CN117980026A

CN117980026A - Breathing assembly

Info

Publication number: CN117980026A
Application number: CN202280054343.9A
Authority: CN
Inventors: 都铎·托马斯; 丹尼尔·里斯-惠比; 卡西姆·普尔曼德
Original assignee: Flexicare Group Ltd
Current assignee: Flexicare Group Ltd
Priority date: 2021-06-04
Filing date: 2022-06-01
Publication date: 2024-05-03

Abstract

A respiratory assembly (10) for supplying gas to a patient includes a patient end connector (12), a chamber end connector (14), and a coaxial conduit assembly (18) extending between the patient end connector and the chamber end connector. The coaxial conduit assembly includes inner and outer conduits (20, 22), the inner conduit (20) being disposed within the outer conduit (22) to define a first flow passage (24) within the inner conduit along the coaxial conduit assembly and a second flow passage (26) between the inner and outer conduits along the coaxial conduit assembly. In use, inhaled gas is transported along the first flow path and exhaled gas is transported along the second flow path, and the outer conduit is at least partially formed of a water permeable material which allows water to flow therein.

Description

Breathing assembly

Technical Field

The present disclosure relates to respiratory assemblies.

Background

A patient with impaired spontaneous respiratory ability may support breathing through the respiratory system (i.e., mechanical ventilation). Mechanical ventilation uses externally generated positive air pressure to create a pressure gradient in the lungs, allowing air to flow in. This pressure gradient varies periodically to simulate the normal breathing of the patient. When mechanical ventilation is used, the patient must be connected to a source of pressure change (e.g., a ventilator) through the respiratory system.

In such assisted/assisted breathing, particularly in medical applications, the respiratory system needs to be able to supply gas (referred to as inhaled gas) to the patient at a suitable temperature and humidity level. In known respiratory systems, the high humidity of the gas being delivered can cause condensation to accumulate within the conduit.

It is an object of the present disclosure to overcome or at least alleviate one or more of the problems associated with the prior art.

Disclosure of Invention

In a first aspect, provided herein is a respiratory assembly for supplying gas to a patient, the respiratory assembly comprising: a patient end connector configured to be connectable to an airway device, a chamber end connector configured to be connectable to a humidification chamber and comprising an inhalation inlet for receiving humidified inhalation gas from the humidification chamber, a coaxial conduit assembly extending between the patient end connector and the ventilator end connector and comprising an inner conduit and an outer conduit defined by an inner conduit wall and an outer conduit wall respectively, the inner conduit wall being disposed within the outer conduit wall so as to define a first flow path within the inner conduit along the coaxial conduit assembly and a second flow path between the inner conduit and the outer conduit along the coaxial conduit assembly, wherein the respiratory assembly is configured such that in use inhaled gas is conveyed along the first flow path and exhaled gas is conveyed along the second flow path, and wherein the outer conduit wall is formed at least in part of a water permeable material that allows water to flow therethrough.

It should be appreciated that the airway device may be a subglottal airway (e.g., endotracheal tube, endobronchial airway, tracheostomy tube) device or a supraglottic airway (e.g., oropharyngeal airway, nasopharyngeal airway, and laryngeal mask airway) device.

In this arrangement, the second flow path provides a thermal barrier between the inhaled gas in the first flow path and ambient air, which is advantageous in maintaining the inhaled gas at a desired temperature.

It has been found that by providing an outer conduit formed of a water permeable material that allows water to flow through, the accumulation of water in the second flow channel can be reduced, and also the accumulation of water in the respirator can be reduced.

The water permeable material may be configured to allow liquid water to flow therethrough and restrict the flow of breathing gas therethrough.

The water permeable material may be configured to restrict the flow of liquid water therein.

It has been found that the accumulation of water and water vapour in the second flow channel can be reduced by providing an outer conduit formed of a water permeable material which allows water to flow through and which allows but restricts the flow of liquid water and/or gas.

The outer conduit wall is formed substantially entirely of the water permeable material, e.g., the entire outer conduit wall is formed of the water permeable material.

It has been found that this increases the air permeability of the outer conduit, thereby further reducing the accumulation of water and water vapour in the second flow path.

The outer catheter wall may be self-supporting.

This eliminates the need for additional structural members to be mounted on the outer catheter to provide the necessary structural rigidity/stiffness.

The outer catheter wall may comprise stiffening means.

This increases the structural rigidity/stiffness of the outer catheter.

The stiffening means may comprise a corrugated region of the outer conduit wall, optionally the corrugated region extending over the entire elongate length of the outer conduit wall.

The outer conduit may be configured to support the inner conduit.

The coaxial catheter assembly may include a spacer between the inner catheter wall and the outer catheter wall.

The spacer means may comprise at least one spacer assembly disposed along the elongate length of the coaxial catheter assembly.

Each spacer assembly may include a plurality of spacer members located between the inner conduit wall and the outer conduit wall.

The plurality of spacer members may be equally spaced around the inner conduit wall.

The spacer member may protrude inwardly (i.e. radially inwardly) from the outer conduit wall.

The outer conduit may define an outer conduit wall having a thickness in the range of 0.2mm to 1.0mm, alternatively in the range of 0.3mm to 0.9 mm.

It has been found that by providing the outer conduit wall within this range, it is possible to provide the outer conduit with sufficient rigidity/stiffness while making the outer conduit wall suitably water permeable.

The water permeable material may be formed of an amphiphilic material.

It has been found that this increases the permeability of the outer conduit to water vapour and liquid water, thereby reducing the accumulation of water and water vapour in the second flow path. The water permeable material may be formed from a hydrophobic and hydrophilic block copolymer.

The water permeable material may be formed from a hydrophobic and hydrophilic polyethylene oxide, polybutylene terephthalate (PBT) block copolymer.

It has been found that this increases the permeability of the outer conduit to water vapour and liquid water, thereby reducing the accumulation of water and water vapour in the second flow path.

The outer conduit wall may be configured to absorb water vapor and liquid water.

It has been found that this further increases the permeability of the outer conduit to water vapour and liquid water, thereby further reducing the accumulation of water and water vapour in the second flow path.

The inner catheter wall may not be sufficiently strong to be self-supporting.

The inner catheter wall may be formed of a thermoplastic elastomer.

The inner conduit wall may be configured to prevent water and water vapor from flowing therethrough.

The inner conduit wall may be configured to prevent gas flow therethrough.

This arrangement enables the breathing assembly to actively, rather than passively, control the humidity of the inhaled gas.

The inner catheter may comprise stiffening means.

The combination of the stiffening means enables the thickness of the inner catheter wall to be reduced, thereby reducing the amount of material in the inner catheter.

The stiffening means may comprise stiffening ribs extending around the inner conduit wall, for example, helically extending around the inner conduit wall.

It was found that this further improvement stiffened the inner catheter.

The breathing assembly may include a heating device configured and arranged to heat the inhalation gas flowing along the first flow path, wherein the heating device comprises a first heating member embedded within an inner conduit wall of the inner conduit.

It has been found that this may improve the packaging of the breathing assembly. By arranging the first heating element within the wall of the inner conduit wall, obstruction to the flow of the suction gas is reduced.

The heating means may be configured such that the inhaled gas maintains an absolute humidity of at least 33 mg/l.

The first heating member may extend around the inner conduit wall of the inner conduit, e.g. helically around the inner conduit wall of the inner conduit.

It has been found that arranging the first heating element as a spiral around the wall of the inner conduit may provide more uniform heating of the inhaled gas flowing within the inner conduit.

The first heating member may be configured and arranged to heat inhaled gas flowing along the first flow channel and to heat exhaled gas flowing along the second flow channel.

Arranging the first heating element to heat both the inhaled and exhaled gases may reduce or eliminate the need for a separate heating device for the exhaled gases.

The heating power of the first heating member may be in the range 25 to 40 watts, alternatively in the range 27 to 35 watts, alternatively in the range 29 to 33 watts, for example about 31 watts.

The first heating member may be configured to heat the suction gas to a temperature in the range of 36 ℃ to 41 ℃, for example, a temperature in the range of 37 ℃ to 40 ℃.

The inner conduit wall may include a stiffening rib extending therearound, and the first heating member is embedded within the stiffening rib.

It has been found that arranging the first heating element within the stiffening rib may improve the encapsulation of the breathing assembly.

The respiratory assembly may include a catheter mount coupled to the patient-end connector.

The respiratory assembly may include a second temperature sensor at or near the patient-end connection.

The second temperature sensor may be integrally formed with the patient-end connector. Or the second temperature sensor may be separate from and connectable to the patient-end connector (i.e., the second temperature sensor may be reusable).

The inner conduit wall may include a stiffening rib extending therearound and one or more wires connected to the second temperature sensor are embedded within the stiffening rib.

It has been found that the placement of the wires within the stiffening ribs may improve the packaging of the respiratory assembly.

The breathing assembly may include a first temperature sensor at or near the ventilator end connector.

The first temperature sensor may be integrally formed with the ventilator end connector. Or the first temperature sensor may be separate from and connectable to the ventilator end connector (i.e., the first temperature sensor may be reusable).

The heating device may comprise a second heating member configured to heat the gas flowing along the second flow channel, wherein the second heating element is located in the second flow channel or embedded within the wall of the outer conduit.

The second heating member may be configured to heat the outer conduit wall to a predetermined temperature range or predetermined temperature.

This allows the second heating member to heat the outer conduit wall to a temperature or temperature range to maximize its permeability to water.

The heating power of the second heating member may be in the range of 5 to 40 watts.

The breathing assembly may include an exhalation outlet for delivering exhaled gas out of the breathing assembly, wherein the exhalation outlet is disposed at or near the patient end connector.

The respiratory assembly may include a flow valve at or near an interface between the coaxial conduit assembly and the patient-end connector, the flow valve configured to allow inhaled gas to flow from the first flow channel into the patient-end connector and to direct exhaled gas from the patient-end connector to the coaxial conduit assembly and into the second flow channel.

In a second aspect, provided herein is a respiratory assembly for supplying gas to a patient, the respiratory assembly comprising: a patient-end connector configured to be connectable to an airway device; a ventilator end connector configured to be connectable to a humidification chamber and comprising an inhalation inlet for receiving humidified inhalation gas from the humidification chamber; a coaxial conduit assembly extending between the patient end connector and the ventilator end connector and comprising inner and outer conduits defined by inner and outer conduit walls, respectively, the inner conduit wall being disposed within the outer conduit wall so as to define a first flow channel within the inner conduit wall along the coaxial conduit assembly and a second flow channel between the inner conduit wall and the outer conduit wall along the coaxial conduit assembly, wherein in use the first and second flow channels each deliver one of inhaled or exhaled gas; and a heating device for heating gas flowing along the coaxial conduit assembly, wherein the heating device comprises a first heating member embedded within an inner conduit wall, and the first heating member is configured and arranged to heat gas flowing along the first flow channel and the second flow channel.

It has been found that this may improve the packaging of the breathing assembly. By arranging the first heating element within the wall of the inner conduit (i.e. on the outer surface of the wall) the obstruction to the flow of the suction gas is reduced.

Arranging the first heating element to heat both the inhaled and exhaled gases may reduce the amount of heat that needs to be provided by a dedicated exhaled gas heating device.

The first heating member may extend around the inner conduit wall.

This has been found to provide more uniform heating of the gas flowing within the coaxial conduit assembly.

The first heating member may be helically wound around the inner conduit wall.

The first heating member may comprise two spaced apart heating elements, such as heating wires, embedded within the reinforcing bars.

By providing two heating elements, the feed and return current paths can be contained within the same assembly.

The heating device may include a second heating member configured and arranged to heat the gas flowing along the second flow channel, wherein the second heating member is located in the second flow channel or embedded within the outer conduit wall.

This arrangement helps to further heat the exhaled gas to reduce the accumulation of water and water vapour in the second flow channel, or to heat the inhaled gas to ensure that it is provided to the patient at the correct temperature.

Providing a dedicated heater for the second flow path allows the gas within the inner and outer flow paths to be heated to different temperatures.

The breathing assembly may be configured such that, in use, inhaled gas is delivered along the first flow path and exhaled gas is delivered along the second flow path.

The outer conduit wall may be formed at least in part from a water permeable material configured to allow water to flow therethrough and restrict breathing gas flow therethrough.

It has been found that the accumulation of water and water vapour in the second flow channel can be reduced by providing an outer conduit formed of a water permeable material which allows water to flow through and which allows but restricts the flow of liquid water through.

The entire outer conduit wall may be formed of a water permeable material.

The outer catheter wall may be self-supporting.

The outer conduit wall may be configured to support the inner conduit wall.

The outer catheter may comprise stiffening means.

This increases the structural rigidity/stiffness of the outer catheter.

The stiffening means may comprise a corrugated region of the outer conduit wall.

The corrugated region may extend over the entire elongate length of the outer catheter wall.

It has been found that by providing the outer conduit wall within this range, sufficient strength can be provided to the outer conduit while making the outer conduit wall suitably water permeable.

The inner catheter wall may not be sufficiently strong to be self-supporting.

The inner catheter wall may be formed of a thermoplastic elastomer.

The inner conduit may be configured to prevent liquid water and air/gas from flowing therethrough.

The inner catheter wall may comprise stiffening means.

It was found that this further improvement stiffened the inner catheter.

It has been found that this may improve the packaging of the breathing assembly.

Drawings

Embodiments will be described below with reference to the accompanying drawings, in which:

Fig. 1 is an isometric view of a portion of a respiratory assembly according to an embodiment.

Fig. 2 is a side cross-sectional view of the respiratory assembly of fig. 1.

Fig. 3 is a partial cross-sectional view of the respiratory assembly of fig. 1.

Fig. 4 is a partial cross-sectional view of the inner and outer conduits of the respiratory assembly of fig. 1.

Fig. 5 is a partial cross-sectional view of an outer conduit of the respiratory assembly of fig. 1.

Fig. 6A and 6B are side and side cross-sectional views of an inner conduit of the respiratory assembly of fig. 1.

Detailed Description

Referring first to fig. 1 and 2, there is shown a respiratory assembly, indicated generally at 10, for supplying gas to a patient (not shown).

The respiratory assembly 10 includes a patient-end connector 12. Although not shown, the respiratory assembly 10 may include a catheter mount that is connected to the patient-end connector 12. The patient-side connector 12 is configured to be connectable to an airway device. The patient-end connector 12 may be configured to be connectable to a catheter mount. After installation, the conduit mount delivers inhaled gas to the airway device and exhaled gas from the airway device. Patient-side connector 12 may be configured to be directly connectable to an airway device, such as a subglottal airway (e.g., endotracheal tube, intrabronchial airway, tracheostomy tube) device or a supraglottic airway (e.g., oropharyngeal airway, nasopharyngeal airway, and laryngeal mask airway) device, or any other suitable airway device.

The respiratory assembly 10 includes a chamber end connector 14. Although not shown, the respiratory assembly 10 may be connected to a humidification chamber that is connected to the chamber-end connector 14. In other words, the chamber-end connector 14 is configured to be connectable to a humidification chamber. The chamber-end connection 14 includes an inhalation inlet 16 for receiving inhalation gas from the humidification chamber.

The respiratory assembly 10 includes a coaxial conduit assembly 18. A coaxial catheter assembly 18 extends between the patient end connector 12 and the chamber end connector 14. The coaxial catheter assembly 18 includes an inner catheter 20 and an outer catheter 22. The inner conduit 20 is defined by inner conduit walls. The outer conduit 22 is defined by an outer conduit wall. The inner conduit 20 is disposed within the outer conduit 22 to define a first flow passage 24 within the inner conduit 20 along the coaxial conduit assembly 18 and a second flow passage 22 between the inner conduit 20 and the outer conduit 20 along the coaxial conduit assembly 18.

The respiratory assembly 10 includes an exhalation outlet 28. The exhalation outlet 28 is configured to deliver exhaled gas out of the respiratory assembly 10. In the arrangement shown, the exhalation outlet 28 is provided on a collar 30 interposed between the chamber end connector 14 and the coaxial conduit assembly 18. In alternative arrangements, the exhalation outlet 28 may be provided on the chamber-end connector 14 or may be provided on a region near the coaxial conduit assembly 18 (i.e., near the chamber-end connector 14). In other words, the exhalation outlet 28 may be located at or near the chamber end connector 14.

The respiratory assembly 10 includes an electrical connection 32 for connection to a power source. An electrical connection 32 connects the respiratory assembly 10 to a control system (not shown). As will be discussed in more detail below, electrical connectors 32 are connected to various components of respiratory assembly 10 such that components of respiratory assembly 10 may be connected to a control system and/or such that electrical power may be provided to the components of respiratory assembly 10.

Although not shown, the respiratory assembly 10 may include a flow valve. By providing a flow valve, inhaled gas may be allowed to flow from the coaxial conduit assembly 18 into the patient-end connector 12 and exhaled gas is directed from the patient-end connector 12 to the coaxial conduit assembly 18 into the desired first flow channel 24 or second flow channel 26. Typically, the flow valve is provided at the ventilator (not shown) to reduce the complexity of the breathing assembly. Or the flow valve may be disposed at or near the interface between the coaxial conduit assembly 18 and the patient-end connector 12.

In the arrangement shown, the respiratory assembly 10 is configured such that, in use, inhaled gas is delivered along the first flow path 24 and exhaled gas is delivered along the second flow path 26. In this arrangement, the second flow path 26 (i.e., the outer flow path) provides a thermal barrier between the inhaled gas in the first flow path 24 and ambient air, which facilitates maintaining the inhaled gas at a desired temperature (e.g., about 37 ℃). However, it should be appreciated that in alternative arrangements, the respiratory assembly 10 may be configured such that, in use, inhaled gas is delivered along the second flow path 26 and exhaled gas is delivered along the first flow path 24.

The respiratory assembly 10 includes a first temperature sensor 36. The first temperature sensor 36 is a temperature sensor. The first temperature sensor 36 is located at or near the chamber end connection 14. In the illustrated embodiment, the first temperature sensor 36 is integrally formed with the chamber-end connector 14. However, it should be appreciated that in alternative arrangements, the first temperature sensor 36 may be detachable, e.g., disposable. The first temperature sensor 36 is connected to the electrical connection 32. In other words, the first temperature sensor 36 may be connected to a control system (not shown).

The respiratory assembly 10 includes a second temperature sensor 34. The second temperature sensor 34 is a temperature sensor. A second temperature sensor 34 is located at or near the patient end connection 12. In the illustrated embodiment, the second temperature sensor 34 is integrally formed with the patient-side connector 12. However, it should be appreciated that in alternative arrangements, the second temperature sensor 34 may be detachable, e.g., disposable. The second temperature sensor 34 is connected to the electrical connection 32. In other words, the second temperature sensor 34 may be connected to a control system (not shown) and/or a power source via the electrical connection 32. The second temperature sensor 34 is connected to an electrical connector 32, such as a wire embedded within the wall of the inner conduit 20 or outer conduit 22, via one or more wires (not shown) extending along the coaxial conduit assembly 18.

Referring now to fig. 3, coaxial catheter assembly 18 includes an inner catheter 20 and an outer catheter 22. The outer conduit wall 22 is at least partially formed of a water permeable material. A water permeable material is a material configured to allow water to flow through. It should be appreciated that a substantial portion of the outer conduit wall 22 may be formed of a water permeable material. In this arrangement, the outer conduit wall 22 is formed substantially entirely of water permeable material, e.g., the entire outer conduit wall 22 is formed of water permeable material.

The water permeable material may also be configured to restrict liquid water flow therethrough and/or to restrict gas flow therethrough. It has been found that forming the outer conduit wall from a material that allows water to flow through and allows but restricts the flow of liquid water and/or gas can reduce the accumulation of water and water vapor in the second flow path. The restriction of liquid water and/or gas passage is reduced to within the clinical requirements of respirator requirements, as defined in standard ISO5367 anesthesia and breathing apparatus-breathing apparatus and connection.

The outer catheter wall 22 is self-supporting. In other words, the outer conduit 22 is sufficiently strong to be self-supporting. In this way, there is no need to mount/attach a separate reinforcing member to the outer conduit 22 (which may detract from the breathability of the outer conduit 22). This helps to increase the water permeable area of the outer conduit 22. The outer conduit 22 defines an outer conduit wall having a thickness in the range of 0.2mm to 1.0mm, alternatively in the range of 0.3mm to 0.9 mm.

The outer catheter wall 22 includes stiffening means. In other words, the outer conduit wall 22 is arranged to define a reinforcing structure. This increases the structural strength of the outer catheter 22. The stiffening means is provided in the form of a corrugated region 38 of the outer conduit (i.e. the conduit wall of the outer conduit is corrugated). In the arrangement shown, the corrugated region extends the entire elongate length of the outer conduit 22. The corrugations in the outer conduit 22 act to increase the total surface area of the water permeable outer conduit 22, thereby increasing the area within the outer flow path available for water to flow out of the respiratory assembly 10.

The water permeable material of the outer conduit 22 is formed of an amphiphilic material. The water permeable material is formed from an amphiphilic block copolymer. In other words, the water permeable material is formed from a hydrophobic and hydrophilic block copolymer. One example of such a material is a hydrophobic and hydrophilic polyethylene oxide block copolymer. Further examples of suitable water permeable materials are: nafion (RTM), sympatex (RTM), arnitel (RTM), diaplex (RTM), and water permeability Hytrel (RTM). It should also be appreciated that any suitable water permeable material may be used.

In some arrangements, the water permeable material may be configured to absorb water vapor and liquid water. This has been found to further increase the permeability of the outer conduit 22 to water vapour and liquid water, thereby further reducing the accumulation of water and water vapour in the second flow path.

In this arrangement, the inner conduit wall 20 is not sufficiently strong to be self-supporting. In other words, the conduit wall of the inner conduit may have a low wall thickness (i.e., less than the wall thickness of the outer conduit 22) such that the inner conduit 20 is not sufficiently strong to be self-supporting.

The inner conduit wall 20 is configured to prevent water and water vapor from flowing therethrough. The inner conduit wall 20 may be configured to prevent gas flow therethrough. Because there is no moisture transfer between the inhaled and exhaled gases, the humidity of the inhaled gas can be actively controlled by the respiratory assembly 10 rather than passively. In this arrangement, the inner conduit wall 20 is formed from a thermoplastic elastomer. However, it should be appreciated that in alternative arrangements any suitable material may be used, such as a thermoplastic extrudable polymer, for example polyethylene or polyurethane.

The inner conduit wall 20 is provided with stiffening means. The incorporation of reinforcing means on the inner conduit 20 enables the thickness of the wall of the inner conduit 20 to be reduced, thereby reducing the amount of material in the inner conduit 20. The stiffening means is provided in the form of stiffening ribs 40. The reinforcing ribs 40 extend around the inner catheter 20. In the arrangement shown, the stiffening ribs 40 extend helically (i.e., spiral) around the inner catheter 20.

Referring to fig. 4 and 5, the coaxial catheter assembly 18 includes a spacer between the inner catheter wall 20 and the outer catheter wall 22. The spacing means comprises a spacing assembly 48. The spacer may be provided with an array of spacer assemblies 48 along the elongate length of the coaxial catheter assembly 18.

Each spacer assembly 48 has a plurality of spacer members 50 positioned between the inner conduit 20 and the outer conduit 22. A plurality of spacing members 50 are equally spaced around the inner catheter 20. In the arrangement shown, four spacer members 50 are provided, but it should be appreciated that any suitable number of spacer members 50 may be provided, such as three, five or more spacer members 50.

The spacer member 50 is configured and arranged to support the inner catheter 22. In other words, the outer conduit 22 is configured to support the inner conduit 20. In the arrangement shown, the spacing members 50 project inwardly (i.e., radially inward) from the outer conduit wall 22. In alternative arrangements, the spacer member 50 may be separate from the inner catheter 20 and/or the outer catheter 22, but attached to the inner catheter 20 and/or the outer catheter 22.

Referring to fig. 6A and 6B, the respiratory assembly 10 includes a heating device for heating the gas flowing along the coaxial conduit assembly 18.

The heating means comprises a first heating member 42. The first heating member 42 is configured and arranged to heat the gas flowing along the first flow channel 24 and the second flow channel 26. The first heating member is configured to heat the inhalation gas to a predetermined temperature within a predetermined temperature range. The heating means is configured such that the inhaled gas maintains an absolute humidity of at least 33 mg/l. In the present arrangement, the first heating member is configured to heat the inhalation gas to a temperature in the range of 36 ℃ to 41 ℃, for example 37 ℃ to 40 ℃. In the arrangement shown, the first heating member is configured to heat the suction gas in the first flow channel to a temperature in the range 36 ℃ to 41 ℃, for example 37 ℃ to 40 ℃. The heating power of the first heating member is in the range 25 to 40 watts, or in the range 27 to 35 watts, alternatively in the range 29 to 33 watts, for example about 31 watts.

The first heating member 42 is provided in the form of two spaced apart heating elements 44, such as heating wires. The first heating member 42 is embedded in the wall of the inner conduit wall 20. The first heating member 42 extends around the inner conduit wall of the inner conduit 20, e.g. helically around the inner conduit wall of the inner conduit 20. In the arrangement shown, the first heating member 42 is embedded within the stiffening rib 40. In other words, the inner catheter 20 includes the reinforcing rib 40 having the first heating member 42 therein.

One or more wires 46 are embedded in the wall of the inner conduit wall 20. The electrical wires 46 provide an electrical connection between the second temperature sensor 34 and the electrical connection 32. In the illustrated embodiment, two wires 46 are embedded in the wall of the inner catheter 20. The electrical wire 46 extends around the inner conduit wall of the inner conduit 20, e.g., helically extends around the inner conduit wall of the inner conduit 20. In the arrangement shown, one or more wires 46 are embedded within the reinforcing rib 40. It should be appreciated that in alternative arrangements, the one or more wires 46 may be embedded in the wall of the inner conduit 20, but not embedded within the stiffening rib 40 of the inner conduit 20, or may be located within the second flow channel 26.

The heating means may comprise a second heating member. The second heating member may be configured to heat the gas flowing along the second flow channel 26. Providing a dedicated heater for the second flow path 26 allows the gas within the inner flow path 24 and the outer flow path 26 to be heated to different temperatures. The second heating member is configured to heat the outer conduit wall to a predetermined temperature range or predetermined temperature. The water permeability of the material forming the outer conduit 22 will depend on the temperature of the material. Providing a heater configured to heat the wall of the outer conduit 22 enables the second heating member to heat the wall of the outer conduit 22 to a temperature or temperature range to maximize its permeability to water. It should be appreciated that the second heating element may be located in the second flow channel 26 or may be embedded within the wall of the outer conduit 22. The heating power of the second heating member may be in the range of 5 to 35 watts.

Although not shown, it should be understood that the breathing assembly may be connected to the ventilator and humidification chamber as part of the breathing system. In such a respiratory system, the humidification chamber would be disposed between the respirator and the chamber end connection 14.

During inspiration, a ventilator (not shown) vents through the limb/conduit to the humidification chamber. The inhaled gas flowing through the humidification chamber is heated and humidified. The inhaled gas then flows through the chamber end connector 14 and into the coaxial conduit assembly 18. The inhalation gas is directed to flow along an inhalation flow path (e.g., along the first flow path 24 in the illustrated embodiment) and to the patient-side connector 12. The inhalation gas flows through the patient end connection 12 and is delivered to the patient, for example, via a catheter mount.

During exhalation, exhaled gas is delivered from the patient to the patient-end connector 12, such as through a conduit mount. The exhaled gas is then directed to flow along an exhalation flow path (e.g., along the second flow path 26 in the illustrated embodiment) through a series of respirator valves that inhibit flow in the inhalation path (but optionally also through flow valves in the patient-end connection). The exhaled gas then flows along the coaxial conduit assembly 18 and out of the respiratory assembly 10 through the exhalation outlet 28, releasing the exhaled gas into the atmosphere.

Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope as defined in the following claims.

Claims

1. A respiratory assembly for supplying gas to a patient, the respiratory assembly comprising:

a patient-end connector configured to be connectable to an airway device,

A chamber end connector configured to be connectable to a humidification chamber and including an inhalation inlet for receiving humidified inhalation gas from the humidification chamber, and

A coaxial conduit assembly extending between the patient end connector and the ventilator end connector and including inner and outer conduits defined by inner and outer conduit walls, respectively, the inner conduit wall being disposed within the outer conduit wall to define a first flow passage within the inner conduit along the coaxial conduit assembly and a second flow passage between the inner and outer conduits along the coaxial conduit assembly,

Wherein the breathing assembly is configured such that, in use, inhaled gas is transported along the first flow path and exhaled gas is transported along the second flow path, and

Wherein the outer conduit wall is at least partially formed of a water permeable material that allows water to flow therethrough.

2. The respiratory assembly of claim 1, wherein the water permeable material is configured to allow liquid water to flow therethrough and is configured to restrict flow of respiratory gases therethrough.

3. A respiratory assembly according to claim 1 or 2, wherein substantially all of the outer conduit wall is formed of the water permeable material, e.g. the entire outer conduit wall is formed of the water permeable material.

4. The respiratory assembly of any preceding claims, wherein the outer conduit wall is self-supporting; optionally, the outer catheter comprises stiffening means.

5. The respiratory assembly of any preceding claims, wherein the outer conduit wall comprises a corrugated region; optionally, the corrugated region extends over the entire elongate length of the outer catheter wall.

6. The respiratory assembly of any preceding claims, wherein the outer conduit is configured to support the inner conduit.

7. A respiratory assembly according to any preceding claims, wherein the coaxial conduit assembly comprises a spacing means between the inner conduit wall and the outer conduit wall, and the spacing means comprises a plurality of spacing members projecting inwardly from the outer conduit wall.

8. A respiratory assembly according to any preceding claims, wherein the coaxial conduit assembly comprises a spacing means between the inner conduit wall and the outer conduit wall, and the spacing means comprises at least one spacing assembly disposed along an elongate length of the coaxial conduit assembly, and the or each spacing assembly comprises a plurality of spacing members between the inner conduit and the outer conduit; optionally, the plurality of spacer members are equally spaced around the inner conduit.

9. The respiratory assembly of any preceding claims, wherein the water permeable material is formed from an amphiphilic material.

10. The respiratory assembly of claim 9, wherein the water permeable material is formed from a hydrophobic and hydrophilic block copolymer; optionally, the water permeable material is formed from a hydrophobic and hydrophilic polyethylene oxide block copolymer.

11. The respiratory assembly of any preceding claims, wherein the outer conduit wall is configured to absorb water vapor and liquid water.

12. The respiratory assembly of any preceding claims, wherein the inner conduit wall is configured to prevent water and water vapor from flowing therethrough; optionally, the inner conduit wall is configured to prevent gas flow therethrough.

13. A respiratory assembly according to any preceding claims, wherein the inner conduit comprises stiffening means; optionally, the stiffening means comprises stiffening ribs extending around the inner conduit wall, for example, helically extending around the inner conduit wall.

14. The respiratory assembly of any preceding claims, comprising a heating device configured and arranged to heat the inhaled gas flowing along the first flow channel, wherein the heating device comprises a first heating member embedded within the inner conduit wall, optionally the inner conduit wall comprises a stiffening rib extending therearound, and wherein the first heating member is embedded within the stiffening rib.

15. A respiratory assembly according to claim 14, wherein the first heating member extends around the inner conduit wall, for example helically around the inner conduit wall.

16. The respiratory assembly of claim 14 or 15, wherein the first heating member is configured and arranged to heat inhaled gas flowing along the first flow channel and to heat exhaled gas flowing along the second flow channel.

17. A respiratory assembly according to any preceding claims, comprising a conduit mount connected to the patient-end connector.

18. The respiratory assembly of any preceding claims, wherein the heating device comprises a second heating member configured to heat gas flowing along the second flow channel, wherein the second heating member is located in the second flow channel or embedded within the outer conduit wall.

19. A respiratory assembly according to any preceding claims, comprising an exhalation outlet for delivering exhaled gas out of the respiratory assembly, wherein the exhalation outlet is provided at or near the patient end connection.

20. A respiratory assembly for supplying gas to a patient, the respiratory assembly comprising:

a patient-end connector configured to be connectable to an airway device;

A ventilator end connector configured to be connectable to a humidification chamber and comprising an inhalation inlet for receiving humidified inhalation gas from the humidification chamber;

A coaxial conduit assembly extending between the patient end connector and the ventilator end connector and comprising inner and outer conduits defined by inner and outer conduit walls, respectively, the inner conduit wall being disposed within the outer conduit wall so as to define a first flow channel within the inner conduit wall along the coaxial conduit assembly and a second flow channel between the inner conduit wall and the outer conduit wall along the coaxial conduit assembly, wherein in use the first and second flow channels each deliver one of inhaled or exhaled gas; and

Heating means for heating gas flowing along the coaxial conduit assembly,

Wherein the heating device comprises a first heating member embedded within the inner conduit wall and the first heating member is configured and arranged to heat gas flowing along the first flow channel and the second flow channel.

21. A respiratory assembly according to claim 20, wherein the first heating member extends around the inner conduit wall, for example helically around the inner conduit wall.

22. The respiratory assembly of claim 20 or 21, wherein the inner conduit wall includes a stiffening rib extending therearound, and wherein the first heating member is embedded within the stiffening rib; optionally, the first heating member comprises two spaced apart heating elements, such as heating wires, embedded within the stiffener.

23. The respiratory assembly of any one of claims 20-22, wherein the first heating member has a heating power in the range of 25 to 40 watts; alternatively, the heating power is in the range of 27 to 35 watts, in the range of 29 to 33 watts, for example about 31 watts.

24. A respiratory assembly according to any of claims 20 to 23, wherein the respiratory assembly is configured such that in use inhaled gas is transported along the first flow path and exhaled gas is transported along the second flow path.

25. The respiratory assembly of claim 24, wherein the first heating member is configured to heat the inhalation gas to a temperature in the range of 36 ℃ to 41 ℃, such as a temperature in the range of 37 ℃ to 40 ℃.

26. The respiratory assembly of any one of claims 20 to 25, wherein the heating device comprises a second heating member configured and arranged to heat gas flowing along the second flow channel, and

Wherein the second heating member is located in the second flow channel or embedded within the outer conduit wall.

27. The respiratory assembly of any preceding claims, wherein the outer conduit wall is formed at least in part from a water permeable material configured to allow water to flow therethrough and restrict flow of respiratory gases therethrough; optionally, the entire outer conduit wall is formed of a water permeable material.

28. The respiratory assembly of claims 26 and 27, wherein the second heating member is configured to heat the outer conduit wall to a predetermined temperature range or predetermined temperature.

29. The respiratory assembly of any one of claims 26-28, wherein the second heating member has a heating power in the range of 5 to 40 watts.

30. The respiratory assembly of any one of claims 20 to 29, comprising a first temperature sensor at or near the ventilator end connection and/or comprising a second temperature sensor at or near the patient end connection.