RU2777931C2 - Medical tubes and their manufacturing methods - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: composite tube for use in medical contours intended for the supply of gases to a patient and/or removal of gases from a patient contains the first elongated element containing a hollow body spirally wound up for at least partial formation of an elongated tube with a longitudinal axis, a cavity passing along the longitudinal axis, and a hollow wall at least partially surrounding this cavity. The second elongated element is spirally wound up and attached between adjacent turns of the first elongated element. The second elongated element forms at least part of the cavity of the elongated tube. At least one conductive thread is embedded or enclosed in the second elongated element. A method for the manufacture of a composite tube, and a composite tube for use in medical contours, manufactured according to this method, are disclosed.

EFFECT: provision of insulation from heat losses, and improvement of temperature and moisture content control in medical contours.

35 cl, 7 tbl, 11 dwg

Description

PRIOR ART

The technical field to which the invention belongs

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

Description of the relevant prior 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 pulmonary assisted ventilation circuits, gases inhaled by the patient are supplied from a humidifier heater through an inhalation tube. As another example, in insufflation loops, tubes can deliver humidified gas (typically CO ₂ ) into the abdominal cavity. This can help prevent the patient's internal organs from "drying out" and may shorten the time it takes to recover from 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 carrying the warm humidified air. There continues to be a need for tubes that are insulated from heat loss and which, for example, provide improved temperature and/or humidity control in medical circuits.

BRIEF DESCRIPTION OF THE INVENTION

[0003] Medical tubing and methods for making medical tubing are disclosed herein in various embodiments. In some embodiments, the tube may be a composite structure made from two or more distinct components wound helically to form an elongated tube. For example, one of the components may be a helically wound elongated hollow body, and the other component may be an elongated structural component also helically wound between the turns of the helically wound hollow body. In other embodiments, the implementation of the tube does not have to be made of different components. For example, an elongated hollow body molded (eg, extruded) from a single material may be helically wound to form an elongated tube. The elongated hollow body itself in cross section in the transverse direction may have a thin wall portion and a relatively thicker or stiffer reinforcing portion. The tubes can be used in a wide variety of medical circuits or for other medical applications.

[0004] In at least one embodiment, the composite tube may include a first elongate element that is a hollow body helically 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. The second elongate element may be helically wound and connected between adjacent turns of the first elongate element, with the second elongated element forming at least a portion of the cavity of the elongated tube. The terms "first elongated member" and "second elongated member" do not necessarily imply an order, such as the order in which the components are assembled. As described herein, the first elongate element and the second elongate element may be parts of a single tubular-shaped element.

[0005] In various embodiments, the implementation of the above 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 elongate element may form, in cross section in the longitudinal direction, several bubbles with a flattened surface near the cavity. Adjacent bubbles may be spaced apart over the second elongate member, or may not be directly connected to each other. Bubbles may have holes. The second elongate member may have a cross-section in the longitudinal direction that is wider adjacent to the cavity and narrower at a radial distance from the cavity. In particular, the second elongate member may have a cross section in the longitudinal direction that is substantially triangular, substantially T-shaped, or substantially Y-shaped. One or more conductive threads may be terminated or enclosed in the second elongated element. One or more conductive filaments may be heating filaments (or more specifically resistive heating filaments) and/or measuring filaments. The tube may contain pairs of conductive filaments, such as two or four conductive filaments. Pairs of conductive threads can be connected at one end of the composite tube into a connecting loop. One or more conductive threads may be separated from the wall of the cavity. In at least one embodiment, the second elongate member may have a longitudinal cross-section having a substantially triangular, substantially T-shaped, or substantially Y-shaped shape, and one or more conductive filaments may be embedded or enclosed within the second elongate member at opposite ends. triangular, T-shaped or Y-shaped sides.

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

[0008] A method for manufacturing 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 elongate element that is a hollow body and a second elongate element designed to provide structural support for the first elongate element. The second elongated element is helically wound around the core, while the opposing side edge parts of the second elongated element are spaced apart on adjacent turns, thereby forming a spiral of the second elongated element. The first elongated element is helically wound around the helix of the second elongated element so that parts of the first elongated element overlap adjacent turns of the helix of the second elongated element, and a part of the first elongated element is located close to the core in the space between the turns of the helix of the second elongated element, thereby forming a helix of the first elongated element .

[0009] In various embodiments, the implementation of the above method may have one, more or all of the following. The method may include supplying superatmospheric air to one end of the first elongate member. The method may include cooling the helix of the first elongate element and the helix of the second elongate 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 elongate element with a first extruder. The method may include molding the second elongate element. The method may include extruding the second elongate element with a second extruder. The second extruder may be designed to enclose one or more conductive filaments within the second elongate member. Forming the second elongate element may include embedding the conductive filaments in the second elongate element. The conductive threads may be non-reactive with the second elongated element. The conductive filaments may contain alloys of aluminum or copper or other conductive materials. The method may connect pairs of conductive threads at one end of a 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 helically wound to form an elongated tube having a longitudinal axis, a cavity extending along the longitudinal axis, and a hollow wall surrounding this cavity, the elongated hollow body having a cross-sectional direction of the wall, limiting at least part of the hollow body. The tube may further comprise a reinforcing portion extending along the length of the elongated hollow body, spirally disposed between adjacent coils of the elongated hollow body, the reinforcing portion forming part of the cavity of the elongated tube. The reinforcing portion may be relatively thicker or stiffer than the wall of the elongated hollow body.

[0011] In various embodiments, the implementation of the above tube has one, more or all of the following properties, as well as the properties described in this disclosure. The reinforcing part may be made of the same material as the elongated hollow body. The elongated hollow body in cross section in the transverse direction may contain two reinforcing parts on opposite sides of the elongated hollow body, while the helical winding of the elongated hollow body connects the adjacent reinforcing parts so that the opposing edges of the reinforcing parts touch each other on adjacent turns of the elongated hollow body. The opposing side edges of the reinforcing portions may overlap on adjacent coils of the elongated hollow body. The reinforcing part may be made of a different material than the elongated hollow body. The hollow body can form several bubbles in the longitudinal direction in cross section with a flattened surface near the cavity. Bubbles may have holes. In addition, the medical tube may comprise one or more conductive threads embedded or enclosed within the reinforcement portion. The 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 of the reinforcing parts. The medical tube may contain two conductive threads located on only one side of the elongated hollow body. Pairs of conductive threads can be connected at one end of the elongated tube into a connecting loop. One or more threads may be separated from the wall of the cavity.

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

[0013] A method for manufacturing a medical tube is also provided. In at least one embodiment, the method includes spirally winding an elongated hollow body around a core to form an elongated tube having a longitudinal axis, a cavity extending along the longitudinal axis, and a hollow wall surrounding the cavity, the elongated hollow body having a cross section of in the transverse direction, a wall delimiting at least part of the hollow body, and two reinforcing parts on opposite sides of the elongated body, forming part of the wall of the cavity, while the two reinforcing parts are relatively thicker or stiffer than the wall delimiting at least part of the hollow body. In addition, the method may include such connection of adjacent reinforcing parts that the opposing edges of the reinforcing parts touch each other on the adjacent coils of the elongated hollow body.

[0014] In various embodiments, the implementation of the above method has one, more or all of the following properties, as well as the properties described in this disclosure. Joining adjacent reinforcement pieces may cause the edges of the reinforcement pieces to overlap. The method may further include supplying superatmospheric air to one end of the elongated hollow body. The method may further include cooling the elongate hollow body to join adjacent reinforcement portions. The method may further include extruding an elongated hollow body. The method may further include embedding the conductive threads in the reinforcement portions. The method may further include connecting pairs of conductive filaments at one end of the elongate tube into a connecting loop.

[0015] For the purposes of generalizing 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 necessarily all of these advantages can be achieved by one particular embodiment of the invention. Thus, the present invention may be practiced or performed such that one advantage or group of advantages described herein is achieved or optimized without necessarily achieving other advantages that may be described or suggested herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following describes with reference to the drawings exemplary embodiments that implement various features of the disclosed systems and methods. The drawings and associated descriptions are provided to illustrate embodiments and are not intended to limit the scope of the disclosure.

[0017] FIG. 1 is a schematic illustration of a medical system containing one or more medical tubes.

[0018] FIG. 2A is a top side view of a segment of an exemplary composite tube.

[0019] FIG. 2B shows a longitudinal cross-section of the top of a tube similar to the exemplary composite tube of FIG. 2A.

[0020] FIG. 2C is another cross section in the longitudinal direction illustrating the first elongate member in the composite tube.

[0021] In FIG. 2D shows another longitudinal cross section of the top of the tube.

[0022] FIG. 2E shows another longitudinal cross section of the top of the tube.

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

[0024] In FIG. 3B shows another cross section in the transverse direction of the second elongate member.

[0025] FIG. 3C shows another exemplary second elongate member.

[0026] FIG. 3D shows another exemplary second elongate member.

[0027] FIG. 3E shows another exemplary second elongate member.

[0028] FIG. 3F shows another exemplary second elongate member.

[0029] FIG. 3G shows another exemplary second elongate member.

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

[0031] In FIG. 4B shows a helically wound second elongate member.

[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 yet 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 is another example illustrating a single elongated hollow body being helically wound to form a medical tube.

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

[0038] FIG. 6 shows an exemplary medical circuit in accordance with at least one embodiment.

[0039] FIG. 7 shows an inflation system in accordance with at least one embodiment.

[0040] FIG. 8 is a schematic illustration of a coaxial tube in accordance with at least one embodiment.

[0041] In FIG. 9A-C show exemplary shapes of the first elongated element designed to improve thermal efficiency.

[0042] FIG. 9D-F show examples of heating filament arrangements for improving thermal efficiency.

[0043] FIG. 10A-C show examples of the overlay of the first elongated element.

[0044] FIG. 11A-D show properties in terms of radius of curvature of tubes in accordance with various embodiments.

[0045] Throughout the drawings, reference numerals are used repeatedly to indicate correspondence between reference (or the like) elements. In addition, the first digit of each position indicates the figure in which this element is shown for the first time.

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.

Breathing circuit containing 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 in accordance with at least one embodiment, containing one or more medical tubes. Tube is a broad term and should be given the meaning that is customary to those skilled in the art (ie, 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 may generally be defined as a tube containing two or more parts, or more specifically, in some embodiments, two or more components, as described in more detail below. Such a breathing circuit may be a continuous, variable, or bi-level positive airway pressure system, or some other form of respiratory therapy.

[0048] Gases may be transported in the circuit of FIG. 1 as follows. The 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 while supplying humidified gases to the inhalation tube 103 '. The inhalation tube is a tube for delivering breathing gases to a patient and may be made from a composite tube, as described in more detail below. Gases flow through inhalation tube 103 to outlet 113 (wet gas bleed end) and then into patient 101 via patient interface 115 connected to outlet 113 '.

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

[0050] In this example, dry gases enter fan/blower 105 through opening 119 '. The fan 121 can increase the gas supply to the fan/blower by drawing in air or other gases through the opening 119' . The fan 121 may be, for example, a variable speed fan, with the fan speed controlled by the electronic controller 123 '. In particular, the operation 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 user-set predetermined pressure or fan speed desired value (set point) via the dial 127' .

[0051] The humidifier 107 has a humidification chamber 129 containing a volume of water 130 or other suitable humidifying liquid. Preferably, after use, the humidification chamber 129 can be removed from the humidifier 107 '. Removability allows the humidification chamber 129 to be sterilized or disposed of more easily. However, a portion of the humidification chamber 129 of the humidifier 107 may be a one-piece structure. Humidification chamber 129 can be made of non-conductive glass or plastic material. But the humidification chamber 129 may also contain conductive components. For example, the humidification chamber 129 may have a high thermal conductivity base (eg, an aluminum base) contacting or bonding to the heating plate 131 on the humidifier 107 '.

[0052] In addition, humidifier 107 may include electronic control devices. In this example, humidifier 107 includes an electronic, analog or digital master controller 125 '. Preferably, the main controller 125 is a microprocessor-based controller executing computer software instructions stored in an associated memory. In response to a user-set humidity or temperature input via the user interface 133 , for example, and other inputs, 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 one skilled in the art (ie, it should not be limited to any special or non-standard meaning); this term includes, without limitation, masks (such as tracheal masks, face masks, and nasal masks), prongs, 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 filament (not shown) associated with the temperature sensor may be used to control the temperature of the patient interface 115 and/or inhalation tube 103 to raise the temperature of the inhalation tube 103 and/or patient interface 115 above saturation temperature, thereby reducing the chance of unwanted condensation.

[0054] FIG. 1 , exhaled humidified gases are returned through the exhalation tube 117 from the patient interface 115 to the ventilator/blower 105 '. The expiratory 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 previously known in the art. In any case, the exhalation tube 117 may have a temperature sensor and/or a heating filament, as described above in relation to the inhalation tube 103 ', built into it to reduce the chance of condensation. In addition, the exhalation tube 117 need not necessarily return the exhaled gases to the fan/blower 105 '. Alternatively, the exhaled humidified gases may be transferred directly to the environment or to other ancillary equipment such as an air cleaner/filter (not shown). In some embodiments, the exhalation tube is completely omitted.

Composite tubes

[0055] FIG. 2A is a top side view of a section of exemplary composite tube 201 . Typically, the composite tube 201 includes a first elongate element 203 and a second elongate element 205' . Element is a broad term and should be given its usual meaning to those skilled in the art (ie, 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 from two distinct components, it is clear that in other embodiments (such as those described with reference to FIGS. 5A-5D ), the first elongate member 203 and the second elongate member 205 may also represent portions in the tube made of one material. Thus, the first elongate member 203 may represent the hollow portion of the tube, and the second elongate member 205 may represent a structural support or reinforcement portion of the tube providing structural support to the hollow portion. 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 expiratory tube 117 as described above, a coaxial tube as described below, or any other tubes described in this disclosure.

[0056] In this example, the first elongate member 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 member 203 is flexible. In addition, the first elongated element 203 is preferably transparent or at least translucent or semi-opaque. The degree of optical clarity allows the healthcare professional or user to check the cavity 207 for blockages or contamination, or confirm the presence of moisture. A variety of plastics are suitable for the body of the first elongated member 203 , including plastics for medical applications. Examples of suitable materials include polyolefin elastomers, polyester blockamides (thermoplastic elastomers), thermoplastic copolyester elastomers, mixtures of rubber based on a copolymer of ethylene, propylene and diene monomer and polypropylene, and thermoplastic polyurethanes.

[0057] The hollow body design of the first elongated member 203 contributes to the thermal insulation properties of the composite tube 201 . The heat insulating tube 201 is desirable because, as already explained, this prevents heat loss. This may allow the tube 201 to deliver gas to the patient from the heater-humidifier, maintaining a conditioned state of gas with minimal power consumption.

Вт/м·K при температуре 300 K) и очень низкой стоимости. Преимущественно может также применяться газ, более вязкий, чем воздух, поскольку более высокая вязкость снижает конвективный теплообмен. Таким образом, теплоизоляционные характеристики могут повысить такие газы, как аргон (17,72×10

Вт/м⋅K при температуре 300 K), криптон (9,43×10

Вт/м⋅K при температуре 300 K) и ксенон (5,65×10

Вт/м⋅K при температуре 300 K). Каждый из этих газов нетоксичен, химически инертен, пожаробезопасен и коммерчески доступен. Полая часть первого удлиненного элемента 203 может уплотняться на обоих концах трубки, в результате чего газ является практически неподвижным. Альтернативно, полая часть может также быть вспомогательным пневматическим подключением, например, линией пробы давления для передачи сигнала обратной связи давления из конца трубки со стороны пациента в контроллер. Факультативно, первый удлиненный элемент 203 может быть перфорированным. Например, поверхность первого удлиненного элемента 203 может быть перфорированной на обращенной наружу поверхности, противоположной полости 207. В еще одном варианте осуществления полая часть первого удлиненного элемента 203 наполнена жидкостью. Примеры жидкостей могут включать воду и другие биосовместимые жидкости с высокой теплоемкостью. Например, могут применяться нанофлюиды. Примерный нанофлюид с подходящей теплоемкостью представляет собой воду и наночастицы веществ, таких, как алюминий. [0058] In at least one embodiment, the hollow portion of the first elongated member 203 is filled with gas. The gas may be air, which is desirable due to its low thermal conductivity (2.62×10

W/m K at 300 K) and very low cost. Advantageously, a gas that is more viscous than air can also be used, since the higher viscosity reduces convective heat transfer. Thus, gases such as argon (17.72×10

W/m⋅K at 300 K), krypton (9.43×10

W/m⋅K at 300 K) and xenon (5.65×10

W/m⋅K at 300 K). Each of these gases is non-toxic, chemically inert, non-flammable, and commercially available. The hollow portion of the first elongated member 203 can be sealed at both ends of the tube, whereby the gas is substantially stationary. Alternatively, the hollow part may also be an auxiliary pneumatic connection, such as a pressure sample line for transmitting a pressure feedback signal from the patient end of the tube to the controller. Optionally, the first elongate element 203 may be perforated. For example, the surface of the first elongate member 203 may be perforated on an outwardly facing surface opposite the cavity 207 '. In another embodiment, the hollow portion of the first elongated element 203 is filled with liquid. Examples of liquids may include water and other biocompatible liquids with high heat capacity. For example, nanofluids can be used. An exemplary nanofluid with a suitable heat capacity is water and nanoparticles of substances such as aluminum.

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

[0060] In at least one embodiment, the second elongate member 205 is wider at the base (proximal to cavity 207 ') and narrower at the top. For example, the second elongate element may be substantially triangular, substantially T-shaped, or substantially Y-shaped. However, any shape corresponding to the contours of the first elongated element 203 ' is suitable.

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

[0062] This helically wound structure containing a flexible hollow body and an integral support can provide crush resistance while leaving the tube wall flexible enough for small radius bends without kinks, fractures, blockages, or collapses. Preferably, the 25 mm diameter metal cylinder tube can be bent without kinking, breaking, plugging or crushing, as determined by the bending flow resistance increase test of ISO 5367:2000(E). In addition, this design can provide a smooth surface to cavity 207 (pipe opening), which will help keep the tubing clean of deposits and improve gas flow. It has been found that the hollow body improves the heat-insulating properties of the tube while allowing the tube to remain light.

[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 part of a breathing circuit. Preferably, the composite tube 201 is used at least as an inhalation tube.

[0064] FIG. 2B shows a longitudinal cross-section of the top of the exemplary composite tube 201 of 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 elongate member 203 forms a plurality of hollow bubbles in a cross-section in the longitudinal direction. Portions 209 of first elongate member 203 overlap adjacent coils of second elongate member 205 '. Part 211 of the first elongated element 203 forms the wall of the cavity (tube opening).

[0065] It has been disclosed that the presence of a gap 213 between adjacent turns of the first elongated element 203 , ie 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 thermal resistivity (R value) and, accordingly, reduces the thermal conductivity of the composite tube 201 '. It has also been found that the configuration of this gap increases the flexibility of the composite tube 201 ', allowing for smaller bending radii. The T-shaped second elongate member 205 as shown in FIG. 2B may help maintain a 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 gas flow. In this example, the second elongated element 205 encloses two heating filaments 215 , one on either 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 constituting the second elongate member 205 ' is selected to be non-reactive with the metal in the heating filaments 215 ' when the heating filaments 215 reach their operating temperature. Threads 215 may be spaced away from cavity 207 so as not to be exposed to cavity 207 '. At one end of the composite tube, pairs of threads can be combined into a connecting loop.

[0067] In at least one embodiment, multiple threads are located in the second elongated element 205 . The filaments may be electrically connected to share a common guide. For example, a first filament, such as a heating filament, may be located on the first side of the second elongate member 205 '. The second thread, such as a measuring thread, may be located on the second side of the second elongated element 205 '. A third thread, such as a ground thread, may be located between the first and second threads. The first, second, and/or third threads may be interconnected at one end of the second elongate element 205 '.

[0068] FIG. 2C shows a longitudinal cross-section of the bubbles in FIG. 2B . As shown, the portions 209 of the first elongate member 203 ' overlapping the adjacent coils of the second elongate member 205 ' A large connection area increases the resistance of the tube to delamination at the mating surfaces of the first and second elongated elements. Additionally or alternatively, the shape of the bead and/or bladder can be adapted to increase the area of the connection 217 . For example, FIG. 2D illustrates a relatively small joint area on the left side. fig. 9B also shows a smaller connection area. On the contrary, in Fig. 2E shows a much larger connection area than FIG. 2D , due to the size and shape of the bead. Fig. 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 , other embodiments may be used in other embodiments, including those shown in FIG. 2D , 9B and other variations as may be required.

[0069] FIG. 2D shows a cross-section in the longitudinal direction of the top 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 elongate member 203 and shows how the first elongate member 203 forms a plurality of hollow bubbles in a cross section in the longitudinal direction. In this example, the bubbles are completely separated from each other by a gap of 213 . The substantially triangular second elongate member 205 supports the first elongate member 203' .

[0070] FIG. 2E shows a cross-section in the longitudinal direction of the top of another composite tube. Fig. 2E has the same orientation as FIG. 2B . In the example in 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 increase the heating efficiency, and some embodiments include the present solution. Heating efficiency refers to the ratio of the amount of heat input to the tube to the amount of energy removed or recovered 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 may extend at equal (or nearly equal) distances from one another along the opening of the tube. Alternatively, the threads 215 can be located at the edges of the second elongate element 205 ', which can simplify manufacturing.

[0071] Reference is now made to FIG. 3A-3G showing exemplary designs for the second elongate member 205 . In 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 elongate element 205 does not have heating filaments. Other shapes for the second elongate member 205 ' may be used, including variations of T-shapes, as described below, and triangular shapes.

[0072] FIG. 3B shows another exemplary second elongate member 205 ' having a T-shaped cross section. In this example, the heating filaments 215 are embedded in cutouts 301 in the second elongate member 205 on either side of the vertical portion "T". In some embodiments, cutouts 301 may be extruded into second elongate member 205 . Cutouts 301 may alternatively be made in the second elongate element 205 after extrusion. For example, cutouts in the second elongate member 205 may be made with a cutting tool. Preferably, the cuts are made by the heating filaments 215 ' as they are pressed or drawn (mechanically attached) into the second elongate 205 shortly after extrusion, the second elongate 205 being relatively soft. Alternatively, one or more heating filaments may be positioned (eg, glued, attached, or partially embedded) on the base of the elongate element such that the filament(s) is exposed to the cavity of the tube. In these embodiments, it may be desirable to place the filament(s) in insulation to reduce the risk of fire when a combustible gas, such as oxygen, is passed through the cavity of the tube.

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

[0074] FIG. 3D shows another exemplary second elongated member 205 in cross section. The second elongate member 205 has four grooves 303' . The grooves 303 are recesses or grooves of the cross-sectional profile. In some embodiments, the grooves 303 may facilitate the formation of cutouts (not shown) for embedding threads (not shown). In some embodiments, grooves 303 facilitate the placement of filaments (not shown) that are pressed or retracted into and thereby embedded in second elongate member 205 . In this example, the four start grooves 303 accommodate up to four filaments, such as four heating filaments, four filaments, two heating and 2 measuring filaments, 3 heating and 1 measuring filament, or 1 heating and 3 measuring filaments. In some embodiments, the implementation of the heating threads may be on the outside of the second elongate element 205 . Measuring threads can be on the inside.

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

[0076] FIG. 3F shows another exemplary second elongated member 205 in cross section. Embedded in the second elongated member 205 are four threads 215 , two on each side of the vertical portion "T". As explained in more detail below, the filaments are embedded in the second elongate member 205 as the second elongate member 205 has been extruded around the filaments. The cutouts for embedding the heating threads 215 are not made. In this example, the second elongate element 205 also includes several grooves 303' . Because the heating filaments 215 are already embedded in the second elongate member 205 ', the grooves 303 are not used to facilitate the cutouts for embedding the heating filaments. In this example, the grooves 303 can facilitate separation of the embedded heating filaments, which facilitates the stripping of individual strands, for example when terminating the heating filaments.

[0077] FIG. 3G shows another exemplary second elongate member 205 in cross section. The second elongated element 205 has a substantially triangular shape. In this example, the shape of the second elongate member 205 is similar to that of the second elongate member in FIG. 3C , but in this case, four threads 215 are embedded in the second elongate element 205 , all of which are located in the middle in the lower third of the second elongate 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 in order to increase the heating efficiency. However, in some embodiments, if the heating filaments 215 are embedded in the composite tube 201 ', the filaments 215 may be located relatively centrally in the second elongate member 205 '. The center position increases the durability of the composite tube for reuse in part because this position reduces the likelihood of breakage upon repeated bending of the composite tube 201' . In addition, the central location of the filaments 215 may reduce the risk of fire because the filaments 215 are covered with layers of insulation and removed from the gas path.

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

[0080] Tables 1A and 1B list some preferred sizes for the medical tubing described herein, as well as some preferred ranges for those sizes. The dimensions refer to the cross section in the transverse direction of the tube. In these tables, the cavity diameter represents the inside 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 parts about the adjacent "T" of the second elongated element. The bubble width represents the width (maximum outside diameter) of the bubble. The bubble height represents the bubble height from the tube cavity. The height of the shoulder represents the maximum height of the second elongate element from the cavity of the tube (eg, the height of the vertical part "T"). The bead width represents the maximum width of the second elongated element (eg, the width of the vertical "T"). The bubble thickness represents the thickness of the bubble wall.

Table 1A

Characteristic Child Adult Size (mm) Limits (±) Size (mm) Limits (±) cavity diameter eleven one eighteen 5 Step 4.8 one 7.5 2 Bubble Width 4.2 one 7 one Bead width 2.15 one 2.4 one bubble height 2.8 one 3.5 0.5 Collar height 0.9 0.5 1.5 0.5 bubble thickness 0.4 0.35 0.2 0.15

Table 1B

Characteristic Child Adult Size (mm) Limits (±) Size (mm) Limits (±) cavity diameter eleven one eighteen 5 Step 4.8 one 7.5 2 Bubble Width 4.2 one 7 one Bead width 2.15 one 3.4 one bubble height 2.8 one 4.0 0.5 Collar height 0.9 0.5 1.7 0.5 bubble thickness 0.4 0.35 0.2 0.15

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

Table 2A

Ratios Child Adult Cavity Diameter: Pitch 2.3:1 2.4:1 Pitch: Bubble Width 1.1:1 1.1:1 Pitch: Bead Width 2.2:1 3.1:1 Bubble Width: Bead Width 2.0:1 2.9:1 Cavity Diameter: Bubble Height 3.9:1 5.1:1 Cavity Diameter: Collar Height 12.2:1 12.0:1 Bubble Height: Bead Height 3.1:1 2.3:1 Cavity Diameter: Bubble Thickness 27.5:1 90.0:1

Table 2B

Ratios Child Adult Cavity Diameter: Pitch 2.3:1 2.4:1 Pitch: Bubble Width 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 Cavity Diameter: Bubble Height 3.9:1 4.5:1 Cavity Diameter: Collar Height 12.2:1 10.6:1 Bubble Height: Bead Height 3.1:1 2.4:1 Cavity Diameter: Bubble Thickness 27.5:1 90.0:1

[0082] The following tables list some exemplary properties of the composite tube (labeled "A") described herein having a heating filament embedded within the second elongated member. Also shown for comparison are the properties of the Fisher & Paykel Model RT100 Disposable Corrugated Tubing (labeled "B"), which has a heating filament helically wound inside the opening of the tube.

[0083] The measurement of resistance to flow (RTF) 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 tube.

Table 3

RTF (see H ₂ 0) Flow (l/min) 3 twenty 40 60 A 0 0.05 0.18 0.38 B 0 0.28 0.93 1.99

[0084] Condensate or "washout" in the tube refers to the mass of condensate collected per day 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 weights are recorded before and after each day of testing. Carry out three consecutive tests with drying of the tube before each test. The results are shown in table 4 . The results show that washout is significantly lower in the compound tube than in the model RT100 tube.

Table 4

A tube A (day 1) A (day 2) A (day 3) B (day 1) B (day 2) B (day 3) Weight up to (g) 136.20 136.70 136.70 111.00 111.10 111.10 Weight after (g) 139.90 140.00 139.20 190.20 178.80 167.10 Mass of condensate (g) 3.7 3.3 2.5 79.20 67.70 56.00

[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. Humidification chambers (cm.,for example, camera129 humidification in Fig.one) were fed with MR850 heater bases. The heating filaments in the tubes were fed independently from a DC power source. Different rates were set and the chamber was allowed to cool to a temperature of 37° C. at the outlet of the chamber. The DC voltage supplied to the systems was then changed to obtain a system outlet temperature of 40°C. The voltage required to maintain the outlet temperature was recorded and the resulting power calculated. The results are shown in the table5. The results show that compound tube A consumes significantly more power than tube B. This is because tube B uses a helical heating filament in the tube opening to heat the gas from 37°C to 40°C. The compound tube does not heat the gas quickly because the heating filament is located in the wall of the tube (embedded in the second elongated element). The composite tube is designed to maintain the temperature of the gas and prevent condensation by maintaining the tube opening at a temperature below the dew point of the humidified gas.

Table 5

Flow (l/min) 40 thirty twenty Tube A power consumption (W) 46.8 38.5 37.8 Tube B power consumption (W) 28.0 27.5 26.8

[0086] The flexibility of the tube was tested using a three-point bend test. The tubes were placed on a three point bend test stand and an Instron 5560 Test System was used to measure load and elongation. Each tube sample was tested three times; measured the elongation of the tube as a function of the applied load, to obtain the average corresponding constant stiffness. The average constant stiffnesses for tube A and tube B are given in Table 6 .

Table 6

A tube Hardness (N/mm) A 0.028 B 0.088

Manufacturing methods

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

[0088] Referring first to FIG. 4A . In at least one embodiment, a method for manufacturing a composite tube includes the step of taking the second elongate element 205 & apos ; the turns are spaced apart, thereby forming a spiral of the second elongated element 405 . In some embodiments, the implementation of the second elongated element 205 may be wound directly on the core. In other embodiments, a sacrificial layer may be provided on the core.

[0089] In at least one embodiment, the method further comprises molding the second elongate member 205' . A suitable method of forming the second elongate element 205 is extrusion. A second extruder may be provided to extrude the second elongate member 205 with a predetermined bead height. Thus, in at least one embodiment, the method includes extruding the second elongate member 205' .

[0090] As shown in FIG. 4B , extrusion may be advantageous as it may allow the heating filaments 215 to be embedded in the second elongate member 205 while the second elongate member 205 ' is being formed, for example using an extruder having a transverse die. Thus, in some embodiments, the method includes providing one or more heating filaments 215 ', and terminating the heating filament 215 to form a second elongate member 205 '. Further, the method includes providing a second elongate element 205 ' having one or more heating filaments 215 ' embedded or enclosed within the second elongate element 205 '.

[0091] In at least one embodiment, the method includes terminating one or more threads215 into the second elongated element205. For example, as shown in FIG.4C, thread215 can be pressed (retracted or mechanically placed) into the second elongate element205 to a given depth. Alternatively, in the second elongated element205 notches can be made to a predetermined depth, and threads215 may be placed in these cutouts. Preferably, the indentation or cutting is performed shortly after the second elongate element is extruded.205, and while the second elongated element205 is soft.

[0092] As shown in FIG. 4D and 4E , in at least one embodiment, the method includes providing a first elongate member 203 ', and coiling the first elongate member 203 around the helix of the second elongate member 405 such that portions of the first elongate member 203 overlap adjacent coils of the second elongate member 405 ', and a portion of the first elongate member 203 is positioned adjacent to the core 401 in the space between the helix turns of the second elongate member 405 ', thereby forming the helix of the first elongate member 407 '. In FIG. 4D shows this exemplary method in which the heating filaments 215 are enclosed in the second elongate member 205 prior to the second elongate member being coiled. In FIG. 4E shows this exemplary method in which the heating filaments 215 are enclosed in the second elongate member 205 during the coiling of the second elongate member. An alternative method of enclosing the filament 215 in the composite tube includes enclosing one or more filaments 215 between the first elongate element 203 and the second elongate element 205 in the region where the first elongate element 203 overlaps the second elongate 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 having the heating filaments in a gas path. Providing heating filament(s) 215 outside the gas path improves performance because the filaments heat the tube wall where condensation is most likely to form. This design reduces the risk of fire in high oxygen environments by removing the heating filament from the gas path. However, this feature also degrades the performance, since it reduces the effectiveness of the filaments in heating gases as they pass through the tube. However, in some embodiments, the implementation of the composite tube 201 contains one or more heating threads 215 placed in the gas path. For example, the heating filaments can be placed on the wall of the cavity (orifice of the tube), for example in a spiral fashion. An exemplary method for positioning one or more heating filaments 215 on a cavity wall includes attaching a heating filament, embedding, or otherwise being molded to the surface of second elongate member 205&apos ; which, when assembled, forms the cavity wall. Thus, in some embodiments, the implementation of the method includes the location of one or more heating threads 215 on the wall of the cavity.

[0094] Although the heating filaments 215 are embedded or enclosed in the second elongate element 205 , or located on the second elongate element 205 , or otherwise placed on or in the tube, in at least one embodiment, pairs of filaments can be formed into a connecting loop at one end of the composite tube to form a contour.

[0095] FIG. 4F is a longitudinal cross-sectional view of the assembly shown in FIG. 4E , focusing on the top of the core 401 and the top of the first elongated element helix 407 , and the second elongate element helix 405 . This example shows a second elongate helix 405 having a T-shaped second elongate 205 '. When forming the second elongate element, the heating filaments 215 are embedded in the second elongate element 205' . On the right side of Fig. 4F shows the bubble profile of the helix of the first elongated member described above.

[0096] In addition, the method may include molding the first elongated element 203 . Extrusion is a suitable method for molding the first elongate member 203' . Thus, in at least one embodiment, the method includes extruding the first elongate element 203' . The first elongated member 203 may be made by extruding two or more parts and joining them together to form one part. As yet another alternative, the first elongate member 203 may also be extruded into sections that form a hollow shape when molded or connected during the coiled tube molding process.

[0097] In addition, the method may include supplying one end of the first elongate element 203 with a gas at a pressure above atmospheric pressure. The gas may be, for example, air. As already explained, other gases may be used. The supply of gas to one end of the first elongate member 203 can maintain the shape of the open hollow body as the first elongate member 203 is wound around the core 401 '. The gas may be supplied before the first elongate member 203 is wrapped around the core 401 ', while the first elongate member 203 is wrapped around the core 401 ', or after the first elongate member 203 is wrapped around the core 401 '. For example, an extruder with a die/tip combination may supply air into the deep cavity of the first elongate member 203 while extruding the first elongate member 203' . Thus, in at least one embodiment, the method includes extruding the first elongate element 203 , and feeding the end of the first elongate element 203 after extruding a gas at a pressure above atmospheric pressure. A pressure of 15-30 cm H ₂ O (or about 15-30 cm H ₂ O) is considered acceptable.

[0098] In at least one embodiment, the first elongate member 203 and the second elongate member 205 are helically wound around the core 401 '. For example, the first elongate member 203 and the second elongate member 205 may be discharged from the die at an elevated temperature of 200° C. (or about 200° C.) or higher and then applied to the core a short distance from the die. Preferably, the core is cooled using a water jacket, cooler and/or other 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 helix, the first elongate element 203 and the second elongate element 205 are further cooled by a cooling fluid (liquid or gas). In one embodiment, air expelled from a jet ring enclosing the core is used as the cooling fluid. 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 attachment mechanism is required to connect the first and second elongated members. In other embodiments, an adhesive or other attachment mechanism may be used to bond or otherwise connect the two elements. In yet another embodiment, the second elongate member 205 may be cooled after extrusion and placement of the heating filaments to fix the position of the heating filaments. The second elongate member 205 may then be reheated when applied to the core to improve adhesion. Exemplary reheating methods include the use of spot heaters, heated rollers, and the like.

[0099] The method includes forming pairs of heating or measuring filaments at one end of a composite tube into a connecting loop. For example, the ends of the two heating or measuring filaments may be drawn from the second elongate member 205 and then formed into a connecting loop, such as by binding, bonding, gluing, fusing, etc. two threads. As another example, the ends of the heating filaments may be left protruding from the second elongate member 205 during manufacture and then formed into a connecting loop when the composite tube is assembled.

Medical tubing and manufacturing methods using a single helically wound tubing

[0100] Reference is now made to FIG. 5A-5F , which show transverse cross-sections of tubes comprising a tubular-shaped single member having a first elongate member or portion 203 and a second elongate member or portion 205' . As shown, the second elongated portions 205 are integral with the first elongate portions 203 and extend the entire length of the single tubular member. In the embodiments shown, the single tubular-shaped member is an elongated hollow body having a relatively thin wall in cross-section in the transverse direction, partially delimiting 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 a relatively thin wall. After the elongate hollow body is helically wound, these reinforcements form part of the inner wall of the cavity 207 ', with the reinforcements also helically arranged between adjacent coils of the elongate hollow body.

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

[0102] The elongated hollow body can be molded into a medical tube, as already explained, and the above discussion of this reference is included in the following description. For example, in at least one embodiment, a method for manufacturing a medical tube includes spirally winding an elongated hollow body around a core. This can be done at elevated temperature so that after helical winding, the elongated hollow body is cooled to join adjacent turns. As shown in FIG. 5B , the opposing side edge portions of the reinforcement portions 205 may touch on adjacent turns. In other embodiments, the opposing side edge portions of the second elongate member 205 may overlap on adjacent coils, as shown in FIG. 5D and 5E . Heating filaments 215 ' may be inserted into the second elongate element, as already explained and as shown in FIG. 5A-5F . For example, heating filaments may be provided on opposite sides of the elongate hollow body as shown in FIG. 5A - 5D . Alternatively, heating filaments may be provided on only one side of the elongated hollow body, as shown in FIG. 5E - 5F . Any of these embodiments could include the presence of measuring threads.

medical circuits

[0103] Reference is now made to FIG. 6 , which shows an exemplary medical circuit in accordance with at least one embodiment. The system contains one or more of the composite tubes described above, namely for the inhalation tube 103 and/or the exhalation tube 117 . The properties of the inhalation tube 103 and the expiratory tube 117 are similar to those of the tubes described above with reference to FIGS. 1 . The inhalation tube 103 has an inlet 109 in communication with the humidifier 115 and an outlet 113 through which humidified gases are introduced into the interior of the patient 101 . The exhalation tube 117 also has an inlet 109 to receive exhaled humidified gases from the patient and an outlet 113 . As described above with reference to FIG. 1 , outlet 113 of exhalation tube 117 may vent exhaled gases to the atmosphere, to fan/blower assembly 115 , to an air cleaner/filter (not shown), or to 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.

Inflation system component

[0105] Laparoscopic surgery, also referred to as minimally invasive surgery (MIS) or very small incision surgery, is a modern surgical technique in which abdominal surgery is performed through small incisions (typically 0.5-1.5 cm) compared to with larger incisions required in conventional surgical procedures. Laparoscopic surgery includes operations in the abdominal or pelvic cavity. In laparoscopic inflation surgery, it may be necessary to humidify the injected gas (usually CO ₂ ) before passing it into the abdominal cavity. This can help prevent the patient's internal organs from "drying out" and may shorten the time it takes to recover from surgery. Injection systems usually contain humidification chambers that retain some water. The humidifier typically includes a heating plate that heats water to create water vapor, which is transferred to incoming gases to humidify those gases. These gases are transported from the humidifier by water vapor.

[0106] Reference is now made to FIG. 7 showing an inflation system 701 in accordance with at least one embodiment. The insufflation system 701 includes a powder blower 703 that generates a superatmospheric pressure of insufflated gases for delivery to the patient's abdominal or peritoneal cavity 705 . The gases pass into a humidifier 707 having a heating base 709 and a humidification chamber 711 , with the chamber 711 in use in contact with the heating base 709 , and with the heating base 709 supplying heat to the chamber 711 . In humidifier 707 , blown gases pass through chamber 711 while being humidified to an appropriate moisture level.

[0107] The system 701 includes a delivery channel 713 that provides a connection between the humidification chamber 711 and the patient's peritoneal cavity or operating field 705' . Channel 713 has a first end and a second end, the first end being connected to the outlet of humidification chamber 711 and receiving humidified gases from chamber 711 '. The second end of the channel 713 is placed in the operating field or peritoneal cavity of the patient 705 , and moistened insufflated gases pass from the chamber 711 through the channel 713 and into the operating field to inflate and expand the operating field or peritoneal cavity. In addition, the system includes a controller (not shown) that regulates the amount of moisture supplied to the gases by controlling the power supplied to the heating bed 709 '. In addition, the controller is used to control the water in the 711 humidification chamber. A smoke evacuation system 715 is shown escaping from a patient's body cavity 705 .

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

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

coaxial tube

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

[0111] Reference is now made to FIG. 7 , which shows a coaxial tube 701 in accordance with at least one embodiment. In this example, a 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 outer tube 711 may not be exactly aligned with inner tube 707' . In this case, the term "coaxial" means that one tube is located inside another tube.

[0112] For reasons of heat transfer, the inner tube 707 can carry the inhaled gases in the space 713 inside it, while the 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 reverse configuration is also possible, in which the outer tube 711 carries the inhaled gases and the inner tube 707 carries the exhaled gases.

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

[0114] If the coaxial tube 701 is used, the fan 705 may not be aware of a leak in the inner tube 707 . This leak may shunt the patient 701 , i.e., the patient 701 will not be supplied with sufficient oxygen. This shunting can be detected by a sensor located at the end of the coaxial tube 701 on the patient side. This sensor may be located in the connector 715 at the patient end. Shunting closer to the ventilator 705 will cause the patient 701 to continuously rebreath the volume of air closest to the patient 701 . This will result in an increase in the concentration of carbon dioxide in the inspiratory flow space 713 near the patient 701 , which can be detected directly by the CO ₂ sensor. This sensor may be any of a number of such sensors currently commercially available. Alternatively, this rebreathing may be detected by monitoring the temperature of the gases in the connector 715 at the patient end, where a rise in temperature above a predetermined level indicates that rebreathing is taking place.

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

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 elongate member 203 , resulting in uneven heating. As already explained, one way to compensate for this heat loss is to apply heat from an external heat source to the walls of the first elongate element 203 , which will help regulate the temperature and counter heat loss. However, other methods can be used to optimize thermal properties.

[0117] Reference is now made to FIG. 9A-9C , which show exemplary bubble height constructions (i.e., the cross-sectional height of the first elongated member 203 measured from the surface facing the interior cavity to the surface forming the maximum outer diameter) to improve thermal properties.

[0118] The dimensions of the bubble may be chosen to reduce heat loss from the composite tube 201 '. Generally, increasing the height of the bubble increases the effective thermal resistance of the tube 201 because the higher bubble height allows the first elongated member 203 to hold more heat-insulating air. However, it has been found that at a certain bubble height, changes in air density cause convection in tube 201 , thereby increasing heat loss. Also, at a certain bubble height, the surface area becomes so large that heat lost through the surface negates the benefits of the increased bubble height. Some embodiments include these implementations.

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

[0120] In FIG. 9A shows a cross section in the longitudinal direction of the top of the composite tube. In FIG. 9A shows an embodiment of the composite tube 201 in which the bubble has a higher 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 the height of the second elongated element 205 '.

[0121] In FIG. 9B shows a cross-section in the longitudinal direction of the top of another composite tube. In FIG. 9B shows an embodiment of a 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 member 205 '.

[0122] In FIG. 9C shows a longitudinal cross-section of the top of another composite tube. In 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 curvature between the radii of curvature in FIG. 9A and FIG. 9B and the center of the radius for the top of the bubble is on the outside of 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 elongate member 205 ″, i.e. the height of the bubble is between the heights of the bubbles in FIG. 9A and FIG. 9B .

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

[0124] It should be noted that while in some embodiments, the embodiment of FIG. 9C may be preferred, other embodiments may be used as needed, including those shown in FIG. 9A , 9B and other options.

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

Table 7

Tube (fig.) 9A 9B 9C Bubble height (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

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

Table 7A

Tube (fig.) 11A 11B 11C Bubble height (mm) 6.6 8.4 9.3 Outer Diameter (mm) 24.6 26.4 27.3 Radius of curvature (mm) ten 8.7 5.7

[0127] It should be noted that, in general, the smaller the radius of curvature, the tighter the tube can be bent around itself without collapse or "break". For example, in FIG. 11D shows the tube bent more than its radius of curvature allows (in particular, this figure shows the tube of FIG. 11A bent with a radius of curvature of 5.7 mm), resulting in collapse of the bubble walls. Collapse is generally undesirable as it can degrade the appearance and thermal properties of the tube.

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

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

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

[0131] In FIG. 9D shows a cross-section in the longitudinal direction of the top of another composite tube. In FIG. 9D shows an embodiment of a composite tube 201 in which the heating elements 215 are spaced farther apart than in FIG. 9C in the second elongated element 205 . These heating elements are located closer to the bubble wall and provide better heat control in the composite tube 201 .

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

[0133] In FIG. 9F shows a cross-section in the longitudinal direction of the top of another composite tube. In FIG. 9F shows an embodiment of a 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 close to the bubble wall, especially compared to FIG. 9C-9E .

[0134] Of the four thread arrangements in FIG. 9C-9F , the embodiment of FIG. 9F was determined to have the best thermal properties because, due to their similar bubble shapes, all of these designs suffer similar heat loss from the tube. However, when the same heat energy was applied to the tubes, the filaments arranged as shown in FIG. 9F provided the largest temperature rise along the length of the tube. The design in Fig. 9D was determined to have the next best thermal properties and provide the next highest temperature rise along the length of the tube. Next came the design in FIG. 9C . The design in Fig. 9E had the worst performance and, when the same amount of heat was supplied, provided the smallest temperature increase along the length of the tube.

[0135] It should be noted that while in some embodiments, the embodiment of FIG. 9F may be preferred, in other embodiments, other designs may be used as needed, including those shown in FIG. 9C , 9D , 9E and other variants.

[0136] Reference is now made to FIG. 10A-10C , which show exemplary designs for overlaying the first elongate member 203 . It has been found that in some embodiments, heat distribution can be improved by stacking multiple bubbles. These embodiments may be advantageous when using the internal heating filament 215' . In FIG. 10A shows a longitudinal cross-section of the top of another composite tube. In FIG. 10A shows a cross section of the composite tube 201 without any overlap.

[0137] FIG. 10B shows a cross-section in the longitudinal direction of the top of another composite tube. In FIG. 10B shows another exemplary composite tube 201 with superimposed bubbles. In this example, to form the first elongated element 203 , two bubbles are superimposed one on top of the other. Compared to FIG. 10A , the overall height of the bubbles is maintained, but the spacing of the bubbles 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 transfer between the bubbles 213 and reduces the overall thermal resistance. In superimposed bubbles, the heat flow path is increased, allowing the heat to be more easily distributed through the composite tube 201 '.

[0138] In FIG. 1°C shows a cross-section in the longitudinal direction of the top of another composite tube. In FIG. 1°C shows another exemplary composite tube 201 with superimposed bubbles. In this example, three bubbles are stacked one on top of the other to form the first elongated member 203 . Compared to FIG. 10A , the overall height of the bubbles is maintained, but the spacing of the bubbles is three times smaller than in FIG. 10A . In addition, the embodiment in FIG. 10B has only a slight reduction in air volume. Superposition of bubbles reduces natural convection and heat transfer between the bubbles 213 .

Cleaning

[0139] In at least one embodiment, materials for the composite tube may be selected to accommodate various cleaning methods. In some embodiments, high-level disinfection (about 20 cleaning cycles) may be used to clean the composite tube 201 . In high-level disinfection, the composite tube 201 is pasteurized at a temperature of about 75°C for about 30 minutes. The composite tube 201 is then washed in a 2% glutaraldehyde bath 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 washed in a bath of 0.55% orthophthaldehyde (OPA) for about 10 minutes.

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

[0141] 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 above 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 variations and very 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 in any sense to limit the scope of the present invention.

Claims (40)

1. Composite tube for use in medical circuits designed to supply gases to the patient and / or remove gases from the patient, containing: a first elongated element comprising a hollow body helically wound to form at least partially an elongated tube having a longitudinal axis, a cavity extending along the longitudinal axis, and a hollow wall at least partially surrounding this cavity; and a second elongated element helically wound and connected between adjacent turns of the first elongated element, wherein the second elongated element forms at least part of the cavity of the elongated tube, and at least one conductive thread is embedded or enclosed in the second elongated element. 2. The composite tube of claim 1, wherein the second elongate element is less flexible than the first elongate element. 3. The composite tube of claim 1, wherein the helically wound and attached first and second elongate members are configured to provide crush resistance while remaining flexible enough to allow small radius bends without kinks, blockages, or collapses. 4. A composite tube according to claim 1, in which parts of the first elongated element are configured to overlap adjacent turns of the second elongated element. 5. A composite tube according to claim 1, wherein the second elongated element is solid. 6. The composite tube of claim 1, wherein the first elongated element is configured to form bubbles in longitudinal cross section with an oblate surface at the cavity. 7. A composite tube according to claim 6 wherein adjacent bubbles are separated by a gap above the second elongated element. 8. Composite tube according to claim 7, in which the gap is made with the possibility of providing small radius bends. 9. Composite tube according to claim 6, in which the bubbles have holes. 10. A composite tube according to claim 1, wherein the second elongated element in the cross section of the longitudinal direction of the composite tube is wider at the cavity and already at a radial distance from the cavity. 11. A composite tube according to claim 1, wherein the second elongated element has a cross-section in the longitudinal direction having a triangular, T-shaped or Y-shaped shape, and wherein at least two of the conductive threads are embedded or enclosed on opposite sides triangular, T-shaped or Y-shaped. 12. The composite tube of claim 1, wherein the portion of the hollow wall adjacent to the cavity is thinner than the portion of the hollow body opposite the cavity. 13. Composite tube according to any one of paragraphs. 1-12, in which at least one conductive thread contains a heating thread. 14. Composite tube according to any one of paragraphs. 1-12, in which at least one conductive thread contains a measuring thread. 15. Composite tube according to any one of paragraphs. 1-12, comprising at least one conductive thread embedded or enclosed in the second elongated element. 16. Composite tube according to any one of paragraphs. 1-12, containing four conductive threads embedded or enclosed in a second elongated element. 17. Composite tube according to any one of paragraphs. 1-12, in which, at one end of the composite tube, pairs of conductive threads are connected into a connecting loop. 18. Composite tube according to any one of paragraphs. 1-12, in which at least one conductive thread is separated from the wall of the cavity. 19. Composite tube according to any one of paragraphs. 1-12, which is at least one 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. Composite tube according to any one of paragraphs. 1-12, in which the second elongate element acts as a structural support or reinforcement for the first elongate element and at least one conductive thread contains a heating thread. 21. The composite tube of claim 20, wherein the second elongate element is less flexible than the first elongate element. 22. 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, including the steps at which: provide a first elongated element containing a hollow body, and a second elongated element, and the second elongated element contains at least one conductive thread; helically wound the second elongated element on the core with opposing side edge parts of the second elongated element on the adjacent coils placed at a distance, thereby forming a spiral of the second elongated element; and the first elongated element is helically wound on the second elongated element helix so that parts of the first elongated element overlap adjacent turns of the second elongated element helix, and a part of the first elongated element is located close to the core in the space between the second elongated element helix turns, thereby forming the first elongated element helix . 23. The method of claim. 22, further comprising supplying one end of the first elongated element with air at a pressure above atmospheric pressure. 24. The method of claim 22, further comprising cooling the first elongate coil and the second elongate coil to form a composite tube having a cavity extending along a longitudinal axis and a hollow space surrounding the cavity. 25. The method of claim 22, further comprising the step of forming a second elongated element. 26. The method of claim 25, wherein the step of forming the second elongate element comprises extruding the second elongate element with a second extruder. 27. The method of claim 26 wherein the second extruder is configured to enclose at least one conductive filament in the second elongate member. 28. The method of claim 26, wherein the step of forming the second elongate element comprises embedding the conductive filaments in the second elongate element. 29. The method of claim. 27, wherein at least one conductive thread is non-reactive with the second elongate element. 30. The method of claim 22, wherein at least one conductive thread contains aluminum or copper. 31. The method of claim 22, further comprising converting pairs of conductive filaments at one end of the composite tube into a connecting loop. 32. The method of claim 22, comprising the step of forming a first elongated element. 33. The method of claim 32, wherein the step of forming the first elongate element comprises extruding the first elongate element with a first extruder. 34. The method of claim 33, wherein the first extruder is different from the second extruder. 35. Composite tube for use in medical circuits designed to supply gases to the patient and/or remove gases from the patient, made according to the method according to any one of paragraphs. 22-34.

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