Sample gas filter for therapeutic gas delivery device - Patent Application 20070122997

Abstract

Disclosed herein is a sample gas filter for a therapeutic gas delivery device. The sample gas filter can include a housing having a sample gas inlet that can receive sample gas from a sample line connected to the inlet line of the therapeutic gas delivery device and a sample gas outlet. The housing can include a first chamber having a first filter membrane and a first reservoir between the sample gas inlet and the first filter membrane. The housing can include a second chamber having a second filter membrane and a second reservoir between the first filter membrane and the sample gas outlet. The first and second reservoirs can be axially oriented so that the sample gas filter can operate in any axial orientation. The sample gas filter can remove water vapor from the sample gas and collect water in the first and / or second reservoirs.

Description

[Technical Field]

[0001] The present disclosure is directed to a patient gas sample line and filter and methods of use thereof. More particularly, the present disclosure is directed to a patient gas sample line and filter including a multi-stage filtration system for filtering water vapor from a sample gas in a therapeutic gas delivery system. [Background technology]

[0002] Therapeutic gases can be delivered to a patient through the inspired respiratory gas flowing from a breathing circuit connected to a ventilator. For example, the therapeutic gas can be injected into the inspired respiratory gas flowing through the breathing circuit and then delivered to the patient's airway. One such therapeutic gas is nitric oxide, which can have a vasodilatory effect on the patient.

[0003] During therapeutic gas administration, a sampling system can monitor a portion of the inhaled respiratory gas to ensure that the therapeutic gas is being delivered at the desired dose in the inhaled respiratory gas stream. For example, a patient gas sample line and filter can be used to provide the sample gas (e.g., a portion of the inhaled respiratory gas stream) to a gas sensor module that monitors the concentration of the therapeutic gas being delivered to the patient. In some cases, the breathing circuit that delivers the therapeutic gas to the patient's airway can be humidified. Traditionally, patient gas sample lines and filters have included complex designs to separate liquids from the sample gas. However, these designs can be difficult to manufacture and require the patient gas sample line and filter to be in a specific orientation during use. Furthermore, these designs can allow wicking during various stages of filtration, which can cause premature blockage.

[0004] Therefore, there is a need for patient gas sample lines and filters that are easier to manufacture, more convenient to use, and longer lasting. Summary of the Invention [Means for solving the problem]

[0005] An embodiment of the present disclosure includes a sample gas filter for a therapeutic gas delivery device. The sample gas filter can include a housing, a first chamber, and a second chamber. The housing can have a sample gas inlet that can receive sample gas from a sample line connected to the inlet line of the therapeutic gas delivery device and a sample gas outlet. The first chamber can be within the housing and can include a first filter membrane and a first reservoir. The first reservoir can be located between the sample gas inlet and the first filter membrane. The second chamber can be within the housing and can include a second filter membrane and a second reservoir. The second reservoir can be located between the first filter membrane and the sample gas outlet. The first and second reservoirs can be axially oriented so that the sample gas filter can be used in any axial orientation. The sample gas filter can remove water vapor from the sample gas line and collect water in the first and / or second reservoirs.

[0006] In certain cases, the first chamber can include a baffle plate and a fiber membrane, where the baffle plate can be operable to support the first filter membrane on a first side of the first filter membrane and the fiber membrane can be operable to support the first filter membrane on a second side of the first filter membrane.

[0007] In certain cases, the second chamber can include a press-fit baffle and a labyrinth support. The press-fit baffle can support the second filter membrane on a first side of the second filter membrane. The labyrinth support can be located on a wall of the housing having the sample gas outlet. The labyrinth support can support the second filter membrane on a second side of the second filter membrane.

[0008] In certain cases, the housing and the chamber can each have a substantially circular cross-section. In certain cases, the first filter membrane and the second filter membrane can be substantially circular.

[0009] In certain cases, the first filter membrane can have a larger diameter than the second filter membrane. In certain cases, the first reservoir can have a larger volume than the second reservoir. In certain cases, the first reservoir and the second reservoir can be large enough to contain water for 12 hours of continuous use.

[0010] In certain cases, the first filter membrane can be a glass fiber filter membrane. In certain cases, the second filter membrane can be a 0.22 μm PTFE membrane. In certain cases, the fiber membrane can be made of a coarse sintered porous plastic material (for example, Vyon® fiber membrane). In certain cases, the first filter membrane and the second filter membrane can be separated to prevent wicking between the membranes.

[0011] An embodiment of the present disclosure includes a sample gas filter for a therapeutic gas delivery device. The sample gas filter can include a housing, a first chamber, and a second chamber. The housing can have a sample gas inlet that can receive sample gas from a sample line connected to the inlet line of the therapeutic gas delivery device and a sample gas outlet. The first chamber can be within the housing and can include a first filter membrane, a baffle plate, a fiber membrane, and a first reservoir. The first filter membrane can have a first side and a second side. The baffle plate can support the first filter membrane on the first side, and the fiber membrane can support the first filter membrane on the second side. The first reservoir can be between the sample gas inlet and the baffle plate. The second chamber can be within the housing and can include a second filter membrane, a press-fit baffle, a labyrinth support, and a second reservoir. The second filter membrane can have a first side and a second side. The press-fit baffle can support a second filter membrane on a first side. The labyrinth support can be on a wall of the housing having the sample gas outlet, and the labyrinth support can support a second filter membrane on a second side. The second reservoir can be between the fiber membrane of the first chamber and the press-fit baffle.

[0012] In certain cases, the sample gas filter can remove water vapor from the sample gas and collect the water in the first reservoir and / or the second reservoir.

[0013] In certain cases, the housing and the chamber can each have a substantially circular cross-section.

[0014] In certain cases, the first and second reservoirs can be axially oriented so that the sample gas filter can be used in any axial orientation.

[0015] In certain cases, the first filter membrane and the second filter membrane can be substantially circular.

[0016] In certain cases, the first filter membrane can have a larger diameter than the second filter membrane.

[0017] In certain cases, the first reservoir can have a larger volume than the second reservoir.

[0018] In certain cases, the first and second reservoirs can be large enough to contain water for 12 hours of continuous use.

[0019] In certain cases, the first filter membrane can be a glass fiber filter membrane. In certain cases, the second filter membrane can be a 0.22 μm PTFE filter membrane. In certain cases, the fiber membrane can be made of a sintered porous plastic material (e.g., a coarse Vyon® fiber membrane). In certain cases, the first filter membrane and the second filter membrane can be separated to prevent wicking between the membranes.

[0020] The description will be more fully understood with reference to the following figures and data graphs, which are presented as various embodiments of the present disclosure and should not be construed as a complete recitation of the scope of the present disclosure. It should be noted that for clarity of illustration, certain elements in the various figures may not be drawn to scale. With the understanding that these figures merely depict exemplary embodiments of the present disclosure and therefore should not be considered limiting of its scope, the principles herein will be described and explained with additional specificity and detail through the use of the accompanying drawings. [Brief explanation of the drawings]

[0021] [Figure 1A] 1 illustrates a therapeutic gas delivery system having a sample gas filter assembly. [Figure 1B] 1 illustrates a therapeutic gas delivery system having a sample gas filter assembly. [Figure 2A] 1A and 1B show an example of a sample gas filter assembly; [Figure 2B] 1A and 1B show an example of a sample gas filter assembly; [Figure 2C] 1A and 1B show an example of a sample gas filter assembly; [Figure 2D] 1A and 1B show an example of a sample gas filter assembly; [Figure 2E] 1A and 1B show an example of a sample gas filter assembly; [Figure 2F] 1 shows an example of a sample gas filter assembly; 2 is an enlarged cross-sectional view of a sample gas filter; [Figure 3A] An example of a sample gas filter is shown in a perspective cross-sectional view. [Figure 3B] An example of a sample gas filter is shown in a perspective cross-sectional view. [Figure 3C] An example of a sample gas filter is shown in a perspective cross-sectional view. [Figure 3D] An example of a sample gas filter is shown in a perspective cross-sectional view. DETAILED DESCRIPTION OF THE INVENTION

[0022] It will be understood that for simplicity and clarity of description, reference numerals have been repeated among different figures, where appropriate, to indicate corresponding or similar elements. Additionally, numerous specific details have been set forth in order to provide a thorough understanding of the examples described herein. However, those skilled in the art will understand that the examples described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the relevant features being described. Additionally, this specification should not be considered as limiting the scope of the embodiments described herein. The figures are not necessarily to scale, and the proportions of certain parts may be exaggerated to better illustrate the details and features of the present disclosure.

[0023] Several definitions that apply throughout the above disclosure are now presented.

[0024] The term "coupled," as used herein, is defined as directly or indirectly connected through intervening components, and is not necessarily limited to a physical connection. The connection can be such that the objects are permanently connected or releasably connected.

[0025] The term "substantially" is defined as an element essentially conforming to a particular size, shape, or other word that substantially modifies, so as not to be precise.

[0026] The terms "comprising," "including," and "having" are used interchangeably in this disclosure. The terms "comprising," "including," and "having" mean including, but not necessarily limited to, what is so set forth.

[0027] The terms "filter" and "filtration" are used herein in their broadest sense to encompass any and all of the various types and degrees of removal or separation of liquid from gas, and in some cases may also include the removal of other non-liquid particulates, if present.

[0028] The present disclosure relates to a patient gas sample line and filter (e.g., a sample gas filter assembly) and methods of use thereof. The filter includes a multi-stage filtration system with a liquid reservoir that filters liquid from a liquid-containing sample gas (e.g., a portion of a respiratory gas and therapeutic gas mixture). The liquid component may be any removable liquid, such as, for example, humidity, water vapor, moisture from humidified air, other liquids in a vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.

[0029] The sample gas filter assembly can be used with a therapeutic gas delivery system that delivers a therapeutic gas (e.g., nitric oxide) to a patient's airway. The therapeutic gas is delivered to the patient by administration to a breathing circuit, typically along with a mechanical ventilator. A subsystem of the therapeutic gas delivery system contains a gas sensor module that includes one or more gas sensors that monitor the concentration of the therapeutic gas and / or other gases delivered to the patient. The gas sensor module is connected to the same patient breathing circuit as the therapeutic gas delivery system.

[0030] Breathing circuits are often humidified, and therefore the gas sampled by the gas sensor module has a high percentage of water vapor. The present disclosure filters water vapor from the sample gas and collects it in a reservoir while allowing the remainder of the sample gas to proceed to one or more gas sensors in the gas sensor module. The sample gas filter assembly disclosed herein allows the device to operate at high humidity (e.g., when active humidification is used in the breathing circuit) for extended periods of time (e.g., 12 hours or more).

[0031] The sample gas filter assembly may be more convenient to use than conventional patient gas sample lines and filters. For example, the sample gas filter assembly may be easier to manufacture (e.g., may involve only one or two manufacturing steps). Furthermore, the sample gas filter assembly may be used in any axial orientation.

[0032] 1A-1B illustrate one example of a therapeutic gas delivery system 100 (e.g., a nitric oxide delivery system). Therapeutic gas delivery system 100 can include a therapeutic gas delivery device 102 and a sample gas filter assembly 104 (e.g., a patient gas sample line). Sample gas filter assembly 104 can include a sample gas filter 106 and a sample line 108. Sample gas filter assembly 104 is disconnected from therapeutic gas delivery device 102 in FIG. 1A, while sample gas filter assembly 104 is connected to the therapeutic gas delivery device in FIG. 1B.

[0033] The therapeutic gas delivery device 102 can deliver a therapeutic gas (e.g., nitric oxide) to a patient's airway. In one case, a gas subsystem (not shown) of the therapeutic gas delivery device 102 can be fluidly connected to an inspiratory line 110 (e.g., breathing circuit tubing), thereby establishing a fluid flow path between the gas subsystem and the inspiratory line 110. For example, as shown in FIG. 1B , the gas subsystem can be fluidly connected to a gas insufflation module 112, which can be fluidly connected to the inspiratory line 110. The inspiratory line 110 can include an upstream end 114 and a downstream end 116 opposite the upstream end 114. The upstream end 114 can be fluidly connected to, for example, a ventilator (not shown). The downstream end 116 can be fluidly connected to, for example, a patient (not shown). Thus, gas can flow from the gas subsystem of the therapeutic gas delivery device 102 into the inspiratory line 110 and into the patient's airway.

[0034] The therapeutic gas delivery device 102 may also include a gas sensor module (not shown). The gas sensor module may include one or more gas sensors (e.g., a nitric oxide sensor, a nitrogen dioxide sensor, an oxygen sensor) that can analyze a sample gas (e.g., a portion of the gas being delivered to the patient). The sample gas may include, for example, a respiratory gas and a therapeutic gas (e.g., nitric oxide) delivered to the patient's airway. In one case, the sample gas filter assembly 104 may be in fluid communication with the inlet line 110 and the gas sensor module, thereby establishing a fluid flow path between the inlet line 110 and the gas sensor module of the therapeutic gas delivery device 102. For example, a sample tee 118 may be in fluid communication with the inlet line 110, and the sample tee 118 may be in fluid communication with the inlet line 110. The sample tee 118 may be located downstream of the gas injection module 112. The sample gas can flow from the inlet line 110 through the sample gas filter assembly 104 to the gas sensor module of the therapeutic gas delivery device 102 .

[0035] 2A-2F illustrate one example of a sample gas filter assembly 104. The sample gas filter assembly 104 can include a sample gas filter 106, as shown in the perspective view of FIG. 2A, for example, and can also include a sample line 108. As described above, the sample gas filter assembly 104 can be used in a therapeutic gas delivery device (not shown in FIGS. 2A-2F). For example, the sample gas filter assembly 104 can be used to establish fluid communication (e.g., establish a fluid flow path) between an inspiratory line (e.g., breathing circuit tubing) and a gas sensor module of the therapeutic gas delivery device.

[0036] Starting with the sample line 108 of the sample gas filter assembly 104, the sample line 108 (e.g., a length of tubing) includes an elongate body 220 having an inlet end 222 and an outlet end 224 opposite the inlet end 222, as shown, for example, in the side view of FIG. 2B. The elongate body 220 defines a central lumen 226, as shown, for example, in the cross-sectional views of FIGS. 2E-2F (taken along the cross-sectional line shown in FIG. 2D). The central lumen 226 extends along the longitudinal axis of the elongate body 220 from the inlet end 222 to the outlet end 224. In other words, the inlet end 222 is in fluid communication with the outlet end 224, thereby establishing a fluid flow path through the central lumen 226 of the elongate body 220 of the sample line 108. The central lumen 226 can carry the sample gas through the elongate body 220 (eg, from the inlet end 222 to the outlet end 224).

[0037] The inlet end 222 of the sample line 108 can receive sample gas into the sample line 108. In one example, the inlet end 222 can receive the sample gas from an intake line (not shown in FIGS. 2A-2F ) of a therapeutic gas delivery device (not shown in FIGS. 2A-2F ). The inlet end 222 of the sample line 108 can include a connector 228, such as a Luer fitting. The connector 228 can be configured to removably couple the sample line 108 to the intake line (e.g., via a sample tee) to establish fluid communication (e.g., a fluid flow path) between the intake line and the sample gas filter assembly 104.

[0038] An outlet end 224 of the sample line 108 can discharge the sample gas from the sample line 108, for example, as shown in the side view of the sample gas filter assembly 104 in Figure 2B. In one case, the outlet end 224 can be removably coupled to a sample gas inlet 232 of the sample gas filter 106 to establish fluid communication (e.g., a fluid flow path) between the sample line 108 and the sample gas filter 106.

[0039] Referring to sample gas filter 106 of sample gas filter assembly 104, sample gas filter 106 may include a housing 230 having a sample gas inlet 232 and a sample gas outlet 234. Sample gas inlet 232 may be in fluid communication with sample gas outlet 234, thereby establishing a fluid flow path through sample gas filter 106 (e.g., from sample gas inlet 232 to sample gas outlet 234).

[0040] The sample gas inlet 232 can receive the sample gas into the sample gas filter 106. In one example, the sample gas inlet 232 can receive the sample gas from a sample line 108 connected to an inlet line of a therapeutic gas delivery device (not shown in FIGS. 2A-2F). For example, the sample gas inlet 232 can be removably coupled to the sample line 108, which can be removably coupled to the inlet line, thereby establishing fluid communication between the inlet line and the sample gas filter 106.

[0041] The sample gas outlet 234 can exhaust the sample gas from the sample gas filter 106. In one example, the sample gas outlet 234 can exhaust the sample gas to a gas sensor module of a therapeutic gas delivery device (not shown in FIGS. 2A-2F). The sample gas outlet 234 can be configured to removably couple to a fitting (e.g., a Luer fitting). For example, in one case, the sample gas outlet 234 can extend outward (e.g., away from) the sample gas filter 106 and include male threads for removably coupling to a fitting. In another case (not shown in FIGS. 2A-2F), the sample gas outlet 234 can include female threads for removably coupling to a fitting. The configuration (e.g., male or female threads) of the sample gas outlet 234 can be of the opposite gender to the connector 228 of the sample line 108, such that the sample gas filter assembly 104 is unidirectional.

[0042] Housing 230 can define an outer surface 236 and an inner surface 238 opposite outer surface 236, for example, as shown in Figures 2E-2F. The thickness of housing 230 can be defined by the distance between outer surface 236 and inner surface 238. Housing 230 can have a substantially circular cross-section, which can define a diameter of housing 230.

[0043] In one example, housing 230 can include a first shell 240 and a second shell 242, which can each define an outer surface 236 and a portion of an inner surface 238 of housing 230. First shell 240 can define a first surface 244 opposite sample gas inlet 232. Second shell 242 can define a second surface 246 opposite sample gas outlet 234. First surface 244 of first shell 240 can abut, in whole or in part, against second surface 246 of second shell 242 to form housing 230 that is watertight. In one example, ultrasonic welds 248 can join first shell 240 and second shell 242 to one another at first surface 244 and second surface 246.

[0044] First chamber 250 can be located within housing 230. In other words, housing 230 of sample gas filter 106 can wholly or partially define first chamber 250. In one case, first chamber 250 is partially defined by inner surface 238 of first shell 240. In one case, first chamber 250 can have a substantially circular cross-section, which can define a diameter of first chamber 250.

[0045] Second chamber 252 can be located within housing 230. In other words, housing 230 of sample gas filter 106 can wholly or partially define second chamber 252. In one case, second chamber 252 is partially defined by inner surface 238 of second shell 242. In one case, second chamber 252 can have a substantially circular cross-section, which can define a diameter of second chamber 252.

[0046] 3A-3D show three-dimensional cross-sectional views of one example of sample gas filter 106 of sample gas filter assembly 104. These views illustrate various internal components that may be included in sample gas filter 106. For example, as shown in FIG. 3A, sample gas filter 106 may include first filter membrane 354 and second filter membrane 366.

[0047] For example, as shown in the perspective view of FIG. 3A, a first filter membrane 354 (e.g., a first stage of filtration) can be included in the first chamber 250. The first filter membrane 354 can define a first side 356 and a second side 358 opposite the first side 356. In one case, the first filter membrane 354 can be substantially circular in shape, which can define the diameter of the first filter membrane 354. The first filter membrane 354 can remove vapor from the sample gas (e.g., the sample gas flowing through the first filter membrane 354) and can coalesce and collect liquid in a first reservoir 360 (e.g., a front reservoir), as shown in FIG. 3C, for example. In some cases, the first filter membrane 354 can coalesce liquids that are both oleophobic and hydrophobic. In one case, the first filter membrane 354 can be a glass fiber filter membrane.

[0048] In some cases, first filter membrane 354 can be held in place (e.g., secured) and / or sealed by abutment between first surface 244 of first shell 240 and second surface 246 of second shell 242. For example, ultrasonic weld 248 joining first surface 244 and second surface 246 can secure and / or seal first filter membrane 354.

[0049] For example, as shown in FIG. 3C , first reservoir 360 can be included within first chamber 250 (e.g., integrated into housing 230). In some cases, first reservoir 360 can be located between sample gas inlet 232 and first filter membrane 354. In other cases, first reservoir 360 can be located between sample gas inlet 232 and baffle plate 362. Sample gas filter 106 can remove water vapor from the sample gas (e.g., via first filter membrane 354) and collect water in first reservoir 360. First reservoir 360 can be axially oriented along the length of the filter such that sample gas filter 106 can operate (e.g., remove water vapor from the sample gas and collect water) in any orientation during operation. First reservoir 360 can define a volume and, in some cases, can be configured to contain water for approximately 12 hours of continuous use under humidification before needing to be replaced.

[0050] 3A, the baffle plate 362 can be included within the first chamber 250. In some instances, the baffle plate 362 can mechanically support the first filter membrane 354 on a first side 356 (e.g., a front side facing the flow of sample gas) of the first filter membrane 354.

[0051] The fiber membrane 364, in some cases, can be included within the first chamber 250. In some examples, the fiber membrane 364 can mechanically support the first filter membrane 354 on the second side 358 (e.g., the backside) of the first filter membrane 354. In one example, the fiber membrane 364 can be made of a sintered porous plastic material. In one example, the fiber membrane can be a coarse Vyon® fiber membrane.

[0052] For example, as shown in the perspective view of FIG. 3A, a second filter membrane 366 (e.g., a second stage of filtration) can be included in the second chamber 252. The second filter membrane 366 can define a first side 368 and a second side 370 opposite the first side 368. In one case, the second filter membrane 366 can be substantially circular in shape, which can define the diameter of the second filter membrane 366. The second filter membrane 366 can remove vapor from the sample gas (e.g., the sample gas flowing through the second filter membrane 366) and coalesce and collect liquid in a second reservoir 372 (e.g., a rear reservoir), as shown in FIG. 3C, for example. In some cases, the second filter membrane 366 can be a hydrophobic membrane. For example, the second filter membrane 366 can be a 0.22 μm polytetrafluoroethylene (PTFE) filter membrane.

[0053] The diameter of second filter membrane 366, in some examples, can be smaller than the diameter of first filter membrane 354. In other words, the diameter of first filter membrane 354 can be larger than the diameter of second filter membrane 366, as shown, for example, in FIG.

[0054] The first filter membrane 354 and the second filter membrane 366 can, in some cases, be separated to prevent wicking between the first filter membrane 354 and the second filter membrane 366. For example, as shown in FIG. 3C, a gap may exist between the first filter membrane 354 and the second filter membrane 366 to prevent wicking.

[0055] 3C , the second reservoir 372 can be included within the second chamber 252 (e.g., integrated into the housing 230). In some cases, the second reservoir 372 can be located between the first filter membrane 354 and the sample gas outlet 234. In other cases, the second reservoir 372 can be located between the fiber membrane 364 of the first chamber 250 and a press-fit baffle 374 (described below). The sample gas filter 106 can remove water vapor from the sample gas (e.g., via the second filter membrane 366) and collect the water in the second reservoir 372. The second reservoir 372 can be axially oriented along the length of the filter, allowing the sample gas filter 106 to operate (e.g., remove water vapor from the sample gas and collect water) in any orientation during operation. The second reservoir 372 can define a volume and, in some cases, can be configured to contain water for approximately 12 hours of continuous use under humidification before needing to be replaced.

[0056] The first reservoir 360 and the second reservoir 372 can be axially oriented so that the sample gas filter 106 can operate in any axial orientation. In some cases, the first reservoir 360 and the second reservoir 372 can be large enough (e.g., have sufficient volume) to contain water for at least 12 hours of continuous use. The volume of the second reservoir 372 can, in some cases, be smaller than the volume of the first reservoir 360. In other words, the volume of the first reservoir 360 can be larger than the volume of the second reservoir 372, for example, as shown in FIG. 3C.

[0057] A press-fit baffle 374, in some cases, can be included in the second chamber 252. In some examples, the press-fit baffle 374 can mechanically support the second filter membrane 366 on a first side 368 (e.g., a front side facing the flow of sample gas) of the second filter membrane 366.

[0058] 3D , may be included within second chamber 252. Labyrinth support 376 may be located on inner surface 238 of housing 230 (e.g., inner surface 238 of second shell 242) near sample gas outlet 234. In some examples, labyrinth support 376 may mechanically support second filter membrane 366 on second side 370 (e.g., backside) of second filter membrane 366. Additionally, labyrinth support 376 may facilitate effective circulation of sample gas behind second filter membrane 366.

[0059] The sample gas filter assembly 104, including the sample line 108 and / or sample gas filter 106, can be removed and replaced as needed. In other words, the existing sample line 108 and / or sample gas filter 106 can be removed from the therapeutic gas delivery device, and a new sample line 108 and / or sample gas filter 106 can be connected in its place, as described above.

[0060] The foregoing merely illustrates the principles of the present invention. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in light of the teachings herein. It should thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and methods which, although not explicitly shown or described herein, embody the principles of the present invention and therefore are within the spirit and scope of the present invention. From the above description and drawings, those skilled in the art will appreciate that the specific embodiments shown and described are for illustrative purposes only and are not intended to limit the scope of the invention. Reference to details of specific embodiments is not intended to limit the scope of the invention.

[0061] Reference to an "embodiment," "aspect," "case," or "example" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearances of the phrases "embodiment," "aspect," "case," or "example" in various places throughout this specification do not necessarily all refer to the same embodiment, nor are they separate or alternative embodiments mutually exclusive of other embodiments. Furthermore, various features are described that may be exhibited by some embodiments and not by other embodiments.

[0062] The terms used herein generally have their ordinary meaning in the art, within the context of this disclosure and in the specific context in which each term is used. Alternative language and synonyms may be used for any one or more of the terms discussed herein, and no particular importance should be placed on whether a term is recited or discussed herein. In some cases, synonyms for a particular term are provided. The recitation of one or more synonyms does not preclude the use of other synonyms. The use of examples anywhere in this specification, including examples of any term discussed herein, is merely illustrative and does not further limit the scope and meaning of the disclosure or any exemplary term. Similarly, the present disclosure is not limited to the various embodiments provided herein.

Claims

1. 1. A sample gas filter for a therapeutic gas delivery device, the sample gas filter comprising: a housing having a sample gas inlet and a sample gas outlet, the sample gas inlet operable to receive sample gas from a sample line connected to an inspiratory line of the therapeutic gas delivery device; a first chamber disposed within the housing, the first chamber comprising: a first filter membrane; a first chamber comprising a first reservoir disposed between the sample gas inlet and the first filter membrane; a second chamber disposed within the housing, the second chamber comprising: a second filter membrane; a second chamber comprising a second reservoir disposed between the first filter membrane and the sample gas outlet; the first reservoir and the second reservoir are axially oriented such that the sample gas filter is operable for use in any axial orientation; The sample gas filter is operable to remove water vapor from the sample gas and collect water in the first reservoir and / or the second reservoir.

2. The first chamber comprises: a baffle plate operable to support the first filter membrane on a first side of the first filter membrane; 10. The sample gas filter of claim 1, further comprising: a fabric membrane operable to support the first filter membrane on a second side of the first filter membrane.

3. The second chamber comprises: a press-fit baffle operable to support the second filter membrane on a first side of the second filter membrane; 10. The sample gas filter of claim 1, further comprising: a labyrinth support on a wall of the housing having the sample gas outlet, the labyrinth support operable to support the second filter membrane on a second side of the second filter membrane.

4. 10. The sample gas filter of claim 1, wherein the housing and the chamber each have a substantially circular cross section.

5. 10. The sample gas filter of claim 1, wherein the first filter membrane and the second filter membrane are substantially circular.

6. 6. The sample gas filter of claim 5, wherein the first filter membrane has a larger diameter than the second filter membrane.

7. 10. The sample gas filter of claim 1, wherein the first reservoir has a larger volume than the second reservoir.

8. 8. The gas sample filter of claim 7, wherein the first reservoir and the second reservoir are large enough to contain water for 12 hours of continuous use.

9. 10. The sample gas filter of claim 1, wherein the first filter membrane is a glass fiber filter membrane.

10. 10. The sample gas filter of claim 1, wherein the second filter membrane is a 0.22 μm PTFE filter membrane.

11. 3. The sample gas filter of claim 2, wherein the fiber membrane is a coarse fiber membrane comprising a sintered porous plastic.

12. 10. The sample gas filter of claim 1, wherein the first filter membrane and the second filter membrane are separated to prevent wicking between the membranes.

13. 1. A sample gas filter for a therapeutic gas delivery device, the sample gas filter comprising: a housing having a sample gas inlet and a sample gas outlet, the sample gas inlet operable to receive sample gas from a sample line connected to an inspiratory line of the therapeutic gas delivery device; a first chamber disposed within the housing, the first chamber comprising: a first filter membrane having a first side and a second side; a baffle plate operable to support the first filter membrane on the first side; a fiber membrane operable to support the first filter membrane on the second side; a first chamber comprising a first reservoir disposed between the sample gas inlet and the baffle plate; a second chamber disposed within the housing, the second chamber comprising: a second filter membrane having a first side and a second side; a press-fit baffle operable to support the second filter membrane on the first side; a labyrinth support on a wall of the housing having the sample gas outlet, the labyrinth support operable to support the second filter membrane on the second side; and a second chamber comprising a second reservoir disposed between the fabric membrane and the press-fit baffle of the first chamber.

14. 14. The gas sample filter of claim 13, wherein the sample gas filter is operable to remove water vapor from the gas sample and collect water in the first reservoir and / or the second reservoir.

15. 14. The sample gas filter of claim 13, wherein the housing and the chamber each have a substantially circular cross section.

16. 16. The sample gas filter of claim 15, wherein the first reservoir and the second reservoir are axially oriented such that the sample gas filter is operable for use in any axial orientation.

17. 16. The sample gas filter of claim 15, wherein the first filter membrane and the second filter membrane are substantially circular.

18. 18. The sample gas filter of claim 17, wherein the first filter membrane has a larger diameter than the second filter membrane.

19. 14. The sample gas filter of claim 13, wherein the first reservoir has a larger volume than the second reservoir.

20. 20. The gas sample filter of claim 19, wherein the first reservoir and the second reservoir are large enough to contain water for 12 hours of continuous use.

21. 14. The sample gas filter of claim 13, wherein the first filter membrane is a glass fiber filter membrane.

22. 14. The sample gas filter of claim 13, wherein the second filter membrane is a 0.22 μm PTFE filter membrane.

23. 14. The sample gas filter of claim 13, wherein the fiber membrane is an open fiber membrane comprising a sintered porous plastic material.

24. 14. The sample gas filter of claim 13, wherein the first filter membrane and the second filter membrane are separated to prevent wicking between the membranes.

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