WO2018045555A1

WO2018045555A1 - Pressure control device for cuffed endotracheal tubes and laryngeal masks

Info

Publication number: WO2018045555A1
Application number: PCT/CN2016/098557
Authority: WO
Inventors: Zhiguang Yi
Original assignee: Covidien Lp
Priority date: 2016-09-09
Filing date: 2016-09-09
Publication date: 2018-03-15

Abstract

A pressure control device for maintaining the pressure level of a cuff (100b) of a medical device, wherein the pressure control device comprises an air reservoir (2) filled with air at a pressure between a first predetermined pressure and a second predetermined pressure that is higher than the first predetermined pressure; a first valve (6), which is connected to the air reservoir (2) at one end and to an inflating tube (100c) for the cuff (100b) at the other end so as to form a first air flowing path (A), wherein when the cuff (100b) pressure is below the first predetermined pressure, the first valve (6) allows air in the air reservoir (2) to flow to the cuff (100b) through the first air flowing path (A) so as to increase the cuff (100b) pressure to a level above the first predetermined pressure; and a second valve (7), which is connected to the air reservoir (2) at one end and to the inflating tube (100c) for the cuff (100b) at the other end so as to form a second and parallel air flowing path (B), wherein when the cuff (100b) pressure is above the second predetermined pressure, the second valve (7) allows air in the cuff (100b) to flow to the air reservoir (2) through the second air flowing path (B) so as to decrease the cuff (100b) pressure to a level below the second predetermined pressure. A cuffed endotracheal tube with the pressure control device, and a cuffed laryngeal mask (100) with the pressure control device.

Description

Pressure control device for cuffed endotracheal tubes and laryngeal masks

Technical field

The present disclosure generally relates to a pressure control device for cuffed endotracheal tubes or laryngeal masks, a cuffed endotracheal tube with the pressure control device, and a cuffed laryngeal mask with the pressure control device.

Technical Background

To perform general anesthesia for surgery, patient needs breathing machinery support to maintain the patient hemodynamically stable anesthesia. Usually, there are two major airway devices during typically clinical procedure, that is, the endotracheal tube (ETT) ventilation device and a laryngeal mask device (LM device) .

The ETT ventilation device comprises an elongate conduit constituted endotracheal tube, which is provided with an inflatable cuff at the distal end of the elongated tube. In operation, the distal end of the ETT is inserted into the patient’s mouth, after the patient’s throat inlet (or glottis opening) , and into the patient’s trachea. Once the conduit is positioned, the cuff and the internal passage of the trachea form a seal.

A LM device is a medical device that keeps a patient's airway open during anaesthesia or unconsciousness. A LM device generally includes a flexible airway tube structure defining an airway to direct oxygen or air from a source and a mask with an inflatable cuff structure, which is connected to the airway tube structure at its distal end and is able to be inserted through the patient's mouth, down the windpipe, and once deployed forms an airtight seal on top the glottis, so as to allow a secure airway to be managed by a health care provider.

In both cases, the inflatable cuff or cuff structure (hereinafter called as cuff) may be inflated to a size suitable for abutting against the patient’s airway, thus sealing the airway. Typically, the cuff is in a deflated state during insertion and is subsequently inflated after the tracheal tube is in place.

For tracheal tubes, the cuff pressure, that is, the pressure within the internal volume of the cuff, is essential in tracheal tube management. The cuff pressure should be sufficiently high to prevent leakage that could make mechanical ventilation ineffective, and to prevent the progression of secretions from the oropharynx towards the lower airways, in order to reduce the appearance of breathing machine-associated pneumonia (VAP) . On the other hand, excessively higher cuff pressure damages the tracheal mucosa by compromising capillary perfusion. The tracheal tube cuff pressure for ETT device is usually selected between 20cm H₂O to 30cm H₂O. For laryngeal masks, the cuff pressure is also a key factor, which normally does not exceed 60cm H₂O.

However, when inflated, the cuff may tend to lose shape over time, leading to un-satisfactory sealing of the patient’s airway. Accordingly, it is required to monitor the cuff pressure to determine whether the cuff is properly inflated.

Traditionally, clinicians may attempt to determine the quality of a cuff seal by monitoring the cuff pressure via manometers that are temporarily attached to the cuff inflation line. However, such monitoring is usually done periodically, therefore increasing the workload of clinicians. Moreover, the connection and disconnection of the manometers may cause leakage of air in the cuff, which may influence the integrity of the cuff seal.

Accordingly, nowadays pressure control devices for cuffed endotracheal tubes or laryngeal masks are commonly used to maintain the cuff pressure relatively constant, thus improving the seal.

US20150314092A1 discloses a piezoelectric inflator system, which may continuously deliver an inflation gas at a constant pressure with minimal energy expenditure.

WO2011127407A1 discloses a regulator and control system which controls the pressure in the cuff by fluid connective means communicating with a small air pump, a pressure sensor and a dump valve, a pressure feedback loop with a microprocessor controller contained within the regulator and control system having direct control over both of the air pump and the dump valve.

However, so far the pressure control devices used for cuffed endotracheal tubes or laryngeal masks involve power sources and are generally relatively complex and expensive.

It is therefore desirable to provide a pressure control device which automatically and continuously adjusts the cuff pressure of the endotracheal tube or the laryngeal mask to keep it within a desired range, and which does not involve power sources and are less expensive.

It is also desirable to provide a pressure control device which can ensure the cuff of the endotracheal tube or the laryngeal mask being not over-inflated when first inflating the cuff without the use of the manometer.

It is also desirable to provide a pressure control device which uses the air from the breathing machine as air source that supplements the cuff of the endotracheal tube or the laryngeal mask.

It is also desirable to provide a pressure control device which can be easily re-configured so as to control the cuff pressure of other airway management devices.

Summary of Disclosure

According to the present disclosure, there is provided a pressure control device for maintaining the pressure level of a cuff of a medical device, wherein the pressure control device comprises an air reservoir filled with air at a pressure between a first predetermined pressure and a second predetermined pressure that is higher than the first predetermined pressure； a first valve, which is connected to the air reservoir at one end and to an inflating tube for the cuff at the other end so as to form a first air flowing path, wherein when the cuff pressure is below the first predetermined pressure, the first valve allows air in the air reservoir to flow to the cuff through the first air flowing path so as to increase the cuff pressure to a level above the first predetermined pressure； and a second valve, which is connected to the air reservoir at one end and to the inflating tube for the cuff at the other end so as to form a second and parallel air flowing path, wherein when the cuff pressure is above the second predetermined pressure, the second valve allows air in the cuff to flow to the air reservoir through the second air flowing path so as to decrease the cuff pressure to a level below the second predetermined pressure.

In some embodiments, the first valve is a directional valve of a 2-way, 2 positions, normally open type with a cracking pressure of the first predetermined pressure, which will open when the pressure in the cuff is below the first predetermined pressure and close when the pressure in the cuff is above the first predetermined pressure.

In some embodiments, the second valve is a directional valve of a 2-way, 2 positions, normally close type with a cracking pressure of the second predetermined pressure, which will open when the pressure in the cuff is above the second predetermined pressure and close when the pressure in the cuff is below the second predetermined pressure.

In some embodiments, the pressure control device further comprises a third valve, which is connected to the inflating tube for the cuff at one end and to an inflation device at the other end so as to form a third air flowing path, wherein the third valve allows to inflate the cuff to a pressure between the first predetermined pressure and the second predetermined pressure when first inflating the cuff.

In some embodiments, the third valve is a shut-off valve which is opened when first inflating the cuff.

In some embodiments, the inflation device is also connected to the air reservoir so as to form a fourth air flowing path, so that the air reservoir is filled with air simultaneously with the first inflation of the cuff and to the same pressure between the first predetermined pressure and the second predetermined pressure.

In some embodiments, the pressure control device further comprises a fourth valve, which is connected to the air reservoir so as to form a fifth air flowing path, wherein the fourth valve allows the pressure in the air reservoir to be maintained below the second predetermined pressure.

In some embodiments, the forth valve is a safety valve which will open and release the extra air when the pressure in the air reservoir is above the second predetermined pressure.

In some embodiments, the pressure control device further comprises an additional air supply device connected to the air reservoir so as to form a fifth airway path, the additional air supply device supplies air to the air reservoir when the pressure in the air reservoir is below a third predetermined pressure between the first predetermined pressure and the second predetermined pressure.

In some embodiments, the additional air supply device comprises an adaptor, a fifth valve, and a sixth valve, wherein the adaptor is connected to a breathing machine at one end and to the fifth control means at the other end, the fifth control means is in turn connected to the sixth control means, which is in turn connected to the air reservoir so as to form the fifth air flowing path.

In some embodiments, the fifth valve prevents air from the air reservoir to flow to the breathing machine during the expiration phase, and when the pressure in the air reservoir is below the third predetermined pressure, the sixth valve allows air from the breathing machine to fill the air reservoir during inspiration phase until the pressure of the air reservoir reaches the third predetermined pressure.

In some embodiments, the sixth valve is a directional valve of a 2-way, 2 positions, normally open type with a cracking pressure of the third predetermined pressure, which will open when the pressure in the air reservoir is below the third predetermined pressure and close when the pressure in the air reservoir is above the third predetermined pressure.

In some embodiments, the air reservoir is made of elastic material.

In some embodiments, the air reservoir is a latex cuff or balloon.

In some embodiments, the air reservoir will expand with the increase of the filled air, but remain no change once the pressure inside the air reservoir reaches the second predetermined pressure.

According to the present disclosure, it may also provide an endotracheal tube device with the pressure control device as mentioned above.

According to the present disclosure, it may also provide a laryngeal mask device with the pressure control device as mentioned above.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

Brief Description of the Drawings

Fig. 1 schematically shows a laryngeal mask device (LM device) , including a cuff, to which a control device according to the present disclosure could be applied, and

Fig. 2 schematically shows the configuration of a pressure control device according to the present disclosure for a cuff of a medical device.

Detailed Description of the Embodiments

The embodiments will be described with reference to Figs. 1 and 2. However, the following embodiments are only examples for embodying the invention and are not intended to limit the scope thereof.

With reference to Fig. 1, a laryngeal mask device (LM device) , including a cuff, to which a control device according to the present disclosure could be applied, is shown. However, as described above, the control device according to the present disclosure can also be applied to cuff or cuff structure of other medical devices.

The LM device 100 generally includes a flexible airway tube structure 100a and a mask that is connected to or formed integrally with the airway tube structure and includes an inflatable cuff or cuff structure 100b. The airway tube structure 100a defines an airway therein for supplying oxygen, air or anaesthesia gas and the like. The airway tube structure 100a is connected to a source of oxygen, air or anaesthesia gas and the like at its proximal end, such as a breathing machine.

Optionally, the cuff 100b is self-inflated and is generally kept in an inflated state. The cuff 100b has an elliptical or pear shape, which is close to the shape of inlet of the larynx, and can be inflated further or in a controlled manner after insertion through the inflating passage to establish a seal against the larynx, and can be deflated for easy removal from the larynx.

An inflating tube 100c is provided to be connected to the pressure control device according to the present disclosure at one end and to an inflating passage formed within the sidewall of the tube structure 100a at the other end, to control the pressure within the cuff 100b.

As shown in Fig. 2, the pressure control device according to the present disclosure includes an air reservoir 2 that is filled with air at a predetermined pressure, for example 28cm H₂O, a first directional valve 6 and a second directional valve 7.

The air reservoir 2 is connected to the directional valve 6 and the directional valve 6 is further connected to the inflating tube 100c for a cuff of an ETT or a LM device, optionally through a first connector 10 (for example a Luer male connector) , to form a first air flowing path A.

The directional valve 6 is a 2-way, 2 positions and normally open directional valve with cracking pressure of 20cm H₂O, for example. When the cuff pressure is above 20cm H₂O, the directional valve 6 will close, which means that if the cuff pressure is below 20cm H₂O, the directional valve 6 will open, allowing the air in the air reservoir 2 to flow to the cuff through the first air flowing path A, so as to increase the cuff pressure to a level above 20cm H₂O.

The air reservoir 2 is also connected to a directional valve 7 and the directional valve 7 is further connected to the inflating tube 100c, optionally through the first connector 10, to form a second and parallel air flowing path B.

The directional valve 7 is a 2-way, 2 positions, normally close directional valve with cracking pressure of 30cm H₂O, for example. When the cuff pressure is above 30cm H₂O, the directional valve 7 will open, which means that if the endotracheal tube cuff pressure is above 30cm H₂O, the directional valve 7 will open, allowing the extra air in the cuff to flow to the air reservoir 2 through the air flowing path B and store in the air reservoir 2, so as to decrease the cuff pressure to a level below 30cm H₂O.

In this way, the cuff pressure is automatically and continuously adjusted and kept between 20cm H₂O and 30cm H₂O, reducing the workload of cuff pressure monitoring.

Advantageously, the pressure control device according to the present disclosure further includes a shut-off valve 8, which is connected to the inflating tube 100c, optionally through the first connector 10 at one end, and to an inflation device, optionally through the second connector 9 (for example a Luer female connector) at the other end, to form a third air flowing path C.

The shut-off valve 8 is used in the first inflation of the cuff. In normal case, it should be shut-off. Therefore, when first inflating the cuff, the shut-off valve 8 is opened and the cuff pressure is inflated to a predetermined pressure between 20cm H₂O and 30cm H₂O. After the cuff is inflated, the shut-off valve 8 should be closed.

Advantageously, the inflation device is also connected to the air reservoir 2, optionally through the second connector 9, to form a fourth air flowing path D.

Therefore, when first inflating the cuff, simultaneously with the first inflation of the cuff, the air reservoir 2 could be filled with air to the same pressure, i.e. between 20cm H₂O and 30cm H₂O. The shut-off valve 8 can also be opened regularly to achieve the pressure balance between the air reservoir and the cuff if needed.

Advantageously, the pressure control device according to the present disclosure further comprises a safety valve 3, which is connected to the air reservoir 2 to form a fifth air flowing path E.

When the pressure of the air reservoir 2 is above 30cm H₂O, the safety valve 3 will open and release the extra air. Therefore, the safety valve 3 protects the air reservoir 2 from over-pressuring.

Advantageously, the air reservoir 2 can be made of elastic material, and for example is a latex cuff or balloon. When filling the air reservoir 2, the air reservoir 2 will expand with the increase of the filled air, but remain no change once the air reservoir pressure reaches 30cm H₂O. This could be used as an indicator showing that the filling is enough and could be stopped.

In another preferable embodiment, and again with reference to Fig. 2, the pressure control device according to the present disclosure further comprises an adaptor 11, a third directional valve 4, and a check valve 5.

The adaptor 11 is connected to the Y port of a breathing machine 1 at one end and to the airway tube structure 100a at the other end, to form a breathing path G. The adaptor 11 is also connected to the check valve 5, which is in turn connected to the directional valve 4. The directional valve 4 is connected to the air reservoir 2. Therefore, a fifth air flowing path F is formed between the air reservoir 2 and the breathing machine 1 through the adaptor 11, the check valve 5 and the directional valve 4, in order to fill the air reservoir 2 once the air in the air reservoir 2 is not sufficient, i.e. the air reservoir pressure drops below a third predetermined pressure, for example 28cm H₂O.

The directional valve 4 is a 2-way, 2 positions, normally open directional valve with cracking pressure of 28cm H₂O, for example. When the air reservoir pressure is above 28cm H₂O, the directional valve 4 will close, which means that if the air reservoir pressure is below 28cm H₂O, the directional valve 4 will open. Therefore during the inspiration phase, if the ventilation pressure of the breathing machine is above 28cm H₂O, the air from the breathing machine can fill the air reservoir 2 until its pressure is above 28cm H₂O. This design can ensure the air reservoir being sufficiently filled while at the same time not causing leaks to the breathing machine.

The check valve 5 is used to allow the air to flow from the breathing machine while preventing reverse flow. It is to ensure that when the air reservoir is below 28cm H₂O and the directional valve 4 opens, the air in the air reservoir 2 will not flow to the breathing machine during the expiration phase.

In this way, the air reservoir 2 can be automatically refilled using the air from the breathing machine, therefore further ensuring the maintenance of the cuff pressure.

It should be understood that although the function and configuration of the pressure control device are described with the example of the cuff of a LM device, the pressure device can be used with the cuff of other medical device by simply reconfiguring the cracking pressure of the above mentioned valve.

Furthermore, it should be understood that the values of the pressure mentioned above, for example 20cm H₂O, 28cm H₂O and 30cm H₂O are only examples of the pressure and could be adapted according to the various conditions of the applications, to which the pressure control device is applied.

Furthermore, it should be understood that the specific types of valves 3-8 are only examples of the valves described in the embodiments and could be other types of valves, as long as they can achieve the same or similar functions as that of the above valves 3-8 respectively.

It should also be understood that the components, steps, and features of the various embodiments of the present disclosure can be used individually or combined with, replaced by other components, steps, and features of the embodiments of the present disclosure without depart from the scope of the present disclosure. The embodiments provided herein are not intended to be limited to the particular forms disclosed. Rather, the various embodiments may cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the following appended claims.

Claims

A pressure control device for maintaining the pressure level of a cuff of a medical device, comprising:

an air reservoir filled with air at a pressure between a first predetermined pressure and a second predetermined pressure that is higher than the first predetermined pressure；

a first valve, which is connected to the air reservoir at one end and to an inflating tube for the cuff at the other end so as to form a first air flowing path, wherein when the cuff pressure is below the first predetermined pressure, the first valve allows air in the air reservoir to flow to the cuff through the first air flowing path so as to increase the cuff pressure to a level above the first predetermined pressure； and

a second valve, which is connected to the air reservoir at one end and to the inflating tube for the cuff at the other end so as to form a second and parallel air flowing path, wherein when the cuff pressure is above the second predetermined pressure, the second valve allows air in the cuff to flow to the air reservoir through the second air flowing path so as to decrease the cuff pressure to a level below the second predetermined pressure.
The pressure control device as recited in claim 1, wherein the first valve is a directional valve of a 2-way, 2 positions, normally open type with a cracking pressure of the first predetermined pressure, which will open when the pressure in the cuff is below the first predetermined pressure and close when the pressure in the cuff is above the first predetermined pressure.
The pressure control device as recited in claim 1 or 2, wherein the second valve is a directional valve of a 2-way, 2 positions, normally close type with a cracking pressure of the second predetermined pressure, which will open when the pressure in the cuff is above the second predetermined pressure and close when the pressure in the cuff is below the second predetermined pressure.
The pressure control device as recited in claim 1, further comprise a third valve, which is connected to the inflating tube for the cuff at one end and to an inflation device at the other end so as to form a third air flowing path, wherein the third valve allows to inflate the cuff to a pressure between the first predetermined pressure and the second predetermined pressure when first inflating the cuff.
The pressure control device as recited in claim 4, wherein the third valve is a shut-off valve which is opened when first inflating the cuff.
The pressure control device as recited in claim 4 or 5, wherein the inflation device is also connected to the air reservoir so as to form a fourth air flowing path, so that simultaneously with the first inflation of the cuff the air reservoir is filled with air to the same pressure between the first predetermined pressure and the second predetermined pressure.
The pressure control device as recited in claim 1, further comprises a fourth valve, which is connected to the air reservoir so as to form a fifth air flowing path, wherein the fourth valve allows the pressure in the air reservoir to be maintained below the second predetermined pressure.
The pressure control device as recited in claim 7, wherein the forth valve is a safety valve which will open and release the extra air when the pressure in the air reservoir is above the second predetermined pressure.
The pressure control device as recited in claim 1, further comprises an additional air supply device connected to the air reservoir so as to form a fifth airway path, the additional air supply device supplies air to the air reservoir when the pressure in the air reservoir is below a third predetermined pressure between the first predetermined pressure and the second predetermined pressure.
The pressure control device as recited in claim 9, wherein the additional air supply device comprises an adaptor, a fifth valve, and a sixth valve,

wherein the adaptor is connected to a breathing machine at one end and to the fifth control means at the other end, the fifth control means is in turn connected to the sixth control means, which is in turn connected the air reservoir so as to form the fifth air flowing path.
The pressure control device as recited in claim 10, wherein the fifth valve prevents air from the air reservoir to flow to the breathing machine during the expiration phase, and when the pressure in the air reservoir is below the third predetermined pressure, the sixth valve allows air from the breathing machine to fill the air reservoir during inspiration phase until the pressure of the air reservoir reaches the third predetermined pressure.
The pressure control device as recited in claim 10, wherein the sixth valve is a directional valve of a 2-way, 2 positions, normally open type with a cracking pressure of the third predetermined pressure, which will open when the pressure in the air reservoir is below the third predetermined pressure and close when the pressure in the air reservoir is above the third predetermined pressure.
The pressure control device as recited claim 1, wherein the air reservoir is made of elastic material.
The pressure control device as recited in claim 13, wherein the air reservoir is a latex cuff or balloon.
The pressure control device as recited in claim 13, wherein the air reservoir will expand with the increase of the filled air, but remain no change once the pressure inside the air reservoir reaches the second predetermined pressure.
An endotracheal tube device with the pressure control device as recited in any one of the claims 1-15.
A laryngeal mask device with the pressure control device as recited in any one of the claims 1-15.