WO1995008356A2

WO1995008356A2 - Airway monitoring adapter and use thereof

Info

Publication number: WO1995008356A2
Application number: PCT/US1994/010433
Authority: WO
Inventors: Craig Bell; Keith Cross
Original assignee: Smiths Industries Medical Systems, Inc.
Priority date: 1993-09-16
Filing date: 1994-09-14
Publication date: 1995-03-30
Also published as: AU7728894A; ZA946814B; EP0793520A4; JPH09502894A; WO1995008356A3; EP0793520A2

Abstract

This invention is an airway monitoring adapter (40) that includes a conduit for receiving a first catheter, a conduit (52) having exterior threads (53) located on an outer wall thereof, and communicating with the interior of the adapter, guide means (54, 55) within the interior of the adapter for directing a second catheter towards the center of the adapter, and a collar (56) having interior threads that mate with the exterior threads on the conduit, and for housing a compression slug (58), so that tightening of the threaded collar is capable of sealing and anchoring the second catheter therein is provided. In addition, a process for monitoring distally of tracheal tube in a patient is provided.

Description

AIRWAY MONITORING ADAPTER AND USE THEREOF

Description

Technical Field

The present invention is concerned with an airway monitoring adapter and monitoring catheter. The present invention provides for variable positioning of a monitoring device and makes it possible to monitor, for instance, distally to a tracheal tube positioned in said patient. In addition, the present invention is concerned with a process for tracheally suctioning a patient along with monitoring distally of a tracheal tube. The present invention is also concerned with a suction catheter equipped with the airway monitoring adapter.

Background Art A number of commercially available devices are currently in use for the purpose of ventilating a patient. Use of traditional endotracheal tubes for such purpose is quite satisfactory for ventilation purposes. However, during patient ventilation, frequently fluids accumulate in the trachea and bronchi. Commonly, mucous secretions and other fluids accumulate along the intubated pathway below and within the vicinity of, for instance, an inflated cuff, when employed. The patient may try to swallow the secretions, causing muscle contractions and tissue movement around the endotracheal tube, thereby contributing to the discomfort that is present during intubation. The accumulation of these fluids also can inhibit ventilation and increase the risk of infection. Accordingly, it is necessary for the accumulated fluids to be aspirated or suctioned from the patient.

In the past, suctioning has been achieved by removing the ventilation equipment, thereby interrupting the patient's assisted ventilation, and inserting, such as into the trachea and bronchi, a catheter which in turn is connected to a vacuum source. After the fluid is removed via the catheter by application of the vacuum, the ventilation equipment is reattached to the patient and the ventilation is resumed.

However, this interruption of the patient's mechanically- assisted ventilation can cause extreme anxiety and discomfort. Also, it has been reported that during suctioning, oxygen desaturation can occur and may result in hypoxemia, bradycardia and other arrhythmias, a drop in blood pressure and possible increase in intracranial pressure. Also, it has been reported that during the suctioning atelectasis or bronchoconstriction can also occur.

In order to eliminate or at least significantly minimize any of these problems, closed ventilation suction catheter systems are now in wide use such as that available under the trade designation of SteriCath, Model No. 6100, available from Smiths Industries Medical Systems, Inc. (SIMS) , the assignee of the present application. This ventilation suction catheter system includes a catheter tube; a cross-piece connecting member for connection to an endotracheal tube, and also for connection to a ventilating apparatus; a means for connecting a vacuum located at the end opposite to that nearest the patient; a control valve to control the suction; and a protective sleeve located between the cross-piece and the member for connecting to the vacuum.

Closed ventilation suction catheter systems make it possible to continue the ventilation, while at the time, applying suction to remove undesired accumulated fluid from a patient.

A particularly critical group of patients requiring mechanical ventilation is that group having diffuse lung injury, typically referred to as Adult Respiratory Distress Syndrome (ARDS) . ARDS patients typically do not die from their respiratory insufficiencies, but instead from sepsis and multiple organ failure.

The conventional ventilatory support mode is volume- controlled ventilation with applied positive end expiratory pressure (PEEP) . Unfortunately, recent evidence suggests that this strategy may perpetuate lung damage by injuring delicate alveolar tissue with high pressures.

An alternative to volume controlled ventilation is pressure controlled ventilation with an inverse inspiratory: expiratory (I:E) ratio. This has been found to improve gas exchange by recruiting more alveoli, and decreasing peak airway pressures (PAP) . A potential problem with this type of ventilation is that cardiac output may fall as a result of an increase in mean airway pressure (MAP) and auto-PEEP. It is possible to select I:E ratios that improve gas exchange without adverse hemodynamic consequences.

Presently, the typical manner for monitoring the MAP and PEEP for a given patient is to monitor the pressure in the circuit tubing and use this for clinical judgment. This is so, even though there is data that suggests that the airway pressure needs to be monitored at the tip or distally of the tip of the tracheal tube. Moreover, there are some modes of ventilation which do not allow the lung pressure to equilibrate with the circuit pressure at the end of the expiration phase before the inspiration phase occurs and delivers another volume of air to the lungs. This difference in pressure is called auto-PEEP (or intrinsic PEEP) .

This auto-PEEP pressure can be monitored via a pressure monitoring lumen in a specialty endotracheal (ET) tube. Examples of these tubes are the Mallinckrodt with monitoring line and the Sheridan ET C0₂. The major problem employing such is that the patients are not going to be initially intubated with a specialty tube because intubation normally occurs prior to the onset of ARDS. After the onset of ARDS, these patients are so unstable that a tube change could introduce serious complications. Therefore, this is not usually allowed by the attending physician.

Hamilton Ventilator Company, who sells a ventilator with PC-IRV mode, recommends the use of a Portex Jet Ventilator Adaptor, which provides a depth adjustable airway pressure monitoring catheter. This provides the necessary monitoring means distally to the tracheal tube without changing the tracheal tube to a specialty tube with monitoring capabilities. The drawback that is associated with this adaptor is the inability to suction the patients' lungs of mucous without breaking the circuit. Breaking the circuit in order to suction can be detrimental to these severely compromised patients (e.g., desaturation and tachycardia).

Summary of Invention

The present invention is concerned with an airway monitoring adaptor and monitoring catheter that makes it possible to overcome the above problems associated with the prior art.

In particular, the present invention provides for variable positioning of a monitoring device and makes it possible to monitor distally to a tracheal tube positioned in a patient. Furthermore, the present invention permits a patient to be ventilated, tracheally suctioned and monitored distally to the tracheal tube, without interruption of the ventilation or suctioning.

More particularly, the present invention is concerned with a monitoring catheter and a monitoring adapter. The monitoring adapter includes a conduit for receiving a first catheter, a conduit having exterior threads located on an interior wall of the adapter, and communicating with the interior of the adapter, guide means within the interior of the adapter for directing a second catheter towards the center of the adapter, a collar having interior threads that mate with the exterior threads on the conduit, and for housing a compression slug, so that tightening of the threaded collar is capable of sealing and anchoring the second catheter.

In addition, the present invention is also concerned with a suction catheter that comprises a catheter tube suitable for insertion into a patient; a patient connecting member mounted so as to surround the catheter tube in the vicinity of the distal end of the catheter tube, wherein the distal end is suitable for insertion into a patient. The catheter also includes the above described airway monitoring adapter connected to the patient connecting member in the vicinity of the distal end of the catheter tube, and positioned so as to surround the catheter tube.

A vacuum connection member is located in the vicinity of the proximal end of the catheter tube. A protective sleeve surrounds at least the majority of the length of the catheter tube, and extends between the patient connecting member. The protecting sleeve is adapted to permit the distal end of the catheter tube to be extended from the protective sleeve into a patient, and be withdrawn from the patient.

The present invention is also concerned with a method for monitoring distally to a tracheal tube positioned in a patient. In particular, the method of the present invention comprises interposingventilating/aspirating apparatus between the lung/airway system of a patient, and a ventilator; causing the ventilator and the ventilating apparatus to involuntarily cycle influent ventilating gas to the lungs of the patient, and to remove effluent gas from the patient through a tracheal tube; selectively introducing an aspirating catheter into the airway/lung system to remove secretions from the lungs of the patient, without disconnection of the ventilating apparatus; selectively positioning a monitoring catheter into the ventilating/aspirating apparatus distally of the tracheal tube to provide airway monitoring, without disconnection of the ventilating apparatus, or interruption of either the ventilating or aspirating steps.

Brief Description of Drawings

Figure 1 is a schematic diagram of the suction catheter of the present invention.

Figure 2 is a schematic diagram of the airway monitoring adaptor and monitoring catheter assembly of the present invention.

Figure 3 is a cross-section of a monitoring adapter pursuant to the present invention.

Best and Various Modes for Carrying Out the Invention

Figure 1 is a schematic elevation of a suction catheter equipped with an airway monitoring adapter pursuant to the present invention. The suction catheter 21 can be connected through legs 15 and 12 of the cross-shaped piece 11 through airway monitoring adapter 40 and endotracheal or tracheostomy connector 41 and endotracheal or tracheostomy tube 42 to a patient. Leg 13 of the cross-piece is connected to a T-shaped adapter 43, which in turn is connected to ventilator 46, via conduits 44 and 45, and adapters 46 and 47, respectively. If desired, the connecting piece 11 can be provided with a swivel mechanism. Moreover, if desired, the adapter 40 may include swivel means, for instance, swivel means located in the vicity of the proximal end of the adapter.

With respect to the discussion of the catheter of the present invention, the proximal ends of various elements are understood as the ends nearest the vacuum source 49, and the distal ends are understood to be those ends nearest the patient.

The suction catheter 21 includes a catheter tube 2, a vacuum connection member 1, and a protective sleeve 3.

The catheter tube 2 is a soft flexible tube made of, for instance, polyvinyl chloride, adapted to be inserted into a patient, such as into the trachea/bronchial tree of a patient for the purpose of removing fluid from the patient by employing a vacuum. In addition, if desired, the catheter tube 2 can be a multilumen catheter tube, such as that disclosed in U.S. Patent 5,073,164 to Hollister, et al., entire disclosure of which is incorporated herein by reference. Also, the catheter tube can include one or a plurality of eyelets at its distal end to reduce occlusion. Also, the catheter tube can include calibrations thereon to provide a reading of the depth of the insert into a patient. The catheter tube, at its distal end, passes through cross-shaped piece 11 through a wiper seal (not shown) , located in the leg 15 of the cross-shaped piece 11, and surrounding the periphery of the catheter tube. The wiper seal can be made of a silicone rubber material.

Located at the proximal end of the catheter tube is provided means for connecting the catheter to vacuum source 49, referred to as vacuum connection member 1. Such includes a bore of the same size as the outside diameter of the suction catheter tube. The vacuum connection means l is normally made of a relatively rigid material, such as SAN (polymer of styrene and acrylonitrile) .

Also located between the vacuum connection means 1 and the catheter tube 2 is a valve member 10. The valve member 10 illustrated is a spool type valve, preferably made of butyl rubber. The valve is operated by manually applying a force to the top of the valve rubber member, whereby the top of the rubber member and the valve member 10 is pushed down, such that it no longer blocks the passage way in the catheter tube, and thereby suction can be applied. Upon release of the manual force, the valve returns to its resting position. The rubber member 16 is retained in the valve body 18 of the valve member by an ultrasonically welded ring (not shown) .

Located between the cross-shaped piece 11 and the valve member 10 is a protective sleeve 3 that surrounds at least the majority of the length of the catheter tube 2. The protective sleeve 3 is adapted to permit the distal end of the catheter tube to be extended from the protective sleeve into a patient, and to be withdrawn from the patient. The flexible protective sleeve is generally cylindrical in shape and is formed of a flexible, lightweight, translucent plastic material, such as a high clarity polyethylene with a typical thickness of about 0.002 inches. The diameter of the protective sleeve is typically about 1.5 to about 1.7 inches, when flattened. The ends of sleeve 3 are adhesively secured to the leg 15 of the cross-shaped piece 11, and leg 18 of the suction valve assembly 1, respectively, via collars la. In assembling, the collars are twisted and threaded over externally threaded legs 15 and 18, respectively, with the ends of the protective sleeve 3, and an adhesive located between the collars and the threaded legs. A typical adhesive is polyvinyl chloride doped tetrahydrofuran.

Figure 2 is an elevation of the monitoring adapter 40 and monitoring catheter 50 in exploded view. In particular, the monitoring adapter 40 includes a fitting member 51 that provides connection between endotracheal fitting 41 and cross- shaped piece 11, and includes a conduit for receiving catheter 2 and the monitoring catheter. Located on an outer wall of monitoring adapter is conduit 52, having exterior threads 53 (see Fig. 3) . This conduit 52 is in communication with the interior of adapter 40. The conduit 51 is disposed at an angle A to the adapter. Typically, this angle is about 115 to about 155°, and more typically, about 135°. Within the interior of the adapter is guide means for directing the monitoring catheter towards the center thereof. In particular, this means includes wall members 54 and 55 (see Fig. 3) disposed spaced from the interior wall of the adapter. Typically, it is spaced about .300 to about .450, and more typically, about .400 inches. Walls 54 and 55 are disposed at an angle B to each other. Wall 54 intersects interior wall of the adapter at an Angle C. The sum of Angle B and Angle C is equal to or greater than 180° with Angle B typically 135° and Angle C typically 45°. A collar or compression housing 56 having interior threads (not shown) that mate with the exterior threads on the conduit is included. This collar include gripping means 57 for tightening and loosening such. When compression housing is tightened onto threaded conduit, it houses a compression slug 58 in such a manner that it is capable of sealing and anchoring catheter monitor 61 inserted therein. The compression slug 58 can be made from rubber (polyisoprene) . When loosened, the monitoring catheter can be positioned as desired. Also included is a steel washer 59 to a protective sleeve 60 is provided around the monitoring catheter 61 and is secured thereto by an o-ring 62 or by a plastic snap fit. The protective sleeve 60 can be made of the same material as the protective sleeve 3 employed around catheter 2. The protective sleeve 60 surrounds at least the majority of the length of the monitoring catheter 61. The monitoring catheter 61 is then connected to a pressure monitor, either stand alone or one that is integral to the ventilator.

The monitoring of the pressure distally or at the tip of the endotracheal tube, as achieved by the present invention is quite important. In particular, such is used to determine the patients work of breathing (WOB) . This provides an indicator to monitor patient 0₂ consumption, calorie requirements, lung compliance, and resistances. In addition to monitoring pressure, the present invention can be used to sample the gases in the airway for compositional analysis. This permits the sampling at the level of the carina so that sample dilution is minimized. Furthermore, a 3-way stop lock can 63 be connected to the proximal end of the monitoring catheter via female even adapter 64 to permit purging of the monitoring catheter 61.

Moreover, the monitoring adapter can also be used as a means for delivering medicaments to the patients lungs. By having the ability to advance the monitoring catheter beyond the tip of the endotracheal tube, medication can be deposited directly into the lungs. This can be achieved by a syringe or by a metered dose inhalation canister. In particular, the proximal connector can be designed to accept both a standard luer and the stems from a MDI canister (see alternate connecter 65 in Figure 2) . A major advantage is that the medicament is directly installed into the lungs, as contrasted to other delivery systems, whereby drug is released into the circuit, so that the majority thereof is deposited on the walls of the circuit, on connectors, and on the inside of the endotracheal tube, rather than in the patient.

Claims

What is Claimed is:

1. A monitoring catheter and monitoring adapter combination, said monitoring adapter comprising a first conduit for receiving a first catheter; a second conduit having exterior threads located on an outer wall of said adaptor and communicating with the interior of said adaptor; guide means within the interior of said adaptor for directing said monitoring catheter towards the center of said adapter; a collar having interior threads that mate with the exterior threads on said conduit, and for housing a compression slug so that tightening of said threaded collar is capable of sealing and anchoring said monitoring catheter; and wherein said monitoring catheter passes through said collar and compression slug and is selectively positioned through said monitoring adapter.

2. The combination of claim 1 wherein said second conduit is disposed at angle of about 115 to about 155° to said adapter.

3. The combination of claim 2 wherein said angle is about 135°.

4. The combination of claim 1 wherein said guide means includes two wall members spaced from the interior wall of the adapter and disposed at an Angle B to each other and wherein one of the wall members intersects the interior wall of said adapter at an Angle C.

5. The combination of claim 4 wherein the sum of Angle B and Angle C is at least 180°.

6. The combination of claim 5 wherein Angle B is 135°.

7. The combination of claim 5 wherein Angle C is 45°.

8. The combination of claim 1 wherein said monitoring catheter is for monitoring pressure.

9. The combination of claim 1 wherein said collar includes grip means.

10. A suction catheter and airway monitoring adaptor combination, said suction catheter comprising: a first catheter tube suitable for insertion into a patient; a patient connecting member mounted so as to surround said catheter tube in the vicinity of the distal end of said catheter tube, and wherein said distal end is suitable for insertion into a patient; an airway monitoring adaptor connected to said patient connecting member in the vicinity of the distal end of said first catheter tube, and positioned so as to surround said first catheter tube; wherein said monitoring adaptor comprises a first conduit for receiving said first catheter tube; a second conduit having exterior threads located on an outer wall of said adaptor and communicating with the interior of said adaptor; guide means within the interior of said adaptor for directing a second catheter towards the center of said adapter; a collar having interior threads that mate with the exterior threads on said conduit, and for housing a compression slug so that tightening of said threaded collar is capable of sealing and anchoring the second catheter; a vacuum connection member located in the vicinity of the proximal end of the first catheter tube; a protective sleeve surrounding at least the majority of the length of said first catheter tube, and extending between said patient connecting member, wherein said protective sleeve is adopted to permit the distal end of said first catheter tube to be extended from said protective sleeve into a patient and be withdrawn from the patient.

11. The combination of claim 10 wherein said second conduit is disposed at angle of about 115 to about 155° to said adapter.

12. The combination of claim 11 wherein said angle is about 135°.

13. The combination of claim 10 wherein said guide means includes two wall members spaced from the interior wall of the adapter and disposed at an Angle B to each other and wherein one of the wall members intersects the interior wall of said adapter at an Angle C.

14. The combination of claim 13 wherein the sum of Angle B and Angle C is at least 180°.

15. The combination of claim 14 wherein Angle B is 135°.

16. The combination of claim 14 wherein Angle C is 45°.

17. The combination of claim 10 which further comprises a monitoring catheter that passes through said collar, and compression slug, and is selectively positioned through said monitoring adapter.

18. The combination of claim 10 which further includes a protective sleeve surrounding at least the majority of the length of the monitoring catheter.

19. The combination of claim 17 wherein said monitoring catheter is for monitoring pressure.

20. The combination of claim 10 wherein said collar includes grip means.

21. A method for monitoring distally to a tracheal tube positioned in a patient which comprises: interposing ventilating/aspirating apparatus between the lung/airway system of a patient, and a ventilator; causing the ventilator and the ventilating apparatus to involuntarily cycle influent ventilating gas to the lungs of the patient, and to remove effluent gas from the patient through a tracheal tube; selectively introducing an aspirating catheter into the airway/lung system to remove secretions from the lungs of the patient, without disconnection of the ventilating apparatus; selectively positioning a monitoring catheter into the ventilating/aspirating apparatus distally of the tracheal tube to provide airway monitoring without disconnection of the ventilating apparatus, or interruption of either the ventilating or aspirating steps.

22. The method of claim 21 wherein said patient is monitored for pressure.