WO2011141841A1

WO2011141841A1 - System and method of delivering positive airway pressure therapy to individual airway orifices of a subject

Info

Publication number: WO2011141841A1
Application number: PCT/IB2011/051787
Authority: WO
Inventors: Michael Edward Colbaugh
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2010-05-14
Filing date: 2011-04-25
Publication date: 2011-11-17

Abstract

Positive airway pressure therapy is delivered to the airway of a subject through a single airway orifice. The positive airway pressure therapy is configured to support the airway of the subject to reduce or eliminate obstructive respiratory events (e.g., apneas, etc.). The delivery of the positive airway pressure therapy to the airway of the subject through a single airway orifice may provide an enhanced comfort. This may enhance compliance by the subject.

Description

SYSTEM AND METHOD OF DELIVERING POSITIVE AIRWAY PRESSURE THERAPY TO

INDIVIDUAL AIRWAY ORIFICES OF A SUBJECT

[01] The invention relates to the delivery of positive airway pressure therapy to the

airway of a subject to support the airway against obstructive respiratory events.

[02] Systems that provide a pressurized flow of breathable gas to the airway of a subject to support the airway of the subject against obstructive respiratory events are known.

Typically, such systems are used to support the airway of the subject during sleep.

Generally, the pressurized flow of breathable gas is delivered to the subject through a conventional patient interface appliance. These appliances are configured to engage two or more external orifices of the airway of the subject, and the pressurized flow of breathable gas is delivered through all of the engaged orifices simultaneously, with the appliance maintaining fluid substantially unencumbered fluid communication between the engaged orifices. For example, conventional appliances include nasal cannula that engage both nostrils of the subject, and masks that engage the nostrils and mouth of the subject.

[03] One aspect of the invention relates to a system configured to delivery positive

airway pressure therapy to a subject. In one embodiment, the system comprises a subject interface appliance configured to deliver a pressurized flow of breathable gas to the airway of the subject, the subject interface appliance being configured to deliver the pressurized flow of breathable gas to only a first nostril of the subject such that the airway of the subject is pressurized by the pressurized flow of breathable gas through the first nostril.

[04] Another aspect of the invention relates to a method of delivering positive airway pressure therapy to a subject. In one embodiment, the method comprises delivering a pressurized flow of breathable gas to only a first nostril of the subject such that the airway of the subject is pressurized by the pressurized flow of breathable gas through the first nostril.

[05] Yet another aspect of the invention relates to a system configured to deliver a

positive airway pressure therapy to a subject. In one embodiment, the system comprises means for delivering a pressurized flow of breathable gas to only a first nostril of the subject such that the airway of the subject is pressurized by the pressurized flow of breathable gas through the first nostril.

[06] These and other objects, features, and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. In one embodiment of the invention, the structural components illustrated herein are drawn to scale. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not a limitation of the invention. In addition, it should be appreciated that structural features shown or described in any one embodiment herein can be used in other embodiments as well. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification and in the claims, the singular form of "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[07] FIG. 1 illustrates a system configured to deliver positive airway pressure therapy to the airway of a subject, in accordance with one or more embodiments of the invention.

[08] FIG. 2 illustrates a patient interface appliance, according to one or more

embodiments of the invention.

[09] FIG. 3A illustrates a patient interface appliance, in accordance with one or more embodiments of the invention.

[10] FIG. 3B illustrates a patient interface appliance seated in a nostril of a subject,

according to one or more embodiments of the invention.

[11] FIG. 4A illustrates a patient interface appliance, in accordance with one or more embodiments of the invention.

[12] FIG. 4B illustrates a patient interface appliance seated in a nostril of a subject,

according to one or more embodiments of the invention. [13] FIG. 5A illustrates a patient interface appliance, in accordance with one or more embodiments of the invention.

[14] FIG. 5B illustrates a patient interface appliance seated in a nostril of a subject,

according to one or more embodiments of the invention.

[15] FIG. 6A illustrates a patient interface appliance, in accordance with one or more embodiments of the invention.

[16] FIG. 6B illustrates a patient interface appliance seated in a nostril of a subject,

according to one or more embodiments of the invention.

[17] FIG. 7 illustrates a patient interface appliance, in accordance with one or more

embodiments of the invention.

[18] FIG. 8 illustrates a patient interface appliance, in accordance with one or more

embodiments of the invention.

[19] FIG. 9 illustrates a system configured to deliver positive airway pressure therapy to the airway of a subject, in accordance with one or more embodiments of the invention.

[20] FIG. 10 illustrates a system configured to deliver positive airway pressure therapy to the airway of a subject, in accordance with one or more embodiments of the invention.

[21] FIG. 1 1 illustrates a system configured to deliver positive airway pressure therapy to the airway of a subject, in accordance with one or more embodiments of the invention.

[22] FIG. 1 illustrates a system 10 configured to deliver positive airway pressure therapy to the airway of a subject 12. The positive airway pressure therapy is configured to support the airway of subject 12 to reduce or eliminate obstructive respiratory events (e.g., apneas, etc.). The system 10 delivers the positive airway pressure therapy to the airway of subject 12 with an enhanced comfort. This may enhance compliance by subject 12. In one embodiment, system 10 includes one or more of a pressure generator 14, electronic storage 16, a user interface 18, a gas delivery circuit 20, a sensor 22, a controller 24, and/or other components.

[23] In one embodiment, pressure generator 14 is configured to generate a pressurized flow of breathable gas for delivery to the airway of subject 12. The pressure generator 14 may control one or more parameters of the pressurized flow of breathable gas (e.g., flow rate, pressure, volume, humidity, temperature, gas composition, etc.) for therapeutic purposes, or for other purposes. By way of non-limiting example, pressure generator 14 may be configured to control the flow rate and/or pressure of the pressurized flow of breathable gas to provide positive airway pressure therapy to the airway of subject 12. The pressure generator 14 may include a ventilator, a positive airway pressure generator such as, for example, the device described in U.S. Patent No. 6, 105,575, hereby incorporated by reference in its entirety, and/or other pressure generation devices. The pressure support provided by subject 14 via the pressurized flow of breathable gas may include, for example, non-invasive ventilation, positive airway pressure support, continuous positive airway pressure support, bi-level support, BiPAP®, and/or other types of positive airway pressure therapy. The flow rate of the pressurized flow of breathable gas to subject 12 may be between 0 Liters Per Minute (LPM) and about 150 LPM. In one embodiment, the pressurized flow of breathable gas is delivered to subject 12 for at least a portion of a therapy session at a flow rate of greater than about 75 LPM.

[24] In one embodiment, electronic storage 16 comprises electronic storage media that electronically stores information. The electronic storage media of electronic storage 16 may include one or both of system storage that is provided integrally (i.e., substantially non-removable) with system 10 and/or removable storage that is removably connectable to system 10 via, for example, a port (e.g., a USB port, a firewire port, etc.) or a drive (e.g., a disk drive, etc.). Electronic storage 16 may include one or more of optically readable storage media (e.g., optical disks, etc.), magnetically readable storage media (e.g., magnetic tape, magnetic hard drive, floppy drive, etc.), electrical charge-based storage media (e.g., EEPROM, RAM, etc.), solid-state storage media (e.g., flash drive, etc.), and/or other electronically readable storage media. Electronic storage 16 may store software algorithms, information determined by processor 24, information received via user interface 18, and/or other information that enables system 10 to function properly. Electronic storage 16 may be (in whole or in part) a separate component within system 10, or electronic storage 16 may be provided (in whole or in part) integrally with one or more other components of system 10 (e.g., generator 14, user interface 18, processor 24, etc.).

[25] User interface 18 is configured to provide an interface between system 10 and

subject 12 through which subject 12 may provide information to and receive information from system 10. This enables data, cues, results, and/or instructions and any other communicable items, collectively referred to as "information," to be communicated between the subject 12 and one or more of generator 14, electronic storage 16, and/or processor 24. Examples of interface devices suitable for inclusion in user interface 18 include a keypad, buttons, switches, a keyboard, knobs, levers, a display screen, a touch screen, speakers, a microphone, an indicator light, an audible alarm, a printer, a tactile feedback device, and/or other interface devices. In one embodiment, user interface 18 includes a plurality of separate interfaces. In one embodiment, user interface 18 includes at least one interface that is provided integrally with generator 14.

[26] It is to be understood that other communication techniques, either hard-wired or wireless, are also contemplated by the present invention as user interface 18. For example, the present invention contemplates that user interface 18 may be integrated with a removable storage interface provided by electronic storage 16. In this example, information may be loaded into system 10 from removable storage (e.g., a smart card, a flash drive, a removable disk, etc.) that enables the user(s) to customize the

implementation of system 10. Other exemplary input devices and techniques adapted for use with system 10 as user interface 18 include, but are not limited to, an RS-232 port, RF link, an IR link, modem (telephone, cable or other). In short, any technique for

communicating information with system 10 is contemplated by the present invention as user interface 18.

[27] The pressurized flow of breathable gas generated by external information sources 14 is delivered to the airway of subject 12 via a gas delivery circuit 26. As such, gas delivery circuit 26 is configured to communicate the pressurized flow of breathable gas generated by pressure generator 14 to the airway of subject 12. Gas delivery circuit 26 includes a conduit 28 and an interface appliance 30, and/or other components. Conduit 28 conveys the pressurized flow of breathable gas to interface appliance 30, and interface appliance 30 delivers the pressurized flow of breathable gas to the airway of subject 12.

[28] To enhance the comfort of subject 12 during the provision of the positive airway pressure therapy, system 10 is configured to deliver the pressurized flow of breathable gas to only one airway orifice of subject 12 (e.g., only one nostril). In one embodiment, interface appliance 30 is configured to deliver the pressurized flow of breathable gas to only a first nostril of subject 12. The interface appliance 30 may include one or more of a conduit 32, a first nostril interface 34, a second nostril interface 36, a resistive flow path 38, and/or other components.

[29] The conduit 32 has a first opening 40 and a second opening 42. The conduit 32 is configured to form a flow path between first opening 40 and second opening 42. The first opening 40 is configured to receive the pressurized flow of breathable gas generated by pressure generator 14. In one embodiment, first opening 40 of conduit 32 is connected to conduit 28 to receive the pressurized flow of breathable gas from conduit 28. This connection may be removable, permanent, or substantially permanent. For example, conduit 32 may be selectively, and reattachably, disconnected from conduit 28 for cleaning. In one embodiment, conduit 32 is formed from a flexible material. This may enhance the comfort of interface appliance 30 to subject 12 (e.g., as subject 12 moves during use).

[30] The first nostril interface 34 is configured to interface with a first nostril of subject 12.

Through this interface, the pressurized flow of breathable gas is delivered to the first nostril of subject 12. The interface may be sealed, or the interface may not be sealed. As such, first nostril interface 34 is in fluid communication with conduit 32 to receive the pressurized flow of breathable gas from the conduit 32, and to deliver the pressurized flow of breathable gas to the first nostril. For example, first nostril interface 34 may be connected directly to second opening 42 of conduit 32, or first nostril interface 34 may be connected to a manifold, coupler, or bus, that places first nostril interface 34 in fluid communication with second opening 42 of conduit 32. The connection between first nostril interface 34 and resistive flow path 38 may be removable, permanent, or substantially permanent. For example, first nostril interface 34 may be selectively, and reattachably disconnected from conduit 38 for cleaning. As an example, first nostril interface 34 may be removable from conduit 38, and replaced with a new first nostril interface 34.

[31] The second nostril interface 36 is configured to interface with a second nostril of subject 12. The interface may be sealed, or may be unsealed. The second nostril interface 36 places resistive flow path 38 in fluid communication with the second nostril such that respiration through the second nostril is also through resistive flow path 38. The resistive flow path 38 is configured to provide a resistance to gas exhaled from the second nostril. This may create a back pressure within the airway of subject 12 during exhalation that provides further support for the airway of subject 12 (over and above that provided solely by the pressurized flow of breathable gas).

[32] In one embodiment, the resistive flow path 38 includes one or more valves placed in the flow path that communicates with the second nostril of subject 12. The one or more valves may be removable/replaceable to facilitate removal for cleaning and/or for swapping to configure the resistance of resistive flow path 38. A valve within resistive flow path 38 may have a lower resistance for inhaled gas than for exhaled gas, or the valve may have the same resistance for inhalation and exhalation.

[33] Delivery of the pressurized flow of breathable gas through only the first nostril

enhances the comfort of subject 12 with respect to conventional systems in which the pressurized flow of breathable gas is delivered to the airway of subject 12 through both of the first nostril and the second nostril. For example, providing the pressurized flow of breathable gas through only the first nostril may reduce the drying effect of the gas through the sinuses of subject 12. Further, enabling subject 12 to breathe through the second nostril while the pressurized flow of breathable gas is delivered to the first nostril may enable the gas being inhaled and/or exhaled through the second nostril to maintain a more comfortable range of nose temperatures. Still further, only delivering the pressurized flow of breathable gas through the first nostril may reduce a feeling of claustrophobia and/or restriction sometimes experienced by subjects receiving positive airway pressure therapy. Open interfaces like this one also makes talking and equalization of the Eustachian tubes easier. Compared to other open airflow interfaces, like high-flow cannulas, this interface offers advantages as well. Since the nasal passage is utilized as part of the flow path, with a sealed (or unsealed) interface to one nostril, the interface described in this disclosure does a better job of maintaining comfort of the drying effect, temperature, while offering the same advantages of reducing claustrophobic sensations, ease of talking and Eustachian tube pressure manipulation. Further, this single sided sealed interface may be quieter than the other open interfaces, because the output end of the airflow is inside the sinus itself, not the end of an orifice blowing into the nostril. It is because the sinus and flow controlling structures of the sinus are a part of the air flow delivery path that the present invention provides advantages when compared to other open interfaces and added comfort when compared to conventional subject interfaces.

[34] The sensor 22 is configured to generate output signals conveying information

related to respiration of subject 12, position of subject 12, and/or other information related to subject 12. The output signals are implemented in embodiments, such as the ones discussed below, in which interface appliance 30 is configured to selectively swap delivery of the pressurized flow of breathable gas between first nostril interface 34 and second nostril interface 36. By way of non-limiting example, sensor 22 may include a flow meter, a pressure meter, an accelerometer, and/or other sensors. Although sensor 22 is shown in FIG. 1 as a single element, this is not intended to be limiting. In one embodiment, sensor 22 includes a plurality of sensors. The plurality of sensors may be located together, or may be located at physically disparate locations. For example, sensor 22 may be located on one or more of interface appliance 30 (e.g., conduit 32, first nostril interface 34, second nostril interface 36, resistive flow path 38, and/or other components of interface appliance 30), conduit 28, pressure generator 14, and/or other components of system 10.

[35] The controller 24 is configured to provide information processing capabilities in

system 10. As such, controller 24 may include one or more of a digital processor, an analog processor, a digital circuit designed to process information, an analog circuit designed to process information, a state machine, and/or other mechanisms for

electronically processing information. Although controller 24 is shown in FIG. 1 as a single entity, this is for illustrative purposes only. In some implementations, controller 24 may include a plurality of processing units. These processing units may be physically located within the same device (e.g., with pressure generator 14), or controller 24 may represent processing functionality of a plurality of devices operating in coordination. The controller 24 may be configured to execute one or more computer program modules. The controller 24 may be configured to execute the computer program modules by software; hardware; firmware; some combination of software, hardware, and/or firmware; and/or other mechanisms for configuring processing capabilities on controller 24. [36] In one embodiment, controller 24 is configured to control the communication of the pressurized flow of breathable gas generated by pressure generator 14 to either the first nostril or the second nostril of subject 12. In this embodiment, controller 24 may control delivery of the pressurized flow of breathable gas based on output signals generated by sensor 22, based on a schedule (and/or timing intervals), based on user selection (e.g., via user interface 18), and/or based on other parameters.

[37] By way of non-limiting example, in one embodiment, sensor 22 is configured to generate output signals that convey information about the position of subject 12. For example, the output signals may indicate if subject 12 is lying down on his right side, on his left side, on his back, and/or in other positions. The controller 24 is configured to receive the output signals, and to control pressure generator 14, conduit 28, and/or interface appliance 30 such that the pressurized flow of breathable gas is delivered to a single one of the first nostril or the second nostril of subject 12 based on the received output signals. For example, in one embodiment, responsive to receiving an output signal indicating that subject 12 is lying on his right side, controller 24 controls pressure generator 14, conduit 28, and/or interface appliance 30 to deliver the pressurized flow of breathable gas to only the nostril of subject 12 on the left side. This may facilitate delivery of the pressurized flow of breathable gas to the nostril that would typically be "active" due to nasal cycling, and not the nostril that would typically be blocked.

[38] As an example of the manner in which parameters may be implemented by

controller 24 to control delivery of the pressurized flow of breathable gas, in one

embodiment, sensor 22 is configured to generate output signals that convey information about a gas parameters (e.g., flow, pressure, etc.) at or near the airway of subject 12. The output signals may convey information about the gas parameter at or near a single one of the first nostril or the second nostril, separately for each of the first nostril or the second nostril, and/or for the first nostril and the second nostril combined. Responsive to the output signals indicating that delivery of the pressurized flow of breathable gas to the current nostril has become impeded (e.g., due to nasal cycling), controller 24 controls pressure generator 14, conduit 28, and/or interface appliance 30 to swap delivery of the pressurized flow of breathable gas to the other nostril. [39] It will be appreciated that active control of pressure generator 14, conduit 28, and/or interface appliance 30 by controller 24 to swap delivery of the pressurized flow of breathable gas between nostrils is not intended to be limiting. In one embodiment, one or more of pressure generator 14, conduit 28, and/or interface appliance 30 are configured with mechanical components that swap delivery of the pressurized flow of breathable gas without need for electronic control. For example, gravity and/or flow of gas may be used in conjunction with mechanical components to selectively swap between the nostrils. Further, in some embodiments, pressure generator 14, conduit 28, and interface appliance 30 are not configured to facilitate swapping delivery of the pressurized flow of breathable gas between nostrils, unless the interface appliance 30 is physically removed and remounted on the face of subject 12.

[40] FIG. 2 illustrates interface appliance 30, in accordance with one embodiment of the invention. In the embodiment shown, interface appliance 30 is held in place on the head of subject 12 by a head gear 44. FIG. 2 further depicts an engagement between conduit 28 and first opening 40 of conduit 32. At second opening 42 of conduit 32, first nostril interface 34 is configured to receive the pressurized flow of breathable gas that has passed through conduit 32. The first nostril interface 34 is further configured to deliver the pressurized flow of breathable gas into the first nostril of subject 12. In the embodiment shown, first nostril interface 34 is a cannula formed from a flexible material with a shape the facilitates comfortable engagement with the first nostril. The engagement between first nostril interface 34 and the first nostril may be sealed or unsealed.

[41] The second nostril interface 36 is formed separate from the rest of interface

appliance 30 (e.g., conduit 32 and first nostril interface 34). The second nostril interface 36 is held in place at the second nostril of subject 12 by head gear 44. The head gear 44 holds second nostril interface 36 in place such that second nostril interface 36 engages the second nostril of subject 12. The engagement between second nostril interface 36 and the second nostril of subject 12 may be sealed or unsealed.

[42] As was mentioned above, the resistance of resistive flow path 38 to exhalation from the second nostril of subject 12 may be provided by virtue of one or more valves disposed in resistive flow path 38. By way of illustration, FIG. 3A shows interface appliance 30, including first nostril interface 34 and second nostril interface 36. A member 46 extends from head gear 44 to second nostril interface 36, and is configured hold second nostril interface 36 in place in the second nostril. At an end opposite second nostril interface 36, member 46 is attached to head gear 44. This attachment may be removable to facilitate cleaning and/or replacement of second nostril interface 36 and resistive flow path 38.

[43] A vent 48 that communicates with first nostril interface 34 and conduit 32 can also be seen. The vent 48 exhausts gas, such as gas exhaled from the first nostril, gas in the pressurized flow of breathable gas, and/or other gas, from inside conduit 32 and/or first nostril interface 34 to atmosphere. The vent 48 may regulate pressure within conduit 32 and/or first nostril interface 34 to maintain the pressure at a level that is comfortable and/or therapeutic. In one embodiment, flow through vent 48 is regulated by a valve. The valve may include a check valve (e.g., that opens at a certain pressure) and/or a one-way valve.

[44] In the embodiment shown in FIG. 3A, the resistive flow path 38 includes a valve (shown as vents 50) formed in second nostril interface 36. In this embodiment, the resistance of the valve is relatively fixed, and changes in resistance can only be

accomplished by swapping member 46 and second nostril interface 36 (which are formed as a single unit with the valve). FIG. 3B illustrates how the embodiment of member 46, second nostril interface 36, and resistive flow path 38 shown in FIG. 3A would rest in the second nostril of subject 12.

[45] FIG. 4A illustrates interface appliance 30, in accordance with one embodiment. In the embodiment shown in FIG. 4A, second nostril interface 36 and the valve forming resistive flow path 38 are removable from member 46. This facilitates cleaning and/or replacement. Further, the resistance of resistive flow path 38 can be changed by replacing second nostril interface 36 and resistive flow path 38 with another second nostril interface 36 and resistive flow path 38 that have a difference resistance. It will be appreciated that the illustration of second nostril interface 36 and resistive flow path 38 being removable as a single group is not intended to be limiting. In one embodiment, the valve is removable without removing second nostril interface 36 (e.g., by removing the valve forming resistive flow path 38 from the back). FIG. 4B illustrates how the embodiment of member 46, second nostril interface 36, and resistive flow path 38 shown in FIG. 4A would rest in the second nostril of subject 12.

[46] FIG. 5A illustrates interface appliance 30, in accordance with one embodiment. In the embodiment shown in FIG. 5A, the resistance of resistive flow path 38 is configurable by a user (e.g., subject 12). In this embodiment, a barrier 52 is mounted pivotally on second nostril interface 36. Specifically, barrier 52 is mounted on a side of second nostril interface 36 opposite from the side that will interface with the second nostril. By pivoting barrier 52, a larger or smaller portion of resistive flow path 38 is blocked by barrier 52. This will decrease or increase, respectively, the resistance of resistive flow path 38. The pivotal movement of barrier 52 may be indexed at preset intervals to provides some feedback to the adjustor as to how much resistance will be provided. FIG. 5B illustrates how the embodiment of member 46, second nostril interface 36, and resistive flow path 38 shown in FIG. 5B would rest in the second nostril of subject 12.

[47] FIG. 6A illustrates interface appliance 30, in accordance with one embodiment. In the embodiment shown in FIG. 6A, the resistance of resistive flow path 38 is adjustable by moving barrier 52. However, rather than pivoting barrier 52 to open and/or close more or less of resistive flow path 38, the barrier 52 is mounted to second nostril interface 36 to be slidable over more or less of resistive flow path 38. FIG. 6B illustrates how the

embodiment of member 46, second nostril interface 36, and resistive flow path 38 shown in FIG. 6A would rest in the second nostril of subject 12. As can be seen in FIGS. 6A and 6B, in this embodiment, the sliding barrier 52 does not cover vents (as was the case in FIGS. 5A and 5B), but instead simply covers more or less of the cross sectional area of the second nostril.

[48] FIG. 7 illustrates one embodiment of interface appliance 30. Specifically, FIG. 7 shows a sectional view of member 46, second nostril interface 36, and resistive flow path 38. In the embodiment shown in FIG. 7, member 46 is formed from a resiliently flexible material. As such, member 46 forms a flexible arm that resiliently biases second nostril interface 36 in place in the second nostril. The resistive flow path 38 is formed by a flapper valve that includes a flapper 54. During inhalation, flapper 54 pivots or flexes out of resistive flow path 38, thereby opening resistive flow path 38 at least to some degree to inhalation through the second nostril. During exhalation, the flow of gas through resistive flow path 38 will cause flapper 54 to close resistive flow path 38. This will tend to create a back pressure within the airway of the subject, providing further pressure support to the airway.

[49] FIG. 8 illustrations one embodiment of a flapper valve that forms at least a portion of resistive flow path 38. In the flapper valve shown in FIG. 8, flapper 54 does not cover all of resistive flow path 38 even when it is closed. This tends to reduce the resistance of resistive flow path 38 to exhalation.

[50] FIG. 9 is a schematic diagram that illustrates one embodiment of system 10, in

which the delivery of the pressurized flow of breathable gas is swappable between nostrils of subject 12. In the embodiment shown in FIG. 9, interface appliance 30 is connected to pressure generator 14 by two separate conduits 56 and 58. The conduits 56 and 58 cooperate to provide the functionality attributed above to interface appliance 30 (shown in FIGS. 1 and 2). The conduit 56 is in fluid communication with first nostril interface 34, and the conduit 58 is in fluid communication with second nostril interface 36. The first nostril interface 34 includes a one way valve 60 that acts as an inspiratory port, and a vent 62 that exhausts gas to atmosphere. The second nostril interface 36 includes a one way valve 64 that acts as an inspiratory port, and a vent 66 that exhausts gas to atmosphere.

[51] At a given point in time, the pressurized flow of breathable gas providing pressure support therapy to the airway of subject 12 is only delivered through a single one of conduit 56 or conduit 58. To accomplish this, the pressurized flow of breathable gas may be swapped between conduit 56 and conduit 58 at or near pressure generator 14 under the control of controller 24. The controller 24 is configured to control delivery of the

pressurized flow of breathable gas to conduit 56 or conduit 58 based on one or more of various criteria. For example, the controller 24 may control delivery of the pressurized flow of breathable gas to conduit 56 or conduit 58 based on output signals generated by sensor 22.

[52] In one embodiment, whichever one of conduit 56 or conduit 58 is not delivering the pressurized flow of breathable gas in accordance with the positive airway pressure therapy may supply some gas to the airway of subject 12. However, this secondary flow may be at a much lower pressure and/or flow rate than the pressurized flow of breathable gas. This secondary flow may effectively provide the appropriate resistance to expiration to create a back pressure within the airway of subject 12. In other words, in the embodiment shown in FIG. 9, rather than relying on valves and/or other members to create the resistance of resistive flow path 38 to exhalation, the secondary flow is used to create the resistance.

[53] FIG. 10 is a schematic diagram that illustrates one embodiment of system 10, in which the delivery of the pressurized flow of breathable gas is swappable between nostrils of subject 12. In the embodiment shown in FIG. 10, sensor 22 includes a plurality of sensors. The interface appliance 30 further includes a plurality of valves (labeled, for consistency, with numerals corresponding to similar features that were not actively controlled in FIG. 9) that are actively controlled by controller 24. In the embodiment illustrated in FIG. 10, valves 60 and 64 are actively controlled by controller 24. The interface appliance 30 includes a pair of delivery valves 70 and 72. The controller 24 may coordinate the alternate opening and closing of valves 70 and 72 with the swaps of the pressurized flow of breathable gas between conduit 56 and conduit 58. This may enhance delivery of the pressurized flow of breathable gas to a single one of the nostrils through interface appliance 30.

[54] FIG. 1 1 is a schematic diagram that illustrates one embodiment of system 10, in which the delivery of the pressurized flow of breathable gas is swappable between nostrils of subject 12. In the embodiment illustrated in FIG. 1 1 , the pressurized flow of breathable gas is delivered to interface appliance 30 through conduit 28, and not through two separate conduits (e.g., conduits 56 and 58 in FIGS. 9 and 10). In this embodiment, interface appliance 30 includes a single exhaust vent 68, and delivery valves 70 and 72. By controlling delivery valves 70 and 72, the pressurized flow of breathable gas delivered to interface appliance 30 through conduit 28 can selectively be delivered to either first nostril interface 34 or second nostril interface 36. A supplementary inspiratory port 74 provides freer inhalation through the nostril that is receiving the pressurized flow of breathable gas.

[55] It will be appreciated that the description of interface appliance 30 above as

providing the pressurized flow of breathable gas to a single nostril of subject 12 is not intended to be limiting. In one embodiment, the mouth of subject 12 is used to deliver the pressurized flow of breathable gas, while the nostrils remain relatively free for respiration. In this embodiment, the functionality attributed to first nostril interface 34 may be provided by an interface that engages the mouth of subject 12. In this embodiment one or both of the nostrils may be engaged, and exhalation through one or both of the nostrils may be resisted to provide back pressure in the airway of the subject.

[56] Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover

modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention

contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.

Claims

CLAIMS:

1. A system configured to delivery positive airway pressure therapy to a subject, the system comprising:

a subject interface appliance configured to deliver a pressurized flow of breathable gas to the airway of the subject, the subject interface appliance being configured to deliver the pressurized flow of breathable gas to only a first nostril of the subject such that the airway of the subject is pressurized by the pressurized flow of breathable gas through the first nostril.

2. The system of claim 1 , wherein the subject interface appliance comprises:

a conduit having a first opening and a second opening, the conduit being configured to form a flow path for the pressurized flow of breathable gas between the first opening and the second opening, the first opening being configured to receive the pressurized flow of breathable gas;

a first nostril interface in fluid communication with the second opening of the conduit, the first nostril interface being configured to receive the pressurized flow of breathable gas from the second opening of the conduit, and to deliver the pressurized flow of breathable gas to the first nostril of the subject.

3. The system of claim 2, wherein the subject interface appliance further comprises: a second nostril interface configured to interface with a second nostril of the subject; and

a resistive flow path in fluid communication with the second nostril interface such that gas breathed through the second nostril of the subject is breathed through the resistive flow path, and wherein the resistive flow path is configured to provide a resistance to gas exhaled from the second nostril.

4. The system of claim 3, wherein the subject interface appliance is configured to selectively swap fluid communication of the pressurized flow of breathable gas from the first nostril interface to the second nostril interface, thereby providing the pressurized flow of breathable gas to the airway of the subject through only the second nostril, and wherein responsive to swapping fluid communication of the pressurized flow of breathable gas from the first nostril interface to the second nostril interface.

5. The system of claim 4, further comprising a controller configured to control fluid communication of the pressurized flow of breathable gas with either the first nostril interface or the second nostril interface.

6. A method of delivering positive airway pressure therapy to a subject, the method comprising:

delivering a pressurized flow of breathable gas to only a first nostril of the subject such that the airway of the subject is pressurized by the pressurized flow of breathable gas through the first nostril.

7. The method of claim 6, wherein delivering the pressurized flow of breathable gas to the first nostril of the subject comprises:

receiving the pressurized flow of breathable gas from a pressure generator;

communicating the pressurized flow of breathable gas from the pressure generator to a first nostril interface; and

providing the pressurized flow of breathable gas to the first nostril through the first nostril interface.

8. The method of claim 6, further comprising providing resistance to gas exhaled from the second nostril.

9. The method of claim 6, further comprising swapping delivery of the pressurized flow of breathable gas from the first nostril to the second nostril such that subsequent to the swap the pressurized flow of breathable gas is delivered to the airway of the subject only through the second nostril.

10. The method of claim 9, initiating the swap based on detection of a

predetermined criteria.

1 1. A system configured to deliver a positive airway pressure therapy to a subject, the system comprising:

means for delivering a pressurized flow of breathable gas to only a first nostril of the subject such that the airway of the subject is pressurized by the pressurized flow of breathable gas through the first nostril.

12. The system of claim 1 1 , wherein the means for delivering the pressurized flow of breathable gas to the first nostril of the subject comprises:

means for receiving the pressurized flow of breathable gas from a pressure generator;

means for communicating the pressurized flow of breathable gas from the pressure generator to a first nostril interface; and

means for providing the pressurized flow of breathable gas to the first nostril through the first nostril interface.

13. The system of claim 1 1 , further comprising means for providing resistance to gas exhaled from the second nostril.

14. The system of claim 1 1 , further comprising means for swapping delivery of the pressurized flow of breathable gas from the first nostril to the second nostril such that subsequent to the swap the pressurized flow of breathable gas is delivered to the airway of the subject only through the second nostril.

15. The system of claim 14, means for initiating the swap based on detection of a predetermined criteria.