inner surface 954 of protective housing 910, and
• when inflatable portion 950 of balloon 948 is inflated at all pressures at and greater than the inflection-point pressure, base-low-pressure portion 980 of outer surface 952 of inflatable portion 950 of balloon 948 at least partially touches inner surface 954 of protective housing 910.
When inflatable portion 950 of balloon 948 contains the base low-pressure volume Ub of air, at least base-low-pressure portion 980 of outer surface 952 of inflatable portion 950 of balloon 948 does not touch inner surface 954 of protective housing 910. At all pressures greater than 10 cm H20 and less than a touching -point pressure, none of base- low-pressure portion 980 of outer surface 952 of inflatable portion 950 of balloon 948 touches inner surface 954 of protective housing 910. Typically, the touching-point pressure is less than 60 cm H20; for example, the touching-point pressure is greater than 15 cm H20 and less than 30 cm H20. For some applications, the touching -point pressure corresponds to the inflection-point pressure described above. At all pressures at and greater than the touching-point pressure, base-low-pressure portion 980 of outer surface 952 of inflatable portion 950 of balloon 948 at least partially touches inner surface 954 of protective housing 910.
For some applications, when inflatable portion 950 of balloon 948 is inflated at at all pressures at and greater than the touching-point pressure and less than 60 cm H20, pres sure- volume curve 1000 is convex. Alternatively or additionally, for some applications, at all pressures at and greater than the touching -point pressure and less than 60 cm H20, pres sure- volume curve 1010 is convex.
For some applications:
• when inflatable portion 950 of balloon 948 is inflated at a pressure of 20 cm H20, a first area of base-low-pressure portion 980 of outer surface 952 of inflatable portion 950 of balloon 948 touches inner surface 954 of protective housing 910,
• when inflatable portion 950 of balloon 948 is inflated at a pressure of 30 cm H20, a second area of base-low-pressure portion 980 of outer surface 952 of inflatable portion 950 of balloon 948 touches inner surface 954 of protective housing 910, and
• the second area equals at least 3 times the first area.
For some applications, pressure-volume curve 1000 does not include any plateaus. For some applications, pressure-volume curve 1010 does not include any plateaus.
For some applications, inflatable portion 950 of balloon 948 is configured such that, if protective housing 910 were to be removed (or, alternatively, in the absence of protective housing 910), inflatable portion 950 of balloon 948 would be characterized by a removed- protective-housing pressure-volume curve 1020 that represents the pressure in inflatable portion 950 of balloon 948 when inflated with different incremental volumes of air (AV) beyond the base low-pressure volume Vg of air. It is noted that protective housing 910 is not removed during typical use of cuff pressure stabilizer 900; nevertheless, in these applications, inflatable portion 950 would be characterized by removed-protective-housing pres sure- volume curve 1020 if the protective housing were to be removed.
Removed-protective-housing pressure-volume curve 1020 generally provides a good indication of the pressure at which outer surface 952 of inflatable portion 950 of balloon 948 will touch inner surface 954 of protective housing 910 (the inflection point). The flattening of removed-protective-housing pressure-volume curve 1020 means that balloon 948 will expand substantially (and thus reach inner surface 954 of protective housing 910) at this pressure level. For example, in the exemplary pres sure- volume curves, this pressure level is about 22 cm H20. This is also the pressure level about which cuff pressure stabilizer 900 provides maximum volume stability performance. Since the pressure range around 25 cm H20 is of particular importance for the performance of the cuff pressure stabilizer, it may be advantageous to have a balloon for which the pressure- volume curve flattens in the close vicinity of 25 cm H20.
For some applications, removed-protective-housing pres sure- volume curve 1020 includes a local maximum pressure at a pressure (typically, at a single pressure) between 20 and 30 cm H20. (For example, the illustrated removed-protective-housing pressure- volume curve 1020 includes a very shallow local maximum pressure at about 29 cm H20 when inflated with about 200 cc, beyond the limit of the x-axis shown.)
Although cuff pressure stabilizers 100, 300, 600, 700, 800, and 900 have been described as being used with inflatable cuff 11 of airway ventilation device 10, cuff pressure stabilizers 100, 300, 600, 700, 800, and 900 may alternatively be used with other inflatable chambers of other medical devices or non-medical devices. For example, the inflatable chamber may be a Foley catheter balloon, a gastric balloon, a balloon of colonoscope, or a balloon of an endoscope.
In the description and claims of the present application, each of the verbs, "comprise," "include" and "have," and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements or parts of the subject or subjects of the verb. The articles "a" and "an" are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, "an element" means one element or more than one element. The term "including" is used herein to mean, and is used interchangeably with, the phrase "including but not limited to." The term "or" is used herein to mean, and is used interchangeably with, the term "and/or," unless context clearly indicates otherwise. The term "such as" is used herein to mean, and is used interchangeably, with the phrase "such as but not limited to."
All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present patent specification, including definitions, will prevail. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
For brevity, some explicit combinations of various features are not explicitly illustrated in the figures and/or described. It is now disclosed that any combination of the method or device features disclosed herein can be combined in any manner - including any combination of features - any combination of features can be included in any embodiment and/or omitted from any embodiments.
It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.

Claims

1. A cuff pressure stabilizer for use with an airway ventilation device having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the cuff pressure stabilizer comprising:
a stabilizer port, which is configured to be coupled in fluid communication with the inflation lumen proximal port;
a protective housing; and
an elastic balloon, which is in fluid communication with the stabilizer port, and which is arranged such that an inflatable portion of the balloon is disposed inside the protective housing,
wherein the protective housing is more rigid than the elastic balloon,
wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
when the inflatable portion of the balloon contains a base low-pressure volume of air, (a) the inflatable portion of the balloon has a base low pressure of 10 cm H20, and (b) none of or less than 10% of an outer surface of the inflatable portion of the balloon touches an inner surface of the protective housing,
when the inflatable portion of the balloon contains a first- medium-pressure volume of air, (a) the inflatable portion of the balloon has a first-medium pressure of 15 cm H20, and (b) none or less than 15% of an outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, wherein the first- medium-pressure volume of air equals the sum of (a) the base low-pressure volume of air and (b) a first incremental quantity of air of less than 10 cc, and when the inflatable portion of the balloon contains a second-medium- pressure volume of air, (a) the inflatable portion of the balloon has a second-medium pressure of 30 cm H20, and (b) at least 20% of the outer surface of the inflatable portion of the balloon touches a portion of the inner surface of the protective housing, wherein the second-medium-pressure volume of air equals the sum of (a) the base low-pressure volume of air and (b) a second incremental quantity of air that is between 10 cc and 50 cc.
2. The cuff pressure stabilizer according to claim 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that: when the inflatable portion of the balloon contains the second-medium-pressure volume of air, no more than 50% of the outer surface of the inflatable portion of the balloon touches a portion of the inner surface of the protective housing.
3. The cuff pressure stabilizer according to claim 1, wherein the second incremental quantity of air is less than 40 cc.
4. The cuff pressure stabilizer according to claim 3, wherein the second incremental quantity of air is less than 30 cc.
5. The cuff pressure stabilizer according to claim 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
the pressure-volume curve does not include a local maximum pressure at any pressure between 20 and 50 cm H20.
6. The cuff pressure stabilizer according to claim 1, wherein the inflatable portion of the balloon is configured such that, if the protective housing were to be removed:
the inflatable portion of the balloon would be characterized by a removed- protective-housing pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
the removed-protective-housing pres sure- volume curve includes a local maximum pressure at a pressure between 20 and 30 cm H20.
7. The cuff pressure stabilizer according to claim 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air,
the pressure-volume curve includes a local maximum pressure and a local minimum pressure at a greater incremental volume than the local maximum pressure, and
a pressure difference between the local maximum pressure and the local minimum pressure is less than 3 cm H20.
8. The cuff pressure stabilizer according to claim 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air,
the pressure-volume curve includes a local maximum pressure and a local minimum pressure at a greater incremental volume than the local maximum pressure, and
a volume difference between the local maximum pressure and the local minimum pressure is less than 40 cc.
9. The cuff pressure stabilizer according to claim 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
an average rate of change of the pressure-volume curve over a pressure interval between 40 and 50 cm H20 is between 0.5 and 3 cm H20 / cc.
10. The cuff pressure stabilizer according to claim 9, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the pres sure- volume curve includes a rising point of inflection at an inflection-point pressure of between 15 and 35 cm H20.
11. The cuff pressure stabilizer according to claim 10, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
an average rate of change of the pressure-volume curve over a pressure interval between 20 and 30 cm H20 is between 0.3 and 5 cm H20 / cc.
12. The cuff pressure stabilizer according to claim 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
an average rate of change of the pressure-volume curve over a pressure interval between 50 and 60 cm H20 is between 0.5 and 3 cm H20 / cc.
13. The cuff pressure stabilizer according to claim 12, wherein the average rate of change of the pressure-volume curve over the pressure interval between 50 and 60 cm H20 is less than 2 cm H20 / cc.
14. The cuff pressure stabilizer according to claim 13, wherein the average rate of change of the pressure-volume curve over the pressure interval between 50 and 60 cm H20 is less than 1 cm H20 / cc.
15. The cuff pressure stabilizer according to claim 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond the base low-pressure volume of air, and
an average rate of change of the pressure-volume curve over a pressure interval between 20 and 30 cm H20 is between 0.3 and 5 cm H20 / cc.
16. The cuff pressure stabilizer according to claim 15, wherein the average rate of change of the pressure-volume curve over the pressure interval between 20 and 30 cm H20 is less than 4 cm H20 / cc.
17. The cuff pressure stabilizer according to claim 16, wherein the average rate of change of the pressure-volume curve over the pressure interval between 20 and 30 cm H20 is less than 3 cm H20 / cc.
18. The cuff pressure stabilizer according to claim 15, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the pres sure- volume curve includes a rising point of inflection at an inflection-point pressure of between 15 and 35 cm H20.
19. The cuff pressure stabilizer according to claim 18, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
an average rate of change of the pressure-volume curve over a pressure interval between 40 and 50 cm H20 is between 0.5 and 3 cm H20 / cc.
20. The cuff pressure stabilizer according to claim 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is shaped so as to define an inflation inlet that is in fluid communication with the stabilizer port,
the inflatable portion of the balloon is characterized by a pressure-volume curve that represents the pressure in the inflatable portion of the balloon when inflated with different incremental volumes of air beyond a base low-pressure volume of air,
when the inflatable portion of the balloon contains the base low-pressure volume of air, the inflatable portion of the balloon has a base low pressure of 10 cm H20 and at least a base-low-pressure portion of the outer surface of the inflatable portion of the balloon does not touch the inner surface of the protective housing, wherein the base-low-pressure portion excludes all portions of the outer surface of the inflatable portion within 5 mm of the inflation inlet of the inflatable portion of the balloon when the inflatable portion of the balloon has the base low pressure of 10 cm H20,
at all pressures greater than 10 cm H20 and less than a touching-point pressure, less than none of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, wherein the touching-point pressure is less than 30 cm H20,
at all pressures at and greater than the touching-point pressure, the base-low- pressure portion of the outer surface of the inflatable portion of the balloon at least partially touches the inner surface of the protective housing, and
at all pressures at and greater than the touching-point pressure and less than 60 cm H20, the pressure-volume curve is convex.
21. The cuff pressure stabilizer according to claim 20, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that the touching-point pressure is greater than 15 cm H20 and less than 25 cm H20.
22. The cuff pressure stabilizer according to claim 1, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
the inflatable portion of the balloon is shaped so as to define an inflation inlet that is in fluid communication with the stabilizer port,
when the inflatable portion of the balloon contains the base low-pressure volume of air, the inflatable portion of the balloon has a base low pressure of 10 cm H20 and at least a base-low-pressure portion of the outer surface of the inflatable portion of the balloon does not touch the inner surface of the protective housing, wherein the base-low-pressure portion excludes all portions of the outer surface of the inflatable portion within 5 mm of the inflation inlet of the inflatable portion of the balloon when the inflatable portion of the balloon has the base low pressure of 10 cm H20,
at all pressures greater than 10 cm H20 and less than a touching -point pressure, none of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, wherein the touching-point pressure is less than 30 cm H20,
at all pressures at and greater than the touching-point pressure, the base-low- pressure portion of the outer surface of the inflatable portion of the balloon at least partially touches the inner surface of the protective housing,
at a pressure of 20 cm H20, a first area of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing,
at a pressure of 30 cm H20, a second area of the base-low-pressure portion of the outer surface of the inflatable portion of the balloon touches the inner surface of the protective housing, and
the second area equals at least 3 times the first area.
23. The cuff pressure stabilizer according to any one of claims 1-22,
wherein the protective housing is shaped so as to define an inner surface that includes a cylindrical portion, and
wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
when the inflatable portion of the balloon contains the first-medium- pressure volume of air, none or less than 15% of the outer surface of the inflatable portion of the balloon touches the cylindrical portion, and
when the inflatable portion of the balloon contains the second-medium- pressure volume of air, at least 20% of the outer surface of the inflatable portion of the balloon touches at least a portion of the cylindrical portion.
24. The cuff pressure stabilizer according to claim 23, wherein the protective housing is shaped and the inflatable portion of the balloon is configured such that:
when the inflatable portion of the balloon contains the second-medium-pressure volume of air, the at least a portion of the cylindrical portion touched by the inflatable portion has a length of at least 0.5 cm, measured along a central longitudinal axis of the cylindrical portion.
25. The cuff pressure stabilizer according to any one of claims 1-22, further comprising: a pressure sensor, which is configured to sense a pressure in the inflatable portion of the balloon; and
a pressure display, which is configured to display the pressure sensed by the pressure sensor,
wherein the cuff pressure stabilizer is configured to automatically mechanically and non-electrically stabilize the pressure in the inflatable cuff without input from the pressure sensor.
26. The cuff pressure stabilizer according to any one of claims 1-22, wherein the protective housing is configured so as to define an internal volume that is expandable from a base internal volume to a greater, expanded internal volume.
27. The cuff pressure stabilizer according to any one of claims 1-22,
wherein the cuff pressure stabilizer comprises a base portion,
wherein the protective housing comprises a moveable portion that is moveably coupled to the base portion, and
wherein the protective housing is configured such that inflation of the inflatable portion of the balloon to below a threshold volume does not cause the moveable portion to move with respect to the base portion, and to beyond the threshold volume causes the moveable portion to move with respect to the base portion.
28. The cuff pressure stabilizer according to any one of claims 1-22, further comprising: an inflation lumen proximal port connector that is shaped to form an air-tight seal with the inflation lumen proximal port of the airway ventilation device; and
a switchable pre-inflate valve, which is (a) disposed along a fluid-communication path between the stabilizer port and the inflation lumen proximal port connector, and (b) configured to be switchable between a close configuration, in which the valve blocks fluid flow therethrough, and an open configuration, in which the valve allows fluid flow therethrough.
29. The cuff pressure stabilizer according to any one of claims 1-22, further comprising a flow limiter, which is configured to slow a pressure -regulation response time of the cuff pressure stabilizer.
30. A system comprising the cuff pressure stabilizer according to any one of claims 1- dl, wherein the system further comprises the airway ventilation device.
31. The system according to claim 30, wherein the airway ventilation device comprises a tracheal ventilation tube.
32. The system according to claim 30, wherein the airway ventilation device comprises a laryngeal mask airway (LMA) device.
EP19758270.3A 2018-02-20 2019-02-14 Catheter inflatable cuff pressure stabilizers Withdrawn EP3755408A4 (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US201862632668P 2018-02-20 2018-02-20
US16/160,668 US10286170B1 (en) 2018-02-20 2018-10-15 Catheter inflatable cuff pressure stabilizer
US201862758007P 2018-11-09 2018-11-09
US201862774588P 2018-12-03 2018-12-03
PCT/IL2019/050176 WO2019162939A1 (en) 2018-02-20 2019-02-14 Catheter inflatable cuff pressure stabilizers

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EP3755408A1 true EP3755408A1 (en) 2020-12-30
EP3755408A4 EP3755408A4 (en) 2022-01-12

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CN112156306B (en) * 2020-09-10 2023-03-21 西安交通大学 Trachea cannula for monitoring cuff pressure in real time

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Publication number Priority date Publication date Assignee Title
US4119101A (en) * 1976-03-01 1978-10-10 Victor Igich Multiple lumen endotracheal tube and cuff with limited inflation and pressure
US4134407A (en) * 1977-03-25 1979-01-16 Elam James O External pressure-volume monitor for endotracheal cuff
US4552558A (en) * 1983-07-14 1985-11-12 Rudolph Muto Pressure warning, indicating and applying monitor for cuff type indwelling devices
DK163282C (en) * 1990-01-15 1992-08-03 Vagn Niels Finsen Lomholt AIR RESERVIR FOR REGULATING THE PRESSURE IN A RESPIRATORY CATALOG SEALERS
DE102012112097A1 (en) * 2012-12-11 2014-06-12 TRACOE medical Frankfurt Pressure-balancing device

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