Breathing Circuit Sensing

Abstract

To provide a controller for a breathing assistance apparatus comprising a conduit for conveying gases therein, the conduit comprising circuitry.SOLUTION: A circuitry may comprise: at least one heater wire part for heating gases in the conduit in use; and at least one sensor wire part comprising at least one sensor for monitoring a parameter of the gases in the conduit. There is also provided a controller for controlling provision of AC power or AC voltage to the heater wire part, and controlling selective reading of the sensor. The controller may be configured to read the sensor at or about a particular portion of an AC power waveform provided to the heater wire part.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates generally to systems, devices and methods for providing humidified gas to a user, and more particularly to their application for use with a breathing circuit for a humidification system that involves both sensing and driving or powering one or more elements, such as a heater coil. [Background technology]

[0002] Many gas humidification systems deliver heated and humidified gases for various medical procedures, including respiratory therapy, laparoscopy, and the like. These systems can be configured to control temperature, humidity, and flow rate using feedback from sensors. To maintain desired characteristics during delivery to the user, the breathing circuit can have a heater associated with the gas line, where the heater provides heat to the gas as it flows to and / or from the user. The line heater can be controlled to provide heat to the gas so that it arrives at the user with desired characteristics, such as temperature and / or humidity. The humidification system can include a temperature sensor and provide feedback to a humidification controller, which can adjust and / or modify the power sent to the line heater to achieve a target temperature at a location along the associated line. Additionally or alternatively, other sensors can be provided that measure any one or more of, for example, flow rate, pressure, humidity, or other characteristics of the gas and / or other characteristics of one or more components of the system, such as the patient interface or line.

[0003] Some exemplary breathing circuit components are disclosed in PCT application PCT / NZ2015 / 050028, filed March 17, 2015, entitled "MEDICAL TUBES FOR RESPIRATORY SYSTEMS," which is incorporated by reference in its entirety.

[0004] PCT Application PCT / NZ2013 / 000208, filed Nov. 14, 2014, entitled "ZONE HEATING FOR RESPIRATORY CIRCUITS," which is incorporated herein by reference in its entirety, discloses a breathing circuit for a humidification system. More particularly, it describes an arrangement for monitoring parameters within the humidification system and adjusting its operation based at least in part on the parameters. For example, the temperature of gas in an inspiratory line of the breathing circuit may be monitored and power supplied to heater wires for heating the gas in the inspiratory line may be adjusted accordingly.

[0005] According to some embodiments disclosed in PCT application PCT / NZ2013 / 000208, the sensor and heater wires terminate at one end of the conduit at or proximate the cuff. This configuration conveniently provides a pneumatic connection line of the conduit to a gas source while at the same time establishing an electrical connection line between the heater and sensor wires and a wider control / power circuit. Additionally, the heater and sensor wires are disclosed as being positioned adjacent to one another along at least a portion of the length of the tubing and connected to a common circuit board. While this configuration can reduce the total number of components and simplify manufacturing, it has been found that the power supplied to the heater wires creates noise that affects the accuracy of the readings from the sensor connected to the sensor wires. For the multi-zone embodiment in infants disclosed in PCT / NZ2013 / 000208, when the patient end temperature set point is near 40°C, an error in the region of ±0.3°C is introduced, and for the embodiment in adult tubing, an error of approximately ±0.15°C is introduced. Any possible reduction in these errors is desirable to improve the performance of the system as a whole, and in its humidification aspects in particular. Summary of the Invention [Means for solving the problem]

[0006] The systems, methods, and devices described herein have innovative aspects, none of which are essential or solely responsible for their desirable attributes. Without limiting the scope of the claims, some of the advantageous features are summarized below.

[0007] The present invention is generally described herein with reference to or as applied to the inspiratory limb. However, the present invention is not limited to the inspiratory limb and has broad application. For example, the present invention may be applied to the expiratory limb and / or limbs used for purposes of providing and / or removing gases and the like during an insufflation procedure. Thus, references to the inspiratory limb are for reference purposes only.

[0008] According to one aspect of the invention there is provided a control device for a respiratory assistance apparatus, the respiratory assistance apparatus comprising a conduit for transmitting gas therethrough, the conduit comprising a circuit, the circuit comprising at least one heater wire portion for heating gas in the conduit during use, and at least one sensor wire portion comprising at least one sensor for monitoring a parameter of the gas in the conduit during use, Controlling the provision of AC power or AC voltage to the heater wires; Controlling selective reading of the sensors; A control device configured to: A controller is provided that is configured to read the sensor at or about a particular portion of the AC power waveform provided to the heater wires.

[0009] The controller may be configured such that the particular portion of the AC power or voltage waveform begins at a first zero crossing, preferably a falling zero crossing, around or after the first zero crossing of the AC power or voltage waveform and begins at or before a second zero crossing of the AC power or voltage waveform, the first and second zero crossings being consecutive zero crossings of the same type.

[0010] The controller can be configured to control the repetition of said selective reading of the sensor between a third zero crossing and a fourth zero crossing, the second, third and fourth zero crossings being successive zero crossings of the same type.

[0011] The controller may comprise or be communicatively coupled to a monitor for monitoring the AC power or voltage waveform, the controller controlling when to selectively read the sensor based at least in part on a signal indicative of or derived from the monitored AC power or voltage waveform. The controller may be configured to use the monitor to detect zero crossings, preferably falling zero crossings, of the AC power or voltage waveform. The controller may be configured to use the monitor to detect portions of the AC power or voltage waveform other than the zero crossings. The controller may be adapted to establish timing of the zero crossings based at least in part on timing of detected portions of the AC power or voltage waveform that are not zero crossings.

[0012] The controller may be adapted to establish timing of particular portions of the AC power or voltage waveform based at least in part on one or more known and / or detected characteristics of the AC power waveform, said characteristics of the AC power or voltage waveform may include its frequency.

[0013] The at least one heater wire portion may comprise at least one heater wire connectable to said AC power or voltage. There may be two or four of said heater wires.

[0014] The at least one sensor wire section may comprise at least one sensor wire. There may be two of said sensor wires. At least a portion of said sensor wire may be positioned adjacent to at least a corresponding portion of said heater wire. The heater wire section and the sensor wire section may comprise independent circuits.

[0015] The controller may comprise or be coupled to a multiplexer, the multiplexer being coupled or configured to couple to the sensor wire portions. The multiplexer may be coupled to a number of sensor wires to enable reading of corresponding sensors coupled to the sensor wires. The controller may be configured to reset the multiplexer at a positive rising edge of the AC power or voltage waveform and / or during a positive phase of the AC power or voltage waveform. The controller may be configured to use the multiplexer to read the sensors during a falling edge of the AC power or voltage waveform.

[0016] The controller may include or be communicatively coupled to a memory for storing information related to the AC power or voltage waveform, such as phase information, and / or information related to the sensors of the sensor wire portions.

[0017] The controller may comprise at least two sensors, the controller being configured to control the reading of a first one of the sensors at a first zero crossing, preferably a falling zero crossing, around or after the first zero crossing and at or before a second zero crossing of the AC power or voltage waveform, the first and second zero crossings being consecutive zero crossings of the same type, and the controller being configured to control the reading of a second one of the sensors at a third zero crossing, around or after the third zero crossing and at or before a fourth zero crossing, the first, second, third and fourth zero crossings being consecutive zero crossings of the same type.

[0018] The conduit may comprise first and second segments or portions connectable together to provide an elongated conduit, and the controller is configured to receive signals indicative of the presence and / or absence of the first and / or second segments and to implement control depending on which segments are present and / or absent. If it is determined that only the first segment is present, the controller may employ a first mode, the first mode preferably adapted for adult users and / or applications, and in the first mode the environmental conditions are substantially the same along the length of the conduit. The controller may: and / or the waveform transitions from a flat portion to the negative half of a full cycle; The waveform transitions from the positive half cycle to the flat portion of the full cycle. The application of power to the at least one heater wire may be configured to be controlled. If a second section is determined to be present, the first section may comprise a first heater wire section and the second section may comprise a second heater wire section, and the controller may be configured to control the selective application of power to the first heater wire section during a first time period and to control the selective application of power to both the first heater wire section and the second heater wire section and / or to only the second heater wire section during a second time period.

[0019] The control device includes: to the first heater wire portion such that the waveform transitions from the flat portion to a first of two positive half cycles and / or to the flat portion following the two positive half cycles; to the second heater wire portion such that the waveform transitions from the flat or off portion to the first of the two negative half cycles and / or to the flat portion following the two negative half cycles; and / or to both heater wires such that the waveform transitions from a flat or off portion to the first of two negative half cycles and / or to a flat portion following the two negative half cycles. The application of power may be adapted to be controlled.

[0020] The controller may be adapted to determine the frequency of the AC power or voltage.

[0021] According to another aspect of the present invention, A pipeline for transmitting gas therein A respiratory assistance apparatus comprising: at least one heater wire portion for heating gas in the pipeline during use; at least one sensor wire portion comprising at least one sensor for monitoring a parameter of the gas in the pipeline; Any one of the control devices described above A respiratory assistance apparatus is provided, comprising:

[0022] At least one heater wire portion and / or said at least one sensor wire portion may terminate at or proximate to a first end of the conduit, preferably within 20 mm of the end of the conduit, more preferably within 10 mm of the end of the conduit, even more preferably within 5 mm of the end of the conduit, said end being the patient end of the conduit in use.

[0023] At least one heater wire portion and / or said at least one sensor wire portion may be coupled to a printed circuit board PCB. The PCB may be positioned inside, around and / or within a wall forming the conduit. The PCB may be provided at or proximate to a second end of the conduit. The or at least one of said sensors may be mounted on or to the PCB.

[0024] The heater wires may be associated with at least a portion of the length of the conduit by being provided within, around, and / or within a wall forming the conduit.

[0025] The sensor wire may be associated with at least a portion of the length of the conduit by being provided within, around and / or within a wall forming the conduit.

[0026] The respiratory assistance device may comprise two of said heater wires and two of said sensor wires, the wires being provided in or embedded in the wall of the duct and spirally wound and arranged into a series of heater wire 1, sensor wire 1, sensor wire 2 and heater wire 2.

[0027] According to another aspect of the present invention, A control device according to any one of the preceding claims, and / or Respiratory support devices of any of the above descriptions A respiratory humidification system is provided comprising:

[0028] According to a further aspect of the present invention, Controlling the delivery of AC power or voltage to a heater wire portion of the medical tubing; controlling selective readings of sensors provided to, coupled to, or otherwise associated with the medical tubing at or about specific portions of an AC power or voltage waveform provided to the heater wires; A respiratory humidification method is provided, comprising:

[0029] A medical conduit for use as a conduit as referred to in any one of the above statements.

[0030] Some embodiments provide an inspiratory limb for a breathing circuit and / or a system and / or method including the inspiratory limb. The inspiratory limb described herein is particularly useful or applicable in situations where heated and humidified gas is delivered through the inspiratory limb. According to some embodiments, the heated and humidified gas can pass through two different environments. This can be problematic, for example, in an infant incubator, where the temperature is significantly higher than the surrounding environment or where a portion of the ductwork delivering gas to the patient is under a blanket. However, some embodiments disclosed herein can be used in any environment where heated and / or humidified gas is delivered to a patient and are not limited to applications where the inspiratory limb passes through two different environments.

[0031] The inspiratory limb may include a first section of the inspiratory limb comprising a first structure forming a conduit configured to transport the humidified gas, the first section of the inspiratory limb including a first heater wire section or circuit. The inspiratory limb may include a second section of the inspiratory limb comprising a second structure forming a conduit configured to transport the humidified gas, the second structure configured to mechanically couple or otherwise join or integrate with the first structure of the first section to form an extended conduit for the humidified gas, the second section of the inspiratory limb including a second heater wire section or circuit. The inspiratory limb may include an intermediate connector including a connection circuit electrically coupling the first heater wire circuit to the second heater wire circuit, the intermediate connector may be coupled to a patient end of the first section of the inspiratory limb and a chamber end of the second section of the inspiratory limb to form a single conduit for the humidified gas. The intermediate connector may be covered by a portion of the first segment of the inspiratory limb, a portion of the second segment of the inspiratory limb, or a portion of both the first and second segments of the inspiratory limb such that the intermediate connector is internal to the inspiratory limb.

[0032] The inspiratory limb can be configured to operate in two heating modes. In a first heating mode, power passes through the intermediate connector to provide power to the first heater wire circuit and not to the second heater wire circuit. In a second heating mode, power passes through the intermediate connector to provide power to both the first heater wire circuit and the second heater wire circuit. For example, the intermediate connector can include electrical components configured to route power along different paths based at least in part on a direction of current and / or a polarity of voltage. The intermediate connector can include a conductive track, which can provide a short circuit (e.g., a direct electrical connection without an intervening electrical component) between one or more wires in the first heater wire circuit and one or more wires in the second heater wire circuit. The intermediate connector can include a conductive track, which can electrically couple one or more wires in the first heater wire circuit to one or more wires in the second heater wire circuit, where the conductive track includes electrical components such as, for example, but not limited to, diodes, transistors, capacitors, resistors, logic gates, integrated circuits, etc. In certain embodiments, the intermediate connector includes a diode electrically coupled to both the first heater wire circuit and the second heater wire circuit. In certain embodiments, the inspiratory limb can further include a first sensor portion or circuit having a first sensor positioned at the intermediate connector. In certain embodiments, the inspiratory limb can further include a second sensor circuit having a second sensor positioned at the patient-end connector, the patient-end connector being positioned at the patient-end of the second section of the inspiratory limb. The inspiratory limb can be configured to operate in two sensing modes. In the first sensing mode, a signal from the first sensor is received and a signal from the second sensor is not received. In the second sensing mode, a signal from the second sensor is received and a signal from the first sensor is not received. In some embodiments, the sensing includes receiving signals in parallel from both the first sensor and the second sensor.In such an embodiment, the algorithm may determine a parameter measured by the first sensor based at least in part on signals received in parallel from both the first sensor and the second sensor. In certain embodiments, the intermediate connector includes a diode electrically coupled to both the first sensor circuit and the second sensor circuit. The patient-end connector may be configured to provide an electrical connection for the second sensor circuit. Similarly, the patient-end connector may also be configured to provide an electrical connection for the second heater wire circuit. The sensor may be a temperature sensor, a humidity sensor, a flow sensor, or the like. The first and second sensors may be sensors configured to measure one or more parameters, such as temperature, humidity, flow, oxygen content, or the like. In some embodiments, the first and second sensors are configured to measure at least one similar parameter (e.g., temperature, humidity, flow, or the like). In some embodiments, three or more sensors may be included and may be positioned in the intermediate connector and / or the patient-end connector.

[0033] Some embodiments provide a respiratory humidification system comprising an inspiratory limb and a controller. The inspiratory limb may include a first segment having a first heater wire section or circuit, a second segment having a second heater wire section or circuit, an intermediate connector having a connector circuit configured to electrically couple the first heater wire circuit to the second heater wire circuit, a first sensor positioned at a patient end of the first segment, and a second sensor positioned at a patient end of the second segment. The controller may be adapted to selectively switch between a first mode and a second mode, where in the first mode the controller provides power to the first heater wire circuit through the connector circuit and in the second mode the controller provides power to the first and second heater wire circuits. In certain embodiments, the respiratory humidification system switches modes based at least in part on input from one or both sensors. In certain embodiments, the switching is based at least in part on parameters including one or more of temperature, flow rate, humidity, power, or any combination thereof. The parameters may be derived or obtained directly from the first sensor, the second sensor, or a combination of both sensors. In certain embodiments, the first and second modes are defined by the direction of current or polarity of voltage provided by the power source. In some embodiments, the respiratory humidification system may include three or more sensors, which provide inputs used to control the heating of the inspiratory limb.

[0034] Some embodiments provide a dual limb circuit that can include an inspiratory limb. Such an inspiratory limb can include a first segment having a first heater wire section or circuit, a second segment of the inspiratory limb having a second heater wire section or circuit, an intermediate connector having a connector circuit configured to electrically couple the first heater wire circuit to the second heater wire circuit, a first sensor positioned at a patient end of the first segment, and a second sensor positioned at a patient end of the second segment. The dual limb circuit can also include an expiratory limb with an expiratory heater wire circuit. The dual limb system can further include an interface connected to the inspiratory limb and the expiratory limb. The dual limb system can further include a controller adapted to selectively switch between a first mode and a second mode, where in the first mode the controller provides power to the first heater wire circuit through the connector circuit, and in the second mode the controller provides power to the first and second heater wire circuits. In certain embodiments, the heating of the expiratory limb is performed using an expiratory heater wire circuit separate from the heating of the inspiratory limb using the first and second heater wire circuits. In certain embodiments, the expiratory limb is powered in parallel with the first heater wire circuit in the first section of the inspiratory limb and / or in parallel with the first and second heater wire circuits. In certain embodiments, the expiratory limb can be designed to be powered in only the first mode, only the second mode, or in both the first and second modes. In certain embodiments, the interfaces are connected by a Y-piece. Any suitable patient interface can be incorporated. Patient interface is a broad term and should be interpreted in its ordinary and customary sense to those skilled in the art (i.e., should not be limited to a special or specialized sense), including, but not limited to, masks (such as tracheal masks, face masks, and nasal masks), cannulas, and nasal pillows.

[0035] In some embodiments, a segmented inspiratory limb is provided, where the segment structure comprises an elongated tube. The elongated tube can include a first elongated member having a hollow body helically wound to at least partially form a conduit having a longitudinal axis, a lumen extending along the longitudinal axis, and a hollow wall surrounding the lumen. The elongated tube can include a second elongated member helically wound and joined between adjacent turns of the first elongated member, the second elongated member forming at least a portion of the lumen of the elongated tube. In certain implementations, the first elongated member forms a plurality of bubbles in the lumen having a flattened surface in a longitudinal cross section. In certain implementations, adjacent bubbles are separated by a gap above the second elongated member. In certain implementations, adjacent bubbles are not directly connected to each other. In certain implementations, the plurality of bubbles have perforations.

[0036] In some embodiments, a medical conduit such as an inspiratory limb is provided that includes a conduit, a connector or cuff connected to one end of the conduit for pneumatically coupling to a gas source, a heater wire section, a sensor wire section, and an outlet for transmitting the gas toward a desired destination. For example, the outlet can include a connector or cuff for connecting to a patient interface. The heater wire sections each include one or more heater wires extending at least a portion of the length of the conduit to heat the gas as it flows through the conduit. Similarly, one or more sensor wires can extend at least a portion of the length of the conduit and couple the sensor to a control unit. Although the sensor can be positioned at any point, it is often desirable to include a temperature sensor at or closest to the patient end of the conduit to obtain an accurate indication of the temperature of the gas delivered to the patient. Consequently, some embodiments provide both the heater wires and the sensor wires that extend completely or substantially the entire length of the conduit. According to some embodiments, the patient ends of the heater wire section and the sensor wire section are connected to a common circuit board. One or more sensors can be attached to the circuit board and read using the sensor wires.

[0037] In some embodiments, the heater wire section is connected to an AC source, and the sensor wire section is also connected to the AC source, to allow selective reading of the sensor included in or coupled to the sensor wire section. According to some embodiments, the waveform of the AC source is monitored and / or known characteristics of the waveform are used to detect or determine the timing of one or more zero crossings (preferably falling zero crossings) of the AC source waveform. According to such embodiments, the sensor is preferably read at, around or after the zero crossing. Preferably, the sensor is read within ±25 ms of the zero crossing, more preferably within ±15 ms, more preferably within ±10 ms, more preferably within ±5 ms, and even more preferably within about ±3 ms. According to some currently preferred embodiments, the reading is taken within ±150 μs of the zero crossing, more preferably within ±100 μs of the zero crossing, and even more preferably within ±50 μs of the zero crossing. Range reduction can be achieved by using interrupts to measure the sensor. These ranges are also applicable to other criteria of, around or after a zero crossing, but are not repeated for the sake of brevity. Furthermore, the sensor is preferably read before a subsequent zero crossing of the same type (i.e. rising or falling). The sensor reading can preferably be repeated as desired with the zero crossing relationship maintained. By controlling the sensor reading in this manner, the sensor error can be reduced to near zero since the interference of the power applied to the heater wires on the sensor wire signal is minimal. Furthermore, the reading disturbance is induced by changing the voltage polarity applied to at least some of the sensors (e.g. thermistors). Essentially, it takes some time for the signal to settle or stabilize, so the sensing preferably occurs over a period of time directly preceding the zero crossing.

[0038] In some embodiments, a medical conduit, such as an inspiratory limb, is provided that includes a first and a second section. The two sections are preferably arranged and joined or connectable such that gas flows from a first end of the first section to a second end of the first section, then to a first end of the second section, then to a second end of the second section. According to such an embodiment, a first heater wire section can be provided in the first section and a second heater wire section can be provided in the second section. The first and second heater wire sections can be configured in a first mode in which only the first heater wire section is activated (i.e., produces heat) and in a second mode in which both the first heater wire section and the second heater wire section are activated. Such a configuration is desirable when the conduit transmits gas from outside the incubator through different environments, such as to an infant in the incubator, as previously discussed. For example, a diode may be provided intermediate the first and second heater wire sections such that only the first heater wire section is powered when the AC source current flows in one direction, and both heater wire sections are powered when the current flows in the other direction. Other circuit / switching configurations may be used. According to some embodiments, at least one sensor may be provided at or proximate to the second end of the second section (i.e., the patient end of the conduit). For example, a thermistor may be provided to measure the temperature of the gas flowing in the conduit. A sensor wire may be provided to facilitate reading of the sensor. According to some embodiments, the sensor and heater wires may be connectable to the AC source and / or controller at or proximate to the first end of the first section. Such connections may be conveniently made by a cuff such as that described in PCT / NZ2013 / 000208. If the sections are releasably connectable a similar cuff connector can be used, again see PCT / NZ2013 / 000208. As with the previous embodiment, the sensor can be attached to the circuit board at or proximate to the second end of the second section where the heater and sensor wires are joined.Preferably, the AC source waveform is monitored and / or known characteristics of the waveform are used to detect or determine the timing of one or more zero crossings (preferably falling zero crossings) of the AC source waveform. According to such an embodiment, the sensor is preferably read at, around or after a zero crossing. Furthermore, the sensor is preferably read before a subsequent zero crossing of the same type. The sensor readings can be repeated as desired, preferably with the zero crossing relationship maintained. By controlling the sensor readings in this manner, sensor errors can be reduced to near zero.

[0039] As will be apparent to one skilled in the art, the preferred control of sensor readings timed to the falling zero crossing can be applied to any of the embodiments described herein.

[0040] An embodiment further provides a control device for controlling the reading of a sensor associated with a medical line, the control device being configured to read said sensor at, around or after a zero crossing (preferably a falling edge) of an AC source supplying power to an electrical circuit of the medical line. Preferably, said reading is performed before the next falling edge zero crossing of said AC source of the same type. Further features of the control device can be derived from the preceding description.

[0041] Embodiments further provide a respiratory aid apparatus and / or respiratory humidification system adapted to read a sensor at, around or after a zero crossing (preferably a falling edge) of an associated AC power source. Preferably, said reading is performed before the next zero crossing of said AC source. Further features of the respiratory aid apparatus and / or respiratory humidification system can be derived from the preceding description, and in practice said apparatus and / or system may include said conduit and / or said control device adapted to facilitate said controlling of the reading of one or more sensors.

[0042] The embodiments also provide corresponding methods.

[0043] Reference numbers may be repeated throughout the drawings to indicate a general correspondence between referenced elements. The drawings are provided to illustrate example embodiments described herein and are not intended to limit the scope of the present disclosure. [Brief description of the drawings]

[0044] [Figure 1] FIG. 1 is a schematic diagram of a respiratory system for delivering respiratory gas to a patient. [Diagram 2] FIG. 1 illustrates an exemplary respiratory humidification system for delivering humidified gas to a user, the respiratory humidification system having a breathing circuit that includes a segmented inspiratory limb having a sensor within each segment. [Diagram 3] 1 illustrates an exemplary hardware configuration for a breathing circuit with an inspiratory limb having first and second sections. [Figure 4] 1 illustrates an exemplary hardware configuration for a breathing circuit with an inspiratory limb. [Diagram 5] 5 is a chart showing the relationship between mains AC cycles and heater wire cycles for the heater wire depicted in FIGS. 3 and 4. [Figure 6] 1 is a chart depicting sensor measurements versus mains voltage waveform. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] Specific embodiments and examples of medical circuit components including an inspiratory limb, a segmented inspiratory limb and multi-zone heating are described herein. Those skilled in the art will appreciate that the present disclosure encompasses the specifically disclosed embodiments and / or uses, as well as obvious modifications and equivalents thereof. Thus, it is not intended that the scope of the present disclosure disclosed herein be limited by any specific embodiments described herein.

[0046] The present disclosure refers to heater wires, heating elements, and / or heaters in the context of providing heat to a conduit. For example, heater wire is a broad term and should be interpreted in its ordinary and customary sense to one of ordinary skill in the art (i.e., not limited to a special or specialized sense), including, but not limited to, heater strips and / or heat transfer elements that generate heat when power is provided. Examples of such heating elements include wires formed from conductive metals (e.g., copper), conductive polymers, conductive inks printed on the surface of the conduit, conductive materials used to create tracks in the conduit, and the like. Additionally, the present disclosure refers to conduits, limbs, and medical conduits in the context of gas delivery. For example, tubing is a broad term and should be interpreted with its ordinary and customary meaning to those skilled in the art, including, but not limited to, passages having various cross sections, such as cylindrical and non-cylindrical passages. Certain embodiments may incorporate composite tubing, which may be generally defined as tubing with two or more sections or, in particular, in some embodiments, two or more components, as described in more detail below. The segmented limbs comprising the disclosed medical tubing may also be used within breathing circuits, such as continuous, variable, or bi-level positive airway pressure (PAP) systems, or other forms of respiratory therapy. The terms "conduit" and "limb" should be interpreted as equivalent to tubing.

[0047] When a heated and humidified breathing tube is used for an incubator (or any area with a temperature change, such as around a radiant warmer used for a burn patient or under a blanket used by the patient), the breathing tube passes through at least two different zones: a cooler zone (such as an area outside the incubator) and a hotter zone (such as an area inside the incubator). If the tube is heated along its entire length, one of the zones will tend to be at an undesirable, inappropriate, or suboptimal temperature, depending on which zone is sensed (e.g., which zone contains a temperature sensor). If the heater wires are controlled to a sensor inside the incubator (such as a patient end temperature sensor), the section outside the incubator will tend to be too cold, which can result in condensation. Conversely, if the heater wires are controlled to a sensor outside the incubator, the section inside the incubator may be too hot, which can result in gas being delivered to the patient that is too hot. Thus, in some embodiments of the present disclosure, systems and methods are described that allow for control of heat in a segmented breathing tube. Here, each section has an associated sensor that provides feedback to the control module. Although some embodiments are described herein with respect to two sections, such systems may be expanded to accommodate applications with additional sections, sections, or regions. For example, in one embodiment with three temperature sections, the sections of the breathing tube may be heated based at least in part on three different temperature sensors within the sections. Additionally, embodiments disclosed herein may control heat delivered to the breathing tube based on parameters at the patient end, bypassing or ignoring one or more of the sensors at midpoints along the tube. Additionally, embodiments disclosed herein may control heat delivered to the breathing tube using parameters provided by sensors including, for example, but not limited to, temperature sensors, humidity sensors, flow sensors, oxygen sensors, and the like. Other embodiments may use fewer sensors while allowing different sections to be heated to different levels. For example, according to one embodiment, two sections are provided and a single temperature sensor is associated with the breathing tube, preferably at, toward, or near the patient end of the tube. According to this embodiment, the sections can be configured such that only the first section is heated or both sections are heated, with the first section preferably being the section furthest from the patient in terms of the gas flow path through the tube.

[0048] The control module can monitor and control the heating temperature. The control module can be configured to provide heat to a first section of the breathing tube in a first mode and to provide heat to the entire breathing tube in a second mode using some embodiments of the connector assembly described herein. The control module can detect the presence of the first and / or second section of the breathing tube. To accomplish this, the presence and / or absence of one or more sections of the breathing tube can be detected and the control of the gas properties can be altered accordingly based at least in part thereon. Some embodiments described herein can be used without flying leads, exposed connectors, and / or patient-end electrical connections. The term "flying leads" as used herein includes electrical connections that extend external to the breathing tube, electrical connections that extend internally through the breathing tube, and electrical connections that are incorporated, molded, or otherwise formed or included as part of the breathing tube. The control module can be located inside the humidifier or outside the humidifier. In some embodiments, a control device is located inside the humidifier to control heater wires associated with the first segment of the inspiratory limb, the second segment of the inspiratory limb, and the expiratory limb, and to read parameters from sensors associated with the first and second segments of the inspiratory limb and / or the expiratory limb.

[0049] The control module may also adaptively change temperatures associated with the segments. For example, the control module may monitor temperature sensors associated with one or more segments. The monitoring may be continuous, periodic, interrupt or event-based, or other manner. For example, the monitoring of the temperature sensors may be based on reading values ​​from an analog-to-digital converter, determining a voltage or current, sensing a logical condition, reading a thermostat device, measuring a thermistor value, measuring a resistance temperature detector, measuring a thermocouple voltage, or other methods for sensing temperature, such as, but not limited to, using a semiconductor junction sensor, an infrared or thermal radiation sensor, a thermometer, an indicator, etc. In some embodiments, the temperature sensor is a thermistor.

[0050] In some embodiments, the ratio of power delivered to the first segment of the inspiratory limb and the second segment of the inspiratory limb can be varied during use based at least in part on feedback from sensors. For example, the ratio of power can be varied so that each segment is heated to a temperature that reduces or prevents condensation. As a further example, the ratio of power can be varied so that too hot gas is not provided to the patient. In some embodiments, the ratio of power can be varied continuously based on feedback from sensors (e.g., temperature sensors, humidity sensors, oxygen sensors, flow sensors, etc.). The ratio of power can be varied in a variety of ways. For example, the ratio of power can be varied by changing the amplitude (including but not limited to voltage and / or current) of the power signal, the duration of the power signal, or the duty cycle of the power signal, or by other suitable modifications to the power signal. In one embodiment, the ratio of power is varied by changing the magnitude of the current provided.

[0051] Some embodiments provide an inspiratory limb with heater wires that are not internal to the gas path but are contained within a material that separates the heater wires from the gas path and insulates them from the external environment, in some embodiments, the circuitry used to provide power to the heater wires and to read the sensors is internal to the inspiratory limb so that it is not exposed to the external environment. In some segmented tubing embodiments, the heater wires are molded into the inhalation or exhalation tubing such that the ends of the heater wires in the complementary section of the tubing contact an intermediate connector such that the heater wires are electrically coupled to the intermediate connector, where the intermediate connector can be configured to provide circuitry for heater wire control and / or sensor readings. In some embodiments, the duty cycle of the power source applied to the heater wires can be modified or changed to vary the amount of heat delivered to the gas as it flows along the associated section.

[0052] Some embodiments described herein provide a respiratory humidification system configured to deliver warm humidified gas to a patient or other user. The gas is passed through a liquid chamber filled with liquid (e.g., water) that is heated using a heater plate. The liquid evaporates in the chamber and mixes with the gas flowing over it, thereby heating and / or humidifying the gas. The humidified gas can be delivered to an inspiratory limb having one or more heater wires associated therewith. The heater wires can be selectively powered to provide a predetermined, desired, suitable, or selected amount of heat to the humidified gas. In some embodiments, the respiratory humidification system can be used with an incubator or radiant warmer. The inspiratory limb can be segmented such that a first segment is external to the incubator and a second segment is internal to the incubator. Additionally, a first heater wire set can be associated with the first segment and a second heater wire set can be associated with the second segment. The humidification system can be configured to provide power to a first heater wire set in a first mode and to a second heater wire set in a second mode. In some embodiments, the humidification system can be configured to provide power to a first heater wire set in a first mode and to provide power to a second heater wire set in a second mode. The inspiratory limb can include a sensor at the end of each section or a section to provide feedback to the humidification system, which is used in selecting power to deliver to the heater wire sets in a section. In some embodiments, the humidification system can include an expiratory limb having associated heater wires that are also selectively controlled by the humidification system. In this application, the segmented limb is described with reference to the inspiratory limb. However, the features described can be applied to the expiratory limb as well as other medical tubes.

[0053] Respiratory Humidification Systems FIG. 1 shows a respiratory system 1 that may include, but is not limited to, the following components: a pressurized gas source 2 (such as a blower or ventilator) adapted to generate a supply of gas to be delivered to a patient 3, a humidification device 4 adapted to regulate the supply of gas, a medical tubing 6 adapted to deliver gas to a patient interface 8 (which in turn delivers the gas to the patient 3), and a connector 16 adapted to connect the medical tubing 6 to the humidification device 4.

[0054] The patient interface 8 referred to herein may refer to a mask, a nasal mask, a nasal cannula, an oral mask, a tracheal mask, or nasal pillows.

[0055] The humidification device 4 as referred to herein may refer to any device that conditions a gas, which may include heating the gas and / or humidifying the gas.

[0056] The gases referred to in this specification may refer to air, oxygen, carbon dioxide, or a mixture of any such gases, or a combination of any such gases with one or more medications or aerosols that may be delivered to the patient 3 by the patient interface 8.

[0057] The medical tubing 6 as described herein may refer to a tube, conduit, circuit, or hose. The medical tubing 6 may include one or more wires. The one or more wires may include at least one heater wire, at least one sensor wire, and / or any other type of conductor. The one or more wires may be within the medical tubing 6. The one or more wires may be located along an interior or exterior surface of the medical tubing 6. The one or more wires may be helically wound on the medical tubing 6 or helically wound within the medical tubing 6 such that the one or more wires may be embedded in the wall of the medical tubing 6.

[0058] The medical tubing 6 is preferably heated. The medical tubing 6 may include insulation to reduce the formation of condensates within the medical tubing 6. Condensates form when heated and humidified gas within the medical tubing 6 cools during passage. To reduce or prevent the formation of condensates, the medical tubing 6 may be heated. This heating may be provided by one or more wires, including one or more heater wires.

[0059] The end portion of the medical tubing 6 may be provided for terminating one or more wires at a connector 16 such that an electrical connection may be made between the medical tubing 6 and a component of the respiratory system 1. The connector 16 may provide a pneumatic connection line between the medical tubing 6 and a component of the respiratory system 1. The components of the respiratory system 1 mentioned herein may refer to a patient interface or a humidification device. The connector 16 may provide one or both of an electrical and pneumatic connection line between the medical tubing 6 and a component of the respiratory system 1.

[0060] The one or more wires may also include one or more sensing wires. The one or more sensing wires can be used to sense a gas property such as temperature, flow rate, humidity or pressure. In some embodiments, the one or more sensing wires can be used to sense temperature. In some embodiments, the one or more sensing wires can be connected to one or more sensors that can be used to sense one or more of these gas properties.

[0061] 2 illustrates an exemplary respiratory humidification system 100 for delivering humidified gas to a user, the respiratory humidification system 100 having a breathing circuit 200 including a segmented inspiratory limb 202 having sensors 204a, 204b in each segment. The segmented inspiratory limb 202 may be used with an incubator 208 as shown, or may be used with another system, such as a radiant warmer, where there are different temperatures along various segments of the inspiratory limb 202. The segmented inspiratory limb 202 may be used to provide different levels of heat to various segments 202a, 202b of the inspiratory limb to reduce or prevent condensation and / or control the temperature of the gas delivered to the user.

[0062] The respiratory humidification system 100 includes a pressurized gas source 102. In some implementations, the pressurized gas source 102 includes a fan, blower, or the like. In some implementations, the pressurized gas source 102 includes a ventilator or other positive pressure generating device. The pressurized gas source 102 includes an inlet 104 and an outlet 106.

[0063] The pressurized gas source 102 provides a flow of fluid (e.g., oxygen, anesthetic gas, air, etc.) to the humidification unit 108. The fluid flow proceeds from an outlet 106 of the pressurized gas source 102 to an inlet 110 of the humidification unit 108. In the illustrated configuration, the humidification unit 108 is shown separate from the pressurized gas source 102, with the inlet 110 of the humidification unit 108 connected to the outlet 106 of the pressurized gas source 102 by a conduit 112. In some implementations, the pressurized gas source 102 and the humidification unit 108 may be integrated into a single housing.

[0064] Although other types of humidification units may be used to obtain certain features, aspects, and advantages described in this disclosure, the illustrated humidification unit 108 is a pass-over humidifier that includes a humidification chamber 114 and an inlet 110 to the humidification chamber 114. In some implementations, the humidification chamber 114 includes a body 116 to which a base 118 is attached. A compartment may be defined within the humidification chamber 116, the compartment adapted to hold a volume of liquid that may be heated by heat transferred or provided through the base 118. In some implementations, the base 118 is adapted to contact a heater plate 120. The heater plate 120 may be controlled by a controller 122 or other suitable component to vary and control the heat transferred into the liquid.

[0065] The controller 122 of the humidification unit 108 can control the operation of the various components of the respiratory humidification system 100. Although the illustrated system is shown as using a single controller 122, multiple controllers can be used in other configurations. The multiple controllers can communicate or can provide separate functions, and thus the controllers do not need to communicate. In some implementations, the controller 122 can comprise a microprocessor, processing unit, or logic circuitry with associated memory or storage media that includes software code for a computer program. In such implementations, the controller 122 can control the operation of the respiratory humidification system 100 according to instructions contained in, for example, a computer program, and also in response to internal or external inputs. The controller 122, or at least one of the multiple controllers, can be located with the breathing circuit, attached to the breathing circuit, or incorporated as part of the breathing circuit.

[0066] The body 116 of the humidification chamber 114 includes a port 124 that defines an inlet 110 of the humidification chamber 114, and a port 126 that defines an outlet 128. When a liquid contained within the humidification chamber 114 is heated, liquid vapor is mixed with gas introduced into the humidification chamber 114 through the inlet port 124. The gas and vapor mixture exits the humidification chamber 114 through the outlet port 126.

[0067] The respiratory humidification system 100 includes a breathing circuit 200 with an inspiratory limb 202 connected to an outlet 128 that defines an outlet port 126 of the humidification unit 108. The inspiratory limb 202 carries the mixture of gas and water vapor exiting the humidification chamber 114 toward the user. The inspiratory limb 202 can include a heating element 206 positioned along the inspiratory limb 202 that is configured to reduce condensation along the inspiratory limb 202 to control the temperature of the gas reaching the user, maintain the humidity of the gas, or any combination thereof. The heating element 206 can increase or maintain the temperature of the mixture of gas and water vapor carried by the inspiratory limb 202. In some implementations, the heating element 206 can be a wire that defines a resistive heater. By increasing or maintaining the temperature of the mixture of gas and water vapor exiting the humidification chamber 114, water vapor is less likely to condense from the mixture.

[0068] The respiratory humidification system 100 may be used with an incubator 208. The incubator 208 may be configured to maintain a desired environment for a user, such as a selected, predetermined, or desired temperature, inside the incubator 208. Thus, inside the incubator 208, the internal ambient temperature may be different than the temperature outside the incubator 208. Thus, the incubator 208 generates, defines, creates, or maintains zones of different temperatures along the inspiratory limb 202, where the internal temperature is typically higher than the external temperature. Having at least two different temperature zones along the inspiratory limb 202 may create problems during delivery of gas to the user, such as condensation along the inspiratory limb 202, delivery of gas at too high a temperature, or both.

[0069] The respiratory humidification system 100 may include an expiratory limb 210 having an associated heating element 212. In some embodiments, the expiratory limb 210 and the inspiratory limb 202 may be connected using a suitable attachment (e.g., a Y-piece). In some embodiments, the respiratory humidification system 100 may be used with radiant warmers, under blankets, or other systems or situations that create two or more temperature zones. The systems and methods described herein may be used with such systems and are not limited to implementations incorporating incubators.

[0070] The inspiratory limb 202 can be divided into sections 202a and 202b, where the first section 202a can be the portion of the inspiratory limb 202 that is outside the incubator 208 and the second section 202b (e.g., an incubator extension) can be the portion of the inspiratory limb 202 that is inside the incubator 208. The first section 202a and the second section 202b can be of different lengths or the same length. In some embodiments, the second section 202b can be shorter than the first section 202a, and in certain implementations, the second section 202b can be about half the length of the first section 202a. The first section 202a can have a length of, for example, at least about 0.5 m and / or no more than about 2 m, at least about 0.7 m and / or no more than about 1.8 m, at least about 0.9 m and / or no more than about 1.5 m, or at least about 1 m and / or no more than about 1.2 m. The second section 202b can have a length of, for example, at least about 0.2 m and / or no more than about 1.5 m, at least about 0.3 m and / or no more than about 1 m, at least about 0.4 m and / or no more than about 0.8 m, or at least about 0.5 m and / or no more than about 0.7 m.

[0071] The inspiratory limb sections 202a, 202b can be coupled together to form a single gas delivery conduit. In some embodiments, the first section 202a can include one or more first heater wires 206a and one or more first sensors 204a, and can be used without the second section 202b. The controller 122 can be configured to control the first heater wires 206a and read the first sensor 204a even when the second section 202b is not coupled to the first section 202a. Additionally, when the second section 202b is coupled to the first section 202a, the controller 122 can be configured to control the first and second heater wires 206a, 206b in the respective sections and read the first and second sensors 204a, 204b. In some embodiments, the controller 122 can be configured to control the respective first and second heater wires 206a, 206b and read the respective first and second sensors 204a, 204b when the second section 202b is attached, and can be configured to control the first heater wire 206a and read the first sensor 204a when the second section 202b is not attached, without requiring modification of the controller 122 or the humidification unit 108. Thus, the same controller 122 and / or humidification unit 108 can be used regardless of whether the inspiratory limb 202 includes both the first and second sections 202a and 202b, or only the first section 202a. In some embodiments, the controller 122 can be further configured to control the heater wires 212 in the expiratory limb 210 without modification of the controller 122 or the humidification unit 108. Thus, the respiratory humidification system 100 can be operated with or without the second section 202b attached, and / or with or without the expiratory limb 210 attached.

[0072] In some embodiments, the first section 202a and the second section 202b are permanently joined together to form a single gas delivery conduit. As used herein, "permanently joined" means that the sections 202a, 202b are joined together such that it is difficult to separate them, for example, by using adhesives, friction fits, overmolding, mechanical connectors, etc. In some embodiments, the first section 202a and the second section 202b are configured to be releasably coupled. For example, the first section 202a can be used for gas delivery without the second section 202b, or the first section 202a and the second section 202b can be coupled together to form a single gas delivery conduit. In some embodiments, the first section 202a and the second section 202b can be configured to be coupled together in a unique configuration. For example, the first section 202a can have a predetermined chamber end (e.g., an end closest to the chamber 114 or the humidification unit 108 along the direction of flow of humidified gas to the patient) and a predetermined patient end (e.g., an end closest to the patient along the direction of flow of humidified gas to the patient), where the chamber end is configured to couple to components at the chamber 114 and / or the humidification unit 108. The second section 202b can have a predetermined chamber end and a predetermined patient end, where the chamber end is configured to couple only to the patient end of the first section 202a. The chamber end of the first section 202a can be configured not to couple to either end of the second section 202b. Similarly, the patient end of the first section 202a can be configured not to couple to the patient end of the second section 202b. Similarly, the patient end of the second section 202b can be configured not to couple to either end of the first section 202a. Thus, the first section 202a and the second section 202b may be configured to join in only one direction to form a single gas delivery conduit. In some embodiments, the first section 202a and the second section 202b can be configured to be coupled in various configurations. For example, the first section 202a and the second section 202b can be configured to not include a predetermined patient end and / or a predetermined chamber end. As another example, the first section 202a and the second section 202b can be configured such that the patient end and / or the chamber end of the first section 202a can be coupled to the chamber end or the patient end of the second section 202b. Similarly, the first section 202a and the second section 202b can be configured such that the chamber end and / or the patient end of the second section 202a can be coupled to the patient end or the chamber end of the second section 202b.

[0073] The respiratory humidification system 100 includes an intermediate connector 214 that can be configured to electrically couple elements of the first and second segments 202a and 202b of the inspiratory limb 202. The intermediate connector 214 can be configured to electrically couple the heater wires 206a of the first segment 202a to the heater wires 206b of the second segment 202b to enable control of the heater wires 206a, 206b with the controller 122. The intermediate connector 214 can be configured to electrically couple the second sensor 204b of the second segment 202b to the first sensor 204a of the first segment to enable the controller 122 to obtain the outputs of each of the sensors. The intermediate connector 214 can include electrical components that enable selective control of the heater wires 206a, 206b and / or selective reading of the sensors 204a, 204b. For example, the intermediate connector 214 may include electrical components that transmit power through the first heater wire 206a in a first mode and through the first and second heater wires 206a, 206b in a second mode. Electrical components included in the intermediate connector 214 may include, for example, but are not limited to, resistors, diodes, transistors, relays, rectifiers, switches, capacitors, inductors, integrated circuits, microcontrollers, microprocessors, RFID chips, wireless communication sensors, and the like. In some embodiments, the intermediate connector 214 may be configured within the inspiratory limb 202 such that it is substantially shielded from external elements (e.g., less than 1% of water, particulates, contaminants, and the like from the environment outside the inspiratory limb 202 contacts the intermediate connector 214). In some embodiments, some of the electrical components in the intermediate connector 214 may be configured to be physically isolated from the humidified gases within the inspiratory limb 202 to reduce or prevent damage that may occur due to exposure to moisture. In some embodiments, the intermediate connector 214 may include relatively inexpensive passive electrical components to reduce cost and / or increase reliability.

[0074] The inspiratory limb 202 may include sensors 204a, 204b in each section 202a, 202b of the inspiratory limb. The first sensor 204a may be positioned near the end of the first section 202a, near the incubator 208, such that a parameter derived from the first sensor 204a corresponds to a parameter of the humidified gas entering the second section 202b. The second sensor 204b may be positioned near the end of the second section 202b, such that a parameter derived from the second sensor 204b corresponds to a parameter of the humidified gas delivered to the patient or user. The output of the sensors 204a, 204b may be sent to the controller 122 as feedback for use in controlling the power delivered to the heating elements 206a, 206b of the inspiratory limb sections 202a, 202b. In some embodiments, one or both of the sensors 204a, 204b may be a temperature sensor, a humidity sensor, an oxygen sensor, a flow sensor, etc. The temperature sensor may be any suitable type of temperature sensor including, for example, without limitation, a thermistor, a thermocouple, a digital temperature sensor, a transistor, etc. Parameters provided by or derived from the sensor may include, for example, without limitation, temperature, humidity, oxygen content, flow rate, or any combination thereof, etc.

[0075] The controller 122 can be configured to control the heater wires 206a and 206b, receive feedback from the sensors 204a and 204b, provide logic for controlling power to the heater wires 206a and 206b, adjust control of the heater wires 206a and 206b in response to readings from the sensors 204a and 204b, detect the presence of a second segment 202b of the inspiratory limb 202 (e.g., the second segment 202b can have an identification element associated with the second segment 202b, such as a dedicated resistor or other element used specifically or primarily for identification purposes, or an inherent characteristic of the second segment can be used (e.g., a thermistor having a resistance within a predefined range)), derive parameters from readings from the sensors 204a and 204b, and the like. In some embodiments, the controller 122 includes a power source configured to send power to the heater wires. The power source can be an AC or DC power source. In some embodiments, the controller 122 can receive input from a heater plate sensor 130. The heater plate sensor 130 can provide the controller 122 with information regarding the temperature of the heater plate 120 and / or power usage. In some embodiments, the controller 122 can receive input from a flow sensor 132. Any suitable flow sensor 132 can be used, and the flow sensor 132 can be positioned between the ambient air and the humidification chamber 114 or between the pressurized gas source 102 and the humidification chamber 114. In the illustrated system, the flow sensor 132 is positioned at the inlet port 124 of the humidification chamber 114.

[0076] The detection of the presence of the second section can be used to modify the control of the device. For example, a control algorithm adapted to provide humidified gas to the infant in the incubator can be used. Applicable temperature profiles, values ​​and / or ranges can be used accordingly, and the flow rate and / or pressure of the delivered gas can be adjusted.

[0077] Breathing circuit hardware configuration FIG. 3 shows an exemplary diagram of a hardware configuration 800 for a breathing circuit 200 having a first section 202a of the inspiratory limb and a second section 202b of the inspiratory limb, which may include an expiratory limb (not shown) or expel exhaled gas to the atmosphere. The hardware configuration 800 may include a humidifier 108 configured to couple the wiring of the heater wire HW1 and the wiring for the sensor 204. In some embodiments, a sensor cartridge 802 may be configured to couple the wiring of the heater wire HW1 and the wiring for the sensor 204. The heater wire HW1 may be controlled in two modes. In a first mode, the first heater wire 206a receives power, but the second heater wire 206b does not receive power. In a second mode, the first and second heater wires 206a, 206b receive power.

[0078] The hardware configuration 800 can include an intermediate printed circuit board (PCB) 214 that includes a power diode D1. The intermediate PCB 214 can include a heat pad to dissipate heat generated by the diode D1 and reduce its effect on the sensor 204. The hardware configuration 800 can include a patient-end PCB 804 having two heater wires and one sensor 204, with the heater wire 206b electrically coupled directly. In a first mode of operation, power may be provided to HW1 such that current flows through heater wire 206a and diode D1 while substantially no current flows through heater wire 206b (e.g., less than 1% of the current through heater wire 206a flows through heater wire 206b). In a second mode of operation, power may be provided to HW1 such that current flows through heater wires 206a and 206b. The first and second modes of operation may be controlled at least in part by the direction of current through heater wire HW1.

[0079] In some embodiments, the sensor cartridge 802 can be located internal to the humidification system 100 or external to the system.

[0080] 4 shows an exemplary diagram of a hardware configuration 900 for the inspiratory limb 6 of the respiratory system 1, which may include an expiratory limb (not shown) or vent exhaled gases to the atmosphere. The hardware configuration 900 may include a humidifier 4 configured to couple the wiring of the heater wire HW1 and the wiring for the sensor 204. In some embodiments, the sensor cartridge 802 may be configured to couple the wiring of the heater wire HW1 and the wiring for the sensor 204.

[0081] The hardware configuration 900 can include a patient-end PCB 804 having two heater wires and a sensor 204, to which the heater wire 206 is electrically directly coupled. Power can be provided to HW1 such that current flows through the heater wire 206 and generates heat.

[0082] Other configurations, including embodiments in which the expiratory limb is heated and / or in which one or more additional sensors are provided, can be derived from PCT / NZ2013 / 00208 without the exercise of inventive invention, but implementing the novel sensor reading control disclosed in this specification.

[0083] The embodiment of the system shown in Figures 1-4 may include a sinusoidal pulse width modulation (SPWM) driver that provides for switching on or off a heater plate and heater wire, e.g., heater wire HW1 of the intake line, for heating the contents of the humidification chamber. The driver may, for example, provide two 100-bit patterns, one for the heater plate and one for the heater wire. Each bit in the bit pattern may cause the SPWM driver to switch a respective heater on or off. Switching may occur at each falling zero crossing of the voltage of the mains supply to reduce stress on the power supply that would be caused by an abrupt transition from zero power to a maximum power level. The choice of falling or rising edge is somewhat arbitrary; what is important is that switching occurs at a zero crossing once every full AC cycle. Thus, the heater can be switched on or off 50 times per second (every 20 ms) or 60 times per second (every 16.67 ms) for 50 Hz and 60 Hz mains respectively. This is useful because the sensor (e.g., patient end thermistor) measurement cycle can be aligned with the mains cycle, and the mains and heater wire cycles are already aligned.

[0084] FIG. 5 is a chart showing the relationship between mains AC cycles and heater wire cycles for the heater wire depicted in FIGS.

[0085] Figure 6 is a chart depicting sensor measurements against the mains voltage waveform. Various set-up steps can be taken to prepare for a sensor reading, including switching the polarity of the sense wires to positive when the falling zero crossing occurs in the mains cycle. A measurement is taken and the polarity of the sense wires is reversed when the rising zero occurs in the mains cycle. The falling zero crossing and frequency can be detected by analysing the mains voltage in anticipation of the rising zero crossing.

[0086] conclusion Several examples of respiratory humidification systems and methods with sensor reading control and related components have been described with reference to the figures. The figures show various systems and modules and connections between them. The various modules and systems can be combined in various configurations, and the connections between the various modules and systems can represent physical or logical links. The representations in the figures are presented to clearly show the principles associated with providing sensor reading control. Details regarding the division of modules or systems are provided for ease of explanation without attempting to define individual physical embodiments. The examples and figures are intended to illustrate, but not limit, the scope of the inventions described herein. For example, the principles herein can be applied to respiratory humidifiers, as well as other types of humidification systems, including surgical humidifiers. The principles herein can be applied in respiratory applications, as well as other scenarios in which the temperature of a gas is controlled along multiple sections exposed to different ambient temperatures.

[0087] As used herein, the term "processing unit" broadly refers to any suitable device, logic block, module, circuit, or combination of elements for executing instructions. For example, a control unit herein may include any conventional general-purpose single-chip or multi-chip microprocessor, such as a Pentium® processor, a MIPS® processor, a PowerPC® processor, an AMD® processor, an ARM® processor, or an ALPHA® processor. Additionally, the controller may include any conventional dedicated microprocessor, such as a digital signal processor or a microcontroller. The various exemplary logic blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed using general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein, or may be pure software within a main processor. For example, logic module 504 may be a software implemented functional block that does not utilize additional and / or specialized hardware elements. The controller may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a combination of a microcontroller and a microprocessor, multiple microprocessors, one or more microprocessors associated with a DSP core, or any other such configuration.

[0088] A data storage device may represent electronic circuitry that allows a processing device to store and retrieve data. A data storage device may represent an external device or system, such as a disk drive or solid-state drive. A data storage device may also represent high-speed semiconductor memory devices (chips), such as random access memory (RAM) or various forms of read-only memory (ROM), which are connected directly to a communication bus or to a control device. Other types of data storage devices include bubble memory and core memory. A data storage device may be physical hardware configured to store data in a non-transitory medium.

[0089] Although specific embodiments and examples are disclosed herein, the subject matter of the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and / or applications, as well as modifications and equivalents thereof. Thus, the scope of the claims or embodiments appended hereto is not limited by any of the specific embodiments described herein. For example, in any method or process disclosed herein, the acts or operations of the method or process can be performed in any suitable order and are not necessarily limited to any particular disclosed order. Various operations may be described in sequence as multiple separate operations, which may aid in understanding a particular embodiment. However, the order of description should not be construed to imply that these operations are ordered. Furthermore, structures described herein may be embodied as integrated components or as separate components. In order to compare various embodiments, specific aspects and advantages of these embodiments are described. Not all such aspects or advantages are necessarily realized by any particular embodiment. Thus, for example, various embodiments may be implemented to achieve or optimize one advantage or combination of advantages taught herein, without necessarily achieving other aspects or advantages that may also be taught or suggested herein.

[0090] As used herein, conditional expressions, such as "can," "may," "for example," and the like, among others, are generally intended to indicate that a particular embodiment includes a particular feature, element, and / or condition and that other embodiments do not include the particular feature, element, and / or condition, unless otherwise specified or contradicted by the context in which it is used. Thus, such conditional expressions are generally not intended to imply that a feature, element, and / or condition is essential to one or more embodiments. As used herein, the terms "comprise," "include," "have," or any other variant thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that includes a list of elements is not necessarily limited to only those elements, but may include other elements not expressly listed or that are inherent to such process, method, article, or apparatus. Additionally, the term "or" is used in its inclusive sense (rather than its exclusive sense), and thus, for example, when used to join a list of elements, the term "or" means one, some, or all of the elements in the list. Disjunctive phrases such as "at least one of X, Y, and Z" generally indicate that an element, term, etc. may be X, Y, or Z, unless otherwise stated or contradicted by the context in which it is used. Thus, such disjunctive phrases are not intended to suggest that at least one of X, at least one of Y, and at least one of Z, respectively, must be present in a particular embodiment. As used herein, the words "about" or "approximately" can mean that a value is within ±10%, within ±5%, or within ±1% of the specified value.

[0091] The methods and processes described herein may be embodied in software code modules executed by one or more general-purpose and / or special-purpose computers and may be partially or fully automated by such software code modules. The term "module" refers to logic embodied in hardware and / or software, or to a collection of software instructions, which may have entry and exit points, written in a programming language, such as, for example, C or C++. Software modules may be compiled and linked into executable programs installed in a dynamically linked library, or may be written in an interpreted programming language, such as, for example, BASIC, Perl, or Python. It is understood that software modules may be callable from other modules or themselves, and / or may be called in response to a detected event or interrupt. Software instructions may be embedded in firmware, such as an erasable programmable read-only memory (EPROM). Hardware modules may include connected logic units, such as gates and flip-flops, and / or may include programmable units, such as programmable gate arrays, application specific integrated circuits, and / or processing units. The modules described herein may be implemented as software modules, but may also be represented in hardware and / or firmware. Further, in some embodiments, the modules may be separately compiled, while in other embodiments, the modules may represent a subset of a separately compiled program's instructions and may not have an interface available to other logical program units.

[0092] In particular embodiments, the code modules may be implemented and / or stored on any type of computer readable medium or other computer storage device. In some systems, data (and / or metadata) input to the system, data generated by the system, and / or data used by the system may be stored in any type of computer data repository, such as a relational database and / or a flat file system. Any of the systems, methods, and processes described herein may include an interface configured to enable interaction with a user, operator, other systems, components, programs, etc.

[0093] It is emphasized that many variations and modifications can be made to the embodiments described herein, and that these elements should be understood to be included in other acceptable embodiments. All such modifications and variations are intended to be within the scope of this disclosure and protected by the accompanying claims. Moreover, nothing in the above disclosure is intended to imply that any particular component, feature, or process step is required or essential.

Claims

1. 1. A control device for a respiratory assistance device, comprising:

13. The respiratory assistance apparatus comprising a conduit for transmitting gas therethrough, the conduit comprising a circuit, the circuit comprising at least one heater wire portion for heating gas in the conduit during use, and at least one sensor wire portion comprising at least two sensors for monitoring parameters of the gas in the conduit during use, The control device includes: controlling the provision of an AC power waveform to the at least one heater wire; controlling selective reading of the at least two sensors; The device is configured to: the controller is configured to read the at least two sensors at or about a particular portion of the AC power waveform supplied to the heater wires; The controller is configured to adjust delivery of the AC power waveform to the at least one heater wire section based on readings of the at least two sensors.

2. the controller is configured to control reading of a first of the at least two sensors to begin at, about, or after a first zero crossing of the AC power waveform and to end at or before a subsequent second zero crossing of the AC power waveform, the first and second zero crossings being consecutive zero crossings of the same type, the type of zero crossing being a rising zero crossing or a falling zero crossing; 2. The controller of claim 1, wherein the controller is configured to control reading of a second of the at least two sensors to begin at, around, or after a third zero crossing of the AC power waveform and end at or before a fourth zero crossing of the AC power waveform, the first, second, third and fourth zero crossings being consecutive zero crossings of the same type.

3. the controller is configured to control reading of a first of the at least two sensors to begin at, around, or after a first particular portion of the AC power waveform and to control reading of a second of the at least two sensors to begin at a second particular portion of the AC power waveform; The control device according to claim 1 , wherein the first specific portion and the second specific portion are consecutive specific portions.

4. 4. The controller of claim 1, wherein the controller is configured to control application of an AC power waveform to the at least one heater wire section such that the AC power waveform applied to the at least one heater wire section transitions from a flat portion to a negative half cycle of a full cycle of a main AC waveform.

5. 5. The controller of claim 1, wherein the controller is configured to control application of an AC power waveform to the at least one heater wire section such that the AC power waveform applied to the at least one heater wire section transitions from a positive half-cycle to a flat portion of a full cycle of a main AC waveform.

6. the at least one heater wire portion includes first and second heater wire portions; 6. The controller of claim 1, wherein the controller is configured to control selective application of the AC power waveform to only the first heater wire section during a first time period and to control selective application of the AC power waveform to both the first and second heater wire sections or only the second heater wire section during a second time period.

7. 7. The controller of claim 6, wherein the controller is adapted to control application of the AC power waveform to a first of the heater wire sections such that the AC power waveform transitions from a flat portion to a first of two positive half cycles of a mains AC waveform or two negative half cycles of a mains AC waveform.

8. 7. The controller of claim 6, wherein the controller is adapted to control application of the AC power waveform to the first of the heater wires such that the AC power waveform transitions to a flat portion following two positive half cycles or two negative half cycles of a mains AC waveform.

9. 9. The controller of claim 6, wherein the controller is adapted to control application of the AC power waveform to the second heater wire section such that the AC power waveform transitions from a flat portion to a first of two positive half cycles of a mains AC waveform or two negative half cycles of a mains AC waveform.

10. 9. The controller of claim 6, wherein the controller is adapted to control application of the AC power waveform to the second heater wire section such that the AC power waveform transitions to a flat portion following two positive half cycles or two negative half cycles of a mains AC waveform.

11. A control device according to claim 1 , wherein at least a portion of the at least one sensor wire portion is disposed adjacent to at least a corresponding portion of the at least one heater wire portion.

12. 12. The controller of claim 1, wherein the controller is configured to control a current flow direction of the AC power waveform through the at least one heater wire section and / or a voltage polarity of the AC power waveform through the at least one heater wire section.

13. A control device according to claim 1 , wherein the control device is configured to receive signals from the at least two sensors in parallel.

14. A control device as claimed in any preceding claim, wherein the conduit includes an additional section.

15. The control device of claim 14 , wherein the conduit includes a first section and a second section, the first section and the second section being integral or configured to be mechanically coupled.

16. The control device of claim 15 , wherein the first section includes at least one of the at least two sensors and the second section includes at least one of the at least two sensors.

17. The control device of claim 16 , wherein the at least two sensors are positioned near ends of the first section and the second section.

18. The control device of claim 17 , wherein the at least two sensors are disposed at patient ends of the first and second sections.

19. The control device of claim 1 , wherein the conduit comprises an inspiratory limb.

20. The control device of claim 1 , wherein the at least two sensors include one or more of a temperature sensor, a humidity sensor, an oxygen sensor, and a flow sensor.

21. 21. The control device of claim 1, further comprising a multiplexer coupled to the at least one sensor wire portion to enable reading of the at least two corresponding sensors.

22. The control device of claim 1 , wherein the at least two sensors are configured to measure at least one similar parameter.

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