Composite tube for use in medical circuit intended for supplying gases to patient and / or removing gases from patient (variants), and method for manufacturing such composite tube

Abstract

FIELD: medical devices.SUBSTANCE: tubes intended for use in medical circuits intended for the delivery of gases to and / or the removal of gases from a patient, such as in positive airway pressure (PAP), respirator, anesthesia, ventilator and insufflation systems. A composite tube for use in medical circuits intended for supplying gases to a patient and / or removing gases from a patient comprises a first elongated element and a second elongated element. The first elongated element comprises a hollow body spirally wound to form at least a partially elongated tube having a longitudinal axis, a cavity extending along the longitudinal axis, and a hollow wall at least partially surrounding this cavity. The second elongated element is spirally wound and connected between adjacent turns of the first elongated element, wherein the second elongated element forms at least a part of the cavity of the elongated tube. The second elongated element has a cross-section in the longitudinal direction that is wider near the cavity and narrower at a radial distance from the cavity. A method for manufacturing a composite tube for use in medical circuits intended for supplying gases to a patient and / or removing gases from a patient includes the steps of : providing a first elongated element comprising a hollow body and a second elongated element ; spirally winding the second elongated element onto a core, wherein the opposing lateral edge portions of the second elongated element on adjacent turns are arranged at a distance, thereby forming a spiral of the second elongated element; and spirally winding the first elongated element onto the spiral of the second elongated element so that portions of the first elongated element overlap adjacent turns of the spiral of the second elongated element, and a portion of the first elongated element is located close to the core in the space between the turns of the spiral of the second elongated element, thereby forming a spiral of the first elongated element, wherein the second elongated element has a cross-section in the longitudinal direction that is wider near the cavity and narrower at a radial distance from the cavity.EFFECT: improved temperature and / or humidity control in medical circuits.36 cl, 11 dwg

Description

PRIOR ART Field of technology to which the invention relates

[0001] The present disclosure relates generally to tubing intended for medical use, and in particular to tubing for use in medical circuits intended to deliver gases to and / or remove gases from a patient, such as in positive airway pressure (PAP), respirator, anesthesia, ventilator, and insufflation systems. Description of the related art

[0002] In medical circuits, various components transport warm and / or humidified gases to and from patients. For example, in some breathing circuits, such as positive airway pressure circuits or ventilator-assisted ventilation circuits, the patient's inhaled gases are delivered from a heated humidifier through an inspiratory tube. As another example, insufflation circuits, the tubes can deliver humidified gas (usually CO2) into the abdominal cavity. This can help prevent the "drying out" of the patient's internal organs and can reduce the time needed for recovery after surgery. Unheated tubes allow significant heat loss due to natural cooling. This cooling can cause unwanted condensation or "washout" along the length of the tube transporting warm, humidified air.There remains a need for tubes that are insulated against heat loss and that, for example, provide improved temperature and / or humidity control in medical circuits. SUMMARY OF THE INVENTION.

[0003] This document discloses medical tubes and methods for manufacturing medical tubes in various embodiments. In some embodiments, the tube may be a composite structure made from two or more distinct components spirally wound to form an elongated tube. For example, one of the components may be a spirally wound elongated hollow body, and the other component may be an elongated structural component, also spirally wound between the turns of the spirally wound hollow body. In other embodiments, the tube need not be made from distinct components. For example, an elongated hollow body molded (e.g., extruded) from a single material may be spirally wound to form an elongated tube.The elongated hollow body itself, in its transverse cross-section, may have a thin-walled portion and a relatively thicker or more rigid reinforcing portion. These tubes can be used in a wide variety of medical circuits or for other medical applications.

[0004] In at least one embodiment, a composite tube may comprise a first elongated element that is a hollow body spirally wound to form, at least in part, an elongated tube having a longitudinal axis, a cavity extending along the longitudinal axis, and a hollow wall surrounding this cavity. A second elongated element may be spirally wound and connected between adjacent turns of the first elongated element, wherein the second elongated element forms, at least a portion of the cavity of the elongated tube. The terms "first elongated element" and "second elongated element" do not necessarily imply an order, such as the order in which the components are assembled. As described herein, the first elongated element and the second elongated element may be parts of a single tubular element.

[0005] In various embodiments, the above-described component has one, more, or all of the following properties, as well as the properties described in this disclosure.

[0006] The first elongated element may be a tube. The first elongated element may form, in a longitudinal cross-section, a plurality of blisters with a flattened surface near the cavity. Adjacent blisters may be separated by a gap above the second elongated element or may not be directly connected to each other. The blisters may have openings. The second elongated element may have a longitudinal cross-section that is wider near the cavity and narrower at a radial distance from the cavity. In particular, the second elongated element may have a longitudinal cross-section that is substantially triangular, substantially T-shaped, or substantially Y-shaped. One or more conductive threads may be embedded or contained in the second elongated element. The one or more conductive threads may be heating threads (or, more specifically, resistive heating threads) and / or measuring threads.The tube may comprise pairs of conductive threads, such as two or four conductive threads. The pairs of conductive threads may be connected at one end of the composite tube to form a connecting loop. One or more conductive threads may be separated from the cavity wall. In at least one embodiment, the second elongated element may have a longitudinal cross-section that is substantially triangular, substantially T-shaped, or substantially Y-shaped, and one or more conductive threads may be embedded or enclosed within the second elongated element on opposite sides of the triangular, T-shaped, or Y-shaped cross-section.

[0007] The above-described component according to any or all of the previous embodiments can be used, among other applications, as a component of a medical circuit, as an inhalation tube, an exhalation tube, a component of a positive airway pressure system, a component of an insufflation system, a diagnostic component, or a surgical component.

[0008] A method for producing a composite tube is also disclosed. The resulting tube may have one, more, or all of the properties described above or elsewhere in this disclosure. In at least one embodiment, the method includes providing a first elongated element that is a hollow body and a second elongated element designed to provide structural support for the first elongated element. The second elongated element is helically wound onto a core, wherein opposing lateral edge portions of the second elongated element on adjacent turns are spaced apart, thereby forming a helix of the second elongated element.The first elongated element is spirally wound onto the spiral of the second elongated element so that parts of the first elongated element overlap the adjacent turns of the spiral of the second elongated element, and part of the first elongated element is located close to the core in the space between the turns of the spiral of the second elongated element, thereby forming the spiral of the first elongated element.

[0009] In various embodiments, the above-described method may have one, more, or all of the following. The method may include supplying air under pressure above atmospheric pressure to one end of the first elongated element. The method may include cooling the coil of the first elongated element and the coil of the second elongated element, thereby forming a composite tube having a cavity extending along the longitudinal axis and a hollow space surrounding this cavity. The method may include molding the first elongated element. The method may include extruding the first elongated element with a first extruder. The method may include molding a second elongated element. The method may include extruding the second elongated element with a second extruder. The second extruder may be designed to enclose one or more conductive threads in the second elongated element.Forming the second elongated element may include embedding conductive threads in the second elongated element. The conductive threads may be nonreactive with the second elongated element. The conductive threads may comprise aluminum or copper alloys or other conductive materials. The method may involve joining pairs of conductive threads at one end of the composite tube into a connecting loop. The first extruder may be different from the second extruder.

[0010] A medical tube is also provided. In at least one embodiment, the tube comprises an elongated hollow body, spirally wound to form an elongated tube having a longitudinal axis, a cavity extending along the longitudinal axis, and a hollow wall surrounding this cavity, wherein the elongated hollow body has a wall in a cross-section in the transverse direction, limiting at least a portion of the hollow body. The tube may further comprise a reinforcing portion extending along the length of the elongated hollow body, spirally located between adjacent turns of the elongated hollow body, wherein the reinforcing portion forms a portion of the cavity of the elongated tube. The reinforcing portion may be relatively thicker or more rigid than the wall of the elongated hollow body.

[0011] In various embodiments, the above-described tube has one, more, or all of the following properties, as well as the properties described in this disclosure. The reinforcing portion can be made of the same material as the elongated hollow body. The elongated hollow body in a cross-section in the transverse direction can comprise two reinforcing portions on opposite sides of the elongated hollow body, wherein the helical winding of the elongated hollow body connects the adjacent reinforcing portions so that the opposing edges of the reinforcing portions touch each other on adjacent turns of the elongated hollow body. The opposing lateral edges of the reinforcing portions can overlap on adjacent turns of the elongated hollow body. The reinforcing portion can be made of a different material than the elongated hollow body. The hollow body can form several bubbles with a flattened surface near the cavity in the longitudinal direction in a cross-section. The bubbles can have openings.Furthermore, the medical tube may comprise one or more conductive threads embedded or enclosed in a reinforcing portion. A conductive thread may be a heating thread and / or a measuring thread. The medical tube may comprise two conductive threads, with one conductive thread embedded or enclosed in each reinforcing portion. The medical tube may comprise two conductive threads located on only one side of the elongated hollow body. Pairs of conductive threads may be connected at one end of the elongated tube to form a connecting loop. One or more threads may be detachable from the cavity wall.

[0012] The above-described tube according to any or all of the previous embodiments can be used, among other applications, as a component of a medical circuit, as an inhalation tube, an exhalation tube, a component of a positive airway pressure system, a component of an insufflation system, a diagnostic component, or a surgical component.

[0013] A method for producing a medical tube is also provided. In at least one embodiment, the method includes spirally winding an elongated hollow body onto a core to form an elongated tube having a longitudinal axis, a cavity extending along the longitudinal axis, and a hollow wall surrounding this cavity, wherein the elongated hollow body has a wall in a cross-section in the transverse direction, limiting at least a part of the hollow body, and two reinforcing parts on opposite sides of the elongated body, forming a part of the wall of the cavity, wherein the two reinforcing parts are relatively thicker or more rigid than the wall limiting at least a part of the hollow body. In addition, the method can include such a connection of adjacent reinforcing parts that the opposing edges of the reinforcing parts touch each other on adjacent turns of the elongated hollow body.

[0014] In various embodiments, the above-described method has one, more, or all of the following properties, as well as the properties described in this disclosure. The connection of adjacent reinforcing parts may cause the edges of the reinforcing parts to overlap. The method may further include supplying air under pressure above atmospheric pressure to one end of the elongated hollow body. The method may further include cooling the elongated hollow body to connect the adjacent reinforcing parts. The method may further include extruding the elongated hollow body. The method may further include embedding conductive threads in the reinforcing parts. The method may further include connecting pairs of conductive threads at one end of the elongated tube into a connecting loop.

[0015] For the purpose of generalization of the invention, it may be noted that certain aspects, advantages, and novel features of the invention are described herein. It should be understood that not all of these advantages may necessarily be achieved by a single embodiment of the invention. Accordingly, the present invention may be implemented or executed so that one or a group of advantages described herein are achieved or optimized without necessarily achieving other advantages that may be described or suggested herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Next, exemplary embodiments incorporating various features of the disclosed systems and methods are described with reference to the drawings. The drawings and associated descriptions are provided to illustrate the embodiments and are not intended to limit the scope of the disclosure.

[0017] Fig. 1 shows a schematic illustration of a medical system comprising one or more medical tubes.

[0018] Fig. 2A shows a top side view of a section of an exemplary composite tube.

[0019] Fig. 2B shows a cross-section in the longitudinal direction of the upper portion of a tube similar to the exemplary composite tube of Fig. 2A.

[0020] Fig. 2C shows another cross-section in the longitudinal direction illustrating the first elongated element in the composite tube.

[0021] Fig. 2D shows another cross-section in the longitudinal direction of the upper part of the tube.

[0022] Fig. 2E shows another cross-section in the longitudinal direction of the upper part of the tube.

[0023] Fig. 3A shows a cross-section in the transverse direction of the second elongated element in the composite tube.

[0024] Fig. 3B shows another cross-section in the transverse direction of the second elongated element.

[0025] Fig. 3C shows another exemplary second elongated element.

[0026] Fig. 3D shows another exemplary second elongated element.

[0027] Fig. 3E shows another exemplary second elongated element.

[0028] Fig. 3F shows another exemplary second elongated element.

[0029] Fig. 3G shows another exemplary second elongated element.

[0030] Fig. 4A shows one aspect of a method for forming a composite tube.

[0031] Fig. 4B shows a spirally wound second elongated element.

[0032] Fig. 4C shows another aspect of the method for forming a composite tube.

[0033] Fig. 4D shows another aspect of the method for forming a composite tube.

[0034] Fig. 4E shows another aspect of the method for forming a composite tube.

[0035] Fig. 4F shows another aspect of the method for forming a composite tube.

[0036] Fig. 5A-5B show another example illustrating a single elongated hollow body wound helically to form a medical tube.

[0037] Figs. 5C-5F show examples of other single elongated hollow bodies wound helically to form a medical tube.

[0038] Fig. 6 shows an exemplary medical circuit according to at least one embodiment.

[0039] Fig. 7 shows an injection system according to at least one embodiment.

[0040] Fig. 8 is a schematic illustration of a coaxial tube according to at least one embodiment.

[0041] Fig. 9A-C show examples of shapes of the first elongated element intended to increase the thermal efficiency.

[0042] Fig. 9D-F show examples of arrangements of heating threads designed to increase the thermal efficiency.

[0043] Fig. 10A-C show examples of superposition of the first elongated element.

[0044] Fig. 11A-D show the properties in terms of the radius of curvature of tubes according to various embodiments.

[0045] Throughout the drawings, reference numerals are used repeatedly to indicate correspondence between reference (or similar) elements. In addition, the first digit of each reference numeral indicates the figure in which the element is first shown. DETAILED DESCRIPTION OF THE INVENTION

[0046] Details regarding several illustrative embodiments for implementing the devices and methods described herein are described below with reference to the figures. The invention is not limited to these described embodiments. A breathing circuit comprising one or more medical tubes

[0047] For a more detailed understanding of the invention, let us first turn to Fig. 1, which shows a breathing circuit according to at least one embodiment, comprising one or more medical tubes. Tube is a broad term and should be given the meaning usual for a person skilled in the art (that is, it should not be limited to any special or non-standard meaning); this term includes, without limitation, non-cylindrical passages. Some embodiments may include a composite tube, which can generally be defined as a tube containing two or more parts, or, more precisely, in some embodiments, two or more components, as described in more detail below. Such a breathing circuit can be a continuous, variable, or bilevel positive airway pressure system, or another type of respiratory therapy.

[0048] Gases can be transported in the circuit of Fig. 1 as follows. Dry gases pass from the fan / 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 inhalation tube 103 through the channel 111, thereby supplying humidified gases to the inhalation tube 103. The inhalation tube is a tube for supplying respiratory gases to the patient, and can be made of a composite tube, as described in more detail below. Gases flow through the inhalation tube 103 to the outlet 113 (the end for bleeding humidified gases) and then into the patient 101 through the patient interface 115, connected to the outlet 113.

[0049] Exhalation tube 117 is also connected to patient interface 115. An exhalation tube is a tube designed to transport exhaled humidified gases from the patient. In this case, exhalation tube 117 returns exhaled humidified gases from patient interface 115 to ventilator / blower 105.

[0050] In this example, dry gases are supplied to the fan / blower 105 through the opening 119. The fan 121 can increase the gas supply to the fan / blower by drawing air or other gases through the opening 119. The fan 121 can be, for example, a variable speed fan, wherein the fan speed is controlled by an electronic controller 123. In particular, the operation of the electronic controller 123 can be controlled by the electronic main controller 125 in response to input signals from the main controller 125 and a predetermined desired value (set value) of pressure or fan speed set by the user using the dial controller 127.

[0051] The humidifier 107 has a humidification chamber 129 containing a volume of water 130 or another suitable humidifying liquid. Preferably, the humidification chamber 129 can be removed from the humidifier 107 after use. Removability allows for easier sterilization or disposal of the humidification chamber 129. However, a portion of the humidification chamber 129 of the humidifier 107 can be a single-piece structure. The housing of the humidification chamber 129 can be made of a non-conductive glass or plastic material. However, the humidification chamber 129 can also contain conductive components. For example, the humidification chamber 129 can have a base with high thermal conductivity (e.g., an aluminum base) that contacts or is connected to the heating plate 131 on the humidifier 107.

[0052] Furthermore, the humidifier 107 may comprise electronic control devices. In this example, the humidifier 107 comprises 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 the associated memory. In response to an input signal with a user-set humidity or temperature value using the user interface 133, for example, and other input signals, the main controller 125 determines when (or to what level) to heat the heating plate 131 to heat the water 130 in the humidification chamber 129.

[0053] Any suitable patient interface 115 may be used. Patient interface is a broad term and should be given the meaning common to a person skilled in the art (that is, it should not be limited to any special or non-standard meaning); this term includes, but is not limited to, masks (such as a tracheal mask, face masks and nasal masks), cannulas and nasal pillows. The temperature sensor 135 may be connected to the inhalation tube 103 near the patient interface 115 or to the patient interface 115. The temperature sensor 135 monitors the temperature near or on the patient interface 115. A heating thread (not shown) associated with the temperature sensor may be used to regulate the temperature of the patient interface 115 and / or the inhalation tube 103 to increase the temperature of the inhalation tube 103 and / or the patient interface 115 above the saturation temperature, thereby reducing the likelihood of unwanted condensation.

[0054] In Fig. 1, the exhaled humidified gases are returned from the patient interface 115 to the ventilator / blower 105 through the exhalation tube 117. The exhalation tube 117 may also be a composite tube, as described in more detail below. However, the exhalation tube 117 may also be a medical tube, as was previously known in the art. In any case, the exhalation tube 117 may have a temperature sensor and / or a heating thread, as described above with respect to the inhalation tube 103, built into it to reduce the likelihood of condensation. In addition, the exhalation tube 117 does not necessarily have to return the exhaled gases to the ventilator / blower 105. Alternatively, the exhaled humidified gases can be transferred directly to the environment or to other auxiliary equipment, such as an air purifier / filter (not shown). In some embodiments, the exhalation tube is eliminated entirely. Composite tubes

[0055] Fig. 2A shows a top side view of a section of an exemplary composite tube 201. Typically, the composite tube 201 includes a first elongated element 203 and a second elongated element 205. Element is a broad term and should be given its usual meaning for a person skilled in the art (that is, it should not be limited to any special or non-standard meaning); this term includes, without limitation, built-in parts, built-in components, and distinct components. Thus, although Fig. 2A illustrates an embodiment made of two distinct components, it is clear that in other embodiments (such as described with reference to Figs. 5A-5D), the first elongated element 203 and the second elongated element 205 may also represent sections in the tube made of the same material.Thus, the first elongated element 203 may represent a hollow portion of the tube, and the second elongated element 205 represents a structural support or reinforcing portion of the tube, providing the hollow portion with structural support. The hollow portion and the structural support portion may have a helical configuration, as described herein. The composite tube 201 may be used to form an inhalation tube 103 and / or an exhalation tube 117, as described above, a coaxial tube, as described below, or any other tubes described in the present disclosure.

[0056] In this example, the first elongated element 203 comprises a hollow body wound helically to form an at least partially elongated tube having a longitudinal axis LA-LA and a cavity 207 extending along the longitudinal axis LA-LA. In at least one embodiment, the first elongated element 203 is a tube. Preferably, the first elongated element 203 is flexible. In addition, the first elongated element 203 is preferably transparent or at least translucent or translucent. The degree of optical transparency allows a healthcare professional or user to inspect the cavity 207 for blockages or contamination, or to confirm the presence of moisture. A wide variety of plastics are suitable for the body of the first elongated element 203, including plastics for medical use.Examples of suitable materials include polyolefin elastomers, polyether block amides (thermoplastic elastomers), thermoplastic copolyester elastomers, EPDM / PP rubber blends, and thermoplastic polyurethanes.

[0057] The hollow body design of the first elongated element 203 contributes to the thermal insulation properties of the composite tube 201. The thermal insulation of the tube 201 is desirable because, as explained above, it prevents heat loss. This allows the tube 201 to deliver gas from the heater-humidifier to the patient, maintaining the conditioned gas with minimal energy consumption.

[0058] In at least one embodiment, the hollow portion of the first elongated element 203 is filled with a gas. The gas may be air, which is desirable due to its low thermal conductivity (2.62×10 -2W / m⋅K at 300 K) and very low cost. A gas more viscous than air can also be used advantageously, since higher viscosity reduces convective heat transfer. Thus, gases such as argon (17.72×10 -3 W / m⋅K at 300 K), krypton (9.43×10 -3 W / m⋅K at 300 K) and xenon (5.65×10 -3W / m⋅K at a temperature of 300 K). Each of these gases is non-toxic, chemically inert, fire-safe, and commercially available. The hollow portion of the first elongated element 203 can be sealed at both ends of the tube, resulting in the gas being substantially immobile. Alternatively, the hollow portion can also be an auxiliary pneumatic connection, for example, a pressure sampling line for transmitting a pressure feedback signal from the end of the tube on the patient side to the controller. Optionally, the first elongated element 203 can be perforated. For example, the surface of the first elongated element 203 can be perforated on the outwardly facing surface opposite the cavity 207. In another embodiment, the hollow portion of the first elongated element 203 is filled with a liquid. Examples of liquids can include water and other biocompatible liquids with a high heat capacity. For example, nanofluids can be used.An example of a nanofluid with suitable heat capacity is water and nanoparticles of substances such as aluminum.

[0059] The second elongated element 205 is also spirally wound and connected to the first elongated element 203 between adjacent turns of the first elongated element 203. The second elongated element 205 forms at least a part of the cavity 207 of the elongated tube. The second elongated element 205 acts as a structural support for the first elongated element 203.

[0060] In at least one embodiment, the second elongated element 205 is wider at the base (proximal to the cavity 207) and narrower at the top. For example, the second elongated element may have a substantially triangular, substantially T-shaped, or substantially Y-shaped shape. However, any shape that matches the contours of the first elongated element 203 is suitable.

[0061] Preferably, the second elongated element 205 is flexible to allow bending of the tube. Desirably, the second elongated element 205 is less flexible than the first elongated element 203. This increases the ability of the second elongated element 205 to structurally support the first elongated element 203. For example, the modulus of elasticity of the second elongated element 205 is preferably 30-50 MPa (or about 30-50 MPa). The modulus of elasticity of the first elongated element 203 is less than the modulus of elasticity of the second elongated element 205. The second elongated element 205 can be solid or substantially solid. In addition, the second elongated element 205 can embed or enclose a conductive material, such as filaments and, in particular, heating filaments or sensors (not shown). Heating filaments can minimize cold surfaces on which condensation from humidified air can form.Heating filaments can also be used to change the temperature profile of gases in the cavity 207 of the composite tube 201. A wide variety of plastics are suitable for the body of the second elongated element 205, including plastics for medical applications. Examples of suitable materials include polyolefin elastomers, polyether block amides (thermoplastic elastomers), thermoplastic copolyester elastomers, rubber blends based on a copolymer of ethylene, propylene and a diene monomer and polypropylene, and thermoplastic polyurethanes. In some embodiments, the first elongated element 203 and the second elongated element 205 can be made of the same material. In addition, the second elongated element 205 can be made of a material of a different color than the first elongated element 203 and can be transparent, translucent, or opaque.For example, in one embodiment, the first elongated element 203 may be formed from a transparent, colorless plastic, and the second elongated element 205 may be formed from an opaque blue (or other) plastic.

[0062] This spirally wound structure, comprising a flexible hollow body and a one-piece support, can provide crush resistance while maintaining the tube wall flexible enough to form small-radius bends without kinking, breaking, clogging, or crushing. Preferably, the tube can bend around a 25mm diameter metal cylinder without kinking, breaking, clogging, or crushing, as determined by the bending flow resistance increase test in accordance with ISO 5367:2000 (E). In addition, this design can provide a smooth surface of the cavity 207 (tube opening), which helps keep the tube free of deposits and improves gas flow. It has been found that the hollow body improves the thermal insulation properties of the tube while allowing the tube to remain lightweight.

[0063] As already explained, the composite tube 201 can be used as an exhalation tube and / or an inhalation tube in a breathing circuit or as part of a breathing circuit. Preferably, the composite tube 201 is used as at least an inhalation tube.

[0064] Fig. 2B shows a cross-section in the longitudinal direction of the upper portion of the exemplary composite tube 201 in Fig. 2A. Fig. 2B has the same orientation as Fig. 2A. This example further illustrates the shape of the hollow body of the first elongated element 203. As can be seen in this example, the first elongated element 203 forms several hollow bubbles in the cross-section in the longitudinal direction. Portions 209 of the first elongated element 203 overlap adjacent turns of the second elongated element 205. Portion 211 of the first elongated element 203 forms a wall of the cavity (tube opening).

[0065] It was disclosed that the presence of a gap 213 between adjacent turns of the first elongated element 203, that is, between adjacent bubbles, unexpectedly improves the overall thermal insulation properties of the composite tube 201. Thus, in some embodiments, adjacent bubbles are separated by a gap 213. In addition, in some embodiments, the gap 213 between adjacent bubbles increases the specific thermal resistance (R-value) and, accordingly, reduces the specific thermal conductivity of the composite tube 201. It was also found that the configuration of this gap increases the flexibility of the composite tube 201, allowing bends of a smaller radius. The T-shaped second elongated element 205, as shown in Fig. 2B, can help maintain the gap 213 between adjacent bubbles. However, in some embodiments, adjacent bubbles touch each other. For example, adjacent bubbles can connect.

[0066] The second elongated element 205 may contain one or more conductive materials for heating or measuring a gas flow. In this example, the second elongated element 205 contains two heating filaments 215, one on each side of the vertical portion "T". The heating filaments 215 comprise a conductive material, aluminum (Al) and / or copper (Cu) alloys, or a conductive polymer. Preferably, the material forming the second elongated element 205 is selected as non-reactive with the metal in the heating filaments 215 when the heating filaments 215 reach their operating temperature. The filaments 215 may be separated from the cavity 207 so as not to be exposed to the cavity 207. At one end of the composite tube, pairs of filaments may be combined into a connecting loop.

[0067] In at least one embodiment, multiple threads are located in the second elongated element 205. The threads can be electrically connected to share a common guide. For example, a first thread, such as a heating thread, can be located on a first side of the second elongated element 205. A second thread, such as a measuring thread, can be located on a second side of the second elongated element 205. A third thread, such as a grounding thread, can be located between the first and second threads. The first, second, and / or third threads can be connected to each other at one end of the second elongated element 205.

[0068] Fig. 2C shows a cross-section in the longitudinal direction of the bubbles in Fig. 2B. As shown, the portions 209 of the first elongated element 203 overlapping the adjacent turns of the second elongated element 205 are characterized by the angle of inclination of the connection area 217. A large connection area increases the resistance of the tube to delamination at the mating surface of the first and second elongated elements. Additionally or alternatively, the shape of the bead and / or bubble can be adapted to increase the connection area 217. For example, Fig. 2D illustrates a relatively small connection area on the left side. Fig. 9B also shows a smaller connection area. In contrast, Fig. 2E shows a much larger connection area than Fig. 2D, due to the size and shape of the bead. Figs. 9A and 9C also illustrate a large connection area. Each of these figures is discussed in more detail below.It should be understood that while the embodiments of Figs. 2E, 9A, and 9C may be preferred in some embodiments, other embodiments may be used in other embodiments, including those shown in Figs. 2D, 9B, and other variations that may be desired.

[0069] Fig. 2D shows a cross-section in the longitudinal direction of the upper part of another composite tube. Fig. 2D has the same orientation as Fig. 2B. This example further illustrates the shape of the hollow body of the first elongated element 203 and shows how the first elongated element 203 forms several hollow bubbles in the cross-section in the longitudinal direction. In this example, the bubbles are completely separated from each other by a gap 213. A substantially triangular second elongated element 205 supports the first elongated element 203.

[0070] Fig. 2E shows a cross-section in the longitudinal direction of the upper portion of another composite tube. Fig. 2E has the same orientation as Fig. 2B. In the example of Fig. 2E, the heating filaments 215 are separated from each other by a greater distance than the filaments 215 in Fig. 2B. It has been found that increasing the distance between the heating filaments can improve the heating efficiency, and some embodiments include this solution. The heating efficiency refers to the ratio of the amount of heat supplied to the tube to the amount of energy removed or regenerated from the tube. Generally speaking, the more energy (or heat) dissipated from the tube, the lower the heating efficiency. To improve the heating performance, the heating filaments 215 can extend at the same (or almost the same) distance from each other along the opening of the tube. Alternatively, the filaments 215 can be located at the edges of the second elongated element 205, which can simplify the manufacture.

[0071] Next, reference is made to Figs. 3A-3G, showing exemplary structural embodiments for the second elongated member 205. Fig. 3A shows a cross-section in the transverse direction of the second elongated member 205, having a shape similar to the T-shape shown in Fig. 2B. In this exemplary embodiment, the second elongated member 205 does not have heating filaments. Other shapes for the second elongated member 205 can also be used, including T-shape variations, as described below, and triangular shapes.

[0072] Fig. 3B shows another exemplary second elongated element 205 having a T-shaped cross-section. In this example, heating filaments 215 are embedded in cutouts 301 in the second elongated element 205 on both sides of the vertical portion of the "T". In some embodiments, the cutouts 301 can be formed in the second elongated element 205 during extrusion. The cutouts 301 can alternatively be made in the second elongated element 205 after extrusion. For example, the cutouts in the second elongated element 205 can be made with a cutting tool. Preferably, the cutouts are made by the heating filaments 215 when they are pressed or drawn (mechanically fastened) into the second elongated element 205 shortly after extrusion, wherein the second elongated element 205 should be relatively soft.Alternatively, one or more heating filaments may be mounted (e.g., glued, attached, or partially embedded) to the base of the elongated element such that the filament(s) are exposed to the lumen of the tube. In these embodiments, it may be desirable to enclose the filament(s) in insulation to reduce the risk of ignition when a flammable gas, such as oxygen, is passed through the lumen of the tube.

[0073] Fig. 3C shows another exemplary second elongated element 205 in cross-section. The second elongated element 205 has a substantially triangular shape. In this example, heating filaments 215 are embedded on opposite sides of the triangle.

[0074] Fig. 3D shows another exemplary second elongated element 205 in cross-section. The second elongated element 205 comprises four grooves 303. The grooves 303 are recesses or furrows of the cross-sectional profile. In some embodiments, the grooves 303 can facilitate the formation of cutouts (not shown) for embedding threads (not shown). In some embodiments, the grooves 303 facilitate the arrangement of threads (not shown) that are pressed or drawn into the second elongated element 205 and thereby embedded in it. In this example, the four initial grooves 303 provide for the placement of up to four threads, such as four heating threads, four measuring threads, two heating and two measuring threads, three heating and one measuring thread, or one heating and three measuring threads. In some embodiments, the heating filaments may be located on the outer side of the second elongated element 205.The measuring threads may be on the inside.

[0075] Fig. 3E shows another exemplary second elongated element 205 in cross-section. The second elongated element 205 has a T-shaped profile and several grooves 303 for accommodating heating filaments.

[0076] Fig. 3F shows another exemplary second elongated element 205 in cross-section. In the second elongated element 205, four threads 215 are embedded - two on each side of the vertical portion of the "T". As explained in more detail below, the threads are embedded in the second elongated element 205, since the second elongated element 205 was extruded around the threads. Cutouts for embedding the heating threads 215 are not made. In this example, the second elongated element 205 also contains several grooves 303. Since the heating threads 215 are already embedded in the second elongated element 205, the grooves 303 are not used to facilitate the creation of cutouts for embedding the heating threads. In this example, the grooves 303 can facilitate the separation of the embedded heating threads, which facilitates the stripping of individual strands, for example, when terminating the heating threads.

[0077] Fig. 3G shows another exemplary second elongated element 205 in cross-section. The second elongated element 205 has a substantially triangular shape. In this example, the shape of the second elongated element 205 is similar to the shape of the second elongated element in Fig. 3C, but in this case, four threads 215 are embedded in the second elongated element 205, all of which are located in the middle of the lower third of the second elongated element 205 and are located along a substantially horizontal axis.

[0078] As already explained, it may be desirable to increase the distance between the filaments to improve heating efficiency. However, in some embodiments, if the heating filaments 215 are embedded in the composite tube 201, the filaments 215 may be positioned relatively centrally in the second elongated element 205. The central position increases the durability of the composite tube for repeated use, in part because such a position reduces the likelihood of breakage during repeated bending of the composite tube 201. In addition, the central position of the filaments 215 can reduce the risk of fire, since the filaments 215 are covered with layers of insulation and are removed from the gas path.

[0079] As already explained, some of the examples illustrate suitable arrangements of the threads 215 in the second elongated element 205. In the above examples containing more than one thread 215, the threads 215 typically extend along the horizontal axis. Alternative design embodiments are also suitable. For example, two threads may extend along the vertical axis or the diagonal axis. Four threads may extend along the vertical axis or the diagonal axis. The four threads may extend in a cross-shaped configuration: one thread is located at the top of the second elongated element, one thread is located at the bottom of the second elongated element (near the cavity of the tube), and two threads are located on opposite arms of a "T," "Y," or the base of a triangle.

[0080] Tables 1A and 1B provide some preferred dimensions of the medical tubing described in this document, as well as some preferred limits for these dimensions. The dimensions refer to the cross-section in the transverse direction of the tube. In these tables, the lumen diameter represents the inner diameter of the tube. The pitch represents the distance between two repeating points, measured in the axial direction along the tube, namely, the distance between the tips of the vertical portions of the adjacent "T" of the second elongated element. The bubble width represents the width (maximum outer diameter) of the bubble. The bubble height represents the height of the bubble from the lumen of the tube. The bead height represents the maximum height of the second elongated element from the lumen of the tube (e.g., the height of the vertical portion of the "T"). The bead width represents the maximum width of the second elongated element (e.g., the width of the vertical portion of the "T"). The bubble thickness represents the thickness of the bladder wall.

[0081] Tables 2A and 2B provide approximate relationships between the feature sizes for the tubes described in Tables 1A and 1B, respectively.

[0082] The following tables provide some approximate properties of the composite tube (labeled "A") described in this document, which has a heating filament embedded within a second elongated element. For comparison, the properties of a disposable corrugated tube (labeled "B"), model RT100, manufactured by Fisher & Paykel, which has a heating filament spirally wound within the bore of the tube, are also provided.

[0083] The resistance to flow (RTF) measurement was carried out in accordance with Annex A of ISO 5367:2000(E). The results obtained are summarized in Table 3. As shown below, the RTF for the composite tube is lower than the RTF for the RT100 model tube.

[0084] Condensate or "washout" in the tube refers to the mass of condensate collected over a 24-hour period at a gas flow rate of 20 L / min and a room temperature of 18°C. Humidified air is continuously passed through the tube from the chamber. Tube masses are recorded before and after each test day. Three consecutive tests are conducted, with the tube drying before each test. The results are presented in Table 4. The results show that washout in the composite tube is significantly lower than in the RT100 model tube.

[0085] Power consumption refers to the power consumed during the condensation test. In this test, the ambient air was maintained at a temperature of 18°C. The humidification chambers (see, for example, humidification chamber 129 in Fig. 1) were powered by the bases of the MR850 heater. The heating filaments in the tubes were powered independently of the DC power source. Different flow rates were set, and the chamber was left to cool to a temperature of 37°C at the chamber outlet. Then, the DC voltage supplied to the systems was varied to obtain a system outlet temperature of 40°C. The voltage required to maintain the outlet temperature was recorded, and the resulting power was calculated. The results are shown in Table 5. The results show that composite tube A consumes significantly more power than tube B. This is because tube B uses a spiral heating filament in the tube opening to heat the gas from 37°C to 40°C.The composite tube does not heat the gas quickly because the heating filament is embedded in the tube wall (embedded in a second elongated element). The composite tube is designed to maintain the gas temperature and prevent condensation by maintaining the tube opening at a temperature below the dew point of the humidified gas.

[0086] The flexibility of the tube was tested using a three-point bending test. The tubes were placed on a three-point bending rig, and an Instron 5560 Test System was used to measure the load and elongation. Each tube specimen was tested three times; the elongation of the tube was measured as a function of the applied load to obtain the average constant stiffness values. The average constant stiffness values ​​for tube A and tube B are shown in Table 6. Manufacturing methods

[0087] Reference is now made to Figs. 4A-4F, which illustrate exemplary methods for producing composite tubes.

[0088] Referring first to Fig. 4A. In at least one embodiment, a method for producing a composite tube includes a step of taking a second elongated element 205 and a step of spirally winding the second elongated element 205 onto a core 401, wherein the opposing side edge portions 403 of the second elongated element 205 on adjacent turns are spaced apart, thereby forming a spiral of the second elongated element 405. In some embodiments, the second elongated element 205 may be wound directly onto the core. In other embodiments, a sacrificial layer may be provided on the core.

[0089] In at least one embodiment, the method further includes forming a second elongated element 205. A suitable method for forming the second elongated element 205 is extrusion. A second extruder may be used to extrude the second elongated element 205 with a predetermined bead height. Thus, in at least one embodiment, the method includes extruding the second elongated element 205.

[0090] As shown in Fig. 4B, extrusion can be advantageous since it can allow the heating filaments 215 to be embedded in the second elongated element 205 during the molding of the second elongated element 205, for example, using an extruder having a transverse extrusion head. Thus, in some embodiments, the method includes providing one or more heating filaments 215, and embedding the heating filament 215 to mold the second elongated element 205. In addition, the method includes providing the second elongated element 205 having one or more heating filaments 215 embedded or enclosed in the second elongated element 205.

[0091] In at least one embodiment, the method includes embedding one or more threads 215 in the second elongated element 205. For example, as shown in Fig. 4C, the threads 215 can be pressed (drawn or mechanically placed) into the second elongated element 205 to a predetermined depth. Alternatively, cuts can be made in the second elongated element 205 to a predetermined depth, and the threads 215 can be placed in these cuts. Preferably, the pressing or cutting is performed shortly after the second elongated element 205 is extruded, and while the second elongated element 205 is soft.

[0092] As shown in Fig. 4D and 4E, in at least one embodiment, the method includes providing a first elongated element 203, and spirally winding the first elongated element 203 onto the spiral of the second elongated element 405 so that parts of the first elongated element 203 overlap adjacent turns of the spiral of the second elongated element 405, and a part of the first elongated element 203 is located close to the core 401 in the space between the turns of the spiral of the second elongated element 405, thereby forming a spiral of the first elongated element 407. Fig. 4D shows this example method, in which the heating filaments 215 are enclosed in the second elongated element 205 before forming the spiral of the second elongated element. Fig. 4E shows this example method, in which the heating filaments 215 are enclosed in the second elongated element 205 during forming the spiral of the second elongated element.An alternative method of enclosing the thread 215 in the composite tube includes enclosing one or more threads 215 between the first elongated element 203 and the second elongated element 205 in the region in which the first elongated element 203 overlaps the second elongated element 205.

[0093] The above-described alternatives for enclosing one or more heating filaments 215 in a composite tube have advantages over the alternative of arranging the heating filaments in the gas path. Arranging the heating filament(s) 215 outside the gas path improves performance because the filaments heat the tube wall in areas where condensation is most likely to form. This design reduces the risk of ignition in environments with a high oxygen content by removing the heating filament from the gas path. However, this feature also degrades performance because it reduces the efficiency of the heating filaments in heating gases as they pass through the tube. However, in some embodiments, the composite tube 201 comprises one or more heating filaments 215 placed in the gas path. For example, the heating filaments can be arranged on the wall of the cavity (tube opening), for example, in a spiral pattern.An exemplary method for arranging one or more heating filaments 215 on the cavity wall includes attaching, embedding, or otherwise shaping the heating filament onto the surface of the second elongated element 205, which, when assembled, forms the cavity wall. Thus, in some embodiments, the method includes arranging one or more heating filaments 215 on the cavity wall.

[0094] Regardless of whether the heating threads 215 are embedded or enclosed on the second elongated member 205 or located on the second elongated member 205, or otherwise located on or in the tube, in at least one embodiment, pairs of threads may be formed into a connecting loop at one end of the composite tube to form a loop.

[0095] Fig. 4F shows a cross-section in the longitudinal direction of the assembly shown in Fig. 4E, focusing on the upper part of the core 401 and the upper part of the spiral 407 of the first elongated element, and the spiral 405 of the second elongated element. This example shows the spiral 405 of the second elongated element having a T-shaped second elongated element 205. When forming the second elongated element, the heating filaments 215 are embedded in the second elongated element 205. On the right side of Fig. 4F, a bubble-shaped profile of the spiral of the first elongated element described above is shown.

[0096] Furthermore, the method may include molding the first elongated element 203. Extrusion is a suitable method for molding the first elongated element 203. Thus, in at least one embodiment, the method includes extruding the first elongated element 203. The first elongated element 203 may be produced by extruding two or more parts and joining them to form a single part. As another alternative, the first elongated element 203 may be produced by extruding sections that create a hollow shape when molded or joined during the molding process of the spiral tube.

[0097] Furthermore, the method may include feeding a gas under pressure greater than atmospheric pressure into one end of the first elongated element 203. The gas may be, for example, air. As already explained, other gases may also be used. Feeding the gas into one end of the first elongated element 203 may maintain the shape of the open hollow body when the first elongated element 203 is wound onto the core 401. The gas may be fed before the first elongated element 203 is wound onto the core 401, during the winding of the first elongated element 203 onto the core 401, or after the winding of the first elongated element 203 onto the core 401. For example, an extruder with a combination of an extrusion head / tip may feed air into a deep cavity of the first elongated element 203 during the extrusion of the first elongated element 203.Thus, in at least one embodiment, the method includes extruding a first elongated element 203 and feeding a gas at a pressure greater than atmospheric pressure into the end of the first elongated element 203 after extrusion. A pressure of 15-30 cm H2O (or approximately 15-30 cm H2O) is considered acceptable.

[0098] In at least one embodiment, the first elongated element 203 and the second elongated element 205 are spirally wound onto the core 401. For example, the first elongated element 203 and the second elongated element 205 can be released from the extrusion die at an elevated temperature of 200°C (or about 200°C) or higher and then applied to the core at a small distance from the die. Preferably, the core is cooled using a water jacket, a cooler and / or another suitable cooling method to a temperature of 20°C (or about 20°C) or lower, for example, approaching 0°C (or about 0°C). After 5 (or about 5) turns of the spiral, the first elongated element 203 and the second elongated element 205 are further cooled with a cooling fluid (liquid or gas). In one embodiment, the cooling fluid is air discharged from a jet ring surrounding the core.After cooling and removing the components from the core, a composite tube is obtained, having a cavity extending along the longitudinal axis and a hollow space surrounding this cavity. In this embodiment, no adhesive or other fastening mechanism is required to join the first and second elongated elements. In other embodiments, adhesive or another fastening mechanism may be used to bond or otherwise connect these two elements. In yet another embodiment, the second elongated element 205 may be cooled after extrusion and placement of the heating filaments to fix the position of the heating filaments. The second elongated element 205 may then be reheated upon application to the core to improve adhesion. Exemplary reheating methods include the use of spot heating devices, heated rollers, etc.

[0099] The method includes forming pairs of heating or measuring threads at one end of a composite tube into a connecting loop. For example, the end portions of two heating or measuring threads can be pulled out from a second elongated element 205 and then formed into a connecting loop, for example, by tying, adhering, gluing, fusing, etc. two threads. As another example, the end portions of the heating threads can be left protruding from the second elongated element 205 during the manufacturing process and then formed into a connecting loop during assembly of the composite tube. Medical tubes and manufacturing methods using a single spirally wound tube

[0100] Next, reference is made to Fig. 5A-5F, which show cross-sections in the transverse direction of tubes comprising a single tubular-shaped element having a first elongated element or portion 203 and a second elongated element or portion 205. As shown, the second elongated portions 205 are formed as a single unit with the first elongated portions 203 and extend along the entire length of the single tubular-shaped element. In the embodiments shown, the single tubular-shaped element is an elongated hollow body having, in a cross-section in the transverse direction, a relatively thin wall partially limiting the hollow portion 501, with two reinforcing portions 205 of relatively greater thickness or relatively greater rigidity on opposite sides of the elongated hollow body, adjacent to the relatively thin wall.After the spiral winding of the elongated hollow body, these reinforcing parts form part of the inner wall of the cavity 207, and the reinforcing parts are also spirally located between adjacent turns of the elongated hollow body.

[0101] In at least one embodiment, the method includes a step of forming an elongated hollow body comprising a first elongated portion 203 and a reinforcing portion 205. A suitable method for forming the elongated hollow body is extrusion. Suitable cross-sectional shapes for the tubular-shaped element are shown in Figs. 5A-5F.

[0102] The elongated hollow body can be formed into a medical tube, as already explained, and the above discussion is included in the further description by this reference. For example, in at least one embodiment, a method for producing a medical tube includes spirally winding the elongated hollow body onto a core. This can be performed at an elevated temperature so that after the spiral winding, the elongated hollow body cools to connect adjacent turns. As shown in Fig. 5B, the opposing lateral edge portions of the reinforcing portions 205 can touch at adjacent turns. In other embodiments, the opposing lateral edge portions of the second elongated element 205 can overlap at adjacent turns, as shown in Figs. 5D and 5E. Heating filaments 215 can be introduced into the second elongated element, as already explained and as shown in Figs. 5A-5F.For example, heating filaments may be provided on opposite sides of the elongated hollow body, as shown in Figs. 5A-5D. Alternatively, heating filaments may be provided on only one side of the elongated hollow body, as shown in Figs. 5E-5F. Any of these embodiments could include the presence of measuring filaments. Medical circuits.

[0103] Reference is now made to Fig. 6, which shows an exemplary medical circuit according to at least one embodiment. The system comprises one or more composite tubes described above, namely: for an inhalation tube 103 and / or an exhalation tube 117. The properties of the inhalation tube 103 and the exhalation tube 117 are similar to the properties of the tubes described above with reference to Fig. 1. The inhalation tube 103 has an inlet 109 communicating with a humidifier 115, and an outlet 113 through which humidified gases are supplied into the interior of the patient 101. The exhalation tube 117 also has an inlet 109 receiving exhaled humidified gases from the patient, and an outlet 113. As described above with reference to Fig. 1, the outlet 113 of the exhalation tube 117 may release exhaled gases into the atmosphere, into the fan / blower unit 115, into an air purifier / filter (not shown), or into any other suitable location.

[0104] As described above, heating filaments 601 may be placed in the inhalation tube 103 and / or the exhalation tube 117 to reduce the risk of condensation in the tubes by maintaining the tube wall temperature above the dew point temperature. Component of the insufflation system

[0105] Laparoscopic surgery, also known as minimally invasive surgery (MIS) or very small incision surgery, is a modern surgical technique in which abdominal surgery is performed through small incisions (usually 0.5-1.5 cm) compared to the larger incisions required in traditional surgeries. Laparoscopic surgery involves operations in the abdominal or pelvic cavity. In laparoscopic surgery with insufflation, humidification of the insufflated gas (usually CO2) may be required before it is passed into the abdominal cavity. This can help prevent the patient's internal organs from "drying out" and can reduce the time needed to recover from surgery. Insufflation systems typically contain humidification chambers that hold a certain amount of water. The humidifier typically contains a heating plate that heats the water to create water vapor, which is transferred to the incoming gases to humidify them.These gases are transported from the humidifier by water vapor.

[0106] Next, reference is made to Fig. 7, which shows an insufflation system 701 according to at least one embodiment. The insufflation system 701 includes a powder insulator 703 that creates a flow of insufflated gases under pressure above atmospheric pressure for delivery to the abdominal or peritoneal cavity of a patient 705. The gases pass into a humidifier 707 having a heating base 709 and a humidification chamber 711, wherein the chamber 711 is in contact with the heating base 709 during use, and wherein the heating base 709 supplies heat to the chamber 711. In the humidifier 707, the insufflated gases pass through the chamber 711, being humidified to an appropriate humidity level.

[0107] The system 701 includes a delivery channel 713 that provides a connection between the humidification chamber 711 and the peritoneal cavity or the surgical field of the patient 705. The channel 713 has a first end and a second end, wherein the first end is connected to the outlet of the humidification chamber 711 and receives humidified gases from the chamber 711. The second end of the channel 713 is located in the surgical field or the peritoneal cavity of the patient 705, and the humidified insufflated gases pass from the chamber 711, through the channel 713, and into the surgical field for inflating and expanding the surgical field or the peritoneal cavity. In addition, the system comprises a controller (not shown) that regulates the amount of humidity supplied to the gases by controlling the power supplied to the heating base 709. In addition, the controller is used to control the water in the humidification chamber 711. A smoke evacuation system 715 is shown that removes smoke from the patient's body cavity 705.

[0108] The smoke evacuation system 715 can be used together with the insufflation system 701 described above, or can be used with other suitable insufflation systems. The smoke evacuation system 715 includes an outlet part 717, an outlet assembly 719, and a filter 721. The outlet part 717 is connected between the filter 721 and the outlet assembly 719, which, during use, is located in the surgical field or the peritoneal cavity of the patient 705, or near it. The outlet part 717 is a self-supporting tube (that is, the tube is capable of supporting its own weight without collapsing) with two open ends: an end on the side of the surgical field and an outlet end.

[0109] In at least one embodiment, a composite tube is used as a channel 713 that can deliver humidified gases to the patient's surgical site 705 with minimized heat loss. This can advantageously reduce the overall energy consumption of the insufflation system, since less heat input is required to compensate for the heat loss. Coaxial tube

[0110] The coaxial breathing tube may also comprise a composite tube as described above. In the coaxial breathing tube, the first gas space is an inhalation portion or an exhalation portion, and the second gas space is, respectively, another exhalation portion or an inhalation portion. One gas passage is provided between the inlet of said inhalation portion and the outlet of said inhalation portion, and one gas passage is provided between the inlet of said exhalation portion and the outlet of said exhalation portion. In one embodiment, the first gas space is said inhalation portion and the second gas space is said inhalation portion. Alternatively, the first gas space may be an exhalation portion, and the second gas space may be an inhalation portion.

[0111] Next, reference is made to Fig. 7, which shows a coaxial tube 701 according to at least one embodiment. In this example, the coaxial tube 701 is provided between the patient 701 and the ventilator 705. Each of the exhaled gases and inhaled gases flows through the inner tube 707 or the space 709 between the inner tube 707 and the outer tube 711. It should be understood that the outer tube 711 may not be exactly coaxial with the inner tube 707. In this case, the term "coaxial" means that one tube is located inside another tube.

[0112] For heat exchange reasons, the inner tube 707 can carry inhaled gases in the space 713 inside it, while exhaled gases are carried in the space 709 between the inner tube 707 and the outer tube 711. This airflow configuration is indicated by arrows. However, the opposite configuration is also possible, in which the outer tube 711 carries inhaled gases, and the inner tube 707 carries exhaled gases.

[0113] In at least one embodiment, the inner tube 707 is a corrugated tube, such as the disposable tube model RT100 manufactured by Fisher & Paykel. The outer tube 711 may be a composite tube as described above.

[0114] When using the coaxial tube 701, the ventilator 705 may not detect a leak in the inner tube 707. This leak may shunt the patient 701, meaning that the patient 701 will not be supplied with enough oxygen. This shunting can be detected by a sensor located at the patient-side end of the coaxial tube 701. This sensor may be located in the connector 715 at the patient-side end. A shunt closer to the ventilator 705 will result in the patient 701 continuously rebreathing a volume of air closer to the patient 701. This will result in an increase in the carbon dioxide concentration in the inspiratory flow space 713 near the patient 701, which can be directly detected by a CO2 sensor. This sensor may be any of a number of such sensors that are currently commercially available.Alternatively, this rebreathing may be detected by monitoring the temperature of the gases in the patient end connector 715, where an increase in temperature above a predetermined level indicates that rebreathing is occurring.

[0115] In addition to the above, in order to reduce or eliminate the occurrence of condensation in the inner tube 707 or the outer tube 711 and to maintain a substantially uniform temperature in the flow of gases through the coaxial tube 701, a heater, such as a resistive heating filament, may be provided in the inner tube 707 or the outer tube 711, located in the gas spaces 709 or 713 or in the walls of the inner tube 707 or the outer tube 711 itself. Thermal properties

[0116] In embodiments of the composite tube 201 containing the heating filament 215, heat may be lost through the walls of the first elongated element 203, resulting in uneven heating. As previously explained, one way to compensate for this heat loss is to apply heat from an external heating source to the walls of the first elongated element 203, which will help regulate the temperature and counteract heat loss. However, other methods may also be used to optimize thermal properties.

[0117] Reference is now made to Figs. 9A-9C, which show exemplary design embodiments for the height of the bubbles (that is, the height of the cross-section of the first elongated element 203, measured from the surface facing the internal cavity to the surface forming the maximum outer diameter) for improving thermal properties.

[0118] The bubble size can be selected to reduce heat loss from the composite tube 201. Typically, increasing the bubble height increases the effective thermal resistance of the tube 201, since a greater bubble height allows the first elongated element 203 to retain more thermally insulating air. However, it has been found that at a certain bubble height, changes in air density cause convection in the tube 201, thereby increasing heat loss. Furthermore, at a certain bubble height, the surface area becomes so large that the heat lost through the surface negates the benefits of the increased bubble height. Some embodiments include these implementations.

[0119] The radius of curvature and curvature of the bubble can be used to determine the desired bubble height. The curvature of an object is defined as the reciprocal of its radius of curvature. Therefore, the larger the radius of curvature of an object, the less curved it is. For example, a flat surface would have a radius of curvature of ∞, and therefore its curvature would be 0.

[0120] Fig. 9A shows a longitudinal cross-section of the upper portion of the composite tube. Fig. 9A shows an embodiment of the composite tube 201 in which the bubble has a large height. In this example, the bubble has a relatively small radius of curvature and, therefore, a large curvature. In addition, the height of the bubble is approximately three to four times greater than the height of the second elongated element 205.

[0121] Fig. 9B shows a longitudinal cross-section of the upper portion of another composite tube. Fig. 9B shows an embodiment of the composite tube 201 in which the bubble is flattened at the top. In this example, the bubble has a very large radius of curvature but a small curvature. In addition, the height of the bubble is approximately the same as the height of the second elongated element 205.

[0122] Fig. 9C shows a cross-section in the longitudinal direction of the upper portion of another composite tube. Fig. 9C shows an embodiment of the composite tube 201, in which the width of the bubble is greater than the height of the bubble. In this example, the bubble has a radius of curvature and a curvature between the radii of curvature in Fig. 9A and Fig. 9B, and the center of the radius for the upper portion of the bubble is outside the bubble (compared to Fig. 9A). The inflection points on the left and right sides of the bubble are approximately in the middle (in height) of the bubble (as opposed to being at the bottom of the bubble, as in Fig. 9A). In addition, the height of the bubble is approximately twice the height of the second elongated element 205, that is, the height of the bubble is between the heights of the bubbles in Fig. 9A and Fig. 9B.

[0123] The design in Fig. 9A resulted in the lowest heat loss from the tube. The design in Fig. 9B resulted in the highest heat loss from the tube. The design in Fig. 9C had an intermediate heat loss between the design in Fig. 9A and 9B. However, the large outer surface area and convective heat transfer in the design in Fig. 9A resulted in inefficient heating. Thus, of the three bubble designs in Fig. 9A-9C, the design in Fig. 9C was determined to have the best overall thermal properties. When the same thermal energy was supplied to the three tubes, the design in Fig. 9C provided the greatest temperature rise along the length of the tube. The bubble in Fig. 9C is large enough to increase the volume of thermal insulation air, but not so large as to cause significant convective heat loss. The design is shown in Fig.9B was determined to have the worst thermal properties, namely, the design in Fig. 9B provided the lowest temperature rise along the length of the tube. The design in Fig. 9A had intermediate thermal properties and provided a lower temperature rise than the design in Fig. 9C.

[0124] It should be noted that although in some embodiments the design in Fig. 9C may be preferred, in other embodiments other design designs may be used as needed, including those shown in Figs. 9A, 9B and other options.

[0125] Table 7 shows the bubble height, tube outer diameter, and curvature radius of the designs shown in Figs. 9A, 9B, and 9C.

[0126] Table 7A shows the bubble height, tube outside diameter, and radius of curvature of the additional designs shown in Figs. 11A, 11B, and 11C.

[0127] It should be noted that, as a rule, the smaller the radius of curvature, the tighter the tube can be bent around itself without crushing or "breaking." For example, Fig. 11D shows a tube bent beyond its radius of curvature (specifically, this figure shows the tube in Fig. 11A bent with a radius of curvature of 5.7 mm), resulting in crushing of the bubble walls. Crumpling is generally undesirable, as it can degrade the appearance and thermal properties of the tube.

[0128] Accordingly, in some applications, designs with improved bending properties (such as those shown in Fig. 9A or 9B) may be desirable, despite having inferior thermal properties. In some applications, it has been found that a tube with an outer diameter of 25 mm to 26 mm (or about 25 mm to about 26 mm) provides a good balance between thermal efficiency, flexibility, and bending performance. It should be noted that while in some embodiments the designs in Fig. 9A and 9B may be preferred, in other embodiments other designs may be used as needed, including those shown in Fig. 11A-11D and other variants.

[0129] Reference is now made to Figs. 9C-9F, which show an exemplary arrangement of the heating element 215 for similar bubble shapes to improve thermal properties. The arrangement of the heating element 215 can change the thermal properties in the composite tube 201.

[0130] Fig. 9C shows a cross-section in the longitudinal direction of the upper portion of another composite tube. Fig. 9C shows an embodiment of the composite tube 201, in which the heating elements 215 are located centrally in the second elongated element 205. This example shows the heating elements 215 close to each other and not close to the wall of the bubble.

[0131] Fig. 9D shows a cross-section in the longitudinal direction of the upper part of another composite tube. Fig. 9D shows an embodiment of the composite tube 201, in which the heating elements 215 are spaced further apart compared to Fig. 9C in the second elongated element 205. These heating elements are located closer to the wall of the bubble and provide better heat regulation in the composite tube 201.

[0132] Fig. 9E shows a cross-section in the longitudinal direction of the upper portion of another composite tube. Fig. 9E shows an embodiment of the composite tube 201, in which the heating elements 215 are arranged one above the other on the vertical axis of the second elongated element 205. In this example, the heating elements 215 are arranged equally close to each wall of the bubble.

[0133] Fig. 9F shows a cross-section in the longitudinal direction of the upper part of another composite tube. Fig. 9F shows an embodiment of the composite tube 201, in which the heating elements 215 are located at opposite ends of the second elongated element 205. The heating elements 215 are located close to the wall of the bubble, especially in comparison with Figs. 9C-9E.

[0134] Of the four filament arrangements in Figs. 9C-9F, the arrangement in Fig. 9F was determined to have the best thermal properties because, due to their similar bubble shapes, all of these arrangements experience similar heat loss from the tube. However, when the same thermal energy was supplied to the tubes, the filaments arranged as shown in Fig. 9F provided the greatest temperature rise along the length of the tube. The arrangement in Fig. 9D was determined to have the next best thermal properties and provided the next greatest temperature rise along the length of the tube. The arrangement in Fig. 9C was next. The arrangement in Fig. 9E had the worst performance and, when supplied with the same amount of heat, provided the smallest temperature rise along the length of the tube.

[0135] It should be noted that although in some embodiments the design in Fig. 9F may be preferred, in other embodiments other design designs may be used if necessary, including those shown in Figs. 9C, 9D, 9E and other variants.

[0136] Reference is now made to Figs. 10A-10C, which show exemplary design embodiments for superimposing the first elongated element 203. It has been found that in some embodiments, heat distribution can be improved by superimposing several bubbles. These embodiments may be advantageous when using an internal heating thread 215. Fig. 10A shows a cross-section in the longitudinal direction of the upper part of another composite tube. Fig. 10A shows a cross-section of the composite tube 201 without any superposition.

[0137] Fig. 10B shows a cross-section in the longitudinal direction of the upper portion of another composite tube. Fig. 10B shows another exemplary composite tube 201 with superimposed bubbles. In this example, two bubbles are superimposed one on top of the other to form the first elongated element 203. Compared to Fig. 10A, the overall height of the bubbles is maintained, but the bubble pitch is half that of Fig. 10A. In addition, the embodiment of Fig. 10B has only a slight reduction in air volume. The superposition of bubbles reduces natural convection and heat exchange in the space between the bubbles 213 and reduces the overall thermal resistance. In superimposed bubbles, the heat flow path increases, which allows heat to be more easily distributed throughout the composite tube 201.

[0138] Fig. 1C shows a cross-section in the longitudinal direction of the upper portion of another composite tube. Fig. 1C shows another exemplary composite tube 201 with superimposed bubbles. In this example, three bubbles are superimposed one on top of the other to form the first elongated element 203. Compared to Fig. 10A, the overall height of the bubbles is maintained, but the bubble pitch is three times smaller compared to Fig. 10A. In addition, the embodiment of Fig. 10B has only a slight reduction in air volume. The superposition of bubbles reduces natural convection and heat exchange in the space between the bubbles 213. Cleaning

[0139] In at least one embodiment, the materials for the composite tube may be selected based on various cleaning methods. In some embodiments, high-level disinfection (about 20 cleaning cycles) may be used to clean the composite tube 201. During high-level disinfection, the composite tube 201 is pasteurized at a temperature of about 75°C for about 30 minutes. Then, the composite tube 201 is rinsed in a bath of 2% glutaraldehyde for about 20 minutes. Then, the composite tube 201 is removed from the glutaraldehyde and immersed in 6% hydrogen peroxide for about 30 minutes. Finally, the composite tube 201 is removed from the hydrogen peroxide and rinsed in a bath of 0.55% orthophthalaldehyde (OPA) for about 10 minutes.

[0140] In other embodiments, sterilization (approximately 20 cycles) may be used to clean the composite tube 201. First, the composite tube 201 is placed in an autoclave steam at a temperature of approximately 121°C for approximately 30 minutes. Then, the autoclave steam temperature is increased to approximately 134°C for approximately 3 minutes. After autoclaving, the composite tube 201 is placed in a gas environment of 100% ethylene oxide (ETO). Finally, the composite tube 201 is removed from the ETO gas and immersed in approximately 2.5% glutaraldehyde for approximately 10 hours.

[0141] The composite tube 201 may be made of materials that can withstand repeated cleaning processes. In some embodiments, the composite tube 201 may be partially or completely made of, but not limited to, thermoplastic elastomers based on a block copolymer of styrene, ethylene, butene, and styrene, such as Kraiburg TF6STE. In other embodiments, the composite tube 201 may be made of, but not limited to, hytrel, urethanes, or silicones.

[0142] The foregoing description of the invention includes its preferred forms. Changes and modifications are possible within the scope of the invention. Those skilled in the art to which the invention pertains will recognize many design changes and widely different embodiments within the scope of the invention as defined by the appended claims. The disclosures and descriptions herein are illustrative only and are not intended to limit the scope of the present invention in any way.

Claims

1. A composite tube for use in medical circuits intended to supply gases to a patient and / or remove gases from a patient, comprising: a first elongated member comprising a hollow body helically wound to form an at least partially elongated tube having a longitudinal axis, a cavity extending along the longitudinal axis, and a hollow wall at least partially surrounding the cavity; and a second elongated element, spirally wound and connected between adjacent turns of the first elongated element, wherein the second elongated element forms at least a portion of a cavity of the elongated tube, wherein the second elongated element has a cross-section in the longitudinal direction that is wider near the cavity and narrower at a radial distance from the cavity.

2. The composite tube of claim 1, wherein the first elongated element and the second elongated element provide a cavity with a smooth cavity surface.

3. The composite tube of claim 1, wherein the second elongated element is formed from a single material.

4. A composite tube according to claim 1, wherein the second elongated element has a cross-section in the longitudinal direction having a triangular shape.

5. A composite tube according to any one of the preceding claims, wherein the second elongated member is less flexible than the first elongated member.

6. A composite tube according to claim 1, in which the helically wound and connected first and second elongated elements are configured to provide crush resistance while remaining flexible enough to allow bends around a 25 mm diameter metal cylinder without kinking, clogging or crushing.

7. A composite tube according to claim 1, in which the portions of the first elongated element are configured to overlap adjacent turns of the second elongated element.

8. A composite tube according to any one of claims 1 to 4, wherein the second elongated element is solid.

9. A composite tube according to any one of claims 1 to 4, in which the first elongated element is designed with the possibility of forming bubbles with a flattened surface at the cavity in the longitudinal direction in the cross-section.

10. A composite tube according to claim 9, wherein the adjacent bubbles are separated by a gap above the second elongated element.

11. A composite tube according to claim 10, in which the gap is designed to allow bends around a metal cylinder with a diameter of 25 mm without kinking, blockage or crushing.

12. A composite tube according to claim 9, in which the bubbles have openings.

13. A composite tube according to any one of claims 1 to 4, comprising at least one conductive thread embedded or contained in a second elongated element, wherein the second elongated element has a cross-section in the longitudinal direction having a substantially triangular, substantially T-shaped or substantially Y-shaped shape, and at least one conductive thread is embedded or contained in the second elongated element on opposite sides of the triangular, T-shaped or Y-shaped shape.

14. The composite tube of claim 13, wherein at least one conductive thread comprises a heating thread.

15. The composite tube of claim 13, wherein at least one conductive thread comprises a measuring thread.

16. A composite tube according to claim 13, comprising four of the said conductive threads.

17. A composite tube according to claim 13, in which at one end of the composite tube pairs of conductive threads are connected into a connecting loop.

18. The composite tube according to claim 13, in which at least one conductive thread is separated from the cavity wall.

19. A composite tube according to any one of claims 1 to 4, which is one or more of: a medical circuit component, an inhalation tube, an exhalation tube, a PAP component, an insufflation component, a diagnostic component, and a surgical component.

20. A composite tube according to any one of claims 1 to 4, wherein the first elongated element is substantially optically transparent.

21. A composite tube according to any one of claims 1 to 4, wherein the first elongated element has a flattened surface at the cavity and a radius of curvature remote from the cavity.

22. A method for manufacturing a composite tube for use in medical circuits intended for delivering gases to a patient and / or removing gases from a patient, comprising the steps of: providing a first elongated element comprising a hollow body and a second elongated element; the second elongated element is spirally wound onto the core, wherein the opposing side edge portions of the second elongated element on adjacent turns are spaced apart, thereby forming a spiral of the second elongated element; and the first elongated element is spirally wound onto the spiral of the second elongated element so that portions of the first elongated element overlap adjacent turns of the spiral of the second elongated element, and a portion of the first elongated element is located close to the core in the space between the turns of the spiral of the second elongated element, thereby forming a spiral of the first elongated element, wherein the second elongated element has a cross-section in the longitudinal direction that is wider near the cavity and narrower at a radial distance from the cavity.

23. The method according to claim 22, further comprising the step of supplying air at a pressure greater than atmospheric pressure to one end of the first elongated element.

24. The method of claim 22, further comprising the step of cooling the coil of the second elongated element and the coil of the first elongated element to form a composite tube having a cavity extending along the longitudinal axis and a hollow space surrounding the cavity.

25. The method of claim 22, further comprising the step of embedding or enclosing at least one conductive thread in the second elongated element.

26. The method of claim 22, further comprising the step of forming a second elongated element.

27. The method according to claim 26, wherein the step of forming the second elongated element comprises extruding the second elongated element with a second extruder.

28. The method according to claim 27, in which the second extruder is configured to contain at least one conductive thread in the second elongated element.

29. The method of claim 28, wherein the conductive threads are non-reactive with the second elongated element.

30. The method according to claim 25, wherein the conductive threads comprise aluminum or copper.

31. The method of claim 25, further comprising the step of converting the pairs of conductive threads at one end of the composite tube into a connecting loop.

32. The method according to claim 22, comprising the step of forming a first elongated element.

33. The method according to claim 32, wherein the step of forming the first elongated element comprises extruding the first elongated element with a first extruder.

34. The method of claim 33, comprising the step of forming a second elongated element by extruding the second elongated element with a second extruder, wherein the first extruder is different from the second extruder.

35. The method according to any one of paragraphs 22-34, in which: the second elongated element is configured to provide structural support and / or reinforcement to the first elongated element; and / or the second elongated element is relatively thicker or less flexible than the first elongated element.

36. A composite tube for use in medical circuits intended for supplying gases to a patient and / or removing gases from a patient, manufactured according to the method of any one of paragraphs 22-34.

Images