Patent Grant
11511069
1. Field of the Disclosure
The present disclosure generally relates to humidification systems for providing humidified gases to patients. More particularly, certain features, aspects and advantages of the present disclosure relate to features that improve the performance of such humidification systems.
2. Description of the Related Art
Gas humidification systems deliver heated and humidified gases for various medical procedures, including respiratory treatment, laparoscopy, and the like. While a variety of such systems have been developed, further improvements of such systems are desired.
One aspect of the present disclosure involves a heater base for supplying humidified gases to a patient or user. The heater base comprises a base portion. The base portion comprises a recessed region. A heater plate is positioned in the recessed region. The heater plate is configured to contact a heat conductive portion of a removable humidification chamber. A guard is configured to control movement of the removable humidification chamber into and out of the recessed region. The guard has a first end and a second end. An anti-racking mechanism cooperates with the guard to cause vertical movement of the first end to translate into coordinated vertical movement of the second end.
In some configurations, the anti-racking mechanism comprises an elongated rod-like member that connects to the first end of the guard and to the second end of the guard.
In some configurations, the elongated rod-like member extends between a first arm and a second arm with the first arm being connected to the first end of the guard and the second arm being connected to the second end of the guard.
In some configurations, the guard comprises a first post near the first end of the guard and a second post near the second end of the guard. The first arm is connected to the first post and the second arm is connected to the second post.
In some configurations, a biasing member is disposed between the guard and another portion of the heater base.
In some configurations, the biasing member comprises at least one compression spring that is mounted between the guard and the another portion of the heater base.
In some configurations, the guard comprises a first support and a second support and the at least one compression spring comprises a first compression spring mounted to the first support and a second compression spring mounted to the second support.
One aspect of the present disclosure involves a chamber for use with a heater base of a humidification system. The chamber comprises an outer wall. An upper wall is connected to the outer wall. The outer wall and the upper wall at least partially define a chamber. An inlet port defines an opening into the chamber through the upper wall. The inlet port has a downward extension that extends below the upper wall into the cavity such that a recess is defined among the downward extension, the upper wall and the outer wall. A baffle is disposed at a lower end of the downward extension.
In some configurations, the baffle extends downward and outward from the lower end of the downward extension such that the baffle directs airflow outward toward the outer wall.
In some configurations, a float is positioned within the cavity and a removable float retainer is configured to extend into the chamber, alongside of the baffle, such that the float retainer can secure the float against movement.
In some configurations, a float is positioned within the cavity. The float comprises a lower surface designed to direct airflow.
In some configurations, the lower surface comprises a recess.
In some configurations, the lower surface comprises a ridge.
In some configurations, the chamber also comprises an outlet port, the outlet port tapering such that at least a portion of the outlet port has a smaller cross-sectional area than an entrance into the outlet port from within the chamber.
Another aspect of the present disclosure involves a conduit hanging end cap for use with a breathing conduit component. The conduit hanging end cap comprises a body configured to be inserted into the conduit component. The body comprises a first end and a second end. The body also comprises a plurality of outer frustoconical tapers positioned between the first end and the second end. A flange extends from the first end of the body. The flange has an outer perimeter that is non-circular and that extends radially outward of a largest portion of the frustoconical tapers.
In some configurations, each of the frustoconical tapers has a widest portion. The flange is closest to the widest part of at least one of the frustoconical tapers compared to the rest of that frustoconical taper.
In some configurations, the conduit hanging end cap further comprises a hanging component extending from the flange.
In some configurations, the hanging component is a loop that extends away from the flange in a direction opposite to the body.
In some configurations, the hanging component comprises a closed loop.
In some configurations, the flange comprises a hexagonal shape.
In some configurations, the end cap is formed of a material that is soft or pliant enough to not cause material damage to a connector of a conduit after connection of the end cap and the connector.
Another aspect of the present disclosure involves a humidification system for humidifying respiratory gases provided to a patient. The humidification system comprises a heater plate. A base supports the heater plate and is configured to receive a removable chamber configured to hold a liquid. One or more springs apply an upward force to the heater plate and urge the heater plate into contact with the removable chamber. The one or more springs are preloaded so that, when the chamber is inserted into the base, the heater plate is required to travel less than 3 mm without diminishing the upward force exerted by the springs on the heater plate.
In some configurations, the upward force is 30-40 Newtons (N).
In some configurations, the upward force is 36-40 Newtons (N).
In some configurations, the upward force is about 35 Newtons (N).
In some configurations, the system further comprises a spring assembly.
In some configurations, the spring assembly comprises a first spring assembly platform supporting a base of the spring; and a screw secured to and extending downward from the bottom of the heater plate. A body of the screw passes through an opening of the first spring assembly platform and a head of the screw is below the first spring assembly platform, wherein the opening of the first spring assembly platform is large enough to allow the screw body to pass through the opening without resistance but not large enough to allow the screw head to pass through the opening.
In some configurations, the spring assembly comprises a spring preloading assembly.
In some configurations, the spring preloading assembly comprises a second spring assembly platform located below the first spring assembly platform. The second spring assembly platform includes an opening is large enough to allow the screw body to pass through the opening without resistance but not large enough to allow the screw head to pass through the opening.
In some configurations, the one or more springs are preloaded so that when the chamber is inserted into the base, the heater plate is required to travel less than 2 mm without diminishing the upward force exerted by the springs on the heater plate.
In some configurations, the one or more springs are preloaded so that when the chamber is inserted into the base, the heater plate is required to travel less than 1 mm without diminishing the upward force exerted by the springs on the heater plate.
In some configurations, the one or more springs are preloaded so that, when the chamber is inserted into the base, the heater plate is required to travel less than 1 mm without diminishing the upward force exerted by the springs on the heater plate.
Another aspect of the present disclosure involves a heater base for supplying humidified gases to a patient. The heater base comprises a heater plate. A spring assembly supports the heater plate. A chamber receiving assembly is configured to receive a removable chamber configured to hold liquid. A base assembly supports the spring assembly and the chamber receiving assembly with the base assembly including at least one egress hole.
In some configurations, the at least one egress hole is configured to allow liquid which falls from the chamber receiving assembly or removable chamber to drain from the base assembly when the base assembly is placed at a tile angle of between 0 and 20 degrees.
In some configurations, the at least one egress hole is at least partially semicircular.
In some configurations, the at least one egress hole located under an edge of the heater plate.
In some configurations, the heater base comprises a second egress hole.
In some configurations, the heater base comprises a third egress hole.
In some configurations, the first, second and third egress holes are placed around a circumference under the heater plate assembly to allow liquid to drain from any tilt direction.
A further aspect of the present disclosure involves a heating assembly in a humidification system. The heating assembly comprises a heating plate. An at least partially flat filament is configured to heat the heating plate.
In some configurations, the at least partially flat filament is configured to be wound around a non-conductive core.
In some configurations, the non-conductive core is flat so that when the at least partially flat filament is would around the non-conductive core the combination of the filament and core forms a flat heating element.
In some configurations, the at least partially flat filament provides higher heating power at lower temperatures than an equivalent round filament.
In some configurations, the heating assembly is configured to heat 80 liters of liquid per minute (Lpm) at 37 degrees Celsius.
In some configurations, the heating assembly is configured to heat 120 liters of liquid per minute (Lpm) at 31 degrees Celsius.
In some configurations, the heating assembly further comprises at least one insulation layer between the at least partially flat filament and the heating plate.
In some configurations, the heating assembly further comprises at least two insulation layers between the at least partially flat filament and the heating plate.
Another aspect of the present disclosure involves a method of controlling a respiratory humidification system. The method comprises monitoring temperature at an outlet port of a chamber; determining whether the outlet port temperature has increased by more than a predetermined amount within a predetermined period of time; and beginning a second procedure if the outlet port temperature has increased by more than the predetermined amount within the predetermined period of time.
In some configurations, the predetermined amount is at least 2° C. and the predetermined period of time is at least 30 seconds.
In some configurations, the method further comprises determining whether a temperature at an inlet port of the chamber is higher than the temperature at the outlet port of the chamber by more than a predetermined amount.
In some configurations, the method further comprises determining whether a temperature at a patient-end of a conduit is lower than the temperature at the outlet port of the chamber by more than a predetermined amount.
In some configurations, the method further comprises monitoring a flow rate of gases and determining whether a decrease in flow rate greater than a predetermined amount has occurred over a predetermined period of time.
In some configurations, the flow rate is monitored by taking instantaneous measurements of flow rate.
In some configurations, time-averaged measurements are used to monitor the flow rate.
In some configurations, the method further comprises testing whether the flow rate has dropped from a flow rate exceeding a first flow rate value to a flow rate below a second flow rate value if it has been determined that the decrease in flow rate has been greater than the predetermined amount over the predetermined period of time.
In some configurations, the method further comprises monitoring a temperature at a patient end of an inspiratory conduit and determining if the temperature decreases by more than a predetermined temperature over a predetermined period of time and, if the temperature decreases by more than the predetermined temperature over a predetermined period of time, beginning a second procedure.
In some configurations, the second procedure is a cool down mode.
Another aspect of the present disclosure involves a method of controlling a respiratory humidification system to deliver a flow of gases to a patient. The method comprises setting a target dew point for the flow of gases within an inspiratory conduit; setting a target temperature for the flow of gases at a patient-end of the inspiratory conduit; during a first phase, energizing a heater plate to achieve the target dew point at a first time after start of the first phase; and, during a second phase after the first phase, energizing the heater plate to achieve the targeted temperature at a second time after start of the second phase.
In some configurations, the first time is at least 5 minutes and less than or equal to 40 minutes.
In some configurations, the second time is less than or equal to 1.5 hours after the start of the first phase.
In some configurations, the method further comprises monitoring a gas temperature at a chamber outlet of the respiratory humidification system.
In some configurations, the method further comprises estimating a dew point of the flow of gases based at least in part on the gas temperature at the chamber outlet.
In some configurations, the target temperature changes as a function of time, having a first target temperature at the first time and a second target temperature at the second time.
In some configurations, the target temperature increases from the first target temperature to the second target temperature during the second phase.
In some configurations, the method further comprises setting a targeted chamber outlet set point that changes over time during the first phase to achieve a targeted humidity.
In some configurations, the targeted humidity is at least about 0.5 mg/L.
In some configurations, the targeted chamber outlet set point is at least 24° C. and less than or equal to 35° C.
Another aspect of the present disclosure involves a respiratory humidification system configured to deliver a flow of gases to a patient. The humidification system comprises a chamber. A heater plate is configured to provide heat to the chamber. The chamber includes a chamber outlet and an inspiratory conduit is configured to couple to the chamber outlet to deliver humidified gas from the chamber to the patient. A controller is configured to control power delivered to the heater plate. The controller is configured to set a target dew point for the flow of gases within the inspiratory conduit; set a target temperature for the flow of gases at a patient-end of the inspiratory conduit; during a first phase, energize the heater plate to achieve the target dew point at a first time after start of the first phase; and during a second phase after the first phase, energize the heater plate to achieve the targeted temperature at a second time after start of the second phase.
In some configurations, the first time is at least 5 minutes and less than or equal to 40 minutes.
In some configurations, the second time is less than or equal to 1.5 hours after the start of the first phase.
In some configurations, the system further comprises a gas temperature probe positioned at the chamber outlet with the gas temperature probe configured to provide an indication of a gas temperature of the flow of gases to the controller.
In some configurations, the controller is further configured to estimate a dew point of the flow of gases based at least in part on the indication of the gas temperature at the chamber outlet.
In some configurations, the target temperature changes as a function of time, having a first target temperature at the first time and a second target temperature at the second time.
In some configurations, the target temperature increases from the first target temperature to the second target temperature during the second phase.
In some configurations, the controller is further configured to set a targeted chamber outlet set point that changes over time during the first phase to achieve a targeted humidity.
In some configurations, the targeted humidity is at least about 0.5 mg/L.
In some configurations, the targeted chamber outlet set point is at least 24° C. and less than or equal to 35° C.
Another aspect of the present disclosure involves a respiratory humidification system configured to deliver a flow of gases to a patient. The humidification system comprises a humidification body comprising a display with a user interface and a chamber. A heater plate is configured to provide heat to the chamber. A chamber outlet is provided and an inspiratory conduit is configured to couple to the chamber outlet to deliver humidified gas from the chamber to the patient, the inspiratory conduit comprising an identification component. A controller is configured to control power delivered to the heater plate based at least in part on a control algorithm. When coupled to the chamber, the controller receives a signal associated with the identification component, and based at least in part on the signal associated with the identification component, selects a suitable control algorithm.
In some configurations, the controller selects a suitable user interface based at least in part on the signal associated with the identification component.
In some configurations, the identification component comprises an ID resistor.
In some configurations, the controller is configured to limit operational capabilities if the signal associated with the identification component indicates that the inspiratory conduit is for use in an infant mode.
In some configurations, the system further comprises a cartridge associated with the inspiratory conduit, with the identification component positioned within the cartridge.
In some configurations, the inspiratory conduit comprises a segmented inspiratory conduit with a plurality of heaters associated with each segment of the inspiratory conduit.
In some configurations, the controller is further configured to control power to the plurality of heaters.
For purposes of summarizing the disclosure and the advantages achieved over the prior art, certain objects and advantages are described herein. Of course, it is to be understood that not necessarily all such objects or advantages need to be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught or suggested herein without necessarily achieving other objects or advantages as may be taught or suggested herein. All of these embodiments are intended to be within the scope of the disclosure herein. These and other embodiments will become readily apparent to those skilled in the art from the following detailed description having reference to the attached figures, the disclosure not being limited to any particular disclosed embodiment(s).
These and other features, aspects and advantages of the present disclosure will be described with reference to the following drawings, which are illustrative but should not be limiting of the present disclosure.
Although certain embodiments and examples are described below, those of skill in the art will appreciate that the disclosure extends beyond the specifically disclosed embodiments and/or uses and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the disclosure herein should not be limited by any particular embodiments described below.
Various features as described herein can help control the system and increase the likelihood of the patient receiving gases having desired conditions. The features described herein can be used individually or in various combinations and subcombinations in existing humidification systems and/or in improved systems for respiratory humidification, laparoscopy, and other purposes.
Humidification System
An example embodiment of the humidification system 100 can include a heater base 102 and a humidification chamber 104. The heater base 102 can comprise a heater plate 108. The humidification chamber 104 can be configured to hold a volume of a liquid, such as water. The heater plate 108 can be configured to heat the volume of liquid held within the humidification chamber 104.
The humidification system 100 also can include a gases supply 125. In some configurations, the gases supply 125 can comprise a ventilator or any other suitable source of pressurized gases suitable for breathing or for use in medical procedures. The gases supply 125 can be separate from or combined with the heater base 102.
In some configurations, the humidification system 100 also can include a breathing circuit or breathing circuit assembly 123. One or more of the components of the breathing circuit assembly 123 can be separable from, permanently coupled to or user-fitted to the chamber 104. The breathing circuit assembly 123 can include an inspiratory conduit 120. A chamber end of the inspiratory conduit 120 can be configured to connect to an outlet port 412 of the chamber 104. A patient end of the inspiratory conduit 120 can be configured to connect to the patient, for example, via an interface 128 (for example, nasal cannula, nasal pillows, full face mask, oral-nasal mask, etc.). In some configurations, the inspiratory conduit 120 can be coupled directly to the interface 128.
In some configurations, for example, in configurations in which the gases supply 125 is separate from the heater base 102, the breathing circuit assembly 123 can include a supply conduit 132. A gases supply end of the supply conduit 132 can be configured to connect to an output of the gases supply 125. A chamber end of the supply conduit 132 can be configured to connect to an inlet port 410 of the chamber 104.
In some configurations, such as those used with a ventilator as the gases supply 125, the breathing circuit assembly 123 also can include an expiratory conduit 122. A patient end of the expiratory conduit 122 can be configured to connect to the interface 128. A gases supply end of the expiratory conduit 122 can be configured to connect to a return of the gases supply 125.
In some embodiments, for example as shown in
In some configurations, the Y-piece 124 can incorporate structures, coatings or the like to manage condensate. In some configurations, the structures can include microstructures. Interaction between liquids and surfaces including purpose-built microstructures can result in spreading of the liquid onto the surface and inside or on the microstructures. This interaction was further discovered to increase the liquid-vapor interface area and reduce the thickness of the liquid layer on top of the surface. The combination of increased surface area and reduced thickness improve liquid evaporation, compared to liquid of the same volume on a flat surface. As discussed below, the combination of increased surface area, reduced thickness, and heating further improves liquid evaporation.
Accordingly, in various embodiments, at least a portion of the inner walls of the Y-piece 124 can comprise microstructures 301, as shown in
Polymers generally have a low surface energy, resulting in poor wettability. In order to improve the liquid spreading capabilities of the microstructures 301 on the Y-piece 124 or other components of the humidification system 100, it can be advantageous to treat the one or more polymers with a material or materials for increasing the surface energy. Surfactants, such as cationic surfactants, can be particularly desirable additive materials. Suitable surface modifying agents include glycerol monostearate (GMS), ethoxylated amine, alkanesulphonate sodium salt, lauric diethanolamide, and additives comprising these substances. MLDNA-418 supplied by Clariant (New Zealand) Ltd. and under the product name “418 LD Masterbatch Antistatic” is a surface modification agent master batch with 5(±0.25)% glycerol monostearate (CAS No. 123-94-4) as an active ingredient. In extruded components, the surface modifying agent can comprise at least about 0.05 (or about 0.05), 0.1 (or about 0.1), 0.15 (or about 0.15), 0.2 (or about 0.2), 0.25 (or about 0.25), 0.3 (or about 0.3), 0.35 (or about 0.35), 0.4 (or about 0.4), 0.45 (or about 0.45), 0.5 (or about 0.5), 1.1 (or about 1.1), 1.2 (or about 1.2), 1.3 (or about 1.3), 1.4 (or about 1.4), or 1.5 (or about 1.5) wt. % of the total extrudate. For example, in at least one embodiment, a tube extrudate comprises 0.25 wt. % (or about 0.25 wt. %) of surface modifying agent. As another example, in at least one embodiment, the tube extrudate comprises 0.5 wt. % (or about 0.5 wt. %) of surface modifying agent.
Other methods can also be used to increase surface energy. Suitable methods include physical, chemical, and radiation methods. Physical methods include, for example, physical adsorption and Langmuir-Blodgett films. Chemical methods include oxidation by strong acids, ozone treatment, chemisorption, and flame treatment. Radiation methods include plasma (glow discharge), corona discharge, photo-activation (UV), laser, ion beam, electron beam, and gamma irradiation.
By selecting a suitable surface modification method or agent, it is possible to provide a tube wall or other formed component having surface property contact angles of less than 50 (or about 50), 45 (or about 45), 40 (or about 40), 35 (or about 35), 30 (or about 30), 25 (or about 25), 20 (or about 20) degrees)(°, as measurable by an angle measurement device such as a goniometer. For instance, tube walls having surface property contact angles of less than 35° (or about 35°) provide useful results. Desirably, the contact angle is less than π/2 (or about π/2). More desirably, the contact angle is 0° or about 0°.
TABLE 1 below shows contact angle measurements for various LLDPE samples, including a sample treated with a surface-modifying agent and a sample treated with radiation. The contact angle measurements were based on static drop shape testing methods conducted in accordance with ASTM Standard D7334, 2008, “Standard Practice for Surface Wettability of Coatings, Substrates and Pigments by Advancing Contact Angle Measurement.”
The sample with 5% MLDNA-418 surface modifying agent produced the lowest measured contact angle compared to other surface modification methods tested.
As discussed above, in certain embodiments, the additive material is added to the bulk polymer extrudate. It can be desirable to add the material in the polymer matrix so that the additive material replenishes the surface for the useful life of the tube or other component. In certain configurations, the material can be added as a surface treatment on the polymer, for example, by coating a surface of the polymer with the material. For example, a microstructured surface can be brushed, sprayed, or otherwise coated with additive material such as HYDRON anti-fog coating (MXL Industries, Lancaster, Pa.), EXXENE anti-form coatings such as HCAF-100 (Exxene Corporation, Corpus Christi, Tex.), and MAKROLON anti-fog (Bayer Corporation) to produce a thin (for example, 1 μm or thereabout) coating of additive material. A surface coating can be desirable because of low costs and ease of manufacture.
In certain configurations, a thin film of hydrophilic material such as breathable polyurethanes, for example, ESTANE 58245 (Lubrizol Corporation, Wickliffe, Ohio), breathable polyesters, for example, ARNITEL VT3108 (DSM Engineering Plastics, Sittard, Netherlands), or breathable polyamides, for example PEBAX (Arkema, Colombes, France) can be cast as a surface modifying agent. These hydrophilic materials can absorb moisture and become very wettable. An example method of implementing the hydrophilic thin film includes dissolving the breathable polymer in a solvent, casting the mixture, and allowing the solvent to evaporate, thus leaving a thin film of the breathable material on the microstructures. For instance, ESTANE 58245 pellets can be dissolved in a tetrahydrofuran (THF) of dimethylformamide (DMF) solvent and cast onto microstructures machined from brass or aluminum using a micromilling process. Typical dimensions for the thin film are in the range of 1 to 10 μm (or about 1 to 10 μm). Preferably, the solvent, breathable material, and microstructure material combination is selected such that the microstructure shape and quality is not substantially influenced, for example, by dissolving the microstructures with the solvent.
Preferably the surface modification agent comprises at least about 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 1.1, 1.2, 1.3, 1.4, or 1.5 weight percent (wt. %) of the total extrudate. More preferably the surface modification agent comprises about 0.25 wt. % of the total extrudate. Alternatively preferably the surface modification agent comprises about 0.5 wt. % of the total extrudate.
The contact angle is the angle formed by the solid surface of the component or tube wall and the tangent line to the upper surface at the end point of a liquid droplet. Contact angle measurement is a non-destructive method of determining the wetting behavior of liquids on a solid surface. It enables the calculation of surface and interfacial tension along with spreading coefficients. The surface tension calculated from the contact angle data are a characteristic measurement for the respective surface and fluid system.
The contact angle between a liquid and a surface can be measured using a goniometer (angle measurement device). A precise volume of the liquid is dispensed on the cleaned and dried flat test surface using a precision syringe. The droplet is allowed to stabilize for a few seconds and a high magnification camera is used to capture the image of the droplet. The image is digitised and the angle between the test surface and the tangent line along the droplet surface is measured.
Reducing contact angle increases contact area between the droplet and solid surface, and also reduces droplet thickness, enhancing heat conduction through the droplet. Both effects increase droplet evaporation rate.
Increasing the energy of a surface reduces the contact angle of a droplet placed on the surface. In this manner, a droplet of liquid on the surface of a higher energy surface can preferentially have a greater surface area in contact with the surface, than a surface of relatively lower energy.
Advantageously, the droplet may be spread across a larger surface area of the surface and, therefore, be more likely to re-evaporate into the gas stream flowing through the component or tube. For example, the droplet or bead may spread across the internal surface of the Y-piece 124, allowing greater surface area for re-evaporation into the passing gas stream.
In respect of surface modification, it should be appreciated that in various aspects of the disclosed systems, a component and its tubular body can be formed from a single extrudate where the component and/or body has a modified surface. Modified surfaces may preferably facilitate the advantages of re-evaporation rates or droplet migration as described above.
In use, the humidification chamber 104 can be installed on the heater plate 108. The heater plate 108 heats liquid in the chamber 104 to produce vapor. In some configurations, gases flow from the gases supply 125, through the supply conduit 132, and into the humidification chamber 104 through the inlet port 410. The gases pass over the liquid in the humidification chamber 104 and mix with the vapor. Humidified gases exit the humidification chamber 104 through the outlet port 412 and flow through the inspiratory conduit 120 to the patient. The patient inhales the humidified gases supplied through the inspiratory conduit 120. In some embodiments, gases exhaled by the patient are returned to the gases supply 125 through the expiratory conduit 122. Any or all of the components of the breathing circuit assembly 123 can include a heating element, for example, a heating wire 127, to help maintain the gases at a desired temperature and to reduce the likelihood of significant condensation formation in the conduits.
Heater Base
The heater base 102 illustrated in
In the illustrated embodiment, the heater base 102 includes a base portion 202. The base portion 202 is the lower portion in the illustrated embodiment. In some configurations, the base portion 202 supports the balance of the heater base 102. The base portion 202 can include the heater plate 108. In the illustrated configuration, the base portion 202 comprises one or more side surfaces 140 that wrap upward to a top surface 142. The top surface 142 generally encircles, or surrounds at least a portion of, the heater plate 108. In the illustrated configuration, the one or more side surfaces 140 join to a front surface 141.
The heater base 102 also can include a spine portion 210. The spine portion 210 can extend generally upwardly from a rear of the base portion 202. In some configurations, the spine portion 210 is monolithic and integrally formed with the base portion 202. The spine portion 210 can include one or more side surfaces 144. The one or more side surfaces 144 can wrap generally forwardly to a front surface 146. In some configurations, the one or more side surfaces 144 can extend upwardly to an upper surface 148. In the illustrated configuration, the one or more side surfaces 144 extend rearwardly to a rear surface 149 of the spine portion 210.
With reference to
With reference again to
In the illustrated configuration, the heater base display 116 angles between the upper surface 148 of the spine portion 210 and a portion of the front surface 146. Moreover, the heater base display 116 inclines rearwardly relative to vertical, as shown in
With reference again to
With reference to
In some embodiments, the boards 170a, 170b contain many or most of the electrical components of the heater base 102. As described herein and shown in
As illustrated in
In some configurations, the rear surface 149 of the spine portion 210 of the heater base 102 further includes a vent cover 214. The vent cover 214 extends outwardly from the rear surface 149 of the spine portion 210 of the heater base 102 to at least partially or completely cover the air vents 212. As shown in
The heater base 102 can also include one or more data transfer ports 216, 217 as shown in
With reference again to
With reference to
For use, an operator installs the humidification chamber 104 on the heater base 102 by sliding the chamber 104 onto the heater plate 108. The lip 205 of the chamber 104 rests or is trapped in the groove 178. In some embodiments, the inner chassis 174 does not include a rim edge 176, and thus the groove 178 is not formed. As discussed above, the heater plate 108 can be spring loaded in some configurations. For example, as shown in
In some embodiments, the rim edge 176 of the inner chassis 174 helps inhibit excessive downward movement of the chamber 104. Accordingly, the rim edge 176 helps reduce the likelihood of damage to certain components of the system, such as, for example but without limitation, sensors that may be mounted on the heater base 102. Without the rim edge 176, the spring-loaded heater plate 108 may depress, for example, if downward pressure is applied to the chamber 104 when connecting the supply conduit 132 and/or the inspiratory conduit 120. Without the lower rim edge 176, the chamber 104 may have a vertical range of motion of about 2 mm to about 5 mm. The lower rim edge 176 can reduce the range of motion to about 0.5 mm.
The upward force exerted by the springs 182 against the heater plate 108 forces the heater plate 108 up against the bottom surface of the chamber 104. The greater the force exerted by the springs 182, the better the heat conduction between the heater plate 108 and the chamber 104. This is because the greater the upward force, the more heater plate 108 surface area will be in direct contact with the chamber 104 bottom surface, thus increasing conduction. However, the greater the force exerted by the springs 182, the more difficult it is to insert and remove the chamber 104 from the base portion 202. It has been discovered that upward force of 30-40 Newtons (N) is optimal. In an embodiment, the force is in the range of 36-40 N. In an embodiment, the force is in the range of 35+/−5 N.
In order to achieve this type of force while easing a user's ability to insert and remove the chamber 104, the springs 182 can be preloaded. Preloading can be achieved, for example, by dropping the initial height of the heater plate 108 so that the springs 182 have less travel, while providing the optimal amount of force. This allows the user to insert the chamber 104 into the heater base 102 without having to force the heater plate 108 down a greater distance than is necessary to achieve the desired upward force on the heater plate 108.
For example, in an embodiment, the heater plate 108 is configured to travel less than one millimeter to a few millimeters. This can be done, for example, by limiting the range of the support screws 180 (as shown in
An example of a preloaded spring is shown in
Heater Plate Assembly
An embodiment of the heater plate assembly 2900 is shown in
The heater plate assembly 2900 can comprise the heater plate 2903, a heating element 2930, one or more layers of insulation comprising, for example, a back plate set 2920 and a heater plate set 2925, a back plate 2905, and at least two wires 2911. The heater plate comprises a first surface 2903a at a periphery of the heater plate, a second surface 2903b at least partially surrounded by the first surface, and a recess 2903c defined within the second surface that is recessed relative to the first surface and the second surface, the recess configured to receive the heating element therein. A back plate set 2920 as herein described refers to at least one or more layers of insulation located between the back plate 2905 and the heating element 2930. The heater plate set 2925 as herein described refers to at least one or more layers of insulation located between the heating element 2930 and the heater plate 2903. In some embodiments the heater plate assembly 2900 can include at least one insulatory piece 2915. In some embodiments the at least one insulatory piece 2915 can include two, or more than two, insulatory pieces. Each of the at least one insulatory piece 2915 may be defined as a component that provides electrical insulation and may be located around the connection between one of the at least two wires 2911 and the heating element 2930. The heater plate assembly 2900 is clamped to prevent unwanted liquid entry into the heater plate assembly 2900 which could cause a short. In an embodiment, the heater plate assembly 2900 is clamped to prevent liquid entry to the International Protection Marking IP Code IPX2 standard.
The at least two wires 2911 connect a power source to the heating element 2930. The heating element 2930 may be an element that provides a required electrical resistance, such as a metallic element or carbon element. In some cases the heating element 2930 may be a nichrome heating element as shown in
The heating element 2930 comprises a flat filament 2935 wound around a non-conductive core 2936, such as mica, ceramic, or other heat tolerant non-conductive material. The flat filament 2935 can be made from nickel chromium alloy or other material with similar electrical and mechanical properties. The flat filament 2935 provides greater surface area, which allows for better heat transfer and better reduction in hot spots, than a round shaped filament. This is shown, for example, in
The flat filament 2935 is configured such that a small gap separates each winding of the flat filament 2935 in order to avoid shorting the flat filament 2935. In an embodiment, the gap is about 0.3 mm. This gap is smaller than the comparable gap used for a similar performing round shaped filament, because windings of a flat filament are less likely to move closer together. The smaller gap permits a higher density of windings, which allows the heating element 2930 to have an increased thermal efficiency compared to heating elements using similar performing round shaped filament. This allows the heater plate assembly 2900 to supply sufficient energy to significantly increase humidity levels at higher air flow rates. For example, in an embodiment, the power increase is sufficient to supply sufficient energy to heat about 80 liters per minute (Lpm) at 37 degrees Celsius and about 120 Lpm at 31 degrees Celsius.
The flat filament ends 2935a, 2935b are electrically connected to electrical connectors 2933. The electrical connectors 2933 are in electrical communication with the at least two wires 2911 to power the flat filament 2935.
The heating element 2930 also comprises an insulation layer 2932 surrounding the conductive parts of the heating element 2930. The insulation layer 2932 forms part of at least a 0.4 mm layer of insulation. In an embodiment, two layers of 0.2 mm insulation are provided. In an embodiment, 0.8 mm of insulation is provided, comprising one or more layers. Redundant insulation layers provide a fallback in case one layer of insulation fails. The insulation layer 2932 forms a perimeter 2937, 2939 surrounding the heating element 2930. In some embodiments the perimeter 2937, 2939 may be approximately 0.8 mm to approximately 0.9 mm. The perimeter 2937, 2939 may contribute to providing a double insulated system.
The at least one insulatory piece 2915 may insulate the at least two wires 2911 from the back plate 2905. Thus, the at least one insulatory piece 2915 may be located at the connection of the at least two wires 2911 to the heating element 2930. In some embodiments the at least one insulatory piece 2915 may be located such that it surrounds the connection of the at least two wires 2911 to the heating element 2930. The at least two wires 2911 may extend from the centre of the at least one insulatory piece 2915. The at least two wires 2911 may be restrained by a restraining member 2940 as in
The at least one insulatory piece 2915 may be made from a ceramic material. In some embodiments other materials may be used for the at least one insulatory piece 2915. The at least one insulatory piece 2915 may be clamped to one or more of the layers of insulation within the back plate set 2920. The back plate 2905 may be applied onto the back plate set 2925. The back plate 2905 may provide pressure to the at least one insulatory piece 2915. Thus, the at least one insulatory piece 2915 may provide pressure to the back plate set 2920. The pressure applied to the back plate set 2920 holds the heating element 2930 nearer to the heater plate 2903. The increased clamping allowed by the present design allows the heater plate assembly 2900 to run cooler overall and reduces hot spots.
The at least one insulatory piece 2915 may include a flange 2916. The flange 2916 fills at least one opening 2907 on the back plate 2905 as shown in
In an embodiment where the at least one insulatory piece 2915 comprises the flange 2916, the at least one insulatory piece 2915 may maintain a minimum clearance between the at least two wires 2911 and the back plate 2905. The shape of the at least one insulatory piece 2915 may provide a minimum clearance distance between the at least two wires 2911 and the back plate 2905. The flange 2916 may be clamped to the back plate set 2920 which may push the heating element 2930 nearer to the heater plate 2903. This may provide improved contact between the heating element 2930 and the heater plate 2903. Good contact between the heating element 2930 and the heater plate 2903 may provide more even and reliable heating. Good contact between the heating element 2930 and the heater plate 2903 may reduce the formation of hot spots, which may prolong the life of the heating element 2930.
The multiple layers of insulation 2920, 2925 may be located near the heating element 2930. Each of the multiple layers of insulation 2920, 2925 may provide electrical insulation and thermal conduction. The multiple layers of insulation 2920, 2925 may improve the safety of the electrical system. In some embodiments the multiple layers of insulation 2920, 2925 may be made from mica sheets. In other embodiments the multiple layers of insulation 2920, 2925 may be made from other sheet electrical insulators such as silicon, polyether ether ketone (PEEK) or polyimide (for example, Kapton, a registered trademark of E. I. du Pont de Nemours and Co.). If one or more of the multiple layers of insulation 2920, 2925 is too thick, it may compromise heat transfer; if one or more of the multiple layers of insulation 2920, 2925 is too thin, it may become fragile during manufacture. A thick layer of the multiple layers of insulation 2920, 2925 may provide a useful surface for clamping the at least one insulatory piece 2915, but a thin layer may provide better heat transfer.
The multiple layers of insulation 2920, 2925 may comprise one or more layers of insulation of the same thickness, or alternatively of different thicknesses, wherein some of the one or more layers of insulation may be thicker than others. For example, one or more of the layers of insulation may be greater than approximately 0.4 mm thick and others may be less than approximately 0.4 mm thick.
In some embodiments the thickness of the back plate set 2920, as an aggregate, may vary from the thickness of the heater plate set 2925, as an aggregate. In some embodiments the back plate set 2920 may have a greater aggregate thickness than the heater plate set 2925, which may encourage greater thermal conduction of the generated heat to the heater plate 2903. For example, the back plate set 2920 may have a thickness of approximately 0.8 mm and the heater plate set 2925 may have a thickness of approximately 0.4 mm. There may be a range of different thicknesses that would provide good reliability and performance characteristics. In some embodiments the back plate set 2920 and the heater plate set 2925 can each include a plurality of the layers of insulation. In some embodiments the number of the layers of insulation may differ between the back plate set 2920 and the heater plate set 2925. For example, the heater plate set 2925 can include one layer of insulation, and the back plate set 2920 can include two layers of insulation.
In some embodiments, the back plate set 2920 and the heater plate set 2925 can include a single layer of insulation; this single layer may provide a reliable product at lower voltages. In some embodiments the back plate set 2920 and the heater plate set 2925 can each include multiple layers of insulation. In one example, the back plate set can include two layers of insulation, each approximately 0.4 mm thick, and the heater plate set 2925 can include two layers of insulation, each approximately 0.2 mm thick. Any combination of numbers of layers of insulation either side of the heating element 2930 also fall within the scope of the disclosure. The insulation sets 2920 and 2925 can be held together using, for example, thermally resistive tape 2922 placed on two opposites sides to create a clamping effect. These examples are meant to be illustrative only and are in no way limiting. It is to be understood that any combinations of the above embodiments may also fall within the scope of the disclosure.
An electrical component is described herein as having double insulation if it has two forms, layers, or components of insulation in any one plane. The heater plate assembly 2900 described in the present specification has features which may provide double insulation. These features may include the insulation layer 2932, the at least one insulatory piece 2915, the at least one opening 2907, and/or the insulation provided by the back plate set 2920 and the heater plate set 2925.
A thermal cut out reset switch 2947 protrudes from the restraining member 2940. When the heater plate temperature goes over a set temperature, a button portion of the thermal cut out reset switch 2947 clicks out and power from the mains input (not shown) to the heater plate assembly 2900 is disconnected. The thermal cut out reset switch 2947 is located for easy access to allow a user to quickly reset the power connection to the heater plate assembly 2900.
The heater plate assembly 2900 as described throughout this specification should not be limited to a respiratory application but may be used in any application that requires a heating assembly.
Guard
In some embodiments, a guard 107 extends along a front portion of the base portion 202 of the heater base 102 and the rim edge 172. The guard 107 can be depressed to enable the base 105 and the lip 205 of the chamber 104 to access the heater plate 108 and the groove 178 (in embodiments that include the groove 178). The guard 107 can be allowed to revert to a non-depressed position once the chamber 104 has been installed. In the non-depressed position, the guard 107 retains the chamber 104 against inadvertent removal from or movement relative to the heater base 102.
In some such embodiments, the heater base 102 includes an anti-racking mechanism that cooperates with the guard 107. The anti-racking mechanism allows the guard 107 to translate generally vertically without significant movement of one end of the guard 107 relative to the other end of the guard 107 even when only one end of the guard 107 is depressed. In other words, the anti-racking mechanism cooperates with the guard 107 to cause vertical movement of the first end to translate into coordinated vertical movement of the second end.
With reference now to
As shown in
The arms 109b, 109c extend generally perpendicularly from ends of the bar 109a. One arm 109a is coupled to the guard 107 near a first end of the guard 107, and the other arm 109b is coupled to the guard 107 near the other end of the guard 107. In the illustrated configuration, the arms 109b, 109c are joined to the distal ends of the posts 110. As such, the arms 109b, 109c help to coordinate movement of the posts 110. Thus, the use of the torsion bar 109 connected to the guard 107 helps to reduce the ability of the guard 107 to twist about a generally horizontal axis “A” that extends through the guard 107 such that a generally vertical plane extending through the axis “A” substantially bisects the guard 107 into a first half and a second half.
The guard 107 translates axially relative to the inner chassis 174. To return the guard 107 to the non-depressed position, biasing members 113 can be positioned between at least a portion of the guard 107 and the inner chassis 174. In the illustrated configuration, the inner chassis 174 can include mounts 115 while the guard 107 includes supports 119. The biasing members 113 can be springs that are positioned between the mounts 115 and the supports 119. The biasing members 113 urge the guard 107 away from the inner chassis 174 or other relatively stationary portion of the heater base 102. In some configurations, the torsion bar 109 can be biased instead of, or in addition to, the guard being biased relative to the inner chassis 174.
The illustrated guard 107 also comprises a catch 129. The catch 129 is received within a portion of the heater base 102 and secures the guard 107 against removal from the heater base 102 unless removal is desired for servicing or repair, for example but without limitation. In the illustrated configuration, the catch 129 can comprise a forked component with outwardly extending tabs at the distal ends. Other configurations are possible keeping in mind the desire to allow relatively free movement within a range of motion and then restraint against further movement.
In use, if a user depresses the guard 107 near one end, the torsion bar 109 causes the other end of the guard 107 to depress as well. The torsion bar 109 causes the guard 107 to depress more evenly across its length. This advantageously allows the user to insert and remove the chamber 104 more easily. In addition, because a user can depress one side or the other of the guard 107 (as indicated by markings 106) yet cause the length of the guard 107 to translate downward, the anti-racking feature reduces the risk of catching a finger between the guard 107 and the base housing.
Cartridge
The heater base 102 can include a sensor cartridge 300 extending outward from the front surface 146 of the spine portion 210. In some embodiments, the sensor cartridge 300 is permanently coupled to or integrally formed with the spine portion 210. In some embodiments, as shown in
The cartridge 300 can include or support various sensor probes. Any suitable components can be used as the sensors. For example, thermocouples, resistance temperature detectors, fixed resistors and the like can be used as the sensors. In some embodiments, for example as shown in
In the embodiment illustrated in
In some configurations, the first sensor probe comprises a thermistor that can be configured to sense temperatures of gas flow. In some configurations, the second and third sensor probes comprise thermistors that can be configured to sense gases flow rate using a temperature-based flow measurement approach. Other configurations can have any combination of temperature and flow sensors located in various locations as would be understood by a person of skill in the art from the present disclosure. In this approach, one of the thermistors functions as a reference sensor that measures the flow temperature at the sensing location and the other thermistor, which can be a heated thermistor, is heated to a preset temperature differential above the flow temperature. In some embodiments, the heated thermistor is heated to a set temperature, such as, for example, 160 degrees Celsius. In some applications, a resistor can be used to heat the thermistor instead of using a heated thermistor. In some configurations, all of the thermistors can be both heated and non-heated thermistors. Flow velocity can be determined using the measured flow temperature, the known heat transfer characteristics of the heated thermistor and the power consumed to maintain the temperature difference between the second and third thermistors. Other techniques also can be used. For example but without limitation, constant power can be provided to the thermistors and the heat conducted into a nearby thermistor can be used to determine the rate of flow.
With reference to
In the illustrated embodiment, the first sensor probe 330 is positioned vertically higher than the second and third sensor probes 332, 334. The height of the sensor can advantageously allow for sensing the temperature of the gases closer to the beginning of the heated part of the inspiratory conduit 120. In some applications, this can allow for more accurate sensing of the temperature of gases flowing through the inspiratory conduit 120.
Cartridge and Chamber Coupling
The sensor cartridge 300 and a top of the humidification chamber 104 have a coupling configuration. The coupling configuration can promote correct and easy installation of the chamber 104.
As shown in
In some embodiments, the cartridge 300 includes clips 350 configured to engage and secure the chamber 104. As shown in
In an embodiment, the rim edge 176 is removed in order accommodate a greater variety and shape of types of the chamber 104. In such embodiments, the sensor cartridge 300 can be used to hold the chamber 104 in place while the heater plate 108 applies upward force on the chamber 104.
In some embodiments, the cartridge 300 also includes a socket 348. In the embodiment of
In some embodiments, the cartridge 300 includes a low power circuit suitable for operation of sensors electrically coupled to the low power circuit. The sensors can include temperature sensors, flow sensors, and/or other types of sensors adapted to measure gas properties. The low power circuit can be differentiated from a high power circuit that, in use, provides electrical power to one or more heaters (for example, heater wires) in the system. The sensors can be positioned at one or more locations in a breathing circuit such as, for example and without limitation, in an inspiratory conduit, an expiratory conduit, in a segmented inspiratory conduit at a connection location, at a patient end of an inspiratory conduit, at an outlet port of a chamber, at an inlet port of a chamber, or any combination of these. The low power circuit can include electrical components configured to provide electrical voltage and electrical current to one or more sensors, the sensors comprising thermistors, thermocouples, digital sensors, or any combination of these.
In some embodiments, the cartridge 300 is configured for use with a designated, defined, or particular set or type of sensors. For example, the cartridge 300 can include circuitry and electrical components configured to drive and read the sensors. In some implementations, the cartridge 300 can be configured to read a plurality of sensors by switching electrical voltage and/or current to one or more sensor circuits electrically coupled to and/or within the cartridge 300. By associating the cartridge 300 with the sensors, the system can be upgraded with relative ease by obtaining and/or incorporating new and/or upgraded sensors with corresponding low power circuitry and obtaining and/or utilizing a corresponding cartridge 300 configured for use with the upgraded sensors and corresponding low power circuit. In some implementations, the functionality of the system can be modified, updated, and/or upgraded by changing the cartridge 300 to accommodate modified, updated, and/or upgraded sensing circuitry.
In some embodiments, the system can be configured to detect when there is a likely short between the low power circuit and the high power circuit (for example, a short circuit between heater and sensor wires). In certain implementations, the high power circuit and the low power circuit receive electrical power from a common transformer, and additional circuitry rectifies and decreases (for example, using voltage regulators) the output electrical voltage of the transformer for the low power circuit. For example, the high power circuit can be configured to provide about 22 V and the low power circuit can be configured to provide about 3.3 V. Other voltages are also possible. For example, the high power circuit can provide a voltage of at least about 50 V, at least about 30 V and/or less than about 50 V, at least about 20 V and/or less than about 30 V, at least about 10 V and/or less than about 25 V. As another example, the low power circuit can provide a voltage of at least about 5 V, at least about 3 V and/or less than about 5 V, at least about 2 V and/or less than about 3.5 V, at least about 1.5 V and/or less than about 2 V. The actual voltage on the low power circuit can depend on the gas properties measured by the one or more sensors coupled to the low power circuit, for example the temperatures measured by the one or more temperature sensors coupled to the low power circuit. For example, in a low power circuit providing about 3.3 V, a thermistor measuring a temperature of about 50° C. can output a voltage of about 0 V and a thermistor measuring a temperature of about 20° C. can output a voltage of about 1.2 V.
Based at least in part on the expected range of voltages output by a sensor, the system can be configured to trigger a warning, alarm, notification, or signal (for example, for use in other parts of the system or electrical circuits) when the voltage on the low power circuit is outside of the expected range. The system can include a first comparator referenced to the output of a series of dividers electrically coupled to a transformer output configured to provide the voltage for the low power circuit. The first comparator can provide an out of range signal when the voltage exceeds the expected voltage (for example, the voltage that the comparator is configured to detect). For example, where the expected range is between 0 and 1.2 V or 1.5 V, the comparator can be configured to provide a signal indicating a possible short circuit when the voltage exceeds 1.2 V or 1.5 V. The system can include a second comparator referenced to ground and configured to provide a signal indicating a possible short circuit when the voltage is negative. The system can be configured to provide a signal indicating a potential short circuit immediately (for example, in real time or in near real time) upon detecting the voltage outside the expected range. In some implementations, the system can include logic configured to ignore the short circuit signal, to trigger a warning, and/or to turn off or decrease power to the high power circuit and/or the low power circuit.
The short circuit may occur where there is a leak of voltage from the high power circuit to the low power circuit which can increase the voltage on the low power circuit outside the expected range. Similarly, if a negatively-biased electrical voltage to be supplied to the high power circuit leaks to the low power circuit, the voltage on the low power circuit may become negative.
Chamber
As described herein and shown in
As shown, the humidification chamber 104 has a generally rounded shape with generally smooth sides, which can make it difficult for the operator to hold the chamber 104 during set-up and installation. Therefore, as shown in
The chamber 104 can also include an opening or port 117 for the connection of a liquid conduit or feedset 118. The liquid conduit 118 can extend from the port 117, as shown in
In some embodiments, the humidification chamber 104 can include features to help reduce the likelihood of the level of liquid in the chamber 104 from exceeding a particular level. For example, the chamber 104 can include one or more floats 460a, 460b as shown in
In some embodiments, one or more of the floats 460a, 460b can include features to help direct air flow through the chamber 104 from the inlet port 410 to the outlet port 412. For example, as shown in
In some embodiments, the secondary float 460b is made of acrylonitrile butadiene styrene (ABS). This material can advantageously allow for an improved weld joint between two halves of the float 460b and improved thermal properties to inhibit deformation. For example, the secondary float 460b is configured to enclose a volume of air following formation. During transit at high altitudes, if the secondary float 460b is not formed of a sufficiently deformation-resistant materials, the secondary float 460b can be deformed in a manner that does not readily recover upon return to lower altitudes.
In some embodiments, the inlet port 410 and/or the outlet port 412 include one or more apertures extending through the wall of the respective port. For example, in the illustrated embodiment, the back of the inlet port 410 includes two apertures 411, and the back of the outlet port 412 includes one aperture 413. The apertures 411, 413 extend through walls of the inlet port 410 and the outlet port 412, respectively, and provide communication paths through the walls of the inlet port 410 and the outlet port 412. In the illustrated configuration, at least a portion of each of the inlet port 410 and the outlet port 412 can have a respective flattened region 414, 416. The apertures 411, 413 extend through the flattened regions 414, 416.
As shown in
The apertures 411, 413 can be configured to receive sensors to measure various properties of gases entering and exiting the chamber 104. For example, in some embodiments, the apertures 411, 413 are configured to receive sensors mounted on a sensor cartridge 300 as shown in
The seals or grommets 150 can at least substantially pneumatically seal the apertures 411, 413 so that the gas flow path through the chamber 104 is isolated from ambient. Accordingly, in the illustrated configuration, the seals 150 define a barrier that reduces the likelihood of fluid or gas passing through the apertures 411, 413. In some applications, at least one of the seals 150, and preferably all of the seals 150, also is resistant to the passage of vapor. The seals 150 can be configured to receive the sensors so that the sensors can detect properties of gases flowing through the humidification system while remaining pneumatically sealed from the flow path. The seals 150 advantageously allow the sensors to function without being in direct contact with gases in the flow path, so the sensors can be reused and do not require cleaning between uses.
The seals 150 can be formed from any suitable material. In some applications, the seals 150 are formed from a resilient or flexible material. In some applications, one or more of the seals 150 can be formed of a material with a Shore-A hardness of between about 20 and about 80, and more preferably between about 40 and about 60. In some applications, one or more of the seals 150 can be formed of Silicone, polyethylene, or thermoplastic polyurethane.
In some arrangements, the seals 150 can be formed directly into the inlet port 410 and the outlet port 412, for example, by overmoulding. In other arrangements, the inlet port 410 and the outlet port 412 and seals 150 can include features to help retain the seals 150 in position within the apertures 411, 413 and provide for easier manufacturing and assembly. For example, with reference to
In some embodiments, the seals or grommets 150 can include the use of surface modifications and/or microstructures to improve wicking. As described herein, the use of surface modification agents and/or microstructures can result in spreading of liquid onto the surface and inside or on the microstructures. Accordingly, any of the configurations described above can be used in conjunction with the seals or grommets 150. The interaction can increase the liquid-vapor interface area and reduce the thickness of the liquid layer on top of the surface. The combination of increased surface area and reduced thickness improves liquid evaporation, compared to liquid of the same volume of liquid on a flat surface. Accordingly, it can be advantageous to treat the seals or grommets with a material or materials for increasing the surface energy. Surfactants, such as cationic surfactants, can be particularly desirable additive materials. Suitable surface modifying agents include glycerol monostearate (GMS), ethoxylated amine, alkanesulphonate sodium salt, and lauric diethanolamide and additives comprising these substances.
The ribs 156 can deflect to allow the seal 150 to be inserted into the apertures 411, 413. The ribs 156 can then return to an expanded state to help hold the seal 150 in place within the apertures 411, 413. As the ribs 156 depress, they spread into spaces 160 between the ribs 156. In some embodiments, a radio of a width of the rib 156 to a width of the space 160 between ribs 156 is about 1:1. In some embodiments, the ratio is about 3:7. A ratio that is too high (i.e., the space 160 between ribs 156 is small compared to the ribs 156) may not allow the ribs 156 to depress sufficiently, resulting in greater difficulty installing the seal 150 in the apertures 411, 413. A ratio that is too low (i.e., the space 160 is large compared to the ribs 156) may provide a reduced retention force so that the seal 150 is not held as securely in the apertures 411, 413. In the illustrated embodiment, the seal includes eight ribs 156, but more or fewer ribs 156 are also possible. However, if too many ribs 156 are included, the ribs 156 would be made thinner and might be weaker. Alternatively, including too few ribs 156 might require making the ribs 156 larger, leaving less space to spread.
In some embodiments, when a sensor is inserted into the seal 150, a tip 162 of the seal 150 can stretch to conform to the shape of the sensor. As the amount of stretch to accommodate the sensor increases, the seal material becomes thinner. This can advantageously improve the reactivity and accuracy of the sensor, increase the contact area between the sensor and seal as the seal stretches to match the shape of the sensor, and more securely hold the seal in the aperture. However, if the tip 162 of the seal is too flat and requires too great a degree of stretch to accommodate the sensor, it can be more difficult to insert the sensor in the seal and the seal material may degrade or break.
Additionally, the seal can be configured to receive a heated thermistor. At high temperatures, a seal made of, for example, silicone may begin to degrade or deform. Therefore, in some embodiments, the seal 150 can be designed to stretch more evenly along the length of the head 154 rather than the stretch being limited to primarily the tip 162. This can help distribute the forces and help reduce degradation and/or deformation of the seal. In the illustrated embodiment, the seal can have a length of about 5.6 mm or about 6 mm, a base 152 diameter of about 8 mm, a diameter measured at the widest portion of the ribs 156 of about 7.50 mm, and a tip thickness of about 0.20 mm. The ribs 156 can be sized so that the space 160 between ribs is about 1.4 mm.
In some arrangements, at least one of the seals 150 can be permanently or at least semi-permanently attached to the apertures 411, 413. In some arrangements, at least one of the seals 150 can be removable and replaceable. The seals 150 can be configured to have a useable life similar to that of one of the other components. For example, the seals 150 preferably comprise a useable life similar to the chamber 104 such that the chamber 104 and the seals 150 would be disposed of at the same time. In some configurations, especially where the seals 150 are permanently attached to the chamber 104, the seals 150 preferably have a longer life than the chamber 104 such that the seals 150 are not the limiting component on a life span of the chamber 104.
The seals 150 are configured to securely but removably receive sensors. In some embodiments, the sensors can function with higher accuracy if the depth of insertion into the seals 150 and flow path can be controlled and repeated. To help provide for controlled and repeatable insertion of the sensors, in some embodiments the sensors are mounted directly or indirectly on the heater base 102. For example, rather than being mounted directly on the heater base 102, the sensors can be mounted relative to a sensor cartridge 300 that is coupled to the heater base 102.
In some embodiments, one or both of the inlet port 410 and the outlet port 412 includes features to help a user distinguish the ports. One or both of the inlet port 410 and the outlet port 412 can include features to allow for connection of a connector coupled to the supply conduit 132 and/or the inspiratory conduit 120. For example, in the illustrated embodiment, the front of the outlet port 412 includes a rib 418. The rib 418 can be configured to be received by a corresponding recess on a chamber end connector coupled to the inspiratory conduit 120 as discussed in greater detail herein. In addition, in the illustrated embodiment, the aperture 413 can be surrounded by an embossment 440.
The central channel 342 is configured to receive a corresponding boss or raised portion 442 on the top of the chamber 104, shown in
The sidewalls 340 and fins 344, 346 act as lead-in features to help guide the user in correct installation of the chamber 104 on the heater base 102. The sidewalls 340 and fins 344, 346 also help protect the sensors from damage that could be caused by improper contact with the base. For example, if the user attempts to install the chamber 104 with the front or a side of the chamber 104 facing the cartridge 300 so that the apertures 411, 413 in the inlet port 410 and the outlet port 412 are not aligned with the sensor probes 332, 334, 330, the sidewalls 340 and fins 344, 346 will contact surfaces of the chamber 104 to help prevent or inhibit contact between the sensors and relatively hard surfaces of the chamber 104.
The fins 344, 346 can also include features to help stabilize the chamber 104 relative to the cartridge 300 and inhibit rotation, tilting, and/or yaw of the chamber 104. For example, as shown in
Chamber Baffles
In some applications, the humidification system 100 can be used for delivery of gases at relatively high flow rates, for example, up to or greater than about 100 L/min. In some cases, certain features designed to improve humidity delivery at higher flow rates can cause liquid from within the chamber 104 to splash out through the outlet port 412. This is not desirable.
With reference to
In some embodiments, at least one of the inlet port 410 and the outlet port 412 can include one or more features to help inhibit liquid from leaving the chamber 104 other than in a vapor form. For example, one or more of the inlet port 410 and the outlet port 412 can include inner wall extensions 420, 422, respectively, that extend into the chamber 104 from the point at which the ports enter the chamber 104, as shown in
The chamber 104 can also include one or more baffles at or near the end of at least one of the inlet port extension 420 and the outlet port extensions 422. For example, an inlet port baffle 430 extends at an angle downwardly and toward the sidewall 436 of the chamber 104 from the inlet port extension 420. The baffle 430 extends downwardly below the lowermost portion of the extension 422 of the outlet port 412. The baffle 430 can advantageously help direct air flow in the chamber 104. For example, the baffle 430 can help direct air entering the chamber 104 from the inlet port 410 down to the liquid surface. This can help promote mixing of vapor with the gases to increase humidity delivery. The sideways orientation of the inlet port baffle 430 can also help direct incoming gases toward the sidewall 436 of the chamber 104 so that the gases will travel down the side wall and across the liquid surface instead of flowing directly to the outlet port 412.
In the configuration of
Chamber Port Cap
With reference to
In some configurations, the liquid conduit 118 can be wound around, and can be contained by, a winder 480 provided on the chamber 104, as shown in
End Cap
One or more of the components of the breathing circuit assembly 123 can be packaged for shipping and/or storage with an end cap 500 coupled to one or both ends of the conduit. For example, the end cap 500 can be included on the end of the Y-piece 124 configured to couple to the patient interface conduit 126 or the interface 128 as shown in
The body 502 includes frustoconical tapers 508. The tapers 508 promote a friction fit between the end cap 500 and a Y-piece. The tapers 508 also create a seal with the Y-piece. The tapers 508 point toward the leading end of the end cap 500 inserted into the Y-piece. The illustrated embodiment includes three tapers 508, although more or fewer are also possible. Including multiple tapers 508 provides redundancy to help ensure a sufficient seal and friction fit. However, including too many tapers 508 can create too great of a contact area. This can make the end cap 500 difficult to remove. In some embodiments, the body 502 can be sized to fit different sized Y-pieces, for example, both adult and infant Y-pieces.
The flange 504 is located on the end of the end cap 500 facing the bases or widest parts of the tapers 508. As shown, the flange 504 has a hexagonal shape. The hexagonal shape helps seal the end of the Y-piece and aids end cap 500 removal. A width or diameter of the flange 504 is greater than an outer diameter of the Y-piece to create an overhang. For example, for a 22 mm diameter Y-piece, the flange 504 can have a width of about 24 mm. The hexagonal shape can also provide a visual indicator that the Y-piece connector is blocked and further inhibits the user from attempting to attach other components while the end cap 500 is in place, which may be more likely if the flange 504 was round. Other non-circular shapes also can be used.
The hook 506 extends from the flange 504. The hook 506 advantageously allows the user to more easily grasp and remove the end cap 500 when needed. The hook 506 also allows the circuit to hang on a medical stand 520 when not in use and/or during system set up, as shown in
The body 502, flange 504, and hook 506 can be integrally formed or molded to create a single-piece end cap 500. The end cap 500 should be made of a material that is sufficiently strong while remaining soft or pliant enough to inhibit damage to a Y-piece. In some embodiments, the end cap 500 can be made of Thermolast K. In other embodiments, the end cap 500 can be made of Santoprene having a Shore A hardness of between about 20 and 80, for example, about 55. Santoprene has a higher friction coefficient than some alternative materials, which can help improve end cap 500 retention in a Y-piece.
Alternative embodiments of end caps 500 are illustrated in
The hook 506 and flange 504 can have varying dimensions. For example, the embodiment of
The humidification system can be configured to operate in a first mode 3010, which can be referred to as a normal flow mode, a flow chart of which is illustrated in
In block 3012, the humidification system monitors parameters of the flow of gases to detect whether there is a rise in temperature at the chamber outlet port. If the temperature at the chamber outlet port increases by more than a designated temperature over a period of time, then the humidification system can be configured to signal this condition to other components of the system. In some embodiments, the designated temperature can be, for example and without limitation, at least about 2° C., at least about 2.5° C., or at least about 3° C. and the period of time can be at least about 30 sec., at least about 1 min., or at least about 2 min. One purpose of testing this condition is to see whether energy is being carried away from the chamber. When the flow of gas is not operating regularly, the temperature at the chamber outlet port may increase as energy is not being carried away from the chamber as expected.
If the condition in block 3012 is satisfied, the humidification system further tests for heating anomalies in the system in block 3013. For example, the humidification system can test whether the inlet port temperature, Ti, exceeds the outlet port temperature, To, by a designated temperature value, Tv. Similarly, the humidification system can test whether the outlet port temperature, To, exceeds the heater plate temperature, Tp, by a designated temperature value, Tv. Likewise, the humidification system can test whether the outlet port temperature, To, exceeds the patient-end temperature, Tp, by a designated temperature value, Tv. In certain implementations, the designated temperature value, Tv, can be the same for each of the above tests or it can be different for each one. In some implementations, the designated temperature can be, for example and without limitation, at least about 1° C., at least about 1.5° C., at least about 2° C., or at least about 2.5° C. Each of the above temperature anomalies can indicate that the flow of gases is not behaving as expected. If the condition in block 3013 is satisfied, the humidification system can enter a second mode 3020, which can be referred to as a cool down mode.
In block 3014, the humidification system can be configured to monitor parameters of the flow of gases to detect whether there is a decrease in flow over a time period. If the flow of gases decreases suddenly, then it can indicate that a conduit has been disconnected or connected incorrectly. As a first test, the humidification system can monitor the flow of gases to detect a relatively large decrease in flow over a relatively short period of time (for example, the change in flow is greater than a designated flow value, Fv). In some embodiments, the humidification system can monitor the flow of gases by taking instantaneous measurements of flow rate. In some embodiments, the humidification system can monitor the flow of gases by taking filtered measurements of flow rate, such as time-averaged measurements. For example and without limitation, the humidification system can signal that there is a sudden decrease in flow when the flow decreases by at least about 60%, by at least about 50%, or by at least about 40%. Similarly, the humidification system can signal that there is a sudden decrease in flow when the flow decreases by a specified amount over a designated time period that is less than or equal to about 30 sec., less than or equal to about 20 sec., less than or equal to about 10 sec., less than or equal to about 5 sec., or less than or equal to about 3 sec.
If the condition in block 3014 is satisfied, the humidification system can test whether the flow has dropped from a flow value exceeding a first flow value, F1, to a flow value below a second flow value, F2, in block 3015. The first and second flow values can be selected to ensure that flow values are being tested that are not subject to relatively high variability under normal operating conditions. For example, at low flow rates (for example, less than about 1 Lpm), the flow rate can regularly fluctuate by about 50% over relatively short periods of time. In some implementations, the first flow value, F1, can be at least about 5 Lpm, at least about 6 Lpm, at least about 7 Lpm, or at least about 8 Lpm. In certain implementations, the second flow value, F2, can be less than or equal to about 4 Lpm, less than or equal to about 3.5 Lpm, less than or equal to about 3 Lpm, or less than or equal to about 2.5 Lpm. In some embodiments, the humidification system can be configured to ignore the low flow signal when the change in flow has been requested by a user or when the system expects the flow to decrease. The above flow change anomaly can indicate that the flow of gases is not behaving as expected. If the condition in block 3015 is satisfied, the humidification system can enter the second mode 3020.
In block 3016, the humidification system monitors parameters of the flow of gases to detect whether there is a drop in temperature at the patient end of the inspiratory conduit. If the temperature at the patient end decreases by more than a designated temperature over a period of time, then the humidification system can be configured to signal this condition to other components of the system. In some embodiments, the designated temperature can be, for example and without limitation, at least about 0.5° C., at least about 1° C., or at least about 1° C. and the period of time can be at least about 30 sec., at least about 1 min., or at least about 2 min. One purpose of testing this condition is to see whether energy is being carried to the patient end. When the flow of gas is not operating regularly, the temperature at the patient end may decrease as energy is not being carried to the patient end as expected. The above temperature change anomaly can indicate that the flow of gases is not behaving as expected. If the condition in block 3016 is satisfied, the humidification system can enter the second mode 3020.
When entering the second mode 3020 from the first mode 3010, it may be that a reverse-flow flag or a no-flow flag has not been set and the humidification system will operate in the second mode 3020 for a full duration of a timer set in that mode. This may be desirable to stabilize the temperature of the gases throughout the humidification system and associated circuits, to improve the accuracy of subsequent temperature measurements.
In block 3022, the humidification system is configured to turn off the heaters in the system (for example, heater plate, heater wires, etc.). In block 3023, the humidification system is configured to start a timer that determines a maximum amount of time to remain in the second mode of operation 3020 before exiting to another operation mode. The timer can be set to run for at least about 1 min., at least about 1.5 min., at least about 2 min., or at least about 4 min. In block 3024, the humidification system tests whether a reverse-flow flag or a no-flow flag has been set. The respective flags may be set in the third mode 3030, described herein. If no flags have been set, the humidification system cools down for a prescribed amount of time before entering the third mode 3030. This may be useful when temperatures have increased to levels that have been deemed undesirable, as described herein, such as when the gas temperature is high enough that it may injure a user.
If at least one flag is set as discovered in block 3024, the humidification system in block 3025 tests whether the flow exceeds a first designated flow value, Flv, the heater plate temperature, Tp, exceeds a designated temperature, Tpv, and the patient-end temperature, Te, increases more than a designated patient-end temperature change, Tev. If each of these conditions is satisfied, the humidification system can unset all flags in block 3026 and enter the first mode 3010, or normal flow mode. These conditions can be configured to indicate that flow has likely returned to a normal flow mode so that the full length of the timer set in block 3023 need not run before resuming normal operations. This can speed up a return to normal operating conditions, reducing interruption to therapy delivery. The first designated flow value, Flv, can be, for example and without limitation, at least about 1.5 Lpm, at least about 2 Lpm, at least about 2.5 Lpm, or at least about 3 Lpm. The designated temperature, Tpv, can be, for example and without limitation, at least about 43° C., at least about 45° C., at least about 50° C., or at least about 53° C. The designated patient-end temperature change, Tev, can be, for example and without limitation, at least about 1° C., at least about 1.5° C., at least about 2° C., or at least about 2.5° C. The designated patient-end temperature change can be measured as a change in patient-end temperature over a period of time where an initial patient-end temperature can be the measured temperature at the start of the second mode 3020, at the end of the previous operating mode, or the temperature taken at the start of a sliding time window (for example, the temperature 20 seconds ago, 30 seconds ago, 40 seconds ago, etc.).
If the conditions in block 3025 are not satisfied, the humidification system can be configured to monitor the flow in block 3027 to detect whether the flow exceeds a second designated flow value, F2v. When the flow exceeds the second designated flow value, this can indicate that the conduit has been connected properly but that further testing may be preferable to ensure proper connection of the conduit. In certain implementations, the second designated flow value, F2v, can be, for example and without limitation, at least about 2 Lpm, at least about 3 Lpm, at least about 4 Lpm, or at least about 5 Lpm. If this condition is satisfied, the humidification system can proceed to the third mode 3030, or warm-up mode, without requiring the timer set in block 3023 to expire. This can speed up the process of determining whether the breathing circuit is connected properly and reduce interruption to normal therapy delivery.
If the condition in block 3027 is not satisfied, the humidification system can be configured to check whether the timer set in block 3023 has elapsed. If it has, the humidification system can enter the third mode 3030, or warm-up mode. If it has not, the humidification system can return to block 3024 to test whether the flow flags are set.
In block 3034, the humidification system tests whether the temperature of the gas at the patient end exceeds a designated temperature, Tev. This can be done to increase patient safety and to reduce a likelihood of burning or injuring a user by providing gases that are too hot. If the patient-end temperature exceeds the designated temperature, Tev, the humidification system can re-enter the second mode 3020, or the cooldown mode, to allow the temperature of the gases to decrease to acceptable and/or safe levels. In some implementations, the designated temperature, Tev, can be, for example and without limitation, at least about 42° C., at least about 42.5° C., at least about 43° C., or at least about 45° C. This condition can be monitored frequently and/or continuously by the humidification system to allow the system to exit the third mode if the temperature exceeds the designated temperature. When this condition is triggered, no flags may be set such that the humidification system will operate in the second mode 3020 for the full duration of the timer set in that mode.
If the condition is not satisfied in block 3034, the humidification system tests in block 3035 whether the patient-end temperature or the chamber outlet temperature has increased by a designated temperature increase value, Tiv, over a time period. Where there is an increase, this can indicate that the conduits are connected and that there is a flow of gases along the inspiratory conduit. In certain implementations, the designated temperature increase value, Tiv, can be, for example and without limitation, at least about 1° C., at least about 1.5° C., at least about 2° C., or at least about 2.5° C. In some embodiments, the designated temperature increase value applied to the patient-end temperature may be different from the designated temperature increase value applied to the chamber outlet temperature. The designated temperature increase value can be measured as a change in temperature over a period of time where an initial temperature can be the measured temperature at the start of the third mode 3030, at the end of the previous operating mode, or the temperature taken at the start of a sliding time window (for example, the temperature 20 seconds ago, 30 seconds ago, 40 seconds ago, etc.).
If the condition is satisfied in block 3035, the humidification system in block 3036 determines whether the patient-end temperature exceeds the chamber outlet temperature. In some embodiments, the humidification system can determine whether the patient-end temperature exceeds the chamber outlet temperature by a designated temperature difference. For example, the designated temperature difference can be, for example and without limitation, at least about 0° C., at least about 1° C., at least about 2° C., or at least about 2.5° C. When this is the case, it can indicate that the flow of gases is as expected and the humidification system can unset all flags in block 3037 and resume normal therapy by returning to the first mode 3010. If the condition is not satisfied, it can indicate that the flow of gases is reverse to what is expected because temperature is increasing from the patient to the chamber outlet, indicating that the flow of gases is flowing from the patient to the chamber outlet. If this is the case, the humidification system can set the reverse-flow flag in block 3038 and return to the second mode 3020, or the cool down mode. The humidification system can also cause a warning, alarm, notification, or the like to occur to signal to a user that the conduits are potentially connected incorrectly.
If the condition in block 3035 is not satisfied, the humidification system can determine whether the time set in block 3033 has expired. If it has, the humidification system can set the no-flow flag in block 30340 and return to the second mode 3020, or the cool down mode. The humidification system can also cause a warning, alarm, notification, or the like to occur to signal to a user that the conduits are potentially disconnected. The conditions in blocks 3034 and 3035 may not be satisfied when a conduit is disconnected because there will be no significant or substantial increase in temperature at the chamber outlet or the patient-end as gas is not flowing into the chamber to be heated therein.
In block 3105, the humidification system energizes the heater plate to achieve a targeted dew point of flowing gases at a first targeted time. The humidification system can monitor a temperature of the gas at the chamber outlet and/or a temperature of the gas at the patient end and/or a temperature of the heater plate and/or an amount of power provided to the heater plate in order to calculate an estimate of the dew point of the gas. In certain implementations, the humidification system measures ambient temperature, gas inlet temperature, or the like to determine the humidity of the gas. In some embodiments, the humidification system is configured to achieve the targeted humidity after a period of at least about 5 min. and/or less than or equal to about 40 min., at least about 10 min. and/or less than or equal to about 30 min., or at least about 12 min. and/or less than or equal to about 20 min. The humidification system can use a targeted chamber outlet set point that changes over time to achieve the targeted humidity. The targeted humidity can be at least about 0.5 mg/L, at least about 1 mg/L, or at least about 2 mg/L. In some embodiments, the targeted chamber outlet temperature set point after the first targeted time can be at least about 24° C. and/or less than or equal to about 35° C., at least about 25° C. and/or less than or equal to about 28° C., or at least about 25.5° C. and/or less than or equal to about 26.5° C. The increase in temperature can be configured to be relatively slow so as to increase patient comfort and to achieve a targeted humidity during this first phase.
In block 3110, the humidification system energizes the heater plate using the patient-end temperature as a set point to achieve a therapeutic gas humidity and/or temperature. The humidification system can be configured to change the targeted set point as a function of time to achieve a gentle slope of temperature increase and to achieve the targeted therapeutic gas parameters after a second period of time or at the end of a specified, targeted, or desired duration after startup. For example, the targeted total amount of time to achieve the therapeutic gas parameters can be have a particular value, and the durations of the second targeted time and the first targeted time can be configured to total the targeted total amount of time. In some embodiments, the humidification system is configured to achieve the targeted therapeutic gas parameters after a period of at least about 30 min. and/or less than or equal to about 1.5 hrs, at least about 45 min. and/or less than or equal to about 1.25 hrs, or at least about 55 min. and/or less than or equal to about 65 min. In some embodiments, where the total targeted time is about an hour, the first targeted time can be 15 min. and the second targeted time can be 45 min., the first targeted time can be 30 min. and the second targeted time can be 30 min., or the first targeted time can be 10 min. and the second targeted time can be 50 min. The total targeted time can be at least about 30 min. and/or less than or equal to about 2 hrs, at least about 45 min. and/or less than or equal to about 1.5 hrs, at least about 55 min. and/or less than or equal to about 65 min. The increase in temperature can be configured to be relatively slow so as to increase patient comfort and to achieve a therapeutic humidity and temperature during this second phase. In some embodiments, the targeted temperature of the gas (for example, the patient-end set point) can be about 37° C. for an invasive mode or an Optiflow™ mode and about 31° C. for a non-invasive mode.
In some embodiments, the humidification system can be configured to adjust a chamber outlet set point based at least in part on an inlet port temperature. As the ambient temperature changes, the efficiency at which humidity can be passed to a gas changes. To accommodate for this relationship, the humidification chamber can be configured to adjust a chamber outlet set point by adding a chamber outlet set point offset to a targeted chamber outlet set point. By compensating for the inlet gas temperature, more consistent gas humidity can be achieved. The humidification system can use the chamber inlet temperature reading to determine a chamber outlet set point offset and adjust the chamber outlet set point by the determined offset. This may be advantageous where the humidification system is targeting a dew point of the gas rather than merely a gas temperature. The change in the chamber outlet set point can affect the amount of power delivered to the heater plate to achieve the desired gas dew point while accommodating for the gas temperature at the chamber inlet. In some embodiments, the functional relationship between the chamber outlet set point offset and the inlet port temperature can be determined empirically for a particular gas and breathing circuit configuration. In some embodiments, this adjustment can limit overshoot of an estimated dew point. In some implementations, this adjustment can be independent of flow rate.
The humidification system can be configured to update a user interface and control algorithm based at least in part on an identified breathing circuit. The breathing circuit can include a component that provides or results in a signal read by the humidification system. The value or characteristics of the signal can indicate the type of breathing circuit connected (for example, adult circuit, neonatal circuit, etc.) and the operation of the humidification system can be adjusted accordingly. For example, based on an ID resistor value in the circuit, the humidification system can decide whether to use a second heater driver for an expiratory conduit or for a second zone in an inspiratory conduit. The humidification system can be configured to limit operational or functional capabilities based on the breathing circuit attached. For example, in an infant mode, the humidification system can limit the available operating therapies whereas in an adult mode, the humidification system can provide more operating therapies. In some embodiments, a cartridge can be configured to be used with a number of different modes or the cartridge can be particular to a mode. Where the cartridge is configured for use with a number of modes, plugging in a particular breathing circuit can cause the cartridge to operate based on the breathing circuit. This can allow for the humidification system to be a plug and play system by allowing a number of different breathing circuits to be used and plugged in and providing an appropriate operating environment and therapies to the user based at least in part on the breathing circuit.
In some embodiments, the humidification system includes a safety circuit configured to reduce or prevent mal-functioning associated with providing power to the multiple heaters in multiple zones when operating in an infant mode or dual-zone heating mode. The humidification system can be configured to operate where the inspiratory conduit passes through multiple zones, proving a plurality of heating zones within the inspiratory tube. To operate the plurality of heaters in the heating zones, a power supply can be used to provide alternating current, or positively and negatively biased electrical voltages in turn. These currents and/or biased voltages can be controlled by switches in the humidification system. Closing both switches to allow both directions of current or both positively and negatively biased voltages at the same time can damage the system. The humidification system can include a latch that opens a main relay when the system (for example, through a software or hardware malfunction) activates incompatible heater drivers (for example, both sets of switches are activated where there are two zones).
In some embodiments, the humidification system is configured to maintain a short-term storage of running state that is configured to survive a momentary power outage or fault. For example, for a power outage of less than about 1 min., less than about 30 sec., or less than about 15 sec., the running state can be stored so that when operation resumes, the therapy that was running at the time of the power outage of fault resumes.
It should be emphasized that many variations and modifications may be made to the embodiments described herein, the elements of which are to be understood as being among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. Further, nothing in the foregoing disclosure is intended to imply that any particular component, characteristic or process step is necessary or essential.
Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. The following provisional applications are hereby incorporated by reference in their entirety: the U.S. Provisional Application having the title HUMIDIFICATION SYSTEM and Ser. No. 62/032,462, filed on Aug. 1, 2014; U.S. Provisional Application having the title CONNECTIONS FOR HUMIDIFICATION SYSTEM and Ser. No. 61/877,566, filed on Sep. 13, 2013; the U.S. Provisional Application having the title MEDICAL TUBES AND METHODS OF MANUFACTURE and Ser. No. 61/877,622, filed on Sep. 13, 2013; the U.S. Provisional Application having the title ZONE HEATING FOR RESPIRATORY CIRCUITS and Ser. No. 61/877,736, filed on Sep. 13, 2013; the U.S. Provisional Application having the title HEATING ASSEMBLY and Ser. No. 61/971,474, filed on Mar. 27, 2014.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NZ2014/000202 | 9/15/2014 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2015/038014 | 3/19/2015 | WO | A |
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