Medical tube and method of manufacturing the same

Abstract

The present disclosure relates to medical tubing and methods of manufacturing medical tubing. The tubing can be a composite structure made from two or more dissimilar components that are helically wound to form an elongate tube. For example, one of the components can be a helically wound elongate hollow body, and the other component can be an elongate structural component that is also helically wound between the turns of the helically wound hollow body. However, the tubing need not be made from dissimilar components. For example, an elongate hollow body formed (e.g., extruded) from a single material can be helically wound to form an elongate tube. The elongate hollow body itself can have thin-walled portions and relatively thicker or more rigid reinforcing portions in its transverse cross-section. The tubes can be incorporated into various medical circuits, or can be used for other medical purposes.

Description

[0001] This application is a divisional application of the application patent application with the application date of December 4, 2013, the application number of 201811092715.9 and the invention name of "Medical Tube and Methods of Manufacture".

[0002] Cross-references

[0003] This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 61 / 733,359, filed December 4, 2012, entitled MEDICAL TUBES AND METHODS OF MANUFACTURE; U.S. Provisional Application No. 61 / 733,360, filed December 4, 2012, entitled MEDICAL TUBES AND METHODS OF MANUFACTURE; U.S. Provisional Application No. 61 / 877,622, filed September 13, 2013, entitled MEDICAL TUBES AND METHODS OF MANUFACTURE; U.S. Provisional Application No. 61 / 877,566, filed September 13, 2013, entitled HUMIDIFICATION SYSTEM; U.S. Provisional Application No. 61 / 877,784, filed September 13, 2013, entitled CONNECTIONS FOR HUMIDIFICATION SYSTEM; and U.S. Provisional Application No. 61 / 877,736, filed September 13, 2013, entitled ZONE HEATING FOR RESPIRATORY CIRCUITS, each of which is incorporated by reference herein in its entirety.

[0004] In addition, PCT Application No. PCT / IB2012 / 001786, filed May 30, 2012, entitled MEDICAL TUBES AND METHODS OF MANUFACTURE, is also incorporated by reference herein in its entirety. TECHNICAL FIELD

[0005] The present disclosure relates generally to tubes suitable for medical use, and in particular to tubes for use in medical circuits suitable for providing gases to and / or removing gases from a patient, such as in positive airway pressure (PAP), respirators, anesthesia, ventilators, and insufflation systems. BACKGROUND

[0006] In medical circuits, different components carry warm and / or humidified gases to and from a patient. For example, in some respiratory circuits, such as PAP or assisted breathing circuits, gases inhaled by a patient are delivered from a heated humidifier through an inspiratory tube. As another example, a tube can deliver humidified gases, often C02, into the abdominal cavity in an insufflation circuit. This can help prevent "dehydration" of the patient's internal organs, and can reduce the amount of time needed for post-surgical recovery. Unheated tubes can lose a significant amount of heat to natural cooling. This cooling can cause unwanted condensation or "rainout" to form in the direction of length along the tube carrying warm, humidified air. There is also a need for tubes that can be insulated from heat loss and that, for example, can have improved temperature and / or humidity control in medical circuits. It is therefore an object of the present invention to overcome or ameliorate one or more disadvantages of the prior art or to at least provide the public with a useful choice. SUMMARY

[0007] Medical tubes and methods of making medical tubes are disclosed herein in various embodiments. In some embodiments, the tubes can be composite structures made from two or more distinct components that are helically wound to form an elongate tube. For example, one of the components can be a helically wound elongate hollow body, and the other component can be an elongate structural component that is also helically wound between turns of the helically wound hollow body. In other embodiments, the tubes need not be made from distinct components. For example, an elongate hollow body formed (e.g., extruded) from a single material can be helically wound to form an elongate tube. The elongate hollow body itself can have thin-walled portions and relatively thicker or more rigid reinforcing portions in its transverse cross-section. The tubes can be incorporated into various medical circuits, or can be used for other medical purposes.

[0008] In at least one embodiment, a composite tube can include a first elongate member including a hollow body helically wound to at least partially form an elongate tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall around the lumen. A second elongate member can be helically wound and joined between adjacent turns of the first elongate member, the second elongate member forming at least a portion of the lumen of the elongate tube. The names "first elongate member" and "second elongate member" do not necessarily imply an order, such as the order in which the components are assembled. As described herein, the first elongate member and the second elongate member can also be portions of a single tubular shape element.

[0009] In various embodiments, the foregoing components have one, some, or all of the following properties, as well as properties described elsewhere in this disclosure.

[0010] The first elongated member can be a tube. The first elongated member can form a plurality of blisters on its longitudinal cross-section, the blisters having flat surfaces on the lumen. Adjacent blisters can be separated by a gap above the second elongated member, or the adjacent blisters can not be directly connected to each other. The blisters can have eyelets. The second elongated member can have a longitudinal cross-section that is wider at the lumen proximal side and narrows over the radial distance of the lumen. In particular, the second elongated member can have a longitudinal cross-section that is generally triangular, generally T-shaped, or generally Y-shaped. One or more electrically conductive filaments can be embedded or encapsulated in the second elongated member. The one or more electrically conductive filaments can be heating filaments (or more particularly, resistive heating filaments) and / or sensing filaments. The tube can include a pair of electrically conductive filaments, such as two or four electrically conductive filaments. The pair of electrically conductive filaments can form a connection loop at one end of the composite tube. The one or more electrically conductive filaments can be separated from the lumen wall. In at least one embodiment, the second elongated member can have a longitudinal cross-section that is generally triangular, generally T-shaped, or generally Y-shaped, and one or more electrically conductive filaments can be embedded or encapsulated on opposite sides of the triangular, T-shaped, or Y-shaped of the second elongated member.

[0011] The foregoing components according to any or all of the foregoing embodiments can be incorporated into medical circuit components, inspiratory tubes, expiratory tubes, PAP components, insufflation circuits, breathing components, or surgical components, among other applications.

[0012] A method of manufacturing a composite tube is also disclosed. The resulting tube can have one, some, or all of the properties described above or elsewhere in the disclosure. In at least one embodiment, the method includes providing a first elongated member including a hollow body, and a second elongated member configured to provide structural support to the first elongated member. The second elongated member is spirally wrapped around a mandrel, with opposite edge portions of the second elongated member being spaced apart on adjacent wraps, thereby forming a second elongated member spiral. The first elongated member is spirally wrapped around the second elongated member spiral such that portions of the first elongated member overlap adjacent wraps of the second elongated member spiral, and a portion of the first elongated member is disposed adjacent to the mandrel in a space between wraps of the second elongated member spiral, thereby forming a first elongated member spiral.

[0013] In various embodiments, the foregoing method can include one, some or all of the following. The method can include supplying air at a pressure greater than atmospheric pressure to an end of the first elongated member. The method can include cooling the second elongated member spiral and the first elongated member spiral, thereby forming a composite tube having a lumen extending along a longitudinal axis and a hollow space around the lumen. The method can include forming the first elongated member. The method can include extruding the first elongated member with a first extruder. The method can include forming the second elongated member. The method can include extruding the second elongated member with a second extruder. The second extruder can be configured to encase one or more electrically conductive filaments in the second elongated member. Forming the second elongated member can include embedding electrically conductive filaments in the second elongated member. The electrically conductive filaments can be non-reactive with the second elongated member. The electrically conductive filaments can include aluminum or copper or alloys of other electrically conductive materials. The method can include forming a pair of electrically conductive filaments into a connection loop at an end of the composite tube. The first extruder can be different than the second extruder.

[0014] A medical tube is also disclosed. In at least one embodiment, the tube includes an elongated hollow body spirally wound to form an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall around the lumen, wherein the elongated hollow body has a wall defining at least a portion of the hollow body in a transverse cross-section thereof. The tube can further include a reinforcing portion extending along a length of the elongated hollow body, spirally positioned between adjacent turns of the elongated hollow body, wherein the reinforcing portion forms a portion of the lumen of the elongated tube. The reinforcing portion can be relatively thicker or more rigid than the wall of the elongated hollow body.

[0015] In various embodiments, the foregoing tubes have one, some, or all of the following properties, as well as properties described elsewhere in this disclosure. The reinforcing portions can be formed from the same sheet of material as the elongated hollow body. The elongated hollow body can include two reinforcing portions on opposite sides of the elongated hollow body in a transverse cross-section thereof, wherein the helical winding of the elongated hollow body joins adjacent reinforcing portions to one another such that opposite edges of the reinforcing portions contact on adjacent turns of the elongated hollow body. Opposite side edges of the reinforcing portions can overlap on adjacent turns of the elongated hollow body. The reinforcing portions and the elongated hollow body can be made from separate sheets of material. The hollow body can form a plurality of blisters in a longitudinal cross-section thereof, the blisters having flat surfaces on the lumen. The blisters can have eyelets. The medical tube can further include one or more electrically conductive filaments embedded or encapsulated within the reinforcing portions. The electrically conductive filaments can be heating filaments and / or sensing filaments. The medical tube can include two electrically conductive filaments, with one embedded or encapsulated in each reinforcing portion. The medical tube can include two electrically conductive filaments positioned on only one side of the elongated hollow body. The pair of electrically conductive filaments can form a connection loop at one end of the composite tube. The one or more filaments can be spaced apart from the lumen wall.

[0016] The foregoing tubes according to any or all of the foregoing embodiments can be incorporated into medical circuit components, inspiratory tubes, expiratory tubes, PAP components, insufflation circuits, breathing components, or surgical components, among other applications.

[0017] A method of manufacturing a medical tube is also disclosed. In at least one embodiment, the method includes helically winding an elongated hollow body about a mandrel to form an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, wherein the elongated hollow body has a wall in a transverse cross-section thereof defining at least a portion of the hollow body; and two reinforcing portions on opposite sides of the elongated body, the two reinforcing portions forming a portion of the lumen wall, the two reinforcing portions being relatively thicker or more rigid than the wall defining at least a portion of the hollow body. The method can further include joining adjacent reinforcing portions to one another such that opposite edges of the reinforcing portions contact on adjacent turns of the elongated hollow body.

[0018] In various embodiments, the foregoing method can include one, some, or all of the following features, as well as any other features described elsewhere in the present disclosure. Bonding the adjacent reinforcement portions to one another can overlap edges of the reinforcement portions. The method can further include supplying air at a pressure greater than atmospheric pressure to an end of the elongated hollow body. The method can further include cooling the elongated hollow body to cause the adjacent reinforcement portions to bond to one another. The method can further include extruding the elongated hollow body. The method can further include embedding conductive filaments in the reinforcement portions. The method can further include forming pairs of conductive filaments into a connection loop at an end of the elongated tube.

[0019] A breathing tube is also disclosed. In at least one embodiment, the tube includes a first elongated member including a helically wound hollow body at least partially forming an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, the wall having an inner portion proximal to the lumen and an outer portion facing away from the lumen, wherein the inner portion of the wall has a smaller thickness than the outer portion of the wall.

[0020] In various embodiments, the foregoing breathing tube can include one, some, or all of the following features, as well as any other features described elsewhere in the present disclosure. The breathing tube can further include a second elongated member helically wound and bonded between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube. The thickness of the outer portion of the wall can be in a range of about 0.14 mm to about 0.44 mm. The thickness of the outer portion of the wall can be about 0.24 mm. The thickness of the inner portion of the wall can be in a range of about 0.05 mm to about 0.30 mm. The thickness of the inner portion of the wall can be about 0.10 mm.

[0021] A breathing tube is also disclosed. In at least one embodiment, the tube includes a first elongated member including a helically wound hollow body at least partially forming an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, the hollow body forming a plurality of blisters in a longitudinal cross-section thereof, a blister having a maximum width along the longitudinal axis and a maximum height perpendicular to the longitudinal axis between an outwardly facing apex of the wall and the lumen, wherein a ratio of the maximum height to the maximum width is at least about 0.16.

[0022] In various embodiments, the foregoing respiratory tube can include one, some, or all of the following properties, as well as any other properties described elsewhere in the present disclosure. The respiratory tube can further include a second elongated member that is helically wound and bonded between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube. The maximum height can be in a range of about 1.2 mm to about 8.2 mm. The maximum height can be about 3.2 mm. The maximum width can be in a range of about 3.5 mm to about 7.5 mm. The maximum width can be about 5.5 mm. The ratio of the maximum height to the maximum width can be greater than 1.0.

[0023] A respiratory tube is also disclosed. In at least one embodiment, the tube includes a first elongated member including a hollow body helically wound to at least partially form an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, the hollow body forming a plurality of blisters on a longitudinal cross-section thereof, wherein a vertical distance between respective points on adjacent blisters defines a pitch, wherein a ratio of the pitch to the maximum outer diameter of the composite tube is less than about 0.35.

[0024] In various embodiments, the foregoing respiratory tube can include one, some, or all of the following properties, as well as any other properties described elsewhere in the present disclosure. The respiratory tube can further include a second elongated member that is helically wound and bonded between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube. The pitch can be in a range of about 1.2 mm to about 8.1 mm. The pitch can be about 5.1 mm. The maximum outer diameter can be in a range of about 19.5 mm to about 25.5 mm. The maximum outer diameter can be about 22.5 mm.

[0025] Also disclosed is a composite tube. In at least one embodiment, the tube includes a first elongated member including a hollow body helically wound to at least partially form an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, the hollow body forming a plurality of blisters in longitudinal cross-section thereof, the blisters having a maximum height perpendicular to the longitudinal axis between an outwardly facing apex of the wall and the lumen, the maximum height defining a maximum height of the first elongated member; and a second elongated member helically wound and bonded between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube, the second elongated member having a maximum height perpendicular to the longitudinal axis between an outwardly facing apex of the second elongated member and the lumen, wherein a ratio of a difference between the maximum height of the first elongated member and the maximum height of the second elongated member to a maximum outer diameter of the composite tube is less than about 0.049: 1.

[0026] In various embodiments, the foregoing composite tube can include one, some, or all of the following properties, as well as any other properties described elsewhere in the present disclosure. The wall can have an inner portion proximal to the lumen and an outer portion facing away from the lumen, and the inner portion of the wall has a smaller thickness than the outer portion of the wall.

[0027] Also disclosed is a composite tube. In at least one embodiment, the tube includes a first elongated member including a hollow body helically wound to at least partially form an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, the wall having an inner portion proximal to the lumen and an outer portion facing away from the lumen; and a second elongated member helically wound between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube, and the first elongated member is bonded at connection points on adjacent turns of the second elongated member; wherein a bend radius of the composite tube is limited by a length of the outer portion between the connection points.

[0028] In various embodiments, the foregoing composite tube can include one, some, or all of the following properties, as well as any other properties described elsewhere in the present disclosure. The wall has an inner portion proximal to the lumen and an outer portion facing away from the lumen, and the inner portion of the wall has a smaller thickness than the outer portion of the wall.

[0029] Also disclosed is a breathing tube. In at least one embodiment, the tube includes a first elongated member including a hollow body component, wherein a weight / length of the tube within at least a portion of 300 mm closest to an end of the tube is less than about 0.08 g / mm.

[0030] In various embodiments, the foregoing respiratory tube can include one, some, or all of the following properties, as well as any other properties described elsewhere in the present disclosure. The first elongated member can include a helically wound hollow body at least partially forming an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen. The respiratory tube can further include a second elongated member helically wound and bonded between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube. The respiratory tube can include one or more electrically conductive filaments embedded or encapsulated within the second elongated member. At least one of the one or more electrically conductive filaments can be a heating filament. At least one of the one or more electrically conductive filaments can be a sensing filament. A tube mass within 300 mm of a tube end nearest the tube end can be less than about 24 g. A weight per length of the tube within at least a portion of 300 mm of a tube end nearest the tube end can be less than about 0.06 g / mm. A tube mass within 300 mm of a tube end nearest the tube end can be less than about 16 g. A thickness of the wall can be at most about 0.50 mm.

[0031] A respiratory tube is also disclosed. In at least one embodiment, the tube includes a first elongated member including a helically wound hollow body at least partially forming an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, the wall having an inner portion proximal to the lumen and an outer portion facing away from the lumen, wherein in at least a portion of the composite tube, when a force is applied to the outer portion of the wall with a 2.5 mm probe until the outer portion of the wall contacts the inner portion, the outer portion deflects a vertical distance that satisfies the following equation: D > 0.5 x F 2.5 where D represents the vertical distance in millimeters and F 2.5 represents the force in Newtons applied by the 2.5 mm probe.

[0032] In various embodiments, the foregoing respiratory tube can include one, some, or all of the following properties, as well as any other properties described elsewhere in the present disclosure. The respiratory tube can further include a second elongated member helically wound and bonded between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube. The outer portion can deflect more than about 1 mm when a force of about 1 N is applied with a 2.5 mm probe.

[0033] Also disclosed is a conduit adapted for use with a tube for delivering humidified gas to a patient. In at least one embodiment, the conduit includes a connector configured to connect to the tube, the connector including a lumen extending along a longitudinal axis and walls around the lumen, the lumen defining a flow path for the humidified gas when in use; and a printed circuit board assembly including a printed circuit board and further including a partition embedded in the walls of the connector and extending through the lumen of the connector along a diameter or chord line such that the partition generally bisects at least a portion of the flow path, at least a portion of the partition being overmolded with an overmolding composition, a wiring portion adjacent the partition and projecting outward from the walls of the connector in a direction away from the lumen of the connector, and a sensor portion disposed in the lumen of the connector and projecting from the partition along the longitudinal axis, the sensor portion including at least one sensor and the sensor portion being overmolded with the overmolding composition.

[0034] In various embodiments, the foregoing conduit can include one, some, or all of the following features, as well as any other features described elsewhere in the disclosure. The printed circuit board assembly can further include a support portion adjacent the partition and projecting outward from the connector in a direction away from the lumen and in an opposite direction from the wiring portion. The wiring portion can be configured to electrically connect to one or more heating wires from the conduit. The at least one sensor can include a thermistor. The sensor portion can project upstream of the flow path. The at least one sensor can include a sensor adjacent an upstream leading edge of the sensor portion. The sensor portion can project downstream of the flow path. The at least one sensor can include a sensor adjacent a downstream leading edge of the sensor portion. The overmolding composition proximal the sensor portion can have a tapered shape extending along the longitudinal axis. The overmolding can be thinnest proximal a leading edge of the sensor portion. The sensor portion can have an airfoil shape extending along the longitudinal axis. The sensor portion can have a bullet or torpedo shape.

[0035] Also disclosed is a respiratory conduit. In at least one embodiment, the conduit includes a lumen extending along a longitudinal axis and walls around the lumen, the lumen defining a gas flow path when in use; and an overmolded printed circuit board assembly secured to the walls, the printed circuit board assembly including a printed circuit board and further including a mounting portion disposed in the lumen of the connector and projecting along the longitudinal axis, and a temperature sensor on a surface of the mounting portion.

[0036] In various embodiments, the foregoing conduit can include one, some, or all of the following properties, as well as any other properties described elsewhere in the disclosure. The temperature sensor can be a thermistor.

[0037] Also disclosed is a respiratory conduit. In at least one embodiment, the conduit includes a lumen extending along a longitudinal axis, and walls surrounding the lumen, the lumen defining a gas flow path when in use; and a component secured to the walls and extending across the lumen along a diameter or chord line such that the component generally bisects at least a portion of the flow path, the component including a mounting portion disposed in the lumen and projecting along the longitudinal axis; a temperature sensor on a surface of the mounting portion; and an electrical connection on the sensor.

[0038] In various embodiments, the foregoing conduit can include one, some, or all of the following properties, as well as any other properties described elsewhere in the disclosure. The temperature sensor can be a thermistor. The component can be a printed circuit board. The electrical connection can span a length of the component along the diameter or chord line.

[0039] Also disclosed is a respiratory conduit. In at least one embodiment, the conduit includes a lumen extending along a longitudinal axis, and walls surrounding the lumen, the lumen defining a gas flow path when in use; and a component secured to the walls and extending across the lumen along a diameter or chord line such that the component generally bisects at least a portion of the flow path, the component including a mounting portion disposed in the lumen and projecting along the longitudinal axis; a temperature sensor on a surface of the mounting portion; and an electrical connection on the sensor.

[0040] In various embodiments, the foregoing conduit can include one, some, or all of the following properties, as well as any other properties described elsewhere in the disclosure. The temperature sensor can be a thermistor.

[0041] Also disclosed is a respiratory conduit. In at least one embodiment, the conduit includes a lumen extending along a longitudinal axis, and walls surrounding the lumen, the lumen defining a gas flow path when in use; and a component secured to the walls and extending across the lumen along a diameter or chord line such that the component generally bisects at least a portion of the flow path, the component including a mounting portion disposed in the lumen and projecting along the longitudinal axis; a temperature sensor on a surface of the mounting portion; and an electrical connection on the sensor.

[0042] In various embodiments, the foregoing breathing tube can include one, some, or all of the following properties, as well as any other properties described elsewhere in the present disclosure. The temperature sensor can be a thermistor. The temperature sensor can be proximal to an upstream end of the mounting portion. The mounting portion can be overmolded. The overmold can be thinnest proximal to the temperature sensor. The mounting portion can project longitudinally downstream. The mounting portion can have an airfoil shape extending along the longitudinal axis. The mounting portion can have a bullet or torpedo shape. A vertical distance between the mounting portion and the wall can be at least 30% of a diameter of the lumen.

[0043] A breathing conduit segment is also disclosed. In at least one embodiment, the segment includes a lumen extending along a longitudinal axis, the lumen defining a gas flow path when in use, and a wall surrounding the lumen; and a printed circuit board assembly including a printed circuit board and including a first portion extending through the lumen along a diameter or chord line such that a portion of the printed circuit board assembly generally bisects at least a portion of the flow path, the first portion being overmolded with an overmolding composition, a second portion adjacent the first portion projecting outward from the wall in a direction away from the lumen, the second portion including one or more connection pads on the printed circuit board configured to receive one or more wires from a first assembly, a third portion adjacent the first portion projecting outward from the wall in a direction away from the lumen and in an opposite direction from the second portion, the third portion including one or more connection pads on the printed circuit board configured to receive one or more wires from a second assembly different from the first assembly, and one or more conductive tracks on the printed circuit board electrically coupled to the one or more connection pads of the second portion and to the one or more connection pads of the third portion and configured to provide an electrical connection between the first assembly and the second assembly.

[0044] In various embodiments, the foregoing segment can include one, some, or all of the following properties, as well as any other properties described elsewhere in the present disclosure. The first assembly can be a breathing tube. The second assembly can be a breathing tube. The printed circuit board assembly can further include a mounting portion disposed in the lumen of the connection and projecting along the longitudinal axis, and a temperature sensor on a surface of the mounting portion.

[0045] In various embodiments, a respiratory tube includes a first elongated member including a hollow body helically wound to at least partially form an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, the hollow body forming a plurality of bubbles in a longitudinal cross-section thereof, a bubble having a maximum width along the longitudinal axis and a maximum height, perpendicular to the longitudinal axis, between an outwardly facing apex of the wall and the lumen, wherein a ratio of the maximum height to the maximum width is at least about 0.16. A second elongated member can be helically wound and incorporated between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube. The maximum height can be in a range of about 0.7 mm to about 7.7 mm. The maximum height can be about 2.7 mm. The maximum width can be in a range of about 2.0 mm to about 6.0 mm. The maximum width can be about 4.0 mm. The ratio of the maximum height to the maximum width can be greater than 1.0.

[0046] In various embodiments, a respiratory tube includes a first elongated member including a hollow body helically wound to at least partially form an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, the hollow body forming a plurality of bubbles in a longitudinal cross-section thereof, wherein a vertical distance between respective points on adjacent bubbles defines a pitch, wherein a ratio of the pitch to a maximum outer diameter of the composite tube is less than about 0.35. A second elongated member can be helically wound and incorporated between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube. The pitch can be in a range of about 1.2 mm to about 8.1 mm. The pitch can be about 5.1 mm. The maximum outer diameter can be in a range of about 19.5 mm to about 25.5 mm. The maximum outer diameter can be about 22.5 mm.

[0047] In various embodiments, a composite tube includes a first elongated member including a hollow body helically wound to at least partially form an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, the hollow body forming a plurality of blisters in longitudinal cross-section thereof, the blisters having a maximum height perpendicular to the longitudinal axis between an outwardly facing apex of the wall and the lumen, the maximum height defining a maximum height of the first elongated member, and a second elongated member helically wound and bonded between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube, the second elongated member having a maximum height perpendicular to the longitudinal axis between an outwardly facing apex of the second elongated member and the lumen, wherein a ratio of a difference between the maximum height of the first elongated member and the maximum height of the second elongated member to a maximum outer diameter of the composite tube is less than about 0.049: 1. The wall can have an inner portion proximal to the lumen and an outer portion facing away from the lumen, and the inner portion of the wall can have a smaller thickness than the outer portion of the wall.

[0048] In various embodiments, a composite tube includes a first elongated member including a hollow body helically wound to at least partially form an elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall about the lumen, the wall having an inner portion proximal to the lumen and an outer portion facing away from the lumen, and a second elongated member helically wound between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube, and the first elongated member bonded at connection points on adjacent turns of the second elongated member; wherein a bend radius of the composite tube is limited by a length of the outer portion between the connection points. The wall can have an inner portion proximal to the lumen and an outer portion facing away from the lumen, and the inner portion of the wall can have a smaller thickness than the outer portion of the wall.

[0049] In various embodiments, a conduit adapted for use with a tube for delivering humidified gas to a patient includes a connector configured to connect to the tube, the connector including a lumen extending along a longitudinal axis and walls around the lumen, the lumen defining a flow path for the humidified gas when in use; and a printed circuit board assembly including a printed circuit board and further including a partition embedded in the walls of the connector and extending through the lumen of the connector along a diameter or chord line such that the partition generally bisects at least a portion of the flow path, at least a portion of the partition being overmolded with an overmolding composition, a wiring portion adjacent the partition and projecting outward from the walls of the connector in a direction away from the lumen of the connector, and a sensor portion disposed in the lumen of the connector and projecting from the partition along the longitudinal axis, the sensor portion including at least one sensor and the sensor portion being overmolded with the overmolding composition. The printed circuit board assembly can further include a support portion adjacent the partition and projecting outward from the connector in a direction away from the lumen and in an opposite direction from the wiring portion. The wiring portion can be configured to electrically connect to one or more heating wires from the conduit. The at least one sensor can include a thermistor. The sensor portion can project upstream of the flow path. The at least one sensor can include a sensor adjacent an upstream leading edge of the sensor portion. The sensor portion can project downstream of the flow path. The at least one sensor can include a sensor adjacent a downstream leading edge of the sensor portion. The overmolding composition proximal the sensor portion can have a tapered shape extending along the longitudinal axis. The overmolding can be thinnest proximal a leading edge of the sensor portion. The sensor portion can have an airfoil shape extending along the longitudinal axis. The sensor portion can have a bullet or torpedo shape.

[0050] In various embodiments, a respiratory conduit includes a lumen extending along a longitudinal axis and walls around the lumen, the lumen defining a gas flow path when in use; and an overmolded printed circuit board assembly secured to the walls, the printed circuit board assembly including a printed circuit board and further including a mounting portion disposed in the lumen and projecting along the longitudinal axis, and a temperature sensor on a surface of the mounting portion, wherein an overmolding proximal the mounting portion has a tapered shape. The temperature sensor can be a thermistor.

[0051] In various embodiments, a respiratory conduit includes a lumen extending along a longitudinal axis, and a wall about the lumen, the lumen defining a gas flow path in use; and a component connected to the wall and including a mounting portion disposed in the lumen and projecting along the longitudinal axis, the mounting portion including a temperature sensor connected on the wall positioned longitudinally upstream. The temperature sensor can be a thermistor. The temperature sensor can be proximal to an upstream end of the mounting portion. The mounting portion can be overmolded. The overmolding can be thinnest proximal to the temperature sensor. The mounting portion can project longitudinally downstream. The mounting portion can have a wing shape extending along the longitudinal axis. The mounting portion can have a bullet or torpedo shape. A vertical distance between the mounting portion and the wall can be at least 30% of a diameter of the lumen.

[0052] In various embodiments, a respiratory conduit section includes a lumen extending along a longitudinal axis, and a wall about the lumen, the lumen defining a gas flow path in use; and a printed circuit board assembly including a printed circuit board and including a first portion extending through the lumen along a diameter or chord line such that a portion of the printed circuit board assembly generally bisects at least a portion of the flow path, the first portion being overmolded with an overmolding composition, a second portion adjacent the first portion projecting outward from the wall in a direction away from the lumen, the second portion including one or more connection pads on the printed circuit board configured to receive one or more wires from a first assembly, a third portion adjacent the first portion projecting outward from the wall in a direction away from the lumen and in an opposite direction from the second portion, the third portion including one or more connection pads on the printed circuit board configured to receive one or more wires from a second assembly different from the first assembly, and one or more conductive tracks on the printed circuit board electrically coupled to the one or more connection pads of the second portion and to the one or more connection pads of the third portion and configured to provide an electrical connection between the first assembly and the second assembly. The first assembly can be a respiratory tube. The second assembly can be a respiratory tube. The printed circuit board assembly can further include a mounting portion disposed in the lumen of the connection and projecting along the longitudinal axis, and a temperature sensor on a surface of the mounting portion.

[0053] In various embodiments, the composite tube includes a first elongated member comprising a hollow body helically wound to at least partially form the elongated tube, the elongated tube having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall surrounding the lumen; and a second elongated member helically wound and coupled between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube; wherein at least a portion of the first elongated member is formed of a breathable material. In one example, the composite tube may be provided with a humidifying fluid source and / or pre-filled with a certain volume of humidifying fluid, and a heater may be provided to heat the fluid, such that fluid vapor passes through the breathable material into or out of the lumen. The heater may include one or more heating filaments disposed in the second elongated member.

[0054] To summarize the invention, certain aspects, advantages, and novel features of the invention are described herein. It should be understood that not all of these advantages can necessarily be achieved by any particular embodiment of the invention. Therefore, the invention can be embodied or practiced in a manner that achieves or optimizes one or more advantages as taught herein, without requiring the realization of other advantages as may be taught or suggested herein. Attached Figure Description

[0055] Exemplary embodiments of various features of the disclosed systems and methods will now be described with reference to the accompanying drawings. The drawings and associated descriptions are provided to illustrate embodiments and are not intended to limit the scope of this disclosure.

[0056] Figure 1 A schematic diagram of a medical circuit incorporating one or more medical tubes is shown.

[0057] Figure 2A A side-view top view of a cross-section of an example composite pipe is shown.

[0058] Figure 2B The longitudinal section of the top portion of the tube is shown, which is related to... Figure 2A Similar to the example composite pipe.

[0059] Figure 2C Another longitudinal section is shown, which illustrates the first elongated member in the composite tube.

[0060] Figure 2D Another longitudinal section of the top portion of the tube is shown.

[0061] Figure 2E Another longitudinal section of the top portion of the tube is shown.

[0062] Figure 2FThe tube is shown, with a portion of it exposed in its longitudinal section.

[0063] Figure 2G The longitudinal section of a portion of the pipe is shown, which is related to... Figure 2F The example tube is similar.

[0064] Figure 2H The longitudinal section of the top portion of the tube is shown.

[0065] Figure 3 A fixture suitable for determining the deflection of bubbles is shown.

[0066] Figure 4 The curves showing the deflection of the force on the bubble are shown.

[0067] Figure 5A –5C shows an example of the shape of a first elongated member configured to improve thermal efficiency.

[0068] Figure 5D –5F shows an example of a filament arrangement configured to improve thermal efficiency.

[0069] Figure 6A A longitudinal section of a portion of the composite pipe in a neutral position is shown.

[0070] Figure 6B It shows the bent position. Figure 6A The composite tube portion, in which the composite tube has been bent into a ∩ shape.

[0071] Figure 6C The composite tube, bent into a ∩ shape, is shown.

[0072] Figure 6D The image shows a composite pipe that has been bent beyond its minimum radius of curvature.

[0073] Figure 7A The transverse section of the second elongated member in the composite tube is shown.

[0074] Figure 7B Another transverse section of the second elongated member is shown.

[0075] Figure 7C Another example of a second elongated member is shown.

[0076] Figure 7D Another example of a second elongated member is shown.

[0077] Figure 7E Another example of a second elongated member is shown.

[0078] Figure 7F Another example of a second elongated member is shown.

[0079] Figure 7G Another example second elongate member is shown.

[0080] Figure 8A A schematic of a composite tube with variable pitch is shown.

[0081] Figure 8B A graph depicting an example temperature profile in a variable pitch composite tube.

[0082] Figure 9A A front side top view cross-sectional schematic of a resilient clamp is shown.

[0083] Figure 9B A front side perspective view of a resilient clamp is shown. Figure 9A A detailed front side top view cross-sectional schematic of a roller on a resilient clamp is shown.

[0084] Figure 9C - 9F shows a resilient clamp in use. Figure 9C and Figure 9E A front side perspective view of a sample under test in a clamp is shown. Figure 9D and Figure 9F A back side perspective view of a sample under test in a clamp is shown.

[0085] Figure 10A A crush resistance test clamp is shown.

[0086] Figure 10B A graph of load versus extension is shown for determining crush stiffness.

[0087] Figure 11A - 1 ID demonstrates the radius of curvature properties of a tube.

[0088] Figure 12A - 12C shows an example of a first elongate member stack.

[0089] Figure 13 An alternative embodiment of a second elongate member is shown.

[0090] Figure 14A - 14E shows a number of variants of a tube adapted to provide increased lateral stretch of the tube.

[0091] Figure 15A - 15E shows, respectively, Figure 14A - the stretched state of the tube shown in 14E.

[0092] Figure 16 An example medical circuit according to at least one embodiment is shown.

[0093] Figure 17 A gas insufflation system according to at least one embodiment is shown.

[0094] Figure 18 is a schematic view of a coaxial tube according to at least one embodiment.

[0095] Figure 19A - 19B shows a composite tube for use with a patient interface.

[0096] Figure 20A shows a composite tube for use with a full face mask.

[0097] Figure 20B shows a composite tube for use with a nasal mask.

[0098] Figure 20C shows a composite tube for use with a nasal / occipital mask.

[0099] Figure 21A shows one aspect of a method for forming a composite tube.

[0100] Figure 21B shows a second elongate member that is helically wound.

[0101] Figure 21C shows another aspect of a method for forming a composite tube.

[0102] Figure 21D shows another aspect of a method for forming a composite tube.

[0103] Figure 21E shows another aspect of a method for forming a composite tube.

[0104] Figure 21F shows another aspect of a method for forming a composite tube.

[0105] Figure 22A - 22C shows an example configuration of a longitudinal cross section of a plurality of tubes.

[0106] Figure 23A - 23H shows an alternative method of forming a tube.

[0107] Figure 24A - 24B shows another example of a single elongate hollow body that is helically wound to form a medical tube.

[0108] Figure 24C - 24F shows examples of other single elongate hollow bodies that are helically wound to form a medical tube.

[0109] Figure 25A- 25L shows a general flow chart as well as more detailed schematic and photographic illustrations of a method for attaching a connector to the end of a tube that is configured to connect to a humidifier in use.

[0110] Figure 26A - 26E shows a connector for attaching a filament to an electrical connector.

[0111] Figure 27A - 27E shows a clamshell adapted for use with Figure 25A - 25L connector.

[0112] Figure 28A - 28F and Figure 29A - 29L shows connectors that can be used in a method of a medical circuit with wires passing through and associated components.

[0113] Figure 30A - 30O shows a schematic of a connector adapted to attach a tube to a patient interface.

[0114] Figure 31A - 31B shows a tip portion adapted for use with Figure 30A - 30O connector.

[0115] Figure 32A - 32D shows an anti-rotation structure portion adapted for use with Figure 30A - 30O connector.

[0116] Figure 33A - 33D shows an example PCB assembly.

[0117] Figure 34 shows a segmented inspiratory limb for use with a humidification system having an intermediate connector configured to couple heating filaments and / or temperature sensors within two segments.

[0118] Figure 35A - 35E shows a schematic of a connector adapted to attach a tube to a humidifier port, patient interface, or any other suitable component.

[0119] Figure 36A - 36K shows a schematic of another connector adapted to attach a tube to a humidifier port, patient interface, or any other suitable component.

[0120] Figure 37A shows a longitudinal cross-section of a tip portion of a tube that includes two first elongate members.

[0121] Figure 37BAnother longitudinal section of the top end portion of the tube is shown, the tube comprising two first elongate members.

[0122] Generally throughout these drawings, reference numbers are reused to indicate correspondence between referenced (or similar) elements. However, corresponding referenced (similar) elements can in some cases have different reference numbers. Moreover, the first digit(s) of each reference number generally indicates the figure in which the element first appears. DETAILED DESCRIPTION

[0123] Details regarding several illustrative embodiments for implementing the devices and methods described herein are described below with reference to the accompanying drawings. The application is not limited to these described embodiments.

[0124] Breathing circuit including one or more medical tubes

[0125] For a more detailed understanding of the present disclosure, reference is made to the following description in conjunction with the accompanying drawings. Figure 1 which shows a breathing circuit comprising one or more medical tubes, in accordance with at least one embodiment. The tube is a broad term and gives it its ordinary and customary meaning to one of ordinary skill in the art (that is, it is not limited to a special or customized meaning), and includes, without limitation, a cylindrical and non-cylindrical passageway. Certain embodiments can incorporate a composite tube, which can generally be defined as a tube comprising two or more portions, or specifically two or more components in some embodiments, as described in more detail below. Such a breathing circuit can be a continuous, variable, or bi-level positive airway pressure (PAP) system or another form of respiratory therapy.

[0126] Gas can be delivered in a circuit of Figure 1 from the ventilator / blower 105 to the humidifier 107, which humidifies the dry gases. The humidifier 107 is connected to the inlet 109 (the end for receiving humidified gases) of the inspiratory tube 103 via the port 111, thereby supplying humidified gases to the inspiratory tube 103. The inspiratory tube is a tube configured to deliver breathing gases to a patient, and can be comprised of a composite tube as described in further detail below. The gases flow through the inspiratory tube 103 to the outlet 113 (the end for expelling humidified gases), and then to the patient 101 through the patient interface 115 connected to the outlet 113.

[0127] The expiratory tube 117 is optionally connected to the patient interface 115. The expiratory tube is a tube configured to move exhaled humidified gases away from the patient. Here, the expiratory tube 117 returns exhaled humidified gases from the patient interface 115 to the ventilator / blower 105.

[0128] In this example, dry gas enters the ventilator / blower 105 through the vent 119. A fan 121 can improve the flow of gas into the ventilator / blower by drawing air or other gas through the vent 119. For example, the fan 121 can be a variable speed fan, where an electronic controller 123 controls the fan speed. In particular, the function of the electronic controller 123 can be controlled by the electronic main controller 125 in response to inputs from the main controller 125 and a predetermined desired value (preset value) of pressure or fan speed or gas flow rate set by a user via the dial 127.

[0129] The humidifier 107 includes a humidification chamber 129 containing a volume of water 130 or other suitable humidification liquid. Preferably, the humidification chamber 129 is removable from the humidifier 107 after use. Removability allows the humidification chamber 129 to be more easily sterilized or disposed of. However, the humidification chamber 129 portion of the humidifier 107 can be of unitary construction. The body of the humidification chamber 129 can be formed of a non-conductive glass or plastic material. However, the humidification chamber 129 can also include conductive components. For example, the humidification chamber 129 can include a highly thermally conductive base (e.g., an aluminum base) that is in contact with or associated with a heater plate 131 on the humidifier 107.

[0130] The humidifier 107 can also include electronic controls. In this example, the humidifier 107 includes an electronic analog or digital main controller 125. Preferably, the main controller 125 is a microprocessor-based controller that executes computer software commands stored in an associated memory. In response to humidity or temperature values set by a user input via, for example, a user interface 133, as well as other inputs, the main controller 125 determines when (or at what level) to energize the heater plate 131 in order to heat the water 130 within the humidification chamber 129.

[0131] Any suitable patient interface 115 can be incorporated. Patient interface is a broad term and includes, without limitation, masks (such as tracheal masks, face masks, and nasal masks), cannulae, and nasal pillows. A temperature probe 135 can be connected to the inspiratory tube 103 proximate the patient interface 115, or to the patient interface 115. The temperature probe 135 monitors the temperature proximate or at the patient interface 115. A heating filament (not shown) associated with the temperature probe can be used to adjust the temperature of the patient interface 115 and / or the inspiratory tube 103 in order to raise the temperature of the inspiratory tube 103 and / or patient interface 115 above the saturation temperature, thereby reducing the chance of unwanted condensation.

[0132] In Figure 1In some embodiments, the exhaled humidified gases are returned from the patient interface 115 to the ventilator / blower 105 via an expiratory tube 117. The expiratory tube 117 can also be a composite tube, as described in more detail below. However, the expiratory tube 117 can also be a medical tube as previously known in the art. In either case, the expiratory tube 117 can have a temperature probe and / or heating filaments integrated with it (as described above for the inspiratory tube 103) to reduce the chance of condensation. Furthermore, the expiratory tube 117 need not return the exhaled gases to the ventilator / blower 105. Alternatively, the exhaled humidified gases can be delivered directly into the ambient environment or into other ancillary equipment, such as an air washer / filter (not shown). In certain embodiments, the expiratory tube is omitted altogether.

[0133] Composite pipe

[0134] Figure 2A A side view top view of a cross-section of an example composite tube 201 is shown. In general, the composite tube 201 includes a first elongated member 203 and a second elongated member 205. Member is a broad term and given its plain and ordinary meaning to one of ordinary skill in the art (i.e., it is not limited to a special or customized meaning) and includes, without limitation, a unitary portion, a unitary component, and a distinct component. Thus, although Figure 2A While one embodiment is shown as being composed of two distinct components, it will be appreciated that in other embodiments (as described below), the first elongated member 203 and the second elongated member 205 can also represent regions in a tube formed from a single material. Thus, the first elongated member 203 can represent a hollow portion of the tube, while the second elongated member 205 represents a structural support or reinforcing portion of the tube that adds structural support to the hollow portion. The hollow portion and the structural support portion can have a spiral configuration as described herein.

[0135] The composite tube 201 can be used to form the inspiratory tube 103 and / or the expiratory tube 117 in a breathing circuit as described above, or any other tube as described elsewhere in the disclosure. In certain embodiments, the composite tube 201 is at least one inspiratory tube 103.

[0136] The components and features of the example composite tube 201 are described in more detail below. Headings such as "first elongated member" and "second elongated member" are used. These headings are not and should not be considered limiting. For example, aspects of one or more embodiments described under the first elongated member heading can also apply to one or more embodiments described under the second elongated member heading, and vice versa.

[0137] First elongation member

[0138] In Figure 2AIn some embodiments, the first elongated member 203 includes a hollow body that is helically wound to at least partially form an elongated tube having a longitudinal axis LA-LA and a lumen 207 (tube bore) extending along the longitudinal axis LA-LA. The first elongated member 203 has an inner portion 211 proximate the lumen 207. In some embodiments, the surface of the inner portion 211 forms the lumen 207. The first elongated member 203 also has an outer portion 219 that is opposite the inner portion and faces away from the lumen 207 in a radial direction. As discussed in more detail below, the first elongated member 203 can form a plurality of blisters on a longitudinal cross-section thereof. In some embodiments, the blisters have a cross-sectional profile similar to the letter "D." The blisters can be arcuate at the outwardly facing surface. The blisters can be more flattened at the surface of the lumen 207. In at least one embodiment, the first elongated member 203 is a tube.

[0139] Preferably, the first elongated member 203 is flexible. Flexibility refers to the ability to bend. In addition, the first elongated member 203 is preferably transparent, or at least translucent or semi-opaque. The translucency allows a caregiver or user to inspect the lumen 207 for blockage or contamination, or to determine whether moisture is present.

[0140] A variety of plastics, including medical grade plastics, are suitable for the body of the first elongated member 203. Examples of suitable materials include: polyolefin elastomers, polyether amide block, thermoplastic copolyester elastomers, EPDM-polypropylene blends, and thermoplastic polyurethanes. In some embodiments, the material is selected so that the resulting first elongated member 203 has a material density less than or equal to 1 g / cm 3 (or about 1 g / cm 3 ).

[0141] The first elongated member 203 material is preferably soft. Softness reflects the amount that a material "gives" or compresses after a force is applied. A soft material gives or compresses a greater amount than a stiff material. Blistery deflection can be used to quantify the softness of the first elongated member 203 material. Blistery deflection is the distance that the outer portion 219 of the first elongated member 203 vertically deflects (that is, shifts radially inward in the direction of the lumen 207) after a force is applied. Blistery deflection can be tested, for example, using a blistery deflection jig such as the jig 301 shown in the photograph of Figure 3 .

[0142] In one softness test, four samples of composite tubing having the properties shown in Table 1 (hereinafter "Type 1") and four samples of composite tubing having the properties shown in Table 2 (hereinafter "Type 2") were each tested on the jig 301 of Figure 3 .

[0143] Table 1

[0144]

[0145]

[0146] Table 2

[0147]

[0148] A probe 303 with a diameter of 2.5 mm applies force to each sample 305 and measures the deflection of the bubbles. Figure 4 The resulting curves were plotted. Until their respective outer portions 219 contact the inner portions 211, Type 1 samples typically require less force to achieve bubble deflection similar to that of Type 2 samples. In some embodiments, bubble deflection can satisfy the equation: D > 0.5 × F until the outer portions 219 contact the inner portions 211. 2.5 Where D represents bubble deflection in millimeters, and F 2.5 This represents the force, measured in Newtons, applied by a 2.5mm probe. For example, the first elongation member 203 can deflect more than 1mm when a force of 1N is applied with the 2.5mm probe 303 until the outer portion 219 contacts the inner portion 211.

[0149] It should be understood that while the constructions in Table 1 may be preferred in some embodiments, other constructions and variations may be used in other embodiments as desired.

[0150] Figure 2B It shows Figure 2A The longitudinal section of the top portion of the example composite pipe 201. Figure 2B With Figure 2A The same orientation. This example further illustrates the shape of the hollow body of the first elongated member 203. As can be seen in this example, the first elongated member 203 forms a plurality of hollow bubbles in its longitudinal section. Therefore, in this specification, the term "bubble" refers to the cross-sectional shape of a turn or a ring of the first elongated member 203. A portion 209 of the first elongated member 203 overlaps the adjacent sheath of the second elongated member 205. The interior portion 211 of the first elongated member 203 forms the wall of the lumen 207.

[0151] The hollow body structure of the first elongated member 203 contributes to the sound dampening properties of the composite tube 201. In at least one embodiment, the outer diameter of the first elongated member 203 is greater than the outer diameter of the second elongated member 205. The bubble-shaped structure forms a cushion. Thus, the fluid (gas or liquid) filled bubble-shaped first elongated member 203 can dampen the noise generated when the composite tube 201 is dragged over the edge of an object such as a table or nightstand. In this manner, the composite tube 201 can be quieter compared to a one-piece solid body bellows.

[0152] The hollow body structure of the first elongated member 203 also contributes to the insulating properties of the composite tube 201. Insulating the composite tube 201 is desirable because, as explained above, it prevents heat loss. This can enable the composite tube 201 to deliver gas from a heated humidifier to a patient while maintaining the limited state of the gas with minimal energy consumption.

[0153] It has been found that having a gap 213 between adjacent turns of the first elongated member 203, that is, between adjacent bubbles, unexpectedly improves the overall insulating properties of the composite tube 201. Thus, in certain embodiments, adjacent bubbles are separated by a gap 213. Moreover, certain embodiments that include implementations that provide a gap 213 between adjacent bubbles increase the thermal transfer resistivity (R-value) and, thus, decrease the thermal transfer conductivity of the composite tube 201. It has also been found that this gap configuration improves the flexibility of the composite tube 201 by allowing for shorter radius bends. A triangular second elongated member 205 or T-shaped second elongated member 205, as shown in Figure 2B otherwise, in certain embodiments, adjacent bubbles are in contact. For example, adjacent bubbles can be bonded together.

[0154] Figure 2C A longitudinal cross-section of a bubble in Figure 2B is shown. As shown, the portion 209 of the first elongated member 203 that overlaps the adjacent sheath of the second elongated member 205 is characterized by the extent of the bond zone 217. A larger bond zone improves the resistance of the tube to delamination at the interface of the first and second elongated members. Additionally or alternatively, the shape of the bead and / or bubble can be adapted to increase the bond zone 217. For example, Figure 2D A relatively small bond zone on the left-hand side is shown. Figure 5B A smaller bond zone is also shown. Conversely, Figure 2E has a much larger bond zone than the bond zone shown in Figure 2D because of the size and shape of the bead. Figure 5A and Figure 5CLarger bonding regions are also shown. Each of these figures will be discussed in greater detail below. It should be appreciated that while the configurations in Figure 2E , Figure 3 and Figure 5C may be preferred in certain embodiments, other configurations, including those in Figure 2D , Figure 5B and other variants, can be used in other embodiments, as can be desired.

[0155] Figure 2D A longitudinal cross-section of a top end portion of another composite tube is shown. Figure 2D has the same orientation as Figure 2B This example further illustrates the shape of the hollow body of the first elongate member 203 and demonstrates how the first elongate member 203 forms a plurality of hollow bubbles on its longitudinal cross-section. In this example, the bubbles are completely separated from one another by the gaps 213. The generally triangular second elongate member 205 supports the first elongate member 203.

[0156] Figure 2H A longitudinal cross-section of a top end portion of another composite tube is shown. Figure 2H has the same orientation as Figure 2B .

[0157] In the example of Figure 2H , the cross-sectional thickness of the inner portion 211 forming the lumen wall of the first elongate member 203 is less than the thickness of the outer portion 219. As the first elongate member 203 has a D-shaped bubble profile, the outer facing portion of the first elongate member 203 has material gaps between adjacent turns of the second elongate member, which facilitates movement and stretching of the composite tube 201 when bent into a shape. As the configuration of Figure 2H produces thinner bubbles near the lumen 207, this configuration allows the inner portion 211 to more easily compress or "bunch" when the composite tube 201 is bent into a shape. Accordingly, certain embodiments include implementations in which a configuration in which the cross-sectional thickness of the inner portion 211 is less than the cross-sectional thickness of the outer portion 219 can increase flexibility of the composite tube 201 by allowing for shorter radius bends. Further, certain embodiments include implementations in which overall tube flexibility can be increased by providing a first elongate member 203 having a variable cross-sectional wall thickness. It is desirable that the thickness of the inner portion 211 be less than the thickness of the outer portion 219.

[0158] In at least one instance, the thickness of the inner portion 211 is at least 20% (or about 20%) less than the thickness of the outer portion 219. For example, in certain embodiments, the thickness of the inner portion 211 is at least 30% (or about 30%), at least 40% (or about 40%), at least 50% (or about 50%), or at least 60% (or about 60%) less than the thickness of the outer portion 219. In certain embodiments, the thickness of the inner portion 211 is 27% (or about 27%) less than the thickness of the outer portion 219. In certain embodiments, the thickness of the inner portion 211 is 32% (or about 32%) less than the thickness of the outer portion 219. In certain embodiments, the thickness of the inner portion 211 is 58% (or about 58%) less than the thickness of the outer portion 219. In certain embodiments, the thickness of the inner portion 211 is 64% (or about 64%) less than the thickness of the outer portion 219.

[0159] The thickness of the outer portion 219 can be in the range of 0.14 mm (or about 0.14 mm) to 0.44 mm (or about 0.44 mm), such as 0.22 mm (or about 0.22 mm) or 0.24 mm (or about 0.24 mm). The thickness of the inner portion 211 can be in the range of 0.05 mm (or about 0.05 mm) to 0.30 mm (or about 0.30 mm), and preferably is 0.10 mm (or about 0.10 mm) or 0.16 mm (or about 0.16 mm).

[0160] Referring again to Figure 2H , the height (labeled H—H) of the single longitudinal cross-sectional bubble of the first elongate member 203 can be greater than the width (labeled W—W) of the single longitudinal cross-sectional bubble of the first elongate member 203. Such a configuration can improve the flexibility of the composite tube 201 by allowing for shorter radius bends due to the greater height increasing the size of the material voids in the outer wall of the bubble of the first elongate member 203. Accordingly, certain embodiments include the realization that the overall tube flexibility can be improved by providing a first elongate member 203 having a greater longitudinal cross-sectional height than width. It will be appreciated that while such an example configuration can be preferred in certain embodiments, other configurations and variations can be used in other embodiments as can be desired. For example, the height of the longitudinal cross-sectional bubble of the first elongate member 203 can be less than its width.

[0161] In at least one embodiment, the blister height (H—H) can be in a range of 1.2 mm (or about 1.2 mm) to 8.2 mm (or about 8.2 mm), such as 1.2 mm (or about 1.2 mm), 1.7 mm (or about 1.7 mm), 1.8 mm (or about 1.8 mm), 2.7 mm (or about 2.7 mm), 2.8 mm (or about 2.8 mm), 3 mm (or about 3 mm), 3.2 mm (or about 3.2 mm), 3.5 mm (or about 3.5 mm), 3.8 mm (or about 3.8 mm), 4 mm (or about 4 mm), 4.5 mm (or about 4.5 mm), 7.7 mm (or about 7.7 mm), or 8.2 mm (or about 8.2 mm). In at least one embodiment, the blister width (W—W) can be in a range of 1.7 mm (or about 1.7 mm) to 8 mm (or about 8 mm), such as 1.7 mm (or about 1.7 mm), 3.2 mm (or about 3.2 mm), 3.5 mm (or about 3.5 mm), 4.0 mm (or about 4.0 mm), 4.2 mm (or about 4.2 mm), 5.2 mm (or about 5.2 mm), 5.5 mm (or about 5.5 mm), 6 mm (or about 6 mm), 7 mm (or about 7 mm), 7.5 mm (or about 7.5 mm), or 8 mm (or about 8 mm).

[0162] The relationship between the blister height (H—H) and the blister width (W—W) can be expressed as a ratio. A ratio of the blister height (H—H) to the blister width (W—W) equal to 0 has the worst flexibility. Flexibility increases as the ratio increases. In at least one embodiment, the ratio of the blister height (H—H) to the blister width (W—W) can be in a range of 0.15 (or about 0.15) to 1.5 mm (or about 1.5), such as 0.16 (or about 0.16), 0.34 (or about 3.4), 0.50 (or about 0.50), 0.56 (or about 0.56), 0.57 (or about 0.57), 0.58 (or about 0.58), 0.67 (or about 0.67), 0.68 (or about 0.68), 0.73 (or about 0.73), 0.85 (or about 0.85), 1.1 (or about 1.1), and 1.3 (or about 1.3).

[0163] It can be desirable for the outer profile of the bellows to be relatively smooth. Relative smoothness as used in this specification relates to the ridges between the first elongate member 203 and the second elongate member 205 along the length of the composite tube 201. A relatively smoother bellows has flatter, more closely spaced, or otherwise less pronounced ridges. A relatively smoother profile can advantageously reduce the noise emitted when the bellows is dragged over an object such as the edge of a table or counter.

[0164] An example parameter used to quantify relative smoothness is the vertical difference between the outer radial apex 221 of the first elongation member 203 and the outer radial apex 223 of the second elongation member 205 of the composite tube 201 (e.g., in...). Figure 2H (As shown in the diagram). As the distance between the outer radial apex 221 and the outer radial apex 223 decreases, the composite tube 201 feels relatively smoother. In at least one embodiment, the vertical difference is in the range of 1 mm (or about 1 mm) to 4.6 mm (or about 4.6 mm), such as 1.0 mm (or about 1.0 mm), 1.1 mm (or about 1.1 mm), 1.3 mm (or about 1.3 mm), 1.4 mm (or about 1.4 mm), 1.6 mm (or about 1.6 mm), 1.9 mm (or about 1.9 mm), 2.0 mm (or about 2.0 mm), 2.3 mm (or about 2.3 mm), 2.4 mm (or about 2.4 mm), 3.0 mm (or about 3.0 mm), 3.3 mm (or about 3.3 mm), or 4.6 mm (or about 4.6 mm). The relative smoothness can also be quantified as the vertical distance between the outer radial apex 221 of the first elongation member 203 of the composite tube 201 and the outer radial nadir point 225 of the second elongation member 205. For example, this vertical distance could be 1.5 mm (or approximately 1.5 mm).

[0165] Another example parameter used to quantify relative smoothness is the ratio of the vertical difference between the radial vertex 221 of the first elongated member 203 of the composite tube 201 and a radial vertex 223 (or radial nadir point 225) of the second elongated member 205 to the maximum outer diameter of the composite tube 201 (that is, from the outer radial vertex 221 to the outer radial vertex 221 on the opposite side of the tube 201). As the maximum outer diameter increases, the vertical difference between the outer radial vertex 221 and the outer radial vertex 223 or nadir point 225 has a smaller effect on relative smoothness. In at least one embodiment, this ratio is in the range of 0.04 to 0.18, such as 0.04, 0.05, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.16, 0.17, or 0.18 or around them.

[0166] As another example, the distance between corresponding points from one turn to the next (i.e., the pitch) can be selected to quantify relative smoothness. In certain embodiments, the pitch can be in a range of 2.1 mm (or about 2.1 mm) to 9.5 mm (or about 9.5 mm), such as 2.1 mm (or about 2.1 mm), 3.8 mm (or about 3.8 mm), 4.8 mm (or about 4.8 mm), 5.1 mm (or about 5.1 mm), 5.5 mm (or about 5.5 mm), 5.8 mm (or about 5.8 mm), 6.4 mm (or about 6.4 mm), 7.5 mm (or about 7.5 mm), 8.1 mm (or about 8.1 mm), or 9.5 mm (or about 9.5 mm).

[0167] The ratio of the pitch of the composite tube 201 to the vertical difference between the radial apex 221 of the first elongate member 203 and the radial apex 223 of the second elongate member 205 of the composite tube 201 can be selected to quantify relative smoothness. In certain embodiments, the ratio is in a range of 1.3 (or about 1.3) to 4.8 (or about 4.8), such as 1.31 (or about 1.31), 1.76 (or about 1.76), 2.39 (or about 2.39), 2.42 (or about 2.42), 2.53 (or about 2.53), 2.71 (or about 2.71), 2.75 (or about 2.75), 3.26 (or about 3.26), 3.75 (or about 3.75), 4.13 (or about 4.13), 4.64 (or about 4.64), or 4.75 (or about 4.75).

[0168] The ratio of the pitch to the maximum outer diameter can also be selected to increase relative smoothness. In certain embodiments, the ratio of the pitch to the maximum outer diameter of the tube can be in a range of 0.10 (or about 0.10) to 0.35 (or about 0.32), such as 0.11 (or about 0.11), 0.23 (or about 0.23), 0.28 (or about 0.28), 0.29 (or about 0.29), 0.30 (or about 0.30), 0.31 (or about 0.31), or 0.32 (or about 0.32).

[0169] As described above, the hollow portion of the first elongate member 203 can be filled with a fluid, either a liquid or a gas. The first elongate member 203 can be substantially sealed so as to prevent loss of a quantity of the fluid. The first elongate member 203 can also be open at one or both ends so as to allow a continuous flow of liquid or gas.

[0170] The gas can be air, as it has a low thermal conductivity (2.62 x 10 -2W / m-K) is desirable. It can also be advantageous to use a gas that is more viscous than air, as the higher viscosity reduces heat transfer under natural convection conditions. Thus, gases such as argon (17.72 x 10 -3 W / m-K), krypton (9.43 x 10 -3 W / m-K), and xenon (5.65 x 10 -3 W / m-K) can increase insulation performance. Each of these gases is non-toxic, chemically inert, fireproof, and commercially available. The hollow portion of the first elongated member 203 can be sealed at both ends of the tube, resulting in the gas within being substantially stagnant. Alternatively, the hollow portion can be a secondary pneumatic connection, such as a pressure sample line for delivering pressure feedback from the patient end of the tube to a controller.

[0171] Examples of the liquid can include water or other biocompatible liquids with high heat capacity. For example, a nanofluid can be used. One example nanofluid with suitable heat capacity includes water and nanoparticles of a substance such as aluminum.

[0172] In use, the fluid in the hollow portion of the first elongated member 203 can be configured to measure one or more properties of the gas within the tube 201, the first elongated member 203, the second elongated member 205, and / or the lumen 207 of the tube 201. In at least one embodiment, the pressure of the gas moving along the lumen of the tube ("lumen gas") can be measured. A reference measurement of the pressure of the fluid in the hollow portion of the first elongated member 203 ("hollow fluid") is taken before the lumen gas begins to circulate. As the lumen gas begins to pass through the tube 201, the pressure of the lumen gas will tend to cause a proportional rise in the pressure of the hollow fluid within the first elongated member 203. By comparing the measurements taken in use to the reference measurement, the pressure of the lumen gas within the tube 201 can be determined. In another embodiment, a hollow fluid is selected that changes one or more properties based on the operating thermal range of the lumen gas within the tube 201. In this way, by measuring the properties of the hollow fluid, the temperature of the lumen gas can be determined. For example, a hollow fluid that expands with temperature can be used. In use, the temperature of the hollow fluid will tend to be that of the lumen gas flow. The temperature of the lumen gas can then be determined by measuring the pressure of the hollow fluid. This can have particular benefits when the temperature of the lumen gas flow is difficult to measure directly or is undesirable.

[0173] In at least one embodiment, the extrudate used to form the first elongate member 203 further includes a mineral filler. The extrusion process will be described in greater detail below. Talc or hydrated magnesium silicate is a suitable mineral filler. In addition to talc, other suitable mineral fillers include calcium carbonate, magnesium carbonate calcium such as dolomite, barium sulfate, wollastonite, kaolin, and mica, each of which can be added alone or in combination. Suitable mineral fillers can also have a particle size of less than 10 μm (or about 10 mm), or less than 2.5 μm (or about 2.5 mm).

[0174] It has been discovered that the addition of a mineral filler to the plastic extruder reduces the tackiness of the resulting first elongate member 203. Tackiness refers to the touchable stickiness or stickiness of the first elongate member 203 material. A more tacky material feels more sticky than a less tacky material. A more tacky material also tends to stick to more unwanted substances, such as dirt or hair, than a less tacky material. By reducing the degree to which adjacent blisters stick to each other (and do not stick), it has been discovered that the addition of a mineral filler reduces the noise generated when the tube is moved, bent, etc. around the perimeter of a bend (and not around the perimeter of a bend).

[0175] It has also been discovered that the addition of a mineral filler to the extrudate further reduces the noise generated when the first elongate member 203 is dragged over the edge of an object, such as a table or night stand. The mineral filler can help reflect the sound into the surrounding polymer, so that the sound does not travel straight through. Improved sound reflection can also give the polymer phase more opportunity to absorb the sound energy, and the mineral filler thus provides inherent sound dampening. The mineral filler can also reduce the stiffness of the plastic extrudate, and thus improve the sound dampening properties.

[0176] In certain embodiments, the mineral filler ranges from 1.5 to 10 (or from about 1.5 to about 10) by weight percent of the total extrudate. In certain embodiments, the mineral filler ranges from 1.5 to 5 (or from about 1.5 to about 5) by weight percent of the total extrudate. In certain embodiments, the mineral filler is 10 (or about 10) or less by weight percent of the total extrudate. In certain embodiments, the mineral filler is 5 (or about 5) or less by weight percent of the total extrudate. In certain embodiments, the mineral filler is 1.5 (or about 1.5) or more by weight percent of the total extrudate.

[0177] In Figure 2F the first elongate member 203 forms a plurality of hollow blisters in its longitudinal cross-section. In this example, there are a plurality of blisters, and more specifically, two adjacent blisters of the first elongate member 203 between the sheaths of the second elongate member 205. In Figure 2GThis configuration is shown in more detail. As described and illustrated elsewhere in this disclosure, certain configurations can implement two or more, e.g., three, pockets of the first elongated member 203 between pockets of the second elongated member 205.

[0178] Embodiments that include multiple adjacent pockets of the first elongated member 203 between pockets of the second elongated member 205 can be advantageous because they increase the overall tube flexibility. As described below, the flexibility of the substantially solid second elongated member 205 is generally less than that of the hollow first elongated member 203. Thus, certain embodiments include the realization that the overall tube flexibility can be increased by increasing the number of pockets of the first elongated member 203 between pockets of the second elongated member 205.

[0179] Another advantage of embodiments that include multiple adjacent pockets of the first elongated member 203 between pockets of the second elongated member 205 is improved recovery from crush. It has been observed that samples with multiple pockets of the first elongated member 203 between pockets of the second elongated member 205 recover their shape more quickly after being crushed than samples with a single pocket of the first elongated member 203 between pockets of the second elongated member 205.

[0180] Yet another advantage of embodiments that include multiple adjacent pockets of the first elongated member 203 between pockets of the second elongated member 205 is improved crush resistance. Crush resistance is a mechanical property that has important implications for the resilience of a tube in service. Hospital environments can be harsh because tubes can be crushed by a patient's arm or leg, a bed frame, and other equipment. Example crush resistance properties are discussed in more detail below.

[0181] Another advantage of the multi-pocket configuration is that it confers the ability to carry or transport additional fluids. As explained above, the hollow portion of the first elongated member 203 can be filled with a gas. Multiple discrete pockets or hollow portions can be filled with multiple discrete gases. For example, one hollow portion can carry or transport a first gas, and a second hollow portion can be used as a secondary pneumatic connection, such as a pressure sample line for delivering pressure feedback from the patient end of the tube to a controller. As another example, multiple discrete pockets or hollow portions can be filled with a combination of liquids or a combination of liquids and gases. For example, a first pocket can carry or transport a gas, and a second pocket can carry or transport a liquid. Suitable liquids and gases are described above.

[0182] It should be appreciated that while the configurations in Figure 2F and 2G may be preferred in certain embodiments, other configurations can be used in other embodiments as can be desired.

[0183] Second elongation member

[0184] Referring again to Figure 2A and Figure 2B The second elongated member 205 is also helically wound and is coupled with the first elongated member 203 between the turns of the first elongated member 203. The second elongated member 205 can form at least a portion of a lumen 207 of the composite tube 201. The second elongated member 205 acts as a structural support for the first elongated member 203.

[0185] The weight of the CPAP machine is typically in the range of 2 to 4 kg (or about 2 to 4 kg). Therefore, the breaking strength of the composite tube 201 (the level tensile load or force required to separate the first elongated member 203 from the second elongated member 205) is desirably high enough to prevent separation in the event that a user attempts to use the composite tube 201 to lift one of the CPAP machines connected to the composite tube 201. Therefore, the breaking strength is preferably greater than 20 N (or about 20 N), and more preferably greater than 30 N (or about 30 N). In certain embodiments, the breaking strength is in the range of 75 to 80 N (or about 75 to 80 N). The yield strength (the maximum stress that can be produced without causing plastic deformation) can be in the range of 55 to 65 N (or about 55 to 65 N). In certain embodiments, the composite tube 201 does not stretch (horizontally deflect) more than 0.5 mm (or about 0.5 mm) when a lateral force of 2 N is applied.

[0186] In at least one embodiment, the second elongated member 205 is wider at its base (proximal to the lumen 207) and narrower at its top. For example, the second elongated member is generally triangular, generally T-shaped, or generally Y-shaped in shape. However, any shape that conforms to the profile of the corresponding first elongated member 203 is suitable.

[0187] Preferably, the second elongated member 205 is flexible to facilitate bending of the tube. Desirably, the second elongated member 205 is less flexible than the first elongated member 203. This improves the ability of the second elongated member 205 to structurally support the first elongated member 203. For example, the modulus of the second elongated member 205 is preferably 30-50 MPa (or about 30-50 MPa). The modulus of the first elongated member 203 is less than the modulus of the second elongated member 205. The second elongated member 205 can be solid, or predominantly solid.

[0188] Figure 6A A longitudinal cross-section of the composite tube 201 in a neutral position is shown. Figure 6AFocusing on one turn or bubble of the first elongate member 203 and two turns of the second elongate member 205. The first elongate member 203 and the second elongate member 205 have radially outermost connection points 601. In this example, the inner portion 211 of the first elongate member 203 is thinner than the outer portion 219 of the first elongate member 203. In this example, the second elongate member 205 also has a triangular cross-section. The lumen 207 is located below the base of the first elongate member 203 and the second elongate member 205. Figure 6B The composite tube 201 is shown in a curved position Figure 6A of the composite tube 201 has been curved into a shape like a Figure 6C as shown in Figure 6B Again, focusing on one turn or bubble of the first elongate member 203 and two turns of the second elongate member 205. More specifically, Figure 6B the turn or bubble of the first elongate member 203 at the top of the shape, i.e. the position of maximum curvature. The radius of curvature of the composite tube 201 is limited by the length of the segment between the adjacent outermost connection points 601 in the outer portion 219. If the composite tube 201 is curved beyond the minimum radius of curvature, the outer wall forms a dimple 605 as shown in Figure 6D

[0189] A variety of polymers and plastics, including medical grade plastics, are suitable for the body of the second elongate member 205. Examples of suitable materials include: polyolefin elastomers, polyether amide block, thermoplastic copolyester elastomers, EPDM-polypropylene blends, and thermoplastic polyurethanes. In certain embodiments, the first elongate member 203 and the second elongate member 205 can be made of the same material. The second elongate member 205 can also be made of a material that is a different color than the first elongate member 203, and can be transparent, translucent, or opaque. For example, in one embodiment, the first elongate member 203 can be made of a transparent plastic, and the second elongate member 205 can be made of an opaque blue, black, or other colored plastic.

[0190] The combination of a flexible hollow body and a helically wound structure that is integrally supported can provide crush resistance while allowing the tube wall to be flexible enough to permit small radius bending without kinking, occlusion, or collapse. Preferably, the tube can be bent around a metal cylinder having a diameter of 25 mm without kinking, occlusion, or collapse, as defined in the experiment to increase flow resistance by bending according to ISO 5367:2000(E).

[0191] This structure can also provide a smooth lumen 207 surface, which helps to keep the tube from depositing and improves gas flow. The hollow body has been found to improve the insulating properties of the tube while enabling the tube to remain lightweight. ​

[0192] In some embodiments, the second elongated member 205 may be made of a water-absorbing material. For example, a water-absorbing sponge-like material may be used. In such embodiments, the second elongated member 205 may be attached to a water source, such as a water bag. In use, water is delivered along at least a portion (preferably substantially the entire length) of the second elongated member 205. As gas flows through the second elongated member 205, water vapor will tend to be absorbed by the gas within the lumen 207, thereby humidifying the gas flow.

[0193] In some embodiments, one or more heating filaments 215 (such as those embedded in the second elongated member 205) are used. Figure 2B (As shown) can be controlled to change the evaporation rate, and thus change the level of humidification supplied to the gas stream. Although Figure 2B The heating filament 215 is specifically shown, but it should be understood that the second elongated member 205 may encapsulate or contain one or more other conductive materials, such as one or more filaments, and specifically a sensor (not shown). Such conductive materials may be disposed within the second elongated member 205 for heating or sensing the gas flow. The heating filament 215 can minimize the cold surface of condensates that may form from humid air. The heating filament 215 can also be used to alter the temperature profile of the gas within the lumen 207 of the composite tube 201.

[0194] exist Figure 2B In this example, two heating filaments 215 are encapsulated within a second elongated member 205, one on each side of the vertical portion of the "T". The heating filaments 215 comprise an alloy or conductive polymer of a conductive material such as aluminum (Al) and / or copper (Cu). Preferably, when the heating filaments 215 reach their operating temperature, the material forming the second elongated member 205 is selected such that it does not react with the metal in the heating filaments 215. These filaments 215 may be spaced apart from the lumen 207 so that they are not exposed within the lumen 207. At one end of the composite tube, the paired filaments may be formed as a connecting loop.

[0195] In at least one embodiment, multiple filaments are disposed in the second elongation member 205. These filaments can be electrically connected together to share a common track. For example, a first filament, such as a heating filament, can be disposed on a first side of the second elongation member 205. A second filament, such as a sensing filament, can be disposed on a second side of the second elongation member 205. A third filament, such as a grounding filament, can be disposed between the first and second filaments. The first, second, and / or third filaments can be connected together at one end of the second elongation member 205.

[0196] Figure 2E A longitudinal section of the top portion of another composite pipe is shown. Figure 2EWith Figure 2B Same orientation. In Figure 2E In the example, the heating filament 215 is... Figure 2B The filaments 215 are spaced further apart from each other. It has been found that increasing the space between the heating filaments can improve heating efficiency, and some embodiments include this implementation. Heating efficiency refers to the ratio of the amount of heat input into the tube to the amount of energy output from or recoverable from the tube. Generally, the greater the energy (or heat) dissipated from the tube to the ambient atmosphere, the lower the heating efficiency. To improve heating performance, the heating filaments 215 can be spaced equally (or substantially equally) along the tube opening. Alternatively, the filaments 215 can be positioned at the end of the second elongated member 205, which provides simpler manufacturing.

[0197] Next reference Figures 7A to 7G These figures show an example construction of the second elongation member 205. Figure 7A A cross-section of the second elongated member 205 is shown, the shape of which is similar to... Figure 2B Similar to the T-shape shown. In this example embodiment, the second elongated member 205 does not have a heating filament. Other shapes of the second elongated member 205 can also be utilized, including variations of the T-shape as described below, as well as a triangular shape.

[0198] Figure 7B Another example of a second elongated member 205 is shown, which has a T-shaped cross-section. In this example, heating filaments 215 are embedded within a cut 701 on either side of the vertical portion of the "T" in the second elongated member 205. In some embodiments, the cut 701 may be formed in the second elongated member 205 during extrusion. Alternatively, the cut 701 may be formed in the second elongated member 205 after extrusion. For example, a cutting tool may form the cut in the second elongated member 205. Preferably, these cuts are formed by the heating filaments when they are pressed or pulled (mechanically secured) into the second elongated member 205 shortly after extrusion, while the second elongated member 205 is relatively soft. Alternatively, one or more heating filaments may be mounted (e.g., attached, bonded, or partially embedded) on the base of the elongated member, such that the filaments are exposed within the lumen of the tube. In such embodiments, it may be desirable for the filaments to be insulated, thereby reducing the risk of fire when flammable gases such as oxidizers pass through the lumen.

[0199] Figure 7C Another example, the second elongated member 205, is shown in cross-section. The second elongated member 205 has a generally triangular shape. In this example, the heating filament 215 is embedded on opposite sides of the triangle.

[0200] Figure 7D Another example second elongated member 205 is shown in cross-section. The second elongated member 205 includes four grooves 703. The grooves 703 are indentations or channels in their cross-sectional profile. In some embodiments, the grooves 703 can facilitate the formation of cutouts (not shown) for embedding filaments (not shown). In some embodiments, the grooves 703 facilitate the positioning of filaments (not shown) that are pressed or pulled into the grooves and thereby embedded in the second elongated member 205. In this example, the four activation grooves 703 facilitate the placement of up to four filaments, such as four heating filaments, four sensing filaments, two heating filaments and two sensing filaments, three heating filaments and one sensing filament, or one heating filament and three sensing filaments. In some embodiments, the heating filaments can be located on the outside of the second elongated member 205. The sensing filaments can be located on the inside.

[0201] Figure 7E Another example second elongated member 205 is shown in cross-section. The second elongated member 205 has a T-shaped profile and a plurality of grooves 303 for placing heating filaments.

[0202] Figure 7F Another example second elongated member 205 is shown in cross-section. Four heating filaments 215 are encapsulated in the second elongated member 205, two on either side of the vertical portion of the "T". As explained in more detail below, the filaments are encapsulated in the second elongated member 205 because the second elongated member 205 is extruded around the filaments. No cutouts are formed to embed the heating filaments 215. In this example, the second elongated member 205 also includes a plurality of grooves 703. Because the heating filaments 215 are encapsulated in the second elongated member 205, the grooves 703 are not used to help form cutouts for embedding the heating filaments. In this example, the grooves 703 can facilitate the separation of the embedded heating filaments, which makes it easier to peel apart individual cores when, for example, terminating the heating filaments.

[0203] Figure 7G Another example second elongated member 205 is shown in cross-section. The second elongated member 205 has a generally triangular shape. In this example, the shape of the second elongated member 205 is similar to the shape in Figure 7C but four filaments 215 are encapsulated in the second elongated member 205, all of the filaments being located at the center of the bottom third of the second elongated member 205 and disposed along a generally horizontal axis.

[0204] As explained above, it can be desirable to increase the distance between the filaments to improve heating efficiency. In some embodiments, however, when the heating filaments 215 are incorporated into the composite tube 201, the filaments 215 can be positioned in the relative center of the second elongated member 205. Centered positioning improves the robustness of the re-used composite tube, in part, because such positioning reduces the likelihood of filament breakage in repeated flexing of the composite tube 201. Centered filaments 215 can also reduce the risk of fire hazard because the filaments 215 are covered by multiple layers of insulation and can be removed from the gas path.

[0205] As explained above, some examples illustrate the proper placement of the filaments 215 in the second elongated member 205. In the foregoing examples that include more than one filament 215, the filaments 215 are generally aligned along a horizontal axis. Alternative configurations are also applicable. For example, two filaments can be aligned along a vertical axis or along a diagonal axis. Four filaments can be aligned along a vertical axis or along a diagonal axis. Four filaments can be arranged in a cross configuration, with one filament disposed at the top of the second elongated member, one filament disposed at the bottom of the second elongated member (adjacent to the lumen of the tube), and two filaments disposed on opposite arms of a "T," "Y," or triangular base.

[0206] size

[0207] Tables 3 and 4 illustrate some example dimensions of medical tubes described herein and some ranges of these dimensions. The dimensions refer to the transverse cross-section of the tube. In the tables, lumen diameter refers to the inner diameter of the tube. Pitch refers to the distance between two repeating points measured axially along the tube, that is, between the tips of the vertical portions of the "T" adjacent to the second elongated member. Bubble width refers to the width (maximum outer diameter) of a bubble. Bubble height refers to the height of a bubble from the lumen of the tube. Bead height refers to the maximum height of the second elongated member from the lumen of the tube (e.g., the height of the vertical portion of the "T"). Bead width refers to the maximum width of the second elongated member (e.g., the width of the horizontal portion of the "T"). Bubble thickness refers to the thickness of the bubble wall.

[0208] Table 3

[0209]

[0210] Table 4

[0211]

[0212] In another example embodiment, a medical tube has approximate dimensions as shown in Table 5.

[0213] Table 5

[0214]

[0215]

[0216] In another example embodiment, the medical tube has the approximate dimensions as shown in Table 6.

[0217] Table 6

[0218]

[0219] Preferably, the lower limits of the ranges of Table 6 correspond to each other, and the upper limits of the ranges of Table 6 correspond to each other.

[0220] The embodiments of Table 5 and Table 6 can be particularly advantageous for obstructive sleep apnea applications.

[0221] Tables 7, 8, and 9 provide example ratios between the tube size characteristics of the tubes described in Tables 3, 4, and 6, respectively.

[0222] Table 7

[0223]

[0224]

[0225] Table 8

[0226] ratio baby aldult Lumen diameter: pitch 2.3:1 2.4:1 Pitch: width of the bubble 1.1:1 1.1:1 Pitch: Bead width 2.2:1 2.2:1 Bubble width: Bead width 2.0:1 2.1:1 Lumen diameter: Bubble height 3.9:1 4.5:1 Lumen diameter: Bead height 12.2:1 10.6:1 Bubble height: Bead height 3.1:1 2.4:1 Lumen diameter: Bubble thickness 27.5:1 90.0:1

[0227] Table 9

[0228] ratio value Lumen diameter: pitch 3.4:1 Pitch: width of the bubble 0.93:1 Pitch: Bead width 2.2:1 Bubble width: Bead width 1.7:1 Lumen diameter: Bubble height 5.4:1 Lumen diameter: Bead height 10.8:1 Bubble height: Bead height 1.7:1 Lumen diameter: The thickness of the bubble furthest from the lumen at the top. 71.7:1 Lumen diameter: Thickness of the bubble-like structure adjacent to the lumen 172:1

[0229] Variable pitch and / or variable diameter

[0230] The foregoing description discloses different constant pitch and constant diameter configurations. However, certain embodiments can incorporate variable pitch and / or variable diameter.

[0231] Variable pitch can be desirable because it can better allow the heat delivered to the gas stream to vary along the length of the tube. The ability to control where heat is delivered into the tube can be used to control or reduce the rainout effect within the tube. For example, a tube end temperature set point can be achieved for a given condition that is not sufficient to prevent the rainout effect within the tube, particularly at or near the inlet of the tube where the gas temperature can approach the dew point temperature (high relative humidity). Certain embodiments include the following realization: redistributing the heat source to concentrate the heat source near the inlet of the tube can help ensure greater axial concentration of heat Q(z) [W / m] in this region, where z is the axial placement in the tube starting from the device end.

[0232] Figure 8A One example composite tube 201 with a variable pitch is shown. In this example, the tube 201 has a smaller pitch proximal to the device end 801. As a result, the heating filaments 215 in this region will be more closely spaced, resulting in more heating and greater and more accurate temperature control at that portion of the tube 201. The tube 201 has a larger pitch at the patient end 803. The greater spacing between the heating filaments 215 can allow the gas to reduce in temperature closer to the patient. This can prevent the patient from receiving too hot of a gas and can reduce rainout formation. Figure 8B Temperature profiles of the composite tube are shown. Figure 8A Other temperature profiles are possible and can be tailored to achieve a particular desired effect.

[0233] The geometry of the tube 201 also affects the mechanical properties of the tube. By increasing the size of the bubbles of the first elongate member, the flexibility of the tube 201 can be increased. Conversely, a smaller bubble size can result in a more rigid region of the tube 201. By varying the flexibility and rigidity, the mechanical properties of the tube 201 can be tailored. By varying the diameter of the tube 201, it is possible to have a smaller diameter near the patient interface, which can increase patient comfort, improve aesthetics, and reduce invasiveness of the interface.

[0234] Other characteristics

[0235] Tables 10-13 show some example properties of a composite tube (labeled "A") having heating filaments incorporated within a second elongate member, as described herein. For comparison, properties of a Fisher & Paykel model RT100 disposable corrugated tube (labeled "B") having heating filaments helically wound within a tube bore of the tube are also presented.

[0236] Resistance to flow ratio (RTF) was measured according to Annex A of ISO 5367:2000(E). Results are summarized in Table 10. As can be seen below, the RTF of the composite tube is lower than the RTF of the model RT100 tube.

[0237] Table 10

[0238]

[0239] Condensate or "rainout" within the tube refers to the weight of condensate collected per day at a gas flow rate of 20 L / min and at a room temperature of 18°C. Humidified air was continuously flowed through the tube from a chamber. The tube weight was recorded each day prior to testing and each day after testing. Three consecutive tests were performed, with the tube dried between tests. Results are shown in Table 11 below. The results show that rainout in the composite tube is significantly lower than the model RT100 tube.

[0240] Table 11

[0241]

[0242] Power requirements refer to the power consumed during the condensation test. In this test, the ambient air was kept at 18°C. The humidification chamber (see, e.g., the humidification chamber 129 in Figure 1 , is powered by an MR850 heating base. The heating filaments in this tube are independently powered by a DC power supply. Different flow rates are set, and the temperature of the chamber is kept at 37°C at the chamber output. Then, the DC voltage of the circuit is changed to produce a temperature of 40°C at the circuit output. The voltage required to maintain this output temperature is recorded, and the resulting power is calculated. The results are shown in Table 12. The results show that composite tube A uses significantly more power than tube B. This is because tube B uses a helical heating filament in the tube bore to heat the gas from 37°C to 40°C. The composite tube does not heat the gas as quickly, because the heating filaments are located in the wall of the tube (embedded in the second elongated member). Instead, the composite tube is designed to maintain the gas temperature, and to prevent the rainout effect by maintaining the tube bore temperature above the dew point of the humidified gas.

[0243] Table 12

[0244] Flow rate (L / min) 40 30 20 Power required (W) for tube A 46.8 38.5 37.8 Power required (W) for tube B. 28.0 27.5 26.8

[0245] Vertical deflection can be used to quantify the flexibility of the composite tube. Vertical deflection can be tested, for example, using a three-point bend test. A first 300 mm long sample of tube A and a second 300 mm long sample of tube B were tested on a flexible clamp, respectively. Figure 9A A front side top view cross-sectional schematic of the flexible clamp is shown in FIG. 9. The clamp 901 uses a 25-mm rod 903 with a fixed mass of 120 g to apply a force to each tube 201, the rod being positioned between two rollers 905 and 907. The rollers are spaced 150 mm apart. The force applied by the rod 903 is about 1.2 N (0.12 kg x 9.81 m / s 2 ). Figure 9B A detailed front side top view cross-sectional schematic of the rollers 905 and 907 is shown in FIG. 10. Both rollers 905 and 907 have the same dimensions as shown in FIG. 9. An Instron 5560 testing system instrument was used to measure the load and extension. Each tube sample was tested three times; the extension of the tube under the applied load was measured to obtain the respective average stiffness constant. The average stiffness constants of tube A and tube B are reproduced in Table 13. Figure 9B

[0246] Table 13

[0247] Tube Stiffness (N / mm) A 0.028 B 0.088 ​

[0248] Tube weight can be very important, especially for CPAP applications. If the patient experiences less weight near the patient's face, the patient will be more comfortable during sleep. A lighter composite tube 201 will not pull the patient's head in a particular direction as much as a heavier tube. To ensure patient comfort, it can be specified that the total mass or weight in the region near the patient end of the composite tube 201 must be less than a specified value. In certain embodiments, the tube mass 300 mm from the patient end is less than 24 g (or about 24 g). It is desirable that the tube mass 300 mm from the patient end is less than 16 g (or about 16 g). In certain embodiments, the tube mass 300 mm from the patient end is less than 15 g (or about 15 g). It can also be specified that the total mass of the composite tube is less than a specified value. In certain embodiments, the tube mass is less than 130 g (or about 130 g). It is desirable that the tube mass is less than 120 g (or about 120 g). In certain embodiments, the tube mass is less than 100 g (or about 100 g).

[0249] Additional properties related to a composite tube 201 having two blisters between the coverings of the second elongate member 205 as described above will now be discussed.

[0250] A first sample tube 300 mm in length including two blisters between the coverings of the second elongate member 205, and a second sample tube 300 mm in length including one blister between the coverings of the second elongate member 205 were each tested on the elastic clip 901 described above. The vertical deflection was measured using a fixed weight positioning relative to the vertical support 909 of the elastic clip, see Figures 9C to 9F in the photographs.

[0251] Figure 9C A front side perspective view of the second sample under test in the clip 901 is shown. Figure 9D A back side perspective view of the second sample under test in the clip 901 is shown. Figure 9E A front side perspective view of the first sample under test in the clip 901 is shown. Figure 9F A back side perspective view of the first sample under test in the clip 901 is shown. As Figures 9C to 9F shown in the photographs, Figure 9E and Figure 9F the vertical deflection of the second sample was substantially greater than the first sample shown in Figure 9C and Figure 9D Specifically, the vertical deflection of the second sample was 3 mm, while the first sample, which was much more flexible, had a vertical deflection of 42 mm.

[0252] An Instron instrument was used, as Figure 10AThe photograph shown depicts the assembly undergoing a compression resistance test on four tube samples. The cylinder 1001 was inserted downwards 16 mm from the top of the tube at a rate of 60 mm / min. The Instron instrument has a load sensor to accurately measure the ratio of force applied to the component to elongation. This load-to-elongation ratio is plotted, as shown in... Figure 10B As shown in the image.

[0253] By matching the best line with Figure 10B The data were fitted and their gradients were calculated to obtain the compression stiffness of each sample. Table 14A shows the calculated compression stiffness of each sample. In Table 14A (and elsewhere in this disclosure), the term "double bubble" refers to a tubular sample comprising two bubbles between the sheaths of the second elongation member 205 when the sample is viewed in a longitudinal section. The term "single bubble" refers to a tubular sample comprising a single bubble between the sheaths of the second elongation member 205 when the sample is viewed in a longitudinal section. The average compression stiffness (measured in N / mm) represents the average maximum force per unit width without compression.

[0254] Table 14A

[0255]

[0256]

[0257] As shown in the table above, the single-bubble tube has an average crushing stiffness of 3.86 N / mm, while the double-bubble tube has an average crushing stiffness of 3.21 N / mm. In other words, the double-bubble tube has approximately 16.8% lower crushing resistance than the single-bubble tube. However, it has been observed that the crushing stiffness per unit thickness of the double-bubble tube is approximately 165% of the value of the single-bubble tube, as shown in Table 14B below.

[0258] Table 14B

[0259]

[0260] In other words, when considering the outer bubble thickness, the double-bubble variant exhibits approximately 65% ​​greater resistance to compression and extrusion than the single-bubble variant. Figure 2F and Figure 2G Similar to the bubbles shown, the height of the tested bubbles in the double-bubble structure is greater than their width, resulting in more material in their vertical plane. Therefore, it is believed that this unexpected improvement in the compressibility per unit thickness of the bubbles can be attributed to the additional vertical mesh between the beads acting in the compressive direction.

[0261] Tensile tests were also performed on single bubble tube samples and double bubble tube samples. The length of both samples was 230 mm, and they were elongated 15 mm at a rate of 10 mm / min. The force required to elongate the samples was measured. The results are shown in Table 14C.

[0262] Table 14C

[0263] sample Peak force (N) at a 15mm extension Double bubble 17.60 single bubble 54.65

[0264] As shown in Table 14C, the double bubble tube is significantly easier to stretch in the axial (longitudinal) plane. It is believed that this increase in longitudinal stretchability is due to more material between the beads acting in the axial plane for the single bubble tube.

[0265] thermal properties

[0266] In embodiments of a composite tube 201 incorporating one heating filament 215, heat can be lost through the walls of the first elongated member 203, resulting in non-uniform heating. As explained above, one method of compensating for these heat losses is to apply an external heat source to the walls of the first elongated member 203, which helps to regulate the temperature and counteract heat losses. However, other methods for optimizing thermal properties can also be used.

[0267] Referring again to Figures 5A to 5C , these figures illustrate example configurations of bubble height (i.e., the cross-sectional height of the first elongated member 203 measured from the surface facing the inner lumen to the surface forming the maximum outer diameter) to improve thermal properties.

[0268] The dimensions of the bubble can be selected to reduce heat losses of the composite tube 201. Generally, increasing the height of the bubble increases the effective thermal resistance of the tube 201, as a larger bubble height causes the first elongated member 203 to hold more insulating air. However, it has been found that at a certain bubble height, changes in air density cause convection currents within the tube 201, thereby increasing heat losses. Also, at a certain bubble height, the surface area becomes so large that heat losses through the surface outweigh the benefits of the increased height of the bubble. Certain embodiments include these realizations.

[0269] The radius of curvature and the curvature of the bubble can be used to determine a desired bubble height. The curvature of an object is defined as the inverse of the radius of curvature of the object. Thus, the greater the radius of curvature of an object, the less the curvature of the object. For example, a flat surface has an infinite radius of curvature, and thus a curvature of zero.

[0270] Figure 5A A longitudinal cross-section of a top end portion of a composite tube is shown. Figure 5AOne embodiment of a compound tube 201 is shown, where the bubble has a large height. In this example, the bubble has a relatively small radius of curvature, and thus a large curvature. Also, the height of the bubble is about three to four times higher than the height of the second elongated member 205.

[0271] Figure 5B A longitudinal cross-section of the top end portion of another compound tube is shown. Figure 5B One embodiment of a compound tube 201 is shown, where the bubble has a large height. In this example, the bubble has a relatively small radius of curvature, and thus a large curvature. Also, the height of the bubble is about three to four times higher than the height of the second elongated member 205.

[0272] Figure 5C A longitudinal cross-section of the top end portion of another compound tube is shown. Figure 5C One embodiment of a compound tube 201 is shown, where the bubble has a large height. In this example, the bubble has a relatively small radius of curvature, and thus a large curvature. Also, the height of the bubble is about three to four times higher than the height of the second elongated member 205. Figure 5A and between Figure 5B and the center of the radius of the upper portion of the bubble is on the outside of the bubble (as compared to Figure 5A ). The turning points of the left and right sides of the bubble are about in the middle (in height) of the bubble (as compared to the lower portion of the bubble, as shown in Figure 5A . Also, the height of the bubble is about twice the height of the second elongated member 205, such that the bubble height is between Figure 5A and 5B the height shown.

[0273] Figure 5A The configuration of Figure 5B results in the lowest heat loss of the tube. Figure 5C The configuration of Figure 5A results in the highest heat loss of the tube. Figure 5B The heat loss of the configuration of Figure 5A is between the configuration of Figure 5A and Figure 5C . However, the large outer surface area and convective heat transfer in the configuration of Figure 5C results in less efficient heating. Thus, in the arrangement of the three bubbles of -5C, it is determined that Figure 5C has the best overall thermal characteristics. The practical implication of this thermal efficiency is that, when the same amount of thermal energy is input into the three tubes, Figure 5B results in the largest temperature rise along the length of the tube. Figure 5B The bubble of Figure 5AThe construction has intermediate thermal properties and causes its temperature to rise less than Figure 5C the construction of

[0274] It will be appreciated that while Figure 5C the construction of Figure 5A , Figure 5B and other variants can be preferred in some embodiments, other constructions, including those shown in

[0275] Table 15 shows the height of the bubble shown in each of Figure 5A , Figure 5B and Figure 5C , the outer diameter of the tube, and the radius of curvature of the construction.

[0276] Table 15

[0277] Pipe (pictured) 5A 5B 5C Height of the bubble (mm) 3.5 5.25 1.75 Outer diameter (mm) 21.5 23.25 19.75 Radius of curvature (mm) 5.4 3.3 24.3

[0278] Table 16A shows the height of the bubble, the outer diameter, and the radius of curvature of further constructions as shown in Figure 11A , Figure 11B and Figure 11C .

[0279] Table 8A

[0280] Pipe (pictured) 10A 10B 10C Height of the bubble (mm) 6.6 8.4 9.3 Outer diameter (mm) 24.6 26.4 27.3 Radius of curvature (mm) 10 8.7 5.7

[0281] It will be noted that, in general, the tighter the bend of the tube around itself can be made without causing the bubble to collapse or "crimp" the smaller the radius of curvature. For example, Figure 11D shows a tube bent beyond its radius of curvature (in particular, it shows a tube of Figure 11A bent with a radius of curvature of around 5.7mm), thereby causing crimping of the bubble wall. Crimping is generally undesirable as it detracts from the appearance of the tube and can damage the thermal properties of the tube.

[0282] Thus, in some applications, a construction having increased bending properties, such as those shown in Figure 5A or Figure 5B may be desirable, even though it has less efficient thermal properties. In some applications, it has been found that a tube having an outer diameter of 25mm to 26mm (or about 25mm to about 25mm) provides satisfactory performance. It will be appreciated that while the constructions in Figure 5A and Figure 5B may be preferred in some embodiments, other constructions, including those shown in Figure 11A -11D and other variants can be used in other embodiments.

[0283] Referring again toFigures 5C to 5F These figures show example positioning of heating elements 215 that have similar bubble shapes to improve thermal characteristics. The positioning of the heating elements 215 can change the thermal characteristics within the composite tube 201.

[0284] Figure 5C A longitudinal cross-section of the top end portion of another composite tube is shown. Figure 5C An embodiment of a composite tube 201 is shown in which the heating elements 215 are positioned in the center of the second elongated member 205. This example shows the heating elements 215 close to each other but not close to the bubble walls.

[0285] Figure 5D A longitudinal cross-section of the top end portion of another composite tube is shown. Figure 5D An embodiment of a composite tube 201 is shown in which the heating elements 215 are positioned in the center of the second elongated member 205. This example shows the heating elements 215 close to each other but not close to the bubble walls. Figure 5C In comparison, the heating elements 215 are spaced furthest apart from each other in the second elongated member 205. These heating elements are closer to the bubble walls and provide better thermal regulation within the composite tube 201.

[0286] Figure 5E A longitudinal cross-section of the top end portion of another composite tube is shown. Figure 5E An embodiment of a composite tube 201 is shown in which the top ends of the heating elements 215 are spaced apart from each other on the vertical axis of the second elongated member 205. In this example, the heating elements 215 are equidistantly close to each bubble wall.

[0287] Figure 5F A longitudinal cross-section of the top end portion of another composite tube is shown. Figure 5F An embodiment of a composite tube 201 is shown in which the heating elements 215 are spaced apart at opposite ends of the second elongated member 205. The heating elements 215 are close to the bubble walls, especially compared to Figure 5C -5E.

[0288] In Figure 5C -5F, four filament arrangements are shown, it is determined that Figure 5F has the best thermal characteristics. Since they have similar bubble shapes, the thermal losses of the constructed tubes are similar. However, when the same amount of thermal energy is input into the tubes, Figure 5F the filament construction of -5A results in the greatest temperature rise along the length of the tube for the mass of gas within the tube. It is determined that Figure 5D the construction of -5E has the second best thermal characteristics and results in the second greatest temperature rise along the length of the tube. Figure 5C the construction of -5C performs the third best. Figure 5E the construction of -5F has the worst performance and results in the least temperature rise along the length of the tube when the same amount of heat is input.

[0289] It will be appreciated that while the construction of FIGS. 1-2 can be preferred in some embodiments, other constructions, including those shown in FIGS. 3-4, can be used in other embodiments, as can be desired. Figure 5F Figure 5C Figure 5D Figure 5E and other variations shown in FIGS. 3-4 can be used in other embodiments.

[0290] Referring next to Figures 12A to 12C , these figures illustrate example constructions for stacking first elongate members 203. It has been found that in some embodiments, heat distribution can be improved by stacking multiple bubbles. These embodiments can be more beneficial when using internal heating filaments 215. Figure 12A A longitudinal cross-section of a top end portion of another composite tube is shown. Figure 12A A cross-section of a composite tube 201 without any stacking is shown.

[0291] Figure 12B A longitudinal cross-section of a top end portion of another composite tube is shown. Figure 12B Another example composite tube 201 with stacked bubbles is shown. In this example, the tops of two bubbles are stacked on top of each other to form a first elongate member 203. In comparison to Figure 12A , the total bubble height remains the same, but the pitch of the bubbles is Figure 12A half. Also, the amount of air in the embodiment of Figure 12B is only slightly reduced. The stacking of the bubbles reduces the natural convection and heat transfer in the gaps between the bubbles 213, and lowers the overall thermal resistance. The heat flow path is increased in the stacked bubbles, making it easier for heat to be distributed through the composite tube 201.

[0292] Figure 12C A longitudinal cross-section of a top end portion of another composite tube is shown. Figure 12C Another example composite tube 201 with stacked bubbles is shown. In this example, the tops of three bubbles are stacked on top of each other to form a first elongate member 203. In comparison to Figure 12A , the total bubble height remains the same, but the pitch of the bubbles is Figure 12A one-third. Also, the amount of air in the embodiment of Figure 12B is only slightly reduced. The stacking of the bubbles reduces the natural convection and heat transfer in the gaps between the bubbles 213.

[0293] Referring now to Figure 13 ​​​, showing additional possible features of the second elongated member 205. The second elongated member 205 includes one or more coaxial cables 1301 having conductors 1303 surrounded by an insulating layer 1305, a protective layer 1307, and a jacket layer 1309. In some embodiments, the one or more cables 1301 can be multi-axial cables, i.e., having multiple conductors 1303 arranged in the insulating layer 1305. In this manner, a single assembly containing multiple wires, including heating wires and / or sensing wires, can be used in the second elongated member 205, thereby simplifying assembly and providing some protection against RF interference, etc. (via the protective layer 1307).

[0294] In some embodiments, one or more data transmission cables can be included in the second elongated member 205. These data transmission cables can include fiber optic cables. In at least one embodiment, a single fiber optic cable is included in the second elongated member 205 and used in a passive mode. In a passive mode, at a first end of the cable, a light source and a light sensor are provided. At a second end, a reflector is provided. In use, the light source provides some light having certain properties to the reflector. The reflector then reflects the light to the light sensor, which can analyze the reflected light to determine the properties of the light. The reflector can be adapted to change the properties of the reflected light according to a property of the system. For example, the reflector can be used to monitor condensation within the interface. The reflector can contain a material that changes color, for example, according to condensation present at the second end. The reflector can alternatively or additionally contain a material that changes color according to a humidity level (relative humidity or absolute humidity) and / or gas temperature at the second end; and / or gas composition such as inhaled O2 or exhaled CO2, etc., at the second end.

[0295] Referring again to Figure 2B In some embodiments, a fluid (gas or liquid) flow can flow through the space within the first elongated member 203. In such embodiments, it is desirable that at least a portion of the first elongated member 203 be formed of a gas permeable material. Gas permeable is used herein to mean substantially permeable to water vapor and substantially impermeable to liquid water and bulk gas flow. Suitable gas permeable materials include an activated perfluorinated polymer material having extreme hydrophilic properties such as or a hydrophilic polyester block copolymer such as Other suitable materials include EVAQUA TM and EVAQUA 2 TMA suitable material is a polymer commercially available as a conduit (Fisher & Paykel Healthcare Ltd., Auckland, New Zealand). Suitable materials are further described in PCT Publication WO 2011 / 077250, published June 30, 2011, and U.S. Patent No. 6,769,431, issued August 3, 2003, which was filed May 8, 2001.

[0296] The flow through the first elongated member 203 can be used to dry or humidify the flow of gas through the lumen 207 of the tube 201 as desired. Conversely, the flow through the lumen 207 of the tube 201 can be used to dry or humidify the flow of gas through the first elongated member 203 as desired. Exhaled respiratory gases can be carried through the first elongated member 203. As another example, a liquid such as liquid water can be carried. As another example, a humidified or saturated flow of gas can be carried. As another example, a dry flow of gas or a flow of compressed ambient air can be carried. In the foregoing embodiments, the first elongated member 203 can be open at both ends to facilitate the flow of fluid through the first elongated member 203. One end of the first elongated member 203 can be connected to a suitable source as desired, such as a source of exhaled respiratory gases, liquid water, humidified gas, dry gas, or compressed air. The other end can be connected to a suitable outlet or allowed to vent to the atmosphere.

[0297] For example, with reference to Figure 2B The portion 211 of the first elongated member 203 that forms the lumen 207 of the tube 201 can be formed of a gas-permeable material as described above. The outwardly facing portion 219 of the first elongated member 203 (facing the ambient atmosphere and away from the lumen) can be formed of an impermeable material, i.e., a material that is substantially impermeable to water vapor, liquid water, or bulk gas flow, as described elsewhere in this disclosure. In use, some humidification fluid (such as water) can pass through the space formed by the first elongated member 203. Because the humidification fluid is heated (e.g., by the heating filament 215 disposed in the second elongated member 205), a portion of the humidification fluid will tend to evaporate. The water vapor can then pass through the gas-permeable portion 211 into the bulk gas flow passing through the lumen 207, thereby humidifying the bulk gas flow. In this embodiment, the combination of humidification fluid, first elongated member 203, and heating filament 215 can provide a means for humidifying the gas flow within the lumen 207, such that the system can omit a separate humidifier.

[0298] As another example, a flow of gas can pass through the space within the first elongated member 203. For example, exhaled respiratory gases can be carried. Again with reference toFigure 2B As noted above, the first elongated member 203 or at least the outward facing portion 219 of the first elongated member 203 is made of a gas permeable material. In this way, as exhaled gas travels along the length of the first elongated member 203, it tends to dry the gas at the patient end, which is at about 100% relative humidity, to reduce the humidity level at the opposite end.

[0299] Co-extrusion is a suitable method for forming a first elongated member 203 that includes a portion (211 or 219, depending on the desired application) formed of a gas permeable material and a portion (219 or 211, depending on the desired application) formed of an impermeable material.

[0300] Furthermore, while certain of the foregoing embodiments have been described with reference to a single first elongated member 203 that includes a gas permeable portion and an impermeable portion, it will be appreciated that the desired results (e.g., gas flow within the humidified lumen 207) can also be achieved using multiple first elongated members 203. Figure 12B 、 Figure 12C 、 Figure 37A and Figure 37B suitable embodiments are shown.

[0301] Figure 37A A cross-section of a tube including two first elongated members is shown. A first first elongated member 203a is disposed proximal to the lumen 207 of the tube. A second first elongated member 203b faces the ambient atmosphere and is distal from the lumen 207. The inner portion of the first first elongated member 203a forms a wall of the lumen 207. The first first elongated member 203a can define a conduit for a humidification fluid, such as liquid water. The first first elongated member 203a can be formed of a gas permeable material. As the humidification fluid is heated (e.g., by the heating filament 215 disposed in the second elongated member 205), a portion of the humidification fluid will tend to evaporate. The water vapor can then pass through the wall of the first first elongated member 203a into the bulk flow of gas passing through the lumen 207, thereby humidifying the bulk flow of gas. In this embodiment, the combination of the humidification fluid, the first first elongated member 203a, and the heating filament 215 can provide a means for humidifying the flow of gas within the lumen 207, such that the system can omit a separate humidifier. It will be appreciated that Figure 37A The dimensions shown in Figure 12B The first first elongated member 203a can be relatively large and the second first elongated member 203b can be relatively small, as shown in Figure 12BAs shown in

[0302] Figure 37B A cross-section of a tube comprising two first elongated members is also shown. A first first elongated member 203a is disposed proximal to the lumen 207 of the tube. A second first elongated member 203b faces the ambient atmosphere and is distal to the lumen 207. An inner portion of the first first elongated member 203a forms part of the lumen 207 wall. An inner portion of the second first elongated member 203b also forms part of the lumen 207 wall. As discussed above with reference to Figure 37A The first first elongated member 203a can define a conduit for a humidification fluid such as liquid water and the combination of humidification fluid, first first elongated member 203 and heating filament 215 can provide a means for humidifying the gas flow within the lumen 207 such that the system can omit a separate humidifier. Again, it should be appreciated that Figure 37B The dimensions shown in Figure 12B The first first elongated member 203a can be relatively large and the second first elongated member 203b can be relatively small as shown in Figure 12B The second elongated member can be omitted as shown in Referring now to Figure 14A - 14E and Figure 15A - 15E, some variants of the composite tube 201 configuration are shown that are adapted to provide increased lateral expansion in the composite tube 201. Figure 15A - 15E shows respectively Figure 14A - one expanded state of the composite tube shown in

[0303] Comprise Figure 14A , Figure 14B and Figure 14E Some embodiments comprising the tube implementation shown in Figure 14A In Figure 15A this enables the second elongated member 205 to deform outwardly to at least twice its width compared to the second elongated member 205 at rest. In Figure 14B and 14EIn some embodiments, the second elongate member 205 is shaped to have an accordion-like shape. Upon extension, the second elongate member 205 can thus accommodate an increased amount of extension by unfolding (as shown in FIGS. 10A and 10B, respectively). Figure 15B and Figure 15E Upon extension, the first elongate member 203 can thus accommodate an increased amount of extension by deforming outwardly (as shown in FIGS. 11 A and 11B, respectively).

[0304] In some embodiments, the first elongate member 203 is shaped to have an accordion-like shape. Upon extension, the first elongate member 203 can thus accommodate an increased amount of extension by unfolding (as shown in FIGS. 12A and 12B, respectively). Figure 14C and Figure 14D Upon extension, the first elongate member 203 can thus accommodate an increased amount of extension by deforming outwardly (as shown in FIGS. 11 A and 11B, respectively). Figure 15C Figure 15D

[0305] Medical circuit

[0306] Next, reference is made to FIG. 13, which illustrates an example medical circuit in accordance with at least one embodiment. The circuit includes one or more composite tubes as described above, i.e., for the inspiratory tube 103 and / or the expiratory tube 117. The inspiratory tube 103 and the expiratory tube 117 have similar characteristics as the tubes described above with respect to FIG. 9. Figure 16 The inspiratory tube 103 has an inlet 109 in communication with the humidifier 107, and an outlet 113 through which humidified gas is provided to the patient 101. The expiratory tube 117 also has an inlet 109 that receives exhaled humidified gas from the patient, and an outlet 113. As described above with respect to FIG. 9, the outlet 113 of the expiratory tube 117 can exhaust the exhaled gas to the atmosphere, the ventilator / blower device 105, an air washer / filter (not shown), or any other suitable location. Figure 1 Figure 1 As described above, heating filaments 215 can be placed in the inspiratory tube 103 and / or the expiratory tube 117 to reduce the risk of rainout in the tubes by maintaining the tube wall temperature above the dew point temperature.

[0307]

[0308] Components of an insufflation system

[0309] ​​​​Laparoscopic surgery (also known as minimally invasive surgery (MIS) or keyhole surgery) is a modern surgical technique where operations are performed through small incisions (usually 0.5 to 1.5 cm) in the abdomen, rather than the large incisions used in traditional surgery. Laparoscopic surgery includes operations in the abdominal or pelvic cavities. During laparoscopic surgery using insufflation, it can be necessary to humidify the insufflation gas (usually C02) before it is sent into the abdominal cavity. This can help prevent "dehydration" of the patient's internal organs and can reduce the amount of time needed for post-surgery recovery. An insufflation system typically includes a humidifier chamber that holds a quantity of water. The humidifier typically includes a heater plate that heats the water to produce water vapour that is delivered into the incoming gas to humidify the gas. The water vapour is used to carry the gas out of the humidifier.

[0310] Referring next to Figure 17 FIG. 1 illustrates an insufflation system 1701 according to at least one embodiment. The insufflation system 1701 includes an insufflator 1703 that generates a flow of insufflation gas at a pressure above atmospheric pressure for delivery into the abdominal or peritoneal cavity of a patient 1705. The gas enters a humidifier 1707 that includes a heater base 1709 and a humidifier chamber 1711, where the chamber 1711 is in contact with the heater base 1709 in use so that the heater base 1709 can provide heat to the chamber 1711. In the humidifier 1707, the insufflation gas passes through the chamber 1711 so that it becomes humidified to an appropriate humidity level.

[0311] The system 1701 includes a delivery conduit 1713 that is connected between the humidifier chamber 1711 and the peritoneal cavity or surgical site of the patient 1705. The conduit 1713 has a first end that is connected to an outlet of the humidifier chamber 1711 and receives humidified gas from the chamber 1711. The second end of the conduit 1713 is placed in the surgical site or peritoneal cavity of the patient 1705, and the humidified insufflation gas travels from the chamber 1711 through the conduit 1713 into the surgical site to insufflate and inflate the surgical site or peritoneal cavity. The system also includes a controller (not shown) that regulates the amount of humidity supplied to the gas by controlling the power supplied to the heater base 1709. The controller can also be used to monitor the water in the humidifier chamber 1711. An exhaust system 1715 is shown to draw out of the body cavity of the patient 1705.

[0312] The smoke evacuation system 1715 can be used in conjunction with the insufflation system 1701 described above, or can be used with other suitable insufflation systems. The smoke evacuation system 1715 includes a discharge or exhaust branch 1717, a discharge assembly 1719, and a filter 1721. The discharge branch 1717 is connected between the filter 1721 and the discharge assembly 1719, which is positioned in or near the surgical site or peritoneal cavity of the patient 1705 in use. The discharge branch 1717 is a self-supporting tube (i.e., the tube is able to support its own weight without collapsing) having two open ends: an operative site end and an outlet end.

[0313] At least one embodiment includes the implementation of using a composite tube as the conduit 1713 can deliver humidified gases to the surgical site of the patient 1705 with minimal heat loss of the humidified gases.

[0314] Coaxial tube

[0315] The coaxial breathing tube can also include a composite tube as described above. In the coaxial breathing tube, the first gas space is the inspiratory limb or the expiratory limb, and the second gas space is the other inspiratory limb or expiratory limb. A gas passageway is provided between the inlet of the inspiratory limb and the outlet of the inspiratory limb, and a gas passageway is provided between the inlet of the expiratory limb and the outlet of the expiratory limb. In one embodiment, the first gas space is the inspiratory limb, and the second gas space is the expiratory limb. Alternatively, the first gas space can be the expiratory limb, and the second gas space can be the inspiratory limb.

[0316] Referring next to Figure 18 FIG. 18 illustrates a coaxial tube 1801, according to at least one embodiment. In this example, the coaxial tube 1801 is provided between a patient 1801 and a ventilator 1805. Exhaled gases and inhaled gases each flow in an inner tube 1807, or in a space 1809 between the inner tube 1807 and an outer tube 1811. It will be understood that the outer tube 1811 can not be precisely aligned with the inner tube 1807. Additionally, “coaxial” refers to one tube being inside another tube.

[0317] Due to heat transfer reasons, the inner tube 1807 can carry inhaled gases in a space 1813 within it, while the space 1809 between the inner tube 1807 and the outer tube 1811 carries exhaled gases. This air flow configuration is indicated by the arrows. However, it is also possible to have the opposite configuration, where the outer tube 1811 carries inhaled gases, while the inner tube 1807 carries exhaled gases.

[0318] In at least one embodiment, the inner tube 1807 is formed from a corrugated tube, such as Fisher & Paykel model RT100 disposable tube. The outer tube 1811 can be formed from a composite tube as described above.

[0319] Using the coaxial tube 1801, the ventilator 1805 can not notice a leak within the inner tube 1807. Such a leak can short circuit the patient 1801, meaning that the patient 1801 will not receive sufficient oxygen. Such a short circuit can be detected by placing a sensor at the patient end of the coaxial tube 1801. This sensor can be located in the patient end connector 1815. A short circuit closer to the ventilator 1805 will continue to rebreathe the amount of air close to the patient 1801. This will raise the concentration of carbon dioxide in the inhaled gas space 1813 close to the patient 1801, which can be detected directly by a CO2sensor. Such a sensor can comprise any number of such sensors currently available on the market. Alternatively, such rebreathing can be detected by monitoring the temperature of the gas at the patient end connector 1815, where a rise in temperature above a predetermined level indicates rebreathing is occurring.

[0320] In addition to the above to reduce or eliminate the formation of condensate in the inner tube 1807 or the outer tube 1811, and to maintain the temperature of the gas flowing through the coaxial tube 1801 at a substantially uniform temperature, a heater, such as an electrically resistive heating filament, can be provided within the inner tube 1807 or the outer tube 1811, disposed within the gas space 1809 or 1813, or within the walls of the inner tube 1807 or the outer tube 1811 themselves.

[0321] Nasal cannula and other patient interfaces

[0322] Referring next to Figure 19A , this figure illustrates a composite tube 201 used with a nasal cannula patient interface 1901. In this example, the patient interface 1901 is positioned on the face of a patient 1903 using a headgear 1905 secured around the back of the head of the patient 1901. The patient interface includes a cannula body 1907 and a delivery tube 1909. The composite tube 201 as described is in communication with the delivery tube 1909 to supply inhaled gas to the patient interface 1901.

[0323] In the past, delivery tube 1909 was used to decouple the weight of the heated breathing tube from the patient interface 1901. The previously used delivery tube 1909 consisted of a flexible tube of a certain length. Importantly, the delivery tube 1909 was lightweight, so that its mass would not pull the patient interface 1901 off the patient's face. The heated tube was essentially larger and heavier than the unheated tube. Therefore, the previously used delivery tube 1909 was unheated. To achieve satisfactory flexibility, the previously used delivery tube 1909 also had poor insulation properties. Without good insulation and heating, the rain-washing effect in the delivery tube 1909 was a problem. Therefore, the delivery tube 1909 was kept as short as possible to minimize the rain-washing effect. However, a shorter length could not always prevent the weight of the heated breathing tube from pulling off the patient interface 1901. Therefore, the previously used delivery tube had several disadvantages.

[0324] The composite tube 201 described herein provides good insulation while maintaining good flexibility and light weight. Therefore, in some embodiments, the delivery tube 1909 may be the composite tube 201. The composite tube 201 can provide improved insulation properties superior to delivery tubes previously known in the art. Furthermore, the delivery tube can be longer and provides better decoupling of tube drag. The delivery tube 201 of the composite tube 201 may optionally have heating filaments (not shown) in a second elongated member (not shown). The heating filaments (if present) can provide heat input. Alternatively, these heating filaments can provide structural support for the second elongated member when not powered.

[0325] The delivery tube 1909 of the unheated composite tube 201 can be longer than the normal unheated extension, while maintaining the same or less heat loss due to the better insulation properties of the composite tube 201. The increased length of the delivery tube 1909 helps prevent the tube from being pulled off the connection due to patient movement. The increased extension length will also allow for better head movement without compromising patient comfort.

[0326] Furthermore, some embodiments include the following implementation: eliminating the separate delivery tube 1909 can have several benefits, as discussed below. Therefore, as Figure 19B As shown, the delivery tube 1909 and the composite tube 201 may preferably be a single component that extends to the cannula body 1907.

[0327] In a typical patient interface 1901, a heating element (replacing) Figure 19AThe heated composite tube 201 supplies the inhalation gas to the unheated delivery tube 1909. The temperature of the inhalation gas can experience significant heat loss (e.g., 20°C or more or thereabouts) along the length of the unheated delivery tube 1909. To compensate, the temperature of the patient end of the heated tube is maintained higher than the desired temperature actually delivered to the patient 1901. In addition, as the temperature within the delivery tube 1909 drops, condensation can experience a rainout effect. It has been recognized that extending the heated composite tube 201 to the cannula body 1907 instead of the delivery tube 1909, as shown in FIG. 1, can reduce the input energy requirements because the patient end of the composite tube 201 can be maintained at a lower temperature. This configuration can also reduce the rainout effect by eliminating the unheated delivery tube 1909 from the patient interface. Figure 19B

[0328] Desirably, the composite tube 201 can be tapered. In at least one embodiment, the patient end portion of the composite tube 201 is tapered to fit the inlet of the cannula body 1907. In at least one embodiment, the length of the composite tube 201 proximate the patient end has a smaller diameter than the rest of the composite tube 201. For example, the length of the composite tube 201 proximate the patient end can be in the range of 50 to 300 mm (or about 50 to 300 mm). The smaller diameter tube proximate the patient end can advantageously reduce the tube weight near the cannula body.

[0329] The composite tube 201 can include a temperature sensor (not shown) proximate at least the patient end of the composite tube 201. In addition to or instead of the temperature sensor, the composite tube 201 can include another sensor (not shown) proximate at least the patient end of the composite tube 201. For example, the composite tube 201 can include one pressure sensor (not shown) proximate at least the patient end of the composite tube 201. The pressure sensor can be particularly advantageous for CPAP control and nasal high flow therapy. When the composite tube 201 and the delivery tube 1909 are a single component, this or these sensors are proximate the patient's 1903 nostrils, which can provide more accurate information related to the delivered gas. Example patient end sensor configurations are described in more detail below.

[0330] A single construction is also desirable because it can reduce the wiring on the patient 1901. If the cannula body 1907 is equipped with one or more sensors or other electrical components, it is necessary to provide an electrical connection to the cannula body 1907. If the composite tube 201 and the delivery tube are a single component, the electrical wire can extend along the composite tube 201 to the patient end of the composite tube 201 at the cannula body 1907 as described above. A separate electrical connection to the cannula body 1907 is not needed.

[0331] ​As described above, a single configuration can incorporate a variable pitch composite tube 201. In a tube without or with little unheated extension, the insertion tube body 1907 where the sensing element will be positioned will continue to be heated. These tubes require a reduction in the tube end temperature to ensure delivery of 37°C saturated gas. This is because, in general, the tube end temperature is set much higher than 37°C to compensate for heat loss in the unheated extension. However, a configuration without one unheated extension is more likely to encounter condensation at the device end. Re-distributing heat to the region proximal to the device end of the tube will help facilitate T gas >T dew and thus reduce the occurrence of condensation without the need to deliver an excessively high tube end temperature.

[0332] It should be appreciated that while Figure 19B a configuration in some embodiments can be preferred, other configurations, including the configuration shown in Figure 19A may be used in other embodiments as can be desired.

[0333] The composite tube 201 of the present disclosure can also incorporate and / or be used with other patient interfaces, such as a full face mask 2001 Figure 20A , a nasal mask 2003 Figure 20B , and a nasal / pillow mask 2005 Figure 20C . As described above, the composite tube 201 can act as a delivery tube 1909 or eliminate the need for a delivery tube altogether.

[0334] Cleaning

[0335] Returning again Figure 2A , in at least one embodiment, the material used for the composite tube can be selected to handle different cleaning methods. In some embodiments, the composite tube 201 can be cleaned using high level disinfection (about 20 cleaning cycles). During high level disinfection, the composite tube 201 is pasteurized at about 75°C for about 30 minutes. Next, the composite tube 201 is soaked in 2% glutaraldehyde for about 20 minutes. The composite tube 201 is removed from the glutaraldehyde and soaked in 6% hydrogen peroxide for about 30 minutes. Finally, the composite tube 201 is removed from the hydrogen peroxide and soaked in 0.55% o-phenylphenate (OPA) for about 10 minutes.

[0336] In other embodiments, the composite tube 201 can be cleaned using sterilization (about 20 cycles). First, the composite tube 201 is placed in an autoclave steam at about 121 °C for about 30 minutes. Next, the temperature of the autoclave steam is increased to about 134 °C for about 3 minutes. After autoclaving, 100% ethylene oxide (ETO) gas is enclosed around the composite tube 201. Finally, the composite tube 201 is removed from the ETO gas and immersed in about 2.5% glutaraldehyde for about 10 hours.

[0337] The composite tube 201 can be made of a material that can withstand repeated cleaning processes. In some embodiments, part or all of the composite tube 201 can be made of, but is not limited to, a styrene-ethylene-butylene-styrene block thermoplastic elastomer, such as Kraiburg TF6STE. In other embodiments, the composite tube 201 can be made of, but is not limited to, a thermoplastic polyester elastomer, a polyurethane, or a silicone.

[0338] Manufacturing method

[0339] Referring next to Figures 21A to 21F , these figures illustrate an example method for manufacturing a composite tube.

[0340] Turning first to Figure 21A , in at least one embodiment, a method of manufacturing a composite tube includes providing a second elongate member 205 and spirally wrapping the second elongate member 205 around a mandrel 2101, wherein opposite side edge portions 2103 of the second elongate member 205 are spaced apart on adjacent wraps, thereby forming a second elongate member spiral 2105. In certain embodiments, the second elongate member 205 can be directly wrapped around the mandrel. In other embodiments, a sacrificial layer can be provided on the mandrel.

[0341] In at least one embodiment, the method further includes forming the second elongate member 205. Extrusion is one suitable method for forming the second elongate member 205. A second extruder can be configured to extrude the second elongate member 205 at a particular bead height. Thus, in at least one embodiment, the method includes extruding the second elongate member 205.

[0342] As Figure 21BAs shown in FIG. 2, extrusion can be advantageous because it can cause the heating filament 215 to be encapsulated in the second elongated member 205 as the second elongated member 205 is formed, for example using an extruder with a crosshead extrusion die. Thus, in certain embodiments, the method includes providing one or more heating filaments 215, and encapsulating the heating filaments 215 to form the second elongated member 205. The method can also include providing the second elongated member 205 having one or more heating filaments 215 embedded or encapsulated in the second elongated member 205.

[0343] In at least one embodiment, the method includes embedding one or more filaments 215 in the second elongated member 205. For example, as shown in FIG. 2, the filaments 215 can be pressed into (pulled into or mechanically positioned in) the second elongated member 205 to a particular depth. Alternatively, cuts can be made in the second elongated member 205 to a particular depth, and the filaments 215 can be placed in the cuts. Preferably, the pressing or cutting is performed shortly after the second elongated member 205 is extruded, and the second elongated member 205 is soft. Figure 21C

[0344] As shown in FIG. 2, the filaments 215 can be pressed into (pulled into or mechanically positioned in) the second elongated member 205 to a particular depth. Alternatively, cuts can be made in the second elongated member 205 to a particular depth, and the filaments 215 can be placed in the cuts. Preferably, the pressing or cutting is performed shortly after the second elongated member 205 is extruded, and the second elongated member 205 is soft. Figure 21D Figure 21E As shown in FIG. 2, the filaments 215 can be pressed into (pulled into or mechanically positioned in) the second elongated member 205 to a particular depth. Alternatively, cuts can be made in the second elongated member 205 to a particular depth, and the filaments 215 can be placed in the cuts. Preferably, the pressing or cutting is performed shortly after the second elongated member 205 is extruded, and the second elongated member 205 is soft. Figure 21D An example method is shown in which the heating filaments 215 are encapsulated in the second elongated member 205 prior to forming the second elongated member spiral. Figure 21E An example method is shown in which the heating filaments 215 are embedded in the second elongated member 205 as the second elongated member spiral 2105 is formed. An alternative method of incorporating the filaments 215 in the composite tube includes encapsulating one or more filaments 215 between the first elongated member 203 and the second elongated member 205 in the region where the first elongated member 203 and the second elongated member 205 overlap.

[0345] ​​As described above, at least one embodiment includes a tube having a plurality of convolutions of the first elongated member 203 between convolutions of the second elongated member 205. Accordingly, in certain embodiments, the method includes providing the first elongated member 203 and spirally wrapping the first elongated member 203 around the second elongated member spiral 2105 such that a first side of the first elongated member 203 overlaps a convolution of the second elongated member spiral 2105 and a second side of the first elongated member 203 contacts a portion of the adjacent side of the first elongated member 203. A portion of the first elongated member 203 is disposed in the vicinity of the mandrel 2101 in the space between convolutions of the second elongated member spiral 2105 thereby forming a first elongated member spiral 2107 including a plurality of convolutions of the first elongated member 203 between convolutions of the second elongated member 205.

[0346] In at least one embodiment, the first elongated member 203 is wrapped one or more times in the multi-turn second elongated member 205 and one or more of the bubbles between the multi-turn second elongated member 205 are further collapsed into additional discrete bubbles using an appropriate technique such as heat treatment. Figure 22A An example schematic of the resulting longitudinal cross-section is shown in FIG. 21 1. The adjacent convolutions of the first elongated member 203 can be fused using any suitable technique such as heat melting, adhesion or other attachment mechanism. In at least one embodiment, the adjacent molten or softened bubbles can be brought into contact and thereby bonded while hot and subsequently cooled with an air blast. The adjacent convolutions of the first elongated member 203 in a softened state can also be brought together by winding them on a mandrel and allowing them to cool.

[0347] In at least one embodiment, the first elongated member 203 is wrapped one or more times in the multi-turn second elongated member 205 and one or more of the bubbles between the multi-turn second elongated member 205 are further collapsed into additional discrete bubbles using an appropriate technique such as heat treatment. Figure 22B Another example schematic of the resulting longitudinal cross-section is shown in FIG. 21 1. As shown in FIG. 21 1, one bubble of the first elongated member 203 can be collapsed into two or three or more discrete bubbles using any suitable technique such as applying a mechanical force by an object or applying a force by a directed air blast. Figure 22B Another example schematic of the resulting longitudinal cross-section is shown in FIG. 21 1. As shown in FIG. 21 1, one bubble of the first elongated member 203 can be collapsed into two or three or more discrete bubbles using any suitable technique such as applying a mechanical force by an object or applying a force by a directed air blast. Figure 22C Another example schematic of the resulting longitudinal cross-section is shown in FIG. 21 1. In this example, the central portion of the bubble is collapsed such that the top of the bubble is joined with the bottom of the bubble to form two discrete bubbles separated by a flat portion. The adjacent portions of the two discrete bubbles are then joined to form a structure including three discrete bubbles.

[0348] The aforementioned alternative of combining one or more heating filaments 215 with the composite tube has advantages over alternatives that have heating filaments in the gas path. Having one or more heating filaments 215 outside the gas path improves performance because these filaments heat the tube wall where condensation is most likely to occur. This configuration reduces the risk of ignition in high-oxygen environments by removing the heating filaments from the gas path. This feature also reduces performance because it reduces the heating efficiency of the heating filaments on the gas passing through the tube. However, in some embodiments, the composite tube 201 includes one or more heating filaments 215, which are placed within the gas path. For example, the heating filaments can be placed on the tube wall (tube opening), such as in a helical configuration. An example method for placing one or more heating filaments 215 on the tube wall includes bonding, embedding, or otherwise forming a heating filament on the surface of the second elongated member 205, thus forming the tube wall during assembly. Therefore, in some embodiments, the method includes placing one or more heating filaments 215 on the wall of the lumen.

[0349] Whether or not the heating filament 215 is embedded or encapsulated on or disposed on the second elongation member 205, or otherwise placed in or on the tube, in at least one embodiment, the paired filaments may form a connecting loop at one end of the composite tube to form a circuit.

[0350] Figure 21F It shows Figure 21E The longitudinal section of the component shown is concentrated at the top end portion of the mandrel 2101 and the top end portions of the first elongation member spiral 2107 and the second elongation member spiral 2105. This example shows the second elongation member spiral 2105, which has a T-shaped second elongation member 205. When the second elongation member is formed, the heating filament 215 is embedded in the second elongation member 205. Figure 21F The right side shows the bubble-shaped outline of the first elongated member spiral as described above.

[0351] The method may also include forming a first elongated member 203. Extrusion is a suitable method for forming the first elongated member 203. Thus, in at least one embodiment, the method includes extruding the first elongated member 203. The first elongated member 203 can also be manufactured by extruding two or more portions and combining them together to form a single workpiece. As another alternative, the first elongated member 203 can also be manufactured by extruding segments that produce a hollow shape during adjacent formation or bonding in a spiral tube forming process.

[0352] The method can also include supplying a gas at a pressure greater than atmospheric pressure to an end of the first elongated member 203. The gas can be air, for example. Other gases can also be used, as explained above. Supplying a gas to an end of the first elongated member 203 can help maintain an open hollow body shape as the first elongated member 203 is wrapped around the mandrel 2101. The gas can be supplied before the first elongated member 203 is wrapped around the mandrel 2101, while the first elongated member 203 is wrapped around the mandrel 2101, or after the first elongated member 203 is wrapped around the mandrel 2101. For example, an extruder with a die / tip combination can supply or send air into the hollow chamber of the first elongated member 203 as the first elongated member 203 is extruded. Thus, in at least one embodiment, the method includes extruding the first elongated member 203 and supplying a gas at a pressure greater than atmospheric pressure to an end of the first elongated member 203 after extrusion. A pressure of 15 to 30 cm H2O (or about 15 to 30 cm H2O) has been found to be suitable.

[0353] In at least one embodiment, the first elongated member 203 and the second elongated member 205 are helically wound around the mandrel 2101. For example, the first elongated member 203 and the second elongated member 205 can come out of the die at an elevated temperature of 200 °C (or about 200 °C) or above and then be applied to the mandrel after a short distance. Preferably, the mandrel is cooled to a temperature of 20 °C (or about 20 °C) or below, such as near 0 °C (or about 0 °C), using a water jacket, a chiller, and / or other suitable cooling methods. After 5 (or about 5) helical wraps, the first elongated member 203 and the second elongated member 205 are further cooled by a cooling fluid (liquid or gas). In one embodiment, the cooling fluid is air emitted from a ring, where the air flow surrounds the mandrel. After cooling and removing the part from the mandrel, a composite tube is formed having a lumen extending along a longitudinal axis and a hollow space around the lumen. In this embodiment, no adhesive or other attachment means is needed to join the first elongated member and the second elongated member. Other embodiments can also utilize an adhesive or other attachment means to join or otherwise connect the two members. In another embodiment, after extruding and placing the heated filaments, the second elongated member 205 can be cooled to freeze the locations of the heated filaments. The second elongated member 205 can then be reheated to improve the bond when applied to the mandrel. Example methods for reheating include using a localized heating device, a heated wheel, and the like.

[0354] The method can also include forming a pair of heating or sensing filaments into a connecting loop at one end of the composite tube. For example, the ends of two heating or sensing filaments can be stripped from the second elongate member 205 and then formed together into a connecting loop, e.g., by tying, bonding, welding, adhering, fusing, etc. As another example, the ends of the heating filaments can be detached from the second elongate member 205 during the manufacturing process and then formed into a connecting loop when the composite tube is assembled.

[0355] Referring now to Figure 23A -23H, an alternative method of forming a tube 201 involves an extrusion tool 2301 having a set of flow paths extending therealong. The extrusion tool 2301 can be used to form a tube, such as the example tubes shown in Figure 23G and Figure 23H As shown, the tube produced using the extrusion tool 2301 can include a plurality of first elongate members 203 that extend generally along the longitudinal axis of the tube. In some embodiments, the extrusion tool 2301 includes a body 2310 and a central extension 2320. In some embodiments, the body 2310 and the extension 2320 are generally cylindrical. The body 2310 can include one or more flow paths 2312 that enable molten plastic or another material to flow through the body 2310 from an input end 2314 to an output or extension end 2316. In some embodiments, the flow paths have a substantially tapered longitudinal cross-section (i.e., wider where the molten plastic first enters at the input end 2314 and narrower near the extrusion end 2316). The flow paths can have different configurations to produce tubes 201 having different profiles. For example, the flow path configuration shown at the output or extension end 2316 in Figure 23C and Figure 23D can produce a tube 201 whose end view features are shown in Figure 23A . Figure 21B An end view of a tube of Figure 23A is shown that includes second elongate members 205 that can include heating filaments 215 disposed between adjacent blisters or first elongate members 203. In use, the tool 2301 can be adapted to rotate so as to direct helical formation of the tube 201. As shown in Figure 23F The central extension 2320 can couple the extrusion tool 2301 to an extruder 2330. Bearings 2322 disposed between the central extension 2320 and the extruder 2330 can enable the central extension 2320 and the body 2310 to rotate relative to the extruder 2330. The rotational speed of the tool 2301 can be adjusted to vary the pitch or helix angle of the first elongate members 203. For example, a faster rotational speed can produce a smaller helix angle, as shown in Figure 23GThe slower rotational speed can produce a larger helix angle, as shown in Figure 23H The slower rotational speed can produce a larger helix angle, as shown in

[0356] As discussed above with reference to Figure 8A and Figure 8B Certain embodiments can include a composite tube with a variable pitch. In manufacturing such embodiments, it is preferable to provide a mandrel 2101 and a control system that can vary the effective pitch of the first elongate member 203 and the second elongate member 205 (i.e., the "ropes"). This can be accomplished, for example, by controlling the ratio of the strand speed to the mandrel 2101 advance speed while maintaining a constant tangential velocity at the critical dimension (i.e., the pitch center diameter of the ropes). The pitch center diameter determines the center of the pitch through the middle of the rope. This value is dependent on the speed. Thus, it is also possible to predict that if the pitch center diameter differs from the intended, the speed can be adjusted to bring the pitch center diameter back to the desired value. Varying the effective pitch can also be accomplished, for example, by controlling the ratio of the strand speed to the mandrel 2101 advance while maintaining a constant rotational speed of the helical composite tube 201 so formed. By controlling the strand speed, any variation in the extrudate output can be compensated for.

[0357] Another method for manufacturing a variable pitch composite tube 201 uses an integrated system in which the extrusion speed and the mandrel 2101 advance speed are varied in unison. For example, in this mode, the strand speed can remain the same, but the advance of the mandrel 2101 will need to slow down the extrusion speed to match the extrudate output to the tangential velocity of the helical tube 201 so formed when enabled.

[0358] Another method for manufacturing a variable pitch composite tube 201 moves the angle of incidence of the second elongate member 205 and the first elongate member 203 to vary the pitch of the tube 201. In these embodiments, the extruder can be on a slide such as a turntable that will allow the angle to be changed, on which the center of rotation is at the point where the second elongate member 205 and the first elongate member 203 meet the mandrel 2101. This method can allow at most a 3-5 mm (or about 3-5 mm) change in pitch.

[0359] Reference is next made to Figures 24A to 24FThese figures show a transverse cross-section of a tube comprising a single tubular element having a first elongate member or portion 203 and a second elongate member or portion 205. As explained, the second elongate portion 205 is integral with the first elongate portion 203 and extends along the full length of the single tubular element. In the illustrated embodiment, this single tubular element is an elongate hollow body having a relatively thin wall in its transverse cross-section, which wall partially defines a hollow portion 2201, and two reinforcing portions 205 of relatively greater thickness or rigidity on opposite sides of the elongate hollow body adjacent to the relatively thin wall. After the elongate hollow body is helically wound, these reinforcing portions form part of the inner wall of the lumen 207, such that they are also helically positioned between adjacent turns of the elongate hollow body.

[0360] In at least one embodiment, the method comprises forming an elongate hollow body comprising a first elongate portion 203 and a reinforcing portion 205. Extrusion is one suitable method for forming the elongate hollow body. In Figures 24A to 24F Suitable cross-sectional shapes of the tubular element are shown in

[0361] The elongate hollow body can be formed into a medical tube as explained above and by reference to the foregoing discussion. For example, in at least one embodiment, a method of manufacturing a medical tube comprises helically wrapping or winding the elongate hollow body around a mandrel. This can be done at an elevated temperature, such that the elongate hollow body is cooled after being helically wound to bind adjacent turns together. As Figure 24B As shown in Figure 24D and Figure 24E The heating filament 215 can be incorporated into the second elongate member as explained above and as shown in Figures 24A to 24F For example, the heating filament can be provided on opposite sides of the elongate hollow body, for example as shown in Figure 24A -24D. Alternatively, the heating filament can be provided on only one side of the elongate hollow body, for example as shown in Figure 24E -24F. Either of these embodiments can also be combined with the presence of a sensing filament.

[0362] Placement of a chamber end connector with electrical connections

[0363] Referring next to Figure 25A , an example flowchart is shown for attaching a connector to the end of a tube configured for use in connection with a humidifier. For example, as explained above with reference to Figure 1The inlet 109 of the air intake tube 103 is connected to the humidifier 107 via the port 111. Figure 25A An example flow chart can manufacture one inlet 109 that can be physically and electrically connected to the humidifier 107.

[0364] In this example, the seal 2503 is inserted into the seal housing 2501. In Figure 25B The insertion behavior of the seal is also shown in more detail in Figure 25B The seal 2503 can be an O-ring, as shown in The appropriate configuration of the O-ring can be a double annular face configuration, including a thicker concentric annular face connected by a thinner collar. In this example, the O-ring is molded from a single resilient material, such as rubber or silicone. The seal 2503 is seated in a compliant bump in the seal housing 2501. The seal 2503 is designed to seal against the outer surface of the port of the humidifier chamber. The seal 2503 can deflect or extend along the outer surface of the port. In other words, the double O-ring configuration includes an inner O-ring and an outer O-ring connected by a flange. The outer O-ring will be sealed within the connector, while the inner O-ring can deflect along the flange portion and press against the outer surface of the port. In this orientation, the horizontal plane extending through the central axis of the inner O-ring can be in a different plane than the horizontal plane extending through the central axis of the outer O-ring.

[0365] Figure 25A Turning again to the example of Figure 25C The insertion behavior of the PCB is shown in more detail in Figure 25C In The assembly 2505, including the PCB and the PCB electrical connector, is inserted into the compliant dock on the seal housing 2501. Various PCBs having appropriate dimensions and configurations can be used. Various PCB electrical connectors can also be used. For example, the PCB electrical connector can be a straight-through connector or a bidirectional connector. The PCB includes four connection pads adapted to receive four conductive filaments encased in the second elongate member of the tube. However, if the second elongate member contains more than four or fewer than four conductive filaments, the PCB can be configured to receive an appropriate number of conductive filaments.

[0366] Figure 25A Turning again to the example of Figure 25DAs shown in more detail, the sealing ring 2507 is clamped onto an open end of the sealing housing 2501, with the sealing element 2503 situated on the compliant protrusion. Clamping the sealing ring 2507 in place presses the sealing element 2503, thereby forming a liquid-resistant and gas-resistant connection between the sealing housing 2501 and the sealing ring 2507. In this example, the sealing ring 2507 is made of a molded plastic. In this example, the sealing ring 2507 also includes a protrusion whose size and shape mate with the PCB. This protrusion serves to support and protect the more flexible and fragile PCB. However, in some embodiments, this protrusion may be omitted. The resulting assembly, including the sealing housing 2501, the sealing element 2503, the PCB and PCB connector assembly 2505, and the sealing ring 2507, is herein referred to as the connector tube assembly 2515.

[0367] Turn to Figure 25A For example, the tube is prepared for connection to the connector tube assembly 2515. Figure 25A As shown and more detailed as Figure 25E As shown, in step 2511, a portion of the second elongated member at one end of the tube is separated from the first elongated member. Then, in step 2513, a certain length of the separated second elongated member is peeled off to expose four conductive filaments (or the number thereof, which is the number of conductive filaments contained in the second elongated member). Figure 25F Step 2513 is shown in more detail below.

[0368] like Figure 25A The explanation in the text is as follows: Figure 25G As shown in more detail, this portion of the tube, having the stripped length of the second elongation member, is inserted into the connector tube assembly 2515. Figure 25G In this configuration, the second elongated member 205 has a curved shape to accommodate the positioning of the PCB connector assembly 2505. The PCB connector assembly 2505 can also be sized and positioned to reduce or eliminate the curved shape, for example, by further moving the PCB connector assembly toward the connector end. Figure 25A and Figure 25H As shown in step 2517, these four conductive filaments are inserted into the four connection pads of the PCB. Then, as... Figure 25A and Figure 25I As shown, solder beads 2519 are placed on each filament-connector pad to secure the filament to the pad and ensure good electrical connection between each filament and its corresponding pad.

[0369] In some embodiments, the aforementioned step of placing solder beads 2519 may be omitted. Figure 26A- 26E illustrates an example connector assembly configuration that does not require soldering to connect the filaments to the connector assembly.

[0370] Figure 26A A connector assembly 2601 is shown that includes clip housings 2603 and a circuit connector 2605. The second elongated member 205 of the peel length 2607 exposes the heating filament 215 that can be inserted in a clip 2609 within the clip housing 2403. Each clip 2609 is electrically conductive. Suitable materials for the clip 2609 include, for example, aluminum, copper, and gold. The clip 2609 holds one heating filament 215 without the need for solder. Electrical wires 2611 can extend between the various clips 2609 and the circuit connector 2605.

[0371] Figure 26B A top view of the connector assembly 2601 is shown that illustrates the clips 2609 positioned in the clip housings 2603.

[0372] Figure 26C The clip 2609 is shown in more detail. The clip 2609 includes a folded portion 2613, a retaining tab portion 2615, a flange portion 2617, and an elongated portion 2619. One heating filament (not shown) is inserted into the flange portion 2617 such that the folded portion 2613 receives and holds the heating filament. The flange portion 2617 is shaped to facilitate insertion of the heating filament and to guide the heating filament into position. However, the flange portion 2617 can have a straight shape, if desired. The flange portion 2617 can also have another suitable shape, such as a partial flange. The folded portion has a catch portion 2621 that conforms to the retaining tab portion 2615. The retaining tab portion 2615 is angled such that one heating filament can slide in one direction through the retaining tab portion 2615 into the folded portion 2613. The retaining tab portion 2615 also catches the heating filament to prevent it from inadvertently falling out of the folded portion 2613. The elongated portion 2619 is electrically conductive and carries current from the heating filament to and / or through the clip housing 2603.

[0373] Figure 26D is a cross-sectional view of Figure 26C and illustrates in more detail the positioning of the tab portion 2615 and the catch portion 2621. Figure 26E How the clip 2609 is positioned in the clip housing 2603 is shown. The clip housing 2603 is shown transparently to illustrate the positioning of the elongated portion 2619.

[0374] Referring again to Figure 25ATo ensure that all components of the connecting tube assembly 2515 are reliably secured to each other, a layer of adhesive 2521 is then applied. Adhesive is a broad term and refers to a material used to bond, fix, or attach other materials. When adhesive is liquid or semi-solid, it can be tacky or sticky to the touch. When adhesive dries or otherwise cures into a solid state, it can be tacky or non-tacky, or not sticky to the touch. Adhesive can be a resin, such as epoxy resin, or an elastomer (thermosetting or thermoplastic). Using TPE materials can be advantageous because they are generally flexible and can withstand torsion, bending, or stress without breaking.

[0375] exist Figure 25J An example method for applying adhesive 2521 is shown. In this method, a two-block mold is provided. In this example, the mold is made of a metal such as aluminum or stainless steel; however, any suitable material can be used. For example, the mold could be made of... The PTFE modules are made of PTFE. One module is configured to accommodate the protruding PCB of the connector tube assembly 2515 and the PCB connector assembly 2505, as well as the adjacent tube, and another module is configured to accommodate the tube and the opposing portion of the connector tube assembly 2515. The tube is placed in a conforming mold such that these modules are stacked on top of one another. A liquid adhesive is introduced into the inlet hole of the mold and allowed to harden. The mold is then removed to expose the glued tube-connector assembly 2523, which includes a hardened adhesive layer 2521 covering the PCB and bonded between the tube and the connector tube assembly 2515. The adhesive layer can cover the PCB and all solder joints on the PCB. In this way, the adhesive layer can protect the PCB and its connections from corrosion. In other words, the adhesive serves at least three functions: sealing the connector and conduit, holding the PCB in place and encapsulating the PCB; the adhesive layer forms a pneumatic seal, a mechanical bond, and PCB encapsulation. In addition, the adhesive layer can act as an electrical insulating barrier, for example, by preventing moisture and liquid from reaching electrical components and creating a conductive path to the user of the device.

[0376] Return again Figure 25A The pipe-connector assembly 2523 is then in a state ready for final assembly. For example... Figure 25K As shown in more detail, the first clamshell member 2525 and the second clamshell member 2527 engage around the tube-connector assembly 2523, such that a portion of the PCB connector remains exposed. Figure 25K The first clamshell-shaped member 2523 and the second clamshell-shaped member 2527 shown are the top clamshell-shaped member and the bottom clamshell-shaped member, respectively.

[0377] Figure 27A–27E shows an alternative clamshell-shaped component design, wherein the first clamshell-shaped component 2525 and the second clamshell-shaped component 2527 are the left and right clamshell-shaped components, respectively. Clamshell-shaped components 2525 and 2527 are partially ( Figure 25K or Figure 27A –27E) can be made of molded plastic or any other suitable material. Clamshell-shaped parts 2525, 2527 ( Figure 25K or Figure 27A –27E) for further protection of tube-connector assembly 2523 ( Figure 25A and Figure 25J This allows the pipe-connector assembly to be held in a bent position, which during use facilitates the return of condensate to the humidifier unit. For example... Figure 25L As shown, the final component can be easily snapped into the humidifier, with compliant electrical connectors near the connection port.

[0378] Although the aforementioned manufacturing method is described with reference to a flowchart, this flowchart merely provides an example method for attaching the connector to the end of a tube configured to be connected to a humidifier in use. The method described herein does not imply a fixed order for these steps. Nor does it imply that any single step is required to perform the method. The embodiments can be performed in any order, and combinations thereof are also possible.

[0379] Placement of an alternative device end connector

[0380] Next reference Figure 28A -28F, these figures illustrate a connector that can be used for medical circuits with wires passing through it. Connector 2801 includes a circuit breaker 2802, which in some embodiments spans 30 mm (or approximately 30 mm). In some embodiments, one end of the circuit breaker 2802 has an L-shaped arm 2803 that extends partially outward from connector 2801 and is partially parallel to the longitudinal axis of connector 2801.

[0381] Arm 2803 may have one or more electrical conductors 2804 embedded therein. Conductors 2804 may be made of copper or brass or another material suitable for conducting electricity, and may be formed as a flat L-shaped workpiece that extends substantially along the length of arm 2803.

[0382] The connector 2801 may further include an inner portion 2805 adapted to be substantially located inside a portion of the tube 201; and an outer portion 2806 adapted to substantially surround a portion of the tube 201.

[0383] A portion of the second elongate member 205 is peeled back to reveal one or more filaments 215 embedded therein. Preferably, about 5 mm of the filaments 215 are revealed. A connector 2801 is then attached to the tube 215 such that the inner portion 2805 is within the tube 201 and the outer portion 2806 is around the tube 201. Preferably, the connector 2801 is oriented such that the exposed ends of the filaments 215 are at or near the flow interrupter 2802.

[0384] The exposed ends of the filaments 215 are then electrically and / or physically connected to the conductor 2804. This can be done by welding these ends to the conductor 2804 or any other method known in the art.

[0385] A member 2807 can be inserted or molded on top of at least a portion of the connector 2801 and optionally the tube 201 to facilitate attachment between the connector 2801 and the tube 201. The member 2807 can be a hard material or a soft material such as a soft rubber or elastomer.

[0386] In some embodiments, a generally L-shaped elbow 2808 can be placed over the assembly. The elbow 2808 can provide some additional strength to the connection and can provide a predetermined bend in the tube 201 (such that the connector 2801 can easily sit on the body of the tube 201 at an angle of about 90° to the body).

[0387] Reference is next made to Figure 29A -29L, which illustrate another connector 2901 that can be used for medical circuits with wires passing through. Reference is first made to Figure 29A The connector 2901 allows a composite tube to be connected to a device such as a CPAP device (not shown). The L-shaped arm 2903 of the connector 2901 carries electrical terminals that engage with complementary electrical terminals of the device to allow electrical signals or power to be conveyed between the device and the composite tube. In the arrangement shown, the electrical terminals of the connector 2901 are plugs 2905 that are compliant with receptacles or ports of the device. However, this arrangement can be reversed if desired. In this example, the plugs are in electrical communication with electrical contacts 2906 for making electrical connections with the composite tube. Here, the electrical contacts 2906 are molded into the connector 2901. The connector 2901 further includes a filament holder 2907 that is also molded into the connector 2901. The connector 2901 also includes a flow interrupter 2902 that, in some embodiments, spans 30 mm (or about 30 mm).

[0388] As Figure 29B and Figure 29CAs shown in FIG. 20, a portion (e.g., a 10-mm portion) of the second elongated member 205 is stripped to reveal one or more filaments 215 of smaller length embedded therein. Preferably, about 5 mm or 10 mm of the filaments 215 are revealed.

[0389] As Figure 29E As shown in FIG. 22, the connector 2901 is then attached to the tube 201 such that the inner portion 2909 of the connector 2901 is located within the tube 201 and the outer portion 2911 of the connector 2901 is located around the tube 201. Preferably, the connector 2901 and the composite tube 201 are oriented such that the revealed ends of the filaments 215 are located at or near the interrupter 2902 and the filaments 215 are aligned to meet near the contact point 2906.

[0390] As Figure 29F As shown in FIG. 23, the heated filaments 215 are positioned under the filament holder 2907 such that each heated filament 215 is positioned above the contact point 2906.

[0391] As Figure 29G As shown in FIG. 24, a solder bead 2913 is placed on each heated filament 215 at the corresponding contact point 2906. The combination of the connector 2901 and the composite tube 201 is here labeled as a connector-tube assembly 2917. As shown in FIG. 25, the connector-tube assembly 2917 is placed in an injection molding tool 2919. Figure 29H As shown in FIG. 26, a mold tool core 2915 is inserted into the connector 2901. As shown in FIG. 27, the connector-tube assembly 2917 and the core 2915 are placed in the injection molding tool 2919. In Figure 29I Figure 29J As shown in FIG. 28, a molding material 2921 is molded over the interrupter (not shown) to bond the connector 2901 and the composite tube 201. Suitable molding materials 2921 include plastics and rubbers. The connector-tube assembly 2917 and the core 2915 are removed from the injection molding tool (not shown), as shown in FIG. 29. Figure 29K

[0392] As Figure 29L As shown in FIG. 30, the core 2915 is removed, providing the device end connector 2901 to the composite tube 201. Figure 29A ​​- The method of 29J allows the plug 2903 to be electrically connected to the heating filament and / or one or more other electrical elements (not shown) of the composite tube 201. Preferably, the heating circuit of the device provides electrical energy to the heating filament of the composite tube 201, such that the heating filament can provide thermal energy to the flow of humidified air passing through the composite tube 201. As discussed herein, such an arrangement can prevent or limit condensation within the composite tube 201. Additionally, or alternatively, the plug 2903 and the device port can provide other electrical signals, such as data signals, to be communicated between the device and the composite tube 201. For example, a sensor at the patient interface end of the composite tube 201 can provide data regarding one or more parameters of the air flow (e.g., temperature, humidity level) for use by the control system of the device. Any other desired electrical signals can also be conveyed.

[0393] The foregoing methods of attaching a connector to a composite tube are provided by way of example. The described methods do not imply that the steps have a fixed order. They also do not imply that any one step is required to practice the methods. Embodiments can be practiced in any order, and combinations are also possible.

[0394] Placement of a patient end connector with electrical connections

[0395] Reference is next made to Figure 30A - 30O, which shows an example connector 3000 for connecting one end of a tube 201 to a patient interface (not shown). The end of the connector 3000 that connects to the patient interface is indicated by reference 3001.

[0396] Figure 30A A side perspective view of the connector 3000 is shown.

[0397] As Figure 30B - shown in 30F, the connector 3000 includes a PCB assembly 3003 and an insert 3005, which when assembled together are collectively referred to as an insert assembly 3007, and a cover 3009. Figure 30B - 30D and Figure 30F Each shows a side perspective view generally corresponding to the view of Figure 30A - 30E. Figure 30E A side top view is shown.

[0398] Insert 3005 and cap 3009 are preferably molded plastic parts. Insert 3005 can serve one or more purposes, including providing a receiver for tube 201, providing a suitable conduit for a gas flow path, providing a housing for PCB assembly 3003, and providing a housing for a sensor (not shown) such as a thermistor. Cap 3009 protects and covers the relatively fragile PCB assembly 3003 and protects the connection between tube 201 and insert 3005. Figure 30D and 30E As shown, the end of the insert 3005 inserted into the tube 201 (i.e., the end opposite to end 3001) can be angled, which helps in insertion into the tube 201. However, in some embodiments, the end opposite to end 3001 can be blunt or tapered.

[0399] like Figure 30D As shown, the insert preferably includes a stop portion 3006a. The stop portion 3006a facilitates proper placement of the tube 201 relative to the insert 3005. The stop portion 3006a also serves to protect the PCB assembly 3003 from direct contact with the tube 201. Figure 30E An alternative construction is shown in the diagram. Figure 30E In the middle, the stop portion 3006b is formed as a helical or spiral component such as a helical or spiral rib. This construction is advantageous because the shape compensates for the helical winding of the tube 201, thereby providing a secure connection between the insert 3005 and the tube 201.

[0400] Figure 31A and Figure 31B Another alternative construction is shown in these figures. In these figures, the stop portion 3006c is formed as a helical or spiral component, such as a helical or spiral rib. Again, this construction is advantageous because the shape is favorable for the helically wound tube 201 ( Figure 31B This provides compensation, thereby ensuring a secure connection between the insert 3005 and the tube 201. In this configuration, the stop portion 3006c includes a directional stop feature structure 3101. Figure 31B As shown, the surface of the directional stop feature 3101 is tapered, making it resemble a fish fin. The shape of the directional stop feature 3101 can clamp, grip, or otherwise retain the second elongated member 205 of the tube 201. The directional stop feature 3101 can therefore be used to better hold the tube 201 in the correct position by preventing movement and / or rotation of the tube 201.

[0401] return Figure 30E The patient end 3001 of the insert 3005 is larger than Figure 30Dpatient end in FIG. 30I, and illustrates how the size can be modified for different applications (e.g., connection to infant or adult patient interface).

[0402] Figure 30G A cross-section of the connector 3000 is shown, and generally corresponds to the side perspective view of FIG. 30G. Figure 30A In certain embodiments, there is an insulating gap, such as an air gap, between the tube 201 and the insert 3005 to protect the sensor (discussed above) from heat radiation of one or more heating filaments in the tube 201, which at low flow rates can induce sensor errors. In Figure 30G In FIG. 30I, such a gap would appear above and below the sensor portion 3017. Alternatively, in certain embodiments, the insert 3005 is formed such that an air bubble is encapsulated in the insert 3005. For example, the insert 3005 can comprise a porous plastic.

[0403] Figure 30H A cross-section of the insert assembly 3007 is shown, and generally corresponds to the side perspective view of FIG. 30H. Figure 30D A cross-section of the insert assembly 3007 is shown, and generally corresponds to the side perspective view of FIG. 30H. Figure 30I An alternative cross-section of the insert assembly 3007 is shown, and generally corresponds to the side view of FIG. 30J. These figures show further details regarding the relative placement of the tube 201, the insert assembly 3007, and / or the cap 3009. Figure 30E An alternative cross-section of the insert assembly 3007 is shown, and generally corresponds to the side view of FIG. 30J. These figures show further details regarding the relative placement of the tube 201, the insert assembly 3007, and / or the cap 3009.

[0404] As shown in FIG. 30I, the generally annular capture structure 3013 comprises two molded rings extending radially outward from the body of the insert 3005. The molded rings conform to a notch 3011 comprising molded rings extending radially inward from the cap 3009. The notch 3011 and the capture structure 3013 hold the cap 3009 on the insert 3005. Figure 30G

[0405] An alternative configuration of the capture structure 3013 is shown in FIG. 30K. Again, the capture structure 3013 is generally annular, and comprises two molded rings extending radially outward from the body of the insert 3005. A plurality of anti-rotation protrusions 3201 extend perpendicularly between the rings. In this example, there are four evenly spaced (e.g., at 90° intervals) protrusions 3201 around the circumference of the capture structure 3013. The protrusions 3201 engage with a conforming notch (not shown) in the cap, and prevent the cap from rotating on the insert assembly. Figure 32A Figure 32B An alternative configuration of the capture structure 3013 is shown in FIG. 30K. Again, the capture structure 3013 is generally annular, and comprises two molded rings extending radially outward from the body of the insert 3005. A plurality of anti-rotation protrusions 3201 extend perpendicularly between the rings. In this example, there are four evenly spaced (e.g., at 90° intervals) protrusions 3201 around the circumference of the capture structure 3013. The protrusions 3201 engage with a conforming notch (not shown) in the cap, and prevent the cap from rotating on the insert assembly. Figure 32C ​- Another alternative configuration of the capture structure 3013 is shown in 32D. Again, the capture structure 3013 is generally annular and includes two molded rings extending radially outward from the body of the insert 3005. Anti-rotation notches 3203 are provided between the rings. In this example, there are four notches 3203 evenly spaced (e.g., at 90° intervals) around the circumference of the capture structure 3013. The notches 3203 engage with compliant tabs (not shown) in the cap and prevent the cap from rotating on the insert assembly.

[0406] Figure 30G - 30I further shows that the PCB assembly 3003 includes a PCB 3015, a sensor portion 3017, and a positioning portion 3019. The PCB assembly 3003 is positioned such that, in use, the sensor portion 3017 is within the fluid flow path through 3005.

[0407] The sensor portion 3017 includes one or more sensors, such as a temperature sensor. The sensor is preferably positioned on a protruding portion of the sensor portion 3017. Suitable temperature sensors include a thermistor, a thermocouple, a resistance temperature detector, or a bimetallic thermometer.

[0408] The PCB 3015 completes the heating and / or sensing circuitry of the composite tube 201.

[0409] The positioning portion 3019 improves stability and aids in positioning the PCB assembly 3003 during the manufacturing process. However, the positioning portion 3019 can be omitted in certain embodiments.

[0410] Figure 30I It is also shown that the PCB assembly 3003 can be further stabilized in the insert 3005 by recessing at least portions of the PCB 3015 and / or the positioning portion 3019 on the outer surface of the insert 3005. Figure 30N A recessed configuration is also shown in 32E.

[0411] Figure 30G - The configuration of 30I has a number of advantages. For example, certain embodiments include the implementation of placing the sensor portion 3017 within the fluid flow path to facilitate accurate measurements regardless of flow rate, ambient temperature, and the like. In addition, certain embodiments include the implementation of being less likely to have fluid leaks due to poor user setup of the circuitry as compared to configurations having a separate sensor attached to a connector.

[0412] In addition, certain embodiments include the implementation of the PCB assembly 3003 being able to be used to run connection wires throughout the tube 201 as the PCB assembly 3003 spans the entire width of the insert 3005. As described below, Figure 33A- Figure 33D illustrates a PCB assembly 3301 design that enables connection wires to run throughout the tube. The corresponding illustration shows both sides of the PCB assembly 3301. The concept of having connection wires run throughout the tube 201 is discussed below with reference to Figure 34 Further discussion is made in the context of the intermediate connection between two tube 201 segments.

[0413] Turning first to Figure 33A and 33B , the PCB assembly 3301 includes connection pads 3303, 3305 for heating filament and / or sensor connections. The connection pads 3303, 3305 are configured to be on opposite sides of the PCB assembly 3303 to facilitate their connection to the helically wound heating filament.

[0414] The PCB assembly 3301 includes a sensor connection pad 3307 for a sensor. The sensor can be coupled to a diode through a signal connection pad 3309 on the PCB assembly 3301. As shown, the PCB assembly 3301 includes a gap 3311 configured to thermally insulate the sensor from other electrical components and tracks. In some embodiments, the gap 3311 can be filled with an insulating material to further thermally isolate the sensor connected to the sensor connection pad 3307. In addition, the PCB assembly 3301 can be configured to position the sensor to be spaced apart from other active and / or passive electrical components such as a protruding feature 3313.

[0415] The PCB assembly 3301 includes a power connection pad 3315 for a diode that is electrically coupled to the heating filament through a conductive track on the PCB assembly 3301. The power connection pad 3315 can be electrically and thermally coupled to a heat sink 3317 to help dissipate heat, thereby reducing or minimizing the impact on the accuracy of temperature readings to a thermistor coupled to the sensor connection pad 3307.

[0416] Figure 33C and 33D illustrates Figure 33A and Figure 33B the PCB assembly 2901 of Figure 30A -30O discussed above with reference to the insert 2605 or the intermediate connection 3403 discussed below with reference to Figure 34 .

[0417] Therefore, in at least one embodiment, the breathing tube segment such as insert 2605 or intermediate connector 3403 includes a lumen extending along a longitudinal axis and a wall surrounding the lumen, which defines a gas flow path during use; and a PCB assembly 3301, which includes a printed circuit board and further includes a first portion extending through the lumen along a diameter or chord, such that a portion of the printed circuit board assembly substantially divides at least a portion of the flow path in two, the first portion being overmolded with an overmolding composition, and a second portion adjacent to the first portion projecting outward from the wall in a direction away from the lumen, the second portion including one or more connections on the printed circuit board. Pad 3303, the one or more connecting pads being configured to receive one or more metal wires from a first component, a third portion adjacent to the first portion projecting outward from the wall in a direction away from the lumen and in a direction opposite to the second portion, the third portion including one or more connecting pads 3305 on the printed circuit board, the one or more connecting pads being configured to receive one or more metal wires from a second component different from the first component, and one or more conductive tracks on the printed circuit board being electrically coupled to the one or more connecting pads of the second portion and the one or more connecting pads of the third portion, and being configured to provide an electrical connection between the first component and the second component.

[0418] The first component and the second component can each be a breathing tube. Alternatively, the first component can be a breathing tube, and the second component can be, for example, a patient interface.

[0419] Return again Figure 30G In the example of –30I, the sensor portion 3017 is mounted or formed such that the sensor portion 3017, PCB 3015, and positioning portion 3019 form a single unit. For example, the sensor portion 3017, PCB 3015, and positioning portion 3019 can be mounted together with each other using a suitable method such as soldering. The sensor portion 3017, PCB 3015, and positioning portion 3019 can be integrally formed from a suitable material such as a circuit board substrate.

[0420] The sensor portion 3017 can be electrically connected to the PCB 3015 using a suitable technique such as circuit printing. For example, the electrical connection may include conductive tracks such as copper tracks. To electrically connect the conductive filament in the second elongated member of the tube 201 to the connection pad of the PCB assembly 3003, the techniques described above can be used... Figure 25E –25I shows a process similar to the one described. Additional electrical components, such as diodes (not shown), can be positioned on either side of the PCB 3015, inside and / or outside the gas path. Positioning the diodes outside the gas path is discussed above with reference to sensor connection pads 3307 and 3309, and as…Figure 33A - as shown in FIG. 33B.

[0421] Returning again Figure 30G - As an example of 30I, PCB assembly 3003 can be installed within insert 3005 using, for example, an overmolding method known in the art. A material having a thermal conductivity in the range of 0.03 - 0.6 W / m-K or thereabouts, such as polypropylene (thermal conductivity 0.1 - 0.22 W / m-K), can be used for at least a portion of the overmold. Using a material having low thermal conductivity can advantageously reduce interference from the surrounding environment during sensor measurement, as the material is less capable of conducting heat from sensor portion 3017 to the insert 3005 wall. Certain embodiments include the realization that overmolding a single PCB assembly 3003 allows for more consistent placement of the sensor than overmolding individual sensors. Additionally, certain embodiments include the realization that overmolding a sensor placed within the center of the tube can make the sensor less sensitive to radiation.

[0422] As Figure 30G - As shown in 30I, PCB assembly 3003 spans the width of insert 3005 and is supported by opposing walls of insert 3005. Because PCB assembly 3003 is supported on opposite sides of insert 3005, PCB assembly 3003 can be relatively thin (i.e., have a smaller thickness and a smaller width than a PCB having a support on the tube). A thin profile can facilitate fluid flow by providing less resistance to flow than a thicker profile.

[0423] The overmold around sensor portion 3017 is preferably configured to reduce resistance to the fluid flowing around sensor portion 3017. The overmold can have an aerodynamically efficient tapered shape, such as an airfoil shape, for example a bird wing shape, a fully tapered torpedo shape (as shown in Figure 30F and Figure 30G ), or a partially tapered bullet shape with a blunt edge (as shown in Figure 30H ). These tapered shapes facilitate fluid flow. Additionally, when placed in a fluid flow, these tapered shapes reduce turbulence and vortices at the trailing edge of the tapered shape, which can cause unwanted cooling of the humidified gas and formation of condensation. Condensation formation can lead to inaccurate measurements, as well as unwanted temperature drops in the gas delivered to the patient. Thus, the tapered shape can facilitate more accurate readings. Additionally, the tapered shape can reduce the collection of condensation that has formed and also reduce the buildup of patient secretions by facilitating flow.

[0424] The tapered shape can also be selected to reduce turbulence by reducing the formation of vortices in the flow, and increase the likelihood that the flow remains laminar.

[0425] The distance between the tapered shape and the inner wall of the insert 3005 is preferably chosen to allow more space. In at least one embodiment, the distance between the tapered shape and the inner wall of the insert 3005 is at least 10% (or about 10%) or at least 30% (or about 30%) of the inner diameter, such as 33% (or about 33%) or 40% (or about 40%). In at least one embodiment, the distance between the tapered shape and the inner wall of the insert 3005 is greater than 2 mm (or about 2 mm). Allowing more space reduces the likelihood of condensate becoming trapped in the space.

[0426] The overmold helps to read a more average temperature. There is a temperature bias across the insert 3005, with higher temperatures toward the center of the insert 3005, and lower temperatures along the walls of the insert 3005. The asymmetric temperature profile, with the highest temperature offset from the centerline of the insert 3005, is particularly prevalent for curved tubes 203. The overmold has a larger surface area than the sensor portion 3017 of the PCB assembly 3003, and the overmold material spreads the heat, such that the sensors of the sensor portion 3017 measure a more average temperature across the flow path.

[0427] Figure 30J An end view of the connector 3000 taken along the width of the connector is shown, as viewed from the patient end portion 3001 of the connector 3000 toward the tube (not shown). In this view, the overmolded tapered shape, which houses the PCB assembly 3003 (not shown), is generally centered. Figure 30K An alternative configuration is shown. In this view, the tapered shape is offset from the centerline. As Figure 30J and Figure 30K The joint 3018 between the inner wall of the insert 3005 and the overmolded tapered shape that houses the PCB assembly can optionally have a number of fillets, as shown in FIGS. 31 and 32, to reduce fluid disturbance and to reduce areas of fluid accumulation. The fillets of the joint 3018 can be, for example, 1 mm (or about 1 mm) in radius.

[0428] Figure 30L The offset positioning of the tapered shape of the connector 3000 is shown in more detail. Figure 30K Because the sensors 3020 protrude outward from the PCB assembly 3003, the offset configuration can improve accuracy by placing the sensors 3020 closer to the centerline. In addition, the offset configuration can also be desirable because the PCB assembly 3003 can be housed in one side of the molding tool during the manufacturing process, simplifying the manufacturing process.

[0429] Figure 30MA longitudinal section of the insert assembly 3007 is shown, showing additional details of the PCB assembly 3003. A sensor 3020 is placed in the flow path. The sensor 3020 can provide temperature and / or gas flow information, allowing for assessment of conditions near the patient interface. The sensor 3020 is preferably positioned near the edge of the protruding portion of the sensor portion 3017. The thickness of the overmold proximal to the sensor 3020 is preferably thinner than the overmold surrounding other portions of the PCB assembly 3003, as shown in Figure 30O . Reducing the overmold thickness improves heat transfer to facilitate more accurate temperature measurement.

[0430] Referring again to Figure 30M , a conductive track 3021 electrically connects the sensor 3020 to the PCB 3015. (Note that the sensor 3020 is not specifically shown in Figure 30M ; rather, the structure labeled 3020 represents the general location of the sensor. The structure labeled 3020 shows two conductive pads that the sensor will bridge. This structure is labeled as a sensor for illustrative purposes.) A through-hole 3023 allows the component to contact the required conductive layer. Figure 30N An alternative construction of the PCB assembly 3003 is shown. In Figure 30N , the conductive track 3021 has a tortuous path. It has been recognized that increasing the length of the conductive track 3021 within the flow path allows the temperature of the conductive track 3021 to more accurately reflect the temperature within the flow path, reducing the effect of the environment on the sensor 3020 through the conductive track 3021. Preferably, there is increased copper surface area near the sensor 3020. The increased copper helps to accurately detect the temperature around the sensor 3020 area.

[0431] In certain embodiments, the tapered shape can extend upstream along the gasway toward the source of the gas flow. This configuration facilitates more accurate measurements by ensuring that the sensor 3020 protrudes into the fluid flow as it passes through the overmolded portion before the fluid is cooled. This configuration can also facilitate more accurate measurements by reducing the "stem effect." All contact-type temperature sensors suffer from the stem effect. When a probe is immersed in a fluid flow, a thermal conduction path is created through the stem of the probe. In the case where the ambient temperature is cooler than the temperature of the fluid flow being measured, heat is conducted away from the probe tip via the stem of the probe to the outside atmosphere. This causes the sensing tip to read a lower temperature than the actual surrounding fluid. Also, in the case where the ambient temperature is hotter than the temperature of the fluid flow being measured, heat is conducted from the outside atmosphere toward the probe tip via the stem of the probe. This causes the sensing tip to read a higher temperature than the actual surrounding fluid. The configuration of the tapered shape reduces the stem effect by protruding the sensor 3020 away from the portion of the sensor portion 3017 that connects the PCB 3015 and the positioning portion 3019 (i.e., away from the "stem"). In certain embodiments, the tapered shape extends at least 6 mm (or about 6 mm) upstream from the portion of the sensor portion 3017 that connects the PCB 3015 and the positioning portion 3019.

[0432] In certain embodiments, the tapered shape can extend downstream away from the source of the gas flow. This configuration can be advantageous, for example, when the design of the overmolded PCB assembly 3003 significantly alters the average downstream fluid properties, such that it is desirable to be able to accurately measure the fluid properties exiting the tube.

[0433] The heating filaments (not shown here but described above) in the second elongated member can be connected to the PCB 3015, which can provide termination points to complete the heating filament circuit. The PCB 3015 can also be used to provide additional termination points to provide power to additional heating filaments in a secondary tube, such as in a segmented inspiratory limb configuration used with a humidification system having a connection configured to couple the heating filaments in both segments with the sensor. The above discussion with respect to Figure 33A -33D discusses a suitable PCB assembly configuration.

[0434] Returning again Figure 30MThis construction eliminates the need to have a separate power line extending to the heating filament. This construction further ensures that the heating filament extends along the tube 203 and terminates on the tube 203 at approximately the same location as the sensor 3020. Thus, this construction minimizes the temperature drop from the end of the heating filament to the sensor 3020. This construction can also reduce the temperature drop from the end of the heating filament to the second heating filament in the additional section of the tube. This construction can also be used to heat the overlying connector of the sensor 3020, thereby reducing the heat lost to the cold environment and further improving the accuracy of the temperature measurement.

[0435] While the foregoing describes placing one or more sensors at the patient end of the tube 201, it should be appreciated that this sensor construction can be applied along any portion of the fluid path of the tube 201.

[0436] For example, Figure 34 A portion of a segmented inspiratory limb 3401 for use with a respiratory humidification system is shown, the segmented inspiratory limb 3401 including a first section 3401a and a second section 3401b, and having an intermediate connector 3403 configured to couple a first heating filament 3405a to a second heating filament 3405b, and a first temperature sensor 3407a to a second temperature sensor 3407b, in the respective sections 3401a and 3401b. Coupling the two sections 3401a and 3401b can include mechanically coupling the sections to form a single conduit through which humidified gas can be delivered to a user, where mechanically coupling the sections 3401a and 3401b can electrically couple the respective heating filaments 3405a, 3405b and the respective temperature sensors 3407a, 3407b through the intermediate connector 3403. Figure 33A and Figure 33B The PCB assembly 3301 shown in Figure 34 is adapted for use with the intermediate connector 3403 of

[0437] Again returning Figure 34The segmented inspiratory limb 3401 can include a structure 3409 that forms a lumen through which humidified gases can pass. The structure 3409 can include paths formed within the walls of the structure 3409 that are configured to house heating wires 3405a or 3405b such that the heating wires 3405a or 3405b are protected from the effects of humidified gases traveling through the lumen and / or are covered by an outer surface of the structure 3409 such that the heating wires are not exposed. For example, the structure 3409 can be a composite tube in which the heating wire paths are coils that are molded into the tube as described above. The structure 3409 can comprise any type of suitable material and can include insulating and / or flexible materials. In some embodiments, the structure 3409 and the intermediate connector 3403 can be configured such that the heating wires 3405a and 3405b wrap around the intermediate connector 3403 in a manner that electrically couples to the intermediate connector 3403 when the first segment 3401a and the second segment 3401b are mechanically coupled. In some embodiments, the first segment 3401a and / or the intermediate connector 3403 can exclude any flying leads for connection to the second segment 3401b, thereby facilitating connection of the second segment 3401b to the first segment 3401a.

[0438] The structure 3409 at the complementary ends of the first segment 3401a and the second segment 3401b can be configured to house the intermediate connector 3403. Thus, the intermediate connector 3403 can be inside the inspiratory limb 3401. In some embodiments, the complementary ends of the first segment 3401a and the second segment 3401b can be configured to protect the intermediate connector 3403 from the effects of humidified gases traveling through the inspiratory limb 3401. In some embodiments, the intermediate connector 3403 is inside the inspiratory limb 3401 and is protected from the effects of humidified gases in the conduit, thereby reducing or eliminating exposure of electrical connections on the intermediate connector 3403.

[0439] In some embodiments, the first heating wire 3405a can include two wires 3411 and 3413, and the second heating wire 3405b can include two wires 3415 and 3417. The two wires 3411 and 3413 in the first section 3401a can be electrically coupled to each other by an electrical component 3419, where the electrical coupling creates an electrical path through the wire 3411, at least a portion of the electrical component 3419, and the wire 3413. Similarly, the two wires 3415 and 3417 in the second section 3401b can be electrically coupled to each other by an electrical component 3419, and / or electrically shorted together at an end of the section 3401b opposite the middle connection 3401b, such as by one patient end connection (not shown). By coupling the wires 3415 and 3417 of the second section 3401b at the middle connection 3403, the electrical connections at the patient end of the inspiratory limb 3401 are reduced or eliminated, which can reduce cost, system complexity, and / or patient risk.

[0440] The middle connection 3403 can be configured to allow a single controller, such as a humidifier controller, to control the power provided to the heating wires 3405a, 3405b. In some embodiments, the humidifier controller controls the heating wires 3405a, 3405b, while there is no additional control functionality present on the middle connection 3403. For example, the middle connection 3403 can include a passive component that does not have any logic circuitry, where the passive component directs power to the heating wires 3405a and / or 3405b according to a selection of the controller. This can allow for the use of relatively inexpensive components to design the middle connection 3403, and can reduce the complexity of the design.

[0441] In some embodiments, heating of both segments 3401a and 3401b can be accomplished using a maximum of four wires in each segment 3401a, 3401b. For example, in the first segment 3401a, the four wires can include the first heating wire 3411, the second heating wire 3413, the signal temperature sensor wire 3419, and the return temperature sensor wire 3421. In the second segment 3401b, the four wires can include the first heating wire 3415, the second heating wire 3417, the signal temperature sensor wire 3423, and the return temperature sensor wire 3425. By coupling the second heating wires 3415, 3417 over the first heating wires 3411, 3413 at the connection point 3427, and by coupling the second temperature sensor wires 3423, 3425 over the first temperature sensor wires 3419, 3421 at the connection point 3427, the controller can be configured to independently provide power to the first heating wire 3405a and the second heating wire 3405b, and to independently read temperature sensor data from the temperature sensors 204a and 204b, without having to include more than four wires in either segment 3401a or 3401b. In some embodiments, control of the heating wires 3405a and 3405b and reading of the temperature sensors 3407a and 3407b can be accomplished using fewer than four wires in each segment (e.g., using three wires or using two wires) or more than four wires in each segment (e.g., using five wires, using six wires, using seven wires, using eight wires, or using more than eight wires).

[0442] The intermediate connection 3403 can include electrical components 3419 configured to allow a controller to selectively control the heating wires 3405a, 3405b. The controller can be configured to control heating of the inhalation leg 3401 using two modes, where a first control mode includes providing power to the heating wires 3405a in the first section, and a second control mode includes providing power to the heating wires 3405a and 3405b in the first section 3401a and the second section 3401b. Thus, the controller can be configured to independently control the heating wire sections. This capability allows the controller to control heating of the inhalation leg 3401 by controlling heating of the inhalation leg according to the first control mode only when the second section 3401b is not present, allowing the respiratory humidification system to be usable in a variety of situations without having to modify the controller or the humidification device. In some embodiments, these control modes can include one mode where power is delivered to the heating wires 3405b in the second section 3401b only. In some embodiments, the controller includes a power source that provides electrical current. The first control mode and the second control mode can be based at least in part on a voltage supplied by the power source, where a positive voltage or positive current can trigger the first control mode, and a negative voltage or negative current can trigger the second control mode. In some embodiments, the power source provides rectified AC or DC power to the heating wires 3405a, 3405b, and a change in rectification or polarity triggers a change in control mode. By switching control modes, control of heating in the respiratory circuit can be accomplished with any power source that can switch the polarity of the output signal. In some embodiments, the amount of power provided to the heating wires 3405a, 3405b can be adjusted by adjusting a duty cycle of the power applied to the heating wires 3405a, 3405b. For example, pulse-width modulation (PWM) can be used to activate the heating wires 3405a, 3405b, and the duty cycle of the PWM signal can be adjusted to control the power delivered. In another example, the amount of power provided to the heating wires 3405a, 3405b can be adjusted by controlling the amplitude of the power signal.

[0443] The intermediate connection 3403 can include electrical components 3421 configured to allow the controller to selectively read the temperature sensors 3407a, 3407b. Selective reading can be accomplished using a current source, where application of a positive current across the wires 3419 and 3421 can cause the controller to measure a temperature-related signal from the first temperature sensor 3407a, and application of a negative current across the wires 3419 and 3421 can cause the controller to measure a temperature-related signal from the second temperature sensor 3407b or from both the first temperature sensor 3407a and the second temperature sensor 3407b. The controller can use readings from the temperature sensors 3407a, 3407b to regulate power provided to the heating wires 3405a, 3405b using, for example, pulse-width modulation. The first temperature sensor 3407a can be positioned near the junction or intersection of the first section 3401a and the second section 3401b to provide the controller with the temperature of the gas entering the second section 3401b, which can correspond to the entry into an incubator or other such region having a different ambient temperature. The second temperature sensor 3407b can be positioned at the patient end of the second section 3401b to provide the controller with the temperature of the gas delivered to the patient, or the temperature before the final workpiece such as a Y-piece before the patient. The controller can use these temperature readings to regulate power provided to the heating wires 3405a, 3405b in order to maintain the temperature of the gas at the patient end of the inspiratory limb 3401 at a target or suitable temperature. The target or suitable temperature can vary depending at least in part on the application and environment in which it is used, and can be about 37°C, about 40°C, at least about 37°C and / or less than or equal to about 38°C, at least about 36.5°C and / or less than or equal to about 38.5°C, at least about 36°C and / or less than or equal to about 39°C, at least about 35°C and / or less than or equal to about 40°C, at least about 37°C and / or less than or equal to about 41°C, or at least about 39.5°C and / or less than or equal to about 40.5°C. In some embodiments, the second temperature sensor 3407b can be positioned within the incubator, but not attached to the breathing circuit. By measuring the temperature within the incubator, the temperature of the second section 3401b can be calculated.

[0444] The controller can independently control the amount of power delivered in the first control mode and the second control mode as described herein. Based at least in part on feedback from the temperature sensors 3407a and / or 3407b, the controller can independently adjust the power delivered in the first control mode and the second control mode, thereby causing the heater power ratio between the first section 3401a and the second section 3401b to change.

[0445] In some embodiments, the first temperature sensor 3407a is positioned within the flow of gas within the inspiratory limb 3401. In some embodiments, the intermediate connector 3403 or the first section 3401a can include a mechanical component that reduces turbulence in the flow of gas passing through the first temperature sensor 3407a, which can improve the accuracy of the readings of the temperature sensor 3407a. In some embodiments, the mechanical component that reduces turbulence (e.g., a cross member feature within the inspiratory conduit) also secures the temperature sensor 3407a within the flow of gas. In some embodiments, the intermediate connector 3403 and the mechanical component are configured to thermally isolate the temperature sensor 3407a from electrical components on the intermediate connector 3403.

[0446] In some embodiments, the intermediate connector 3403 includes an additional connection point in addition to the connection point 3427 shown in Figure 34 The additional connection point can be used to incorporate additional functionality into the breathing circuit, such as incorporating a memory device (PROM), a microcontroller, additional circuitry, and the like, for example.

[0447] In addition, the composite tube 201 can be an inspiratory tube or an expiratory tube.

[0448] Placement of helical connector

[0449] Reference is next made to Figure 35A - 35F, which illustrate the connector without electrical connection to a PCB. However, as will be appreciated by those skilled in the art, the connector can be identical to one adapted to have electrical connection to a PCB. The connector is adapted to be connected to, for example, a patient interface or a humidifier. It is particularly adapted for use as a patient end connector and / or a device end connector in an obstructive sleep apnoea environment.

[0450] A spiral terminated moulded insert 3501 is provided. The end of the insert 3501 opposite the spiral end is moulded for insertion or attachment to a humidifier port, and / or a patient interface port, and / or any other desired component. The insert 3501 can be a hard material such as a hard plastic, for example polypropylene.

[0451] As shown in Figure 35C The spiral end of the insert 3501 is screwed onto the compliant ring of the tube 201. In this example, the size and configuration of the spiral ring of the insert 3501 is to fit into the rings of the first elongate member 203 of the tube 201.

[0452] It should be noted that if a tube has one or more electrically powered wires, an electrical connection can be provided on at least a portion of the insert 3501. When installing the insert 3501, the electrical connection is preferably aligned with the wires, thereby facilitating the electrical connection. The connection can then be secured using solder or the like.

[0453] A member 3503 can be inserted or molded on top of at least a portion of the insert 3501 and optionally the tube 201 to facilitate attachment between the insert 3501 and the tube 201. The member 3503 can be a hard material or a soft material, such as a soft plastic, rubber or PTFE, e.g., polypropylene. In some cases, the insert 3501 (or at least the spiral end of the insert 3501) provides sufficient lateral crush resistance to enable high pressure molding techniques to be used, where the pressure can exceed the lateral crush resistance of the tube 201 without the insert 3501. The member 3503 can also advantageously provide a soft surface to grip when inserting or removing the tube from a component.

[0454] The foregoing method of attaching a connector to a spiral wound tube is provided by way of example. The method described herein does not imply that the steps have a fixed order. It also does not imply that any one step is required to practice the method. Embodiments can be practiced in any order, and combinations are also possible.

[0455] Placement of alternative patient end connector

[0456] Reference is next made to Figure 36A -36K. Figure 36A and Figure 36B A patient end connector 3601 is shown that does not have an electrical connection. The connector 3601 has a patient end 3603 that has a standard size medical taper suitable for use with a patient interface. The tube end 3605 of the connector 3601 is suitable for connection to a composite tube 201 as described below. The connector 3601 is preferably a pre-molded component formed of a suitable material, such as plastic, rubber or PTFE.

[0457] As shown in Figure 36C and Figure 36D a portion (e.g., 10-mm portion) of the second elongate member 205 is stripped to reveal one or more filaments 215 of a smaller length embedded therein. Preferably, about 5 mm or 10 mm of the filaments 215 are revealed. As shown in Figure 36D the filaments 215 are twisted together and optionally secured, e.g., by welding, to create a closed loop circuit.

[0458] Turning next to Figure 36GThe tube end 3605 of connector 3601 is inserted into tube 201, and twisted filament 215 is positioned below retaining ring 3607. Retaining ring 3607 reduces movement of filament 215 during molding. Retaining ring 3607 also advantageously aligns the rotational pitch of composite tube 201 with connector 3601, which in turn promotes proper alignment of tube 201 in the mold. The combination of connector 3601 and composite tube 201 is here designated as connector-tube assembly 3609.

[0459] like Figure 36H As shown, the molding tool core 3611 is inserted into the connector 3601. Figure 36I As shown, the connector-tube assembly 3609 and the core 3611 are placed in the injection molding tool 3613. Figure 36J In this process, a molding material 3615 is molded onto the mating area between the composite tube 201 and the connector 3601, thereby joining the composite tube 201 and the connector 3601. Suitable molding materials 3615 include plastics and rubbers. The connector-tube assembly 3609 and the core 3611 are removed from an injection molding tool (not shown), as follows: Figure 36K As shown in the diagram, the core 3611 is removed, thereby providing the patient-end connector 3601 to the composite tube 201.

[0460] The aforementioned method for attaching a connector to a composite pipe is provided by way of example. The described method does not imply a fixed order for the steps, nor does it imply that any single step is required to perform the method. The embodiments can be performed in any order, and combinations thereof are also possible.

[0461] The foregoing description of the invention includes preferred forms. Modifications may be made to the invention without departing from its scope. The numerous structural changes, distinct embodiments, and applications of the invention will be apparent to those skilled in the art as they themselves do not depart from the scope of the invention as defined in the appended claims. The disclosure and description herein are entirely illustrative and not intended to be limiting in any sense.

[0462] Throughout this specification and claims, the terms “comprises”, “comprising”, etc., shall be interpreted as including, that is, “including but not limited to”, unless the context clearly requires otherwise.

[0463] While the application has been described by way of example and in terms of the possible embodiments thereof, it is to be understood that many modifications or improvements can be made to the described embodiments without departing from the spirit and scope of the application. In addition, where particular elements or integers have been discussed in relation to specific embodiments, it is to be understood that such elements or integers are not to be confined to those embodiments, but are to be considered as having been described with reference thereto in the broadest context possible.

[0464] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge of the skilled person in any country worldwide.

Claims

1. A breathing tube for delivering humidified gases to a patient, the breathing tube comprising: a first connector at a first end of the tube and a second connector at a second end of the tube, the second end opposite the first end; a lumen extending between the first connector and the second connector, the lumen configured to define a gases flow path in use; a circuit board assembly secured to a wall of the first connector, the circuit board assembly comprising: a partition portion extending into the lumen and partitioning at least a portion of the gases flow path; a wiring portion comprising electrical contact points configured to couple with at least two electrically conductive wires of the breathing tube; a sensor portion disposed in the lumen, at least one sensor disposed on the sensor portion, the sensor portion protruding on a longitudinal axis of the first connector and into the gases flow path; one or more electrically conductive tracks configured to electrically connect the electrical contact points to the at least one sensor; an overmold composition disposed over at least the partition portion and the sensor portion; and an insulating gap disposed between the wall of the first connector and the sensor portion.

2. The breathing tube of claim 1, wherein, The insulating gap is an air gap disposed above and below the sensor portion.

3. The breathing tube of claim 2, wherein, One or more of the at least two electrically conductive wires are heating filaments embedded in the tube, and the insulating gap is configured to protect the sensor from heat radiation from the heating filaments.

4. The breathing tube of claim 1, wherein, The sensor portion extends from a center of the partition portion.

5. The breathing tube of claim 1, wherein, The circuit board assembly is a single printed circuit board assembly, and overmolding the single printed circuit board assembly allows for consistent placement of the at least one sensor.

6. The breathing tube of claim 1, wherein, The at least one sensor is placed proximate an edge of the sensor portion and is configured to assess conditions proximate a patient interface.

7. The breathing tube of claim 1, wherein, The overmold composition comprises a thermal conductivity in a range of 0.03-0.6 W / m-K.

8. The breathing tube of claim 1, wherein, The at least one sensor is located on a surface of the sensor portion.

9. The breathing tube of claim 1, wherein, The circuit board assembly is configured to position the at least one sensor apart from other active and / or passive electrical components.

10. The breathing tube of claim 1, wherein, The at least two electrically conductive wires are heating filaments connected to the wiring portion of the circuit board assembly to provide terminal points.

11. The breathing tube of claim 10, wherein, The heating filaments comprise two heating filaments embedded or encapsulated within the breathing tube.

12. The breathing tube of claim 10, wherein, The heating filaments extend along the breathing tube and terminate at approximately the same location on the tube as the sensor.

13. The breathing tube of claim 1, wherein, The circuit board assembly comprises a positioning portion, the partition portion, the sensor portion, and the positioning portion mounted together.

14. The breathing tube of claim 1, wherein, The circuit board assembly comprises a positioning portion, the partition portion, the sensor portion, and the positioning portion integrally formed from a suitable material.

15. The breathing tube of claim 14, wherein, The suitable material is a circuit board substrate.

16. The breathing tube of claim 1, wherein, The one or more electrically conductive tracks have a tortuous path.

17. The breathing tube of claim 1, wherein, The at least two electrically conductive wires are embedded or encapsulated in a wall of the tube.

18. The breathing tube of claim 1, wherein, The circuit board assembly is a printed circuit board assembly and the circuit board is a printed circuit board.

19. The breathing tube of claim 1, wherein, The at least one sensor is disposed proximate a leading edge of the sensor portion.

20. The breathing tube of claim 1, wherein, The sensor portion comprises a conical shape extending along the longitudinal axis.

21. The breathing tube of claim 20, wherein, The conical shape of the sensor portion comprises an airfoil shape, a bird wing shape, a torpedo shape or a bullet shape.

22. The breathing tube of claim 1, wherein, The thinnest portion of the overmould composition is proximal to the edge of the sensor portion.

23. The breathing tube of claim 1, wherein, The at least one sensor is a temperature sensor.

24. The breathing tube of claim 23, wherein, The temperature sensor is a thermistor.

25. The breathing tube of claim 1, wherein, The circuit board assembly is supported by at least one of the walls of the first connector.

26. The breathing tube of claim 1, wherein, The wiring portion protrudes outwardly from the wall of the first connector in a direction away from the lumen.

27. The breathing tube of claim 26, wherein, comprises a positioning portion which adjoins the partition portion and which protrudes outwardly from the wall of the first connector in a direction away from the lumen and opposite the wiring portion.

28. The breathing tube of claim 1, wherein, The at least two electrically conductive lines comprise heating lines and / or sensing lines.

29. The breathing tube of claim 28, wherein, The circuit board assembly completes a heating circuit of the tube formed by the heating lines; and / or a sensing circuit of the tube formed by the sensing lines.

30. The breathing tube of claim 1, wherein, The circuit board assembly is configured such that the electrical contact points of the wiring portion are positioned outside of the gas flow path.

31. The breathing tube of claim 1, wherein, comprises an elongated body which bounds the lumen and which is in fluid communication with the first connector and the second connector such that the first connector, the second connector and the elongated body form, in use, a gas flow path between the first and second ends of the humidified gas.

32. The breathing tube of claim 31, wherein, The at least two electrically conductive lines are helically wound along the length of the elongated body.

33. The breathing tube of claim 31, wherein, The elongated body comprises a smooth lumen surface.

34. The breathing tube of claim 31, wherein, The elongated body comprises a helically wound hollow body and a reinforcing portion disposed between adjacent turns of the hollow body.

35. The breathing tube of claim 1, wherein, The second connector is configured to removably connect, in use, the breathing tube to a breathing assistance device or a humidification device to form a pneumatic connection or an electrical connection.

36. The breathing tube of claim 35, wherein, The second connector comprises a plug to connect to the breathing assistance device or the humidification device.

37. The breathing tube of claim 1, wherein, The second connector is configured to removably connect, in use, the breathing tube to a gas flow generator, wherein the at least two electrically conductive lines terminate in at least two electrical conductors of the second connector.

38. The breathing tube of claim 35, wherein, The electrical connection of the second connector electrically couples the at least one sensor to at least one controller of the breathing assistance device or the humidification device when the second connector is coupled to the breathing assistance device or the humidification device.

39. The breathing tube of claim 1, wherein, The first connector is configured to pneumatically connect, in use, at least the tube to a patient interface.

40. The breathing tube of claim 1, wherein, The at least two electrically conductive lines are connected to the electrical connection of the second connector and to the electrical contact points of the circuit board assembly of the first connector which are to be electrically connected with the at least one sensor.

41. The breathing tube of claim 1, wherein, The breathing tube is an inspiratory conduit.

42. A breathing assistance device for delivering humidified gas to a patient, comprising: a breathing tube according to any one of claims 1-41; and at least one of the following: a gas source configured to provide dry gas; and A humidifier configured to humidify the dry gas from the gas source when in use, the humidifier comprising a humidification chamber containing a volume of water or other suitable humidification liquid, the humidification chamber comprising an outlet couplable to the gas source.

43. The respiratory assistance device of claim 42, wherein, The respiratory tube comprises the humidifier, and wherein the respiratory tube is removably coupled to the outlet of the humidification chamber.

44. The respiratory assistance device of claim 42, wherein, The gas source comprises a blower or a fan.

45. The respiratory assistance device of claim 42, wherein, The respiratory tube comprises at least one controller configured to control the humidifier and / or the gas source.

46. The respiratory assistance device of claim 42, wherein, The second connector of the respiratory tube is configured to removably connect a tube to the gas source or to the humidifier when in use to form a pneumatic connection and an electrical connection.

47. The respiratory assistance device of claim 42, wherein, The respiratory tube comprises a patient interface.

48. The respiratory assistance device of claim 47, wherein, The patient interface is a nasal cannula comprising a delivery tube, a cannula body, and a headgear, wherein the headgear is configured to secure around a posterior side of a patient's head.

49. The respiratory assistance device of claim 48, wherein, The delivery tube is in fluid communication with the respiratory tube to provide humidified gas to a patient.

50. The respiratory assistance device of claim 48, wherein, The delivery tube is not heated.

51. The respiratory assistance device of claim 48, wherein, The delivery tube and the respiratory tube are a single component that extends to the cannula body.

52. The respiratory assistance device of claim 42, wherein, The device is configured to provide nasal high flow therapy.

53. An overmolded circuit board assembly configured to secure to a wall of a connector of a respiratory tube having a fine longitudinal axis, the overmolded circuit board assembly comprising: a partition portion; a wiring portion adjacent to the partition portion and comprising electrical contact points configured to couple with at least two electrically conductive wires of the respiratory tube; a sensor portion on which at least one sensor is disposed, the sensor portion protruding from the partition portion along the longitudinal axis and into a gas flow path; one or more electrically conductive tracks configured to electrically connect the electrical contact points to the at least one sensor; an overmold composition disposed over at least the partition portion and the sensor portion; and an insulating gap disposed between the wall of the connector and the sensor portion. The insulating gap is an air gap disposed above and below the sensor portion.

54. The overmolded circuit board assembly of claim 53, wherein, The partition portion, the wiring portion, and the sensor portion are integrally formed.

55. The overmolded circuit board assembly of claim 53, wherein, The circuit board assembly is a single printed circuit board assembly, and an overmold composition is disposed over the single printed circuit board assembly.

56. The overmolded circuit board assembly of claim 53, wherein, The sensor is placed proximate an edge of the sensor portion.

57. The overmolded circuit board assembly of claim 53, wherein, The at least one sensor is a temperature sensor.

58. The overmolded circuit board assembly of claim 53, wherein, The temperature sensor is a thermistor.

59. The overmolded circuit board assembly of claim 58, wherein, The one or more electrically conductive tracks have a tortuous path.

60. The overmolded circuit board assembly of claim 53, wherein, The sensor portion comprises a tapered shape.

61. The overmolded circuit board assembly of claim 53, wherein, The tapered shape of the sensor portion comprises a wing shape, a bird wing shape, a torpedo shape, or a bullet shape for aerodynamic efficiency.

62. The overmolded circuit board assembly of claim 61, wherein, A thinnest portion of the overmold composition is proximate an edge of the sensor portion.

63. The overmolded circuit board assembly of claim 61, wherein, 64. A respiratory tube for delivering humidified gas to a patient, the respiratory tube comprising: a first connector at a first end of the tube and a second connector at a second end of the tube, the second end opposite the first end; a lumen extending between the first connector and the second connector, the lumen configured to define a gas flow path when in use; and a second connector at a second end of the tube, the second end opposite the first end. ​ A circuit board assembly secured to a wall of the first connector, the circuit board assembly comprising: a wiring portion comprising electrical contact points configured to couple with at least two electrically conductive lines of the breathing tube, the wiring portion protruding outwardly from the wall of the first connector in a direction away from the lumen; an extension portion extending along a diameter or chord line into the lumen and comprising a sensor portion, the sensor portion being positioned in the gas flow path and comprising at least one temperature sensor; one or more electrically conductive tracks configured to electrically connect the at least one temperature sensor to the electrical contact points; at least one diode electrically coupled to the at least one temperature sensor; wherein the circuit board assembly is configured to position the at least one temperature sensor spaced apart from the at least one diode to thermally insulate the at least one temperature sensor from the at least one diode; and an overmold composition disposed over the sensor portion.

65. The breathing tube of claim 64, wherein, The circuit board assembly is configured to space the at least one temperature sensor from the at least one diode via an included gap.

66. The breathing tube of claim 64, wherein, The circuit board assembly is overmolded by the overmold composition.

67. The breathing tube of claim 64, wherein, The at least one temperature sensor is located proximate an edge of the sensor portion and is configured to assess a condition of patient proximity.

68. The breathing tube of claim 64, wherein, The overmold composition comprises a thermal conductivity in a range of 0.03-0.6 W / m K.

69. The breathing tube of claim 64, wherein, The at least one temperature sensor is located on a surface of the sensor portion.

70. The breathing tube of claim 64, wherein, The circuit board assembly is configured to position the at least one temperature sensor spaced apart from other active and / or passive electrical components.

71. The breathing tube of claim 64, wherein, The at least two electrically conductive lines are heating filaments connected to the electrical contact points of the wiring portion to provide terminal points.

72. The breathing tube of claim 71, wherein, The heating filaments comprise two heating filaments embedded or encapsulated in a wall of the breathing tube.

73. The breathing tube of claim 71, wherein, The heating filaments extend along the breathing tube and terminate at approximately the same location on the tube as the at least one temperature sensor.

74. The breathing tube of claim 64, wherein, The one or more electrically conductive tracks have a tortuous path.

75. The breathing tube of claim 64, wherein, The at least two electrically conductive lines are embedded or encapsulated in a wall of the tube.

76. The breathing tube of claim 64, wherein, The circuit board assembly is a printed circuit board assembly.

77. The breathing tube of claim 64, wherein, A tapered shape of the sensor portion.

78. The breathing tube of claim 77, wherein, The tapered shape of the sensor portion comprises an airfoil shape, a bird wing shape, a torpedo shape, or a bullet shape.

79. The breathing tube of claim 64, wherein, A thinnest portion of the overmold composition is proximate an edge of the sensor portion.

80. The breathing tube of claim 64, wherein, The at least one temperature sensor is a thermistor.

81. The breathing tube of claim 64, wherein, The circuit board assembly is supported by at least one of the walls of the first connector.

82. The breathing tube of claim 64, wherein, The at least two electrically conductive lines comprise heating lines and / or sensing lines.

83. The breathing tube of claim 82, wherein, The circuit board assembly completes a heating circuit of the tube formed by the heating lines; and / or a sensing circuit of the tube formed by the sensing lines.

84. The breathing tube of claim 82, wherein, The circuit board assembly is configured such that the electrical contact points of the wiring portion are positioned outside of the gas flow path.

85. The breathing tube of claim 64, wherein, The elongated body defines the lumen and is in fluid communication with the first connector and the second connector, such that the first connector, the second connector and the elongated body form, in use, a gas flow path between the first end and the second end of the humidified gas.

86. The breathing tube of claim 85, wherein, The at least two electrically conductive wires are helically wound along a length of the elongated body.

87. The breathing tube of claim 85, wherein, The elongated body comprises a smooth lumen surface.

88. The breathing tube of claim 85, wherein, The elongated body comprises a helically wound hollow body and a reinforcing portion disposed between adjacent turns of the hollow body.

89. The breathing tube of claim 64, wherein, The second connector is configured to removably connect, in use, the breathing tube to a breathing assistance device or a humidification device to form a pneumatic connection or an electrical connection.

90. The breathing tube of claim 89, wherein, The second connector comprises a plug configured to connect to the breathing assistance device or the humidification device.

91. The breathing tube of claim 64, wherein, The second connector is configured to removably connect, in use, the breathing tube to a gas flow generator, wherein the at least two electrically conductive wires terminate in at least two electrical conductors of the second connector.

92. The breathing tube of claim 89, wherein, The electrical connection of the second connector electrically couples the at least one temperature sensor to at least one controller of the breathing assistance device or the humidification device when the second connector is coupled to the breathing assistance device or the humidification device.

93. The breathing tube of claim 64, wherein, The first connector is configured to pneumatically connect, in use, the tube at least to a patient interface.

94. The breathing tube of claim 64, wherein, The at least two electrically conductive wires are connected to: the electrical connection of the second connector and the electrical contact points of the circuit board assembly of the first connector to be in electrical communication with the at least one temperature sensor.

95. The breathing tube of claim 64, wherein, The breathing tube is an inspiratory conduit.

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