TREATMENT OF RESPIRATORY CONDITIONSCROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of the filing dates of United States ProvisionalPatent Application No. ,084 filed June 5, 2008 and United States Provisional PatentApplication No. 61/117,375 filed November 24, 2008, the disclosures of which are herebyincorporated herein by reference.1. FIELD OF THE TECHNOLOGY[00 02] The present technology relates to methods and apparatus for treatment of respiratoryions such as the conditions related to sleep disordered breathing (SDB) (including mildobstructive sleep apnea (OSA)), y induced upper airway obstruction or early viral infectionof the upper airway.2. BACKGROUND OF THE TECHNOLOGY Sleep is important for good health. Frequent disturbances during sleep or sleepfragmentation can have severe consequences including me sleepiness (with the attendantpossibility of motor-vehicle accidents), poor mentation, memory problems, depression andhypertension. For example, a person with nasal tion may snore to a point that it disturbsthat person's ability to sleep. Similarly, people with SDB are also likely to disturb their partner’ssleep. One known ive form of treatment for patients with SDB is nasal continuous positiveairway pressure (nasal CPAP) applied by a blower (air pump or compressor) via a connectinghose and patient interface. In some forms the supply of air at positivere is delivered toboth the nose and mouth. The positive pressure can prevent a collapse of the patient’s airwayduring inspiration, thus preventing events such as snoring, s or hypopnoeas and theirsequelae.
Such positive airway pressure may be red inmany forms. For example, apositive re level may be maintained across the inspiratory and expiratory levels of thepatient's breathing cycle at an approximately constant level. Alternatively, pressure levels maybe adjusted to change synchronously with the patient's breathing cycle. For example, pressuremay be set at one level during inspiration and another lower level during expiration for patientcomfort. Such a re treatment systemmay be referred to as bi—level. Alternatively, thepressure levels may be continuously adjusted to smoothly change with the patient's breathingcycle. A pressure setting during expiration lower than inspiration may generally be referred to asexpiratory pressure relief. An automatically adjusting device may increase the treatmentpressure in response to indicatiOns of partial or complete upper airway obstruction. See US.
W0 2009/146484 Patent Nos. 5,245,995; 6,398,739; 6,635,021; 6,770,037; 7,004,908; 7,141,021; 6,363,933 and,704,345. .
Other devices are known for providing atory tract therapy. For example,Schroeder et a1. describes an apparatus for delivering heated and humidified air to the respiratorytract of a human patient in US. Patent No. 7,314,046, which was filed on 8 Dec. 2000 andassigned to Vapotherm Inc. rly, Genger et a1. discloses an anti-snoring device with acompressor and a nasal air cannula in US. Patent No. 7,080,645, filed 21 July 2003 and assignedto Seleon GmbH.
It may be desirable to develop further s and devices for treating upperrespiratory conditions.3. SUMMARY OF THE TECHNOLOGY A first aspect of the some embodiments of the technology is to provide s andapparatus for treatment of respiratory conditions.
Another aspect of some embodiments of the technology is to provide methods andapparatus for treating sleep disordered breathing.
In one embodiment of the technology, air at a high flow rate is delivered to the nasales, preferably in the range of about 10 to about 35 litres/minute.
In another embodiment, air is provided with a temperature in therange of about 30°Cto about 37°C.
In another embodiment, air with a high humidity is provided to the nasalpassages,preferably with an absolute humidity in the range of about 27 to about 44 mg/litre.
In another embodiment, methods and apparatus are provided for servo-controllingsleep disordered ing by varying one or more of flow, temperature and level offication.
Another aspect of the logy is to provide a device for treating respiratoryconditions having one or more start-up and/or shut-down protocols that vary any of flow,temperature and level of humidification. For example, the device may provide for ramping anyone or more of flow, temperature and level dification.
Another aspect of the technology is to vary any of flow, temperature and level ofhumidification within, or as a function of detection of, a respiratory cycle ofa t. Forexample, a device may provide first levels of flow, ature and/or humidification duringinhalation and second or different levels of flow, temperature and/or humidification duringexhalation.
W0 2009/146484 Another aspect of the technology is to provide different levels of flow, temperatureand/or humidification to each naris. For example, in one form of device, levels of flow,temperature and/or humidification are cycled between the nares.
In accordance with the technology, methods and apparatus are provided for varyingthe levels of flow, temperature and/ or humidification.
In accordance with the technology, levels of flow, temperature and/or humidificationmay be varied either manually or automatically.
In accordance with the technology, levels of one or more of flow, temperature andhumidification may be varied over a period having a duration less than, equal to or greater thanthe duration of a respiratory cycle. For example, flow, temperature and humidification may beincreased over several breaths, or decreased over several breaths.
Another aspect of the technology is to provide an air delivery conduit having adiameter that changes along its length.
Another aspect of the technology is to provide each naris with individually controlledlevels offlow, temperature and/or humidity. onal .features of the present respiratory technology will be apparent from areview of the following detailed discussion, drawings and claims.4. BRIEF DESCRIPTION OF DRAWINGS The t technology is illustrated by way of example, and not by way oflimitation, in the figures of the anying drawings, in which like nce numerals refer tosimilar elements including: shows example ents of an tus for treatment of theupper airwayof a patient; FIGS. 2A and 23 illustrate embodiments of a gate valve for adjusting temperatureand/or humidity ofthe treatment provided by an apparatus of the present technology; shows a rechargeable embodiment of an apparatus for treatment according toan embodiment of the t technology;[0026 ] shows an example sing airflow channel er of a delivery conduitfor a flow source of the present technology; is an example flowchart bing the l of the apparatus inwarm-upmode; is another example flowchart describing the control of the apparatus inwarm-up mode;[ 0029] shows a flowchart describing the control of the apparatus in cool-down mode;W0 2009/146484 is an illustration of an ment of a patient interface with internal nasaldilators for insertion within a patient's nares; is a side view illustration of another example embodiment of a patientinterface with external nasal dilators for contact with an external surface ofthe patient‘s nose; is a top View illustration of the example patient interface of is a front cross-sectional view illustration of the example patient ace ofFig. 9; is an illustration of an example diffuser clip configured with an exampleagement sensor; is a further clip with another example disengagement sensor;[003 6] illustrates an example er for a prong of a nasal cannula; and is an ration of a baffle for a prong of a nasal cannula.
. DETAILED DESCRIPTION The embodiments of the present logy may be implemented with an airwaytreatment device 102 that may include some or all of the components illustrated in FIG. ‘1. Forexample, the airway treatment delivery device'will typically include a flow generator such as acontrolled blower 104. The blower 104 will typically e an air inlet and impellerdriven by a motor (not shown). ally, the air inlet may be coupled with a gas supply, suchas for oxygen as shown in to mix with or supplement the breathable gas supplied by theimpeller to the airway of a user. Optionally, the supplementary gas supply may be introducedthrough a port, 133, upstream of the humidifier, and/or downstream of the humidifier, through aport 134. er, an air filter may be provided, such as a HEPA filter, to remove dust or otherallergens from the air drawn into the air inlet. The blower may optionally be configured forgenerating varied flows or pressures.
The delivered breathable gas flow rate may be in therange of about —250 to about+250 liters/min, more preferably between about -100 and about 100 liters/min,more preferably,between about 0 to 100 liters/min, more preferably between about 0 and 75 liters/min,yet furthermore preferably between about 0 to about 50 liters/min with the preferred range being betweenabout 10 to about 35 liters/min, to provide for comfort and efficacy.[004 0] The delivered breathable gas temperaturemay be in the range of about -10°C to about50°C, more preferably about +4°C to about +45°C, yet more preferably room temperatureup to40°C with the most preferred range being 30°C to 37°C, to provide for comfort and efficacy.
The delivered breathable gas relative humiditymay be in the range of room humidityup to 100%, for e in the range of about 50% to about 100%, or about 70% to about 100%,or about 80% to about 95%, with the preferred range being 90% to 100%, to e for comfortW0 46484 and efficacy. An absolute ty range will be about 0 to about 82 mg/liter, or“ morepreferably about 27 to about 44 mg/liter..1 PATIENT INTERFACE The airway treatment device 102 will also typically include a patient interface suchas an air ry conduit 106 and nasal prongs or nasal cannula 108 to carry the flow of air orbreathable gas to the upper airway of a user of the device or patient. The blower 104 can becoupled with the air delivery conduit 106 and the nasal cannula 108 so as to provide thebreathable gas from the blower 104. In one form of patientinterface, as will be disCussed inmore detail with respect to the particular interface embodiments herein, exhaust gas of theblower and/0r expiratory gas from the patient's airway can be vented away from the patientinterface from a location proximate to the patient's airway or the nares themselves. Significantgaps or venting between the patient interface and the nares of the patient can permit a flow fromthe flow generator to escape or leak fi'om the patient's nares without being inspired. A patientinterface that permits such venting can provide a comfortable interface for the treatmentdescribed herein. Thus, a patient interface that provides a leak—free seal with the nares of thet is not required. r, a sealed patient interface may be used as an alternative.
The patient interface will lly be held in place proximate or inside the nares ofthe patient. A harness 110 may be optionally provided for thispurpose. In addition, a nasal orseptum clip and/or adhesive (not shown) may also be provided to maintain the nasal cannula in adesired position for use. Examples of suitable ments ofthe patient interface are disclosedin US. Patent Provisional Patent Application No. 61/058,659, entitled "Unobtrusive InterfaceSystems," filed on June 4, 2008, the disclosure of which is hereby incorporated herein by cross-reference. In some embodiments, the nasal cannula may also or alternatively include earattachment portions connected with the nasal cannula to ensure oning of nasal cannula byor in the nares during treatment. For example, cannula arms extending over and/or around theears from the nasal cannula may be utilized. Optionally, the ry conduit may beincorporated with such cannula arms, which may alternatively be designed to run under the earsrather than over the ears to reduce noise that might otherwise be heard by theuser from the flowof gas through the delivery conduit.
In some embodiments, the patient interface or cannulamay be implemented with anasal r, such as an internal or al nasal dilator. Illustrations of example mentsare shown in FIGS. 8 to 11. In the embodiment of dilator extension members 882R,882L t from a patient interface such as a portion ofa cannula 808 body. For example, theion members may project fromprongs 880R, 880L of the cannula 808 as illustrated in In such a case, the prongs serve as dilator mount portion of the cannulaor patientW0 2009/146484 interface. The extension members in are sized to project inside nares of a patient's noseeven if the prongs 880L, 880R also do not extend within the nares. Such extension membersmay then be formed or shaped to ply an expansion force against an internal e of each nare.
This expansion force, which is illustrated by the arrows in Fig. 8, permits the extension membersto assist with keeping the nasal passages dilated from inside the nares. Thus, the extensionmembers may be formed of a material that is flexible and resilient to e a dilation force.
However, these extensions may otherwise be configured with one or more spring elements (notshown) to provide a suitable expansion force with more rigid extension members.
In some embodiments, the extension members of the patient interface may be formedto ply an expansion force from an exterior surface of a patient’s nares. An example of such an,embodiment is illustrated in FIGS. 9-11. In such an embodiment, the extension members 982may comprise a dilator strip or strips. For example, a portion of the patient interface or cannula908 may e a bridge t 990. The bridge support may be flexible for adjustment so that,it may conform to the nose shapes of ent patients. When the a is in place to providegas flow to the nares of a patient, the bridge support may extend from the cannula so that the 'bridge t is proximate to a ridge area of a patient's nose. The support may then serve as adilator mount portion to permit the dilator ion members to be mounted thereto andpositioned proximate to the exterior surface ofthe patient’s nose.
For example, the bridge support 990 may optionally include agap or clip so that adisposable dilator strip may be releasably retained by the bridge support 990. In such anembodiment, a disposable r strip may be inserted or coupled to the bridge support for use.
Such a dilator strip may then be a flexible and resilient material so as to permit ent atopposing external es of the nose of the patient and yet still be able to ply the expansionforce at those surfaces to assist with dilation of the nares by pulling at the exterior surfaces of thenose. Thus, these strips may also typically include an adhesive so that a surface of the dilatorstrip may adhere to opposing exterior surfaces of the nose. Thus, a left side dilator strip 982Land a right side dilator strip 982R may then be adhered to the left and right sides of the patient'snose respectively. With such embodiments, the ion membersmay serve the purpose ofsecuring the cannula or patient interface in a suitable position for providing a flow to the nares ofthe patient with prongs 980, 980R, 9080L as well as inga dilation force to assist with -keeping the patients nasal passages open during a use of the patient interface. Moreover,although not shown in FiGS. 8-11, onal components of the patient interface may beprovided for further securing of the cannula in the desired position foruse, such as the cannulaarms previously discussed.
W0 2009/146484 In some embodiments, the extension members 982L, 982R may be more permanentlyconstructed with the bridge support by, for example, forming the r strip as an oratedportion of the t interface or bridge support of the cannula 908. Thus, rather than replacingdisposable exterior dilator strips as previously discussed, for each use a suitable ve may bere-applied to the nasal surface sides of the attached or incorporated dilator strip.
In some embodiments, an optional spring element 996 may also be provided with thedilator strip. For example, where extension members themselves are not formed to have asufficient resilience to e the expansion force, the spring element, when coupled with theextension members, may serve to provide the expansion force with the extension members 992R,992L. In the example of a wire or other resilient component may serve as the springelement.
As fiirther illustrated in the t interface may also include one or moreswivels. A swivel 994 can permit the patient interface or carmula 908 to remain in a desirableposition for directing the flow to the nares ofthe patient if a patient moves during sleep. Thus, aswivel provides relative movement between an air delivery portion of the patient interface and adelivery tube portion of the patient interface. For example, one or more swivels may permitrelative rotation between a cannula 908 and delivery tube 906 about one or more different axes(illustrated as perpendicular axes X, Y, Z). As illustrated in the embodiment of a swivelmay permit a rotation of the cannula 908 with respect to the delivery tube 906 along arrows 81or about an ary X axis. Such nt can permit an air delivery n of the cannula(e.g., prongs 980) to vertically rotate with respect to the delivery tube 906.
Similarly, as illustrated in the ment of , a swivel 994 may permit arotation of the a 908 with respect to the delivery tube 906 along arrows 82or about animaginary Y axis. Such movement can permit an air ry portion of the cannula (e.g., prongs980L, 980R) to horizontally rotate with respect to the delivery tube 906.
Finally, as illustrated in the embodiment of FIG. V1 1, a swivel may permit a rotation ofthe cannula 908 with respect to the delivery tube 906 along arrows S3or about an imaginary Zaxis. Such movement can permit an air delivery portion of the cannula (e.g., prongs 980L,980R) to tilt rotation with respect to the delivery tube 906..2 HUMIDIFIER, HEATER AND TUBE Breathable gas is supplied to the patient by a blower (104 of , which may beintegrated with other elements of the apparatus, or from a reticulated source, or from bottledgas,or otherwise. The air may be filtered at the input to the blower (104)or at some other point inthe gas flow path. ally, the apparatusmay also e a humidifier and/or heater (112,111) and a delivery tube heater (135) (or apparatus to regulate heat loss from the delivery tubeW0 2009/146484 106). In the case of a heated delivery tube, insulation material may be provided on the tube toprevent the heat from the tube from bothering the patient or otherwise being transferred to theskin of the patient. Such a tube may be d with an insulating material or the tube almay be selected for is insulation properties. For example, the delivery tube may be increased inthickness to provide or increase its insulating effect. The heater device 111 may be exposed to awater mass and/or to the breathable gas flow. For example, the humidifier device may e areservoir or fluid circuit for passing the breathable gas through or proximate with a fluid or vaporofthe reservoir or fluid circuit. One or more heating elements (not shown separately from heater1 11) may be provided to warm the fluid to create the vapor and/or to warm the breathable gas byconvection. The warming device may further include a pump for circulating fluid within theoir or a fluid circuit of the t interface or blower. For purposes of regulating thetemperature and/or humidity of the warming element, the apparatus may also include humiditysensors (117, 121, 134), and/or temperature sensors, and/or a flow rate sensor, and/or pressuresensors. The sensor(s) generate temperature and/or humidity signals and/or a flow rate signal,and/or pressure signals (illustrated, in for controlling the humidifier and/or heater and/ortube heater using l logic (120) to maintain the ature and/or humidity of thebreathable gas delivered to the patient. In some applications, this device can be controlled to alterthe ature and humidity of the breathable gas such that the delivery conditions are withinthe acceptable or preferred ranges as stated above.
Generally, it has been found that some available devices are slow when changing thelevel or degree of humidification due to the need to heat a relatively large mass or water.
However, in embodiments ofthe present technology, two air streams may be provided, namely afirst relatively dry air stream in one flow channel, and a second relatively moist air stream inanother flow channel. By mixing the streams to a third flow channel, the level dificationof the air delivered to the patient may be rapidly changed as necessitated by the settings of theapparatus.
One means of achieving this is to employ an active flow gate 299 as illustrated in theexamples of FIGS. 2A and 2B. For example, if, when the flow gate is in one position, itdirects flow from the blower to a path that provides for one desired level oftemperature andhumidification of the breathable gas, and in an alternate on directs flow fiom the bloweranother path that provides a significantly different level of ature and humidificationofthebreathable gas, optionally with no fication. The flow gate may be controlled to switchflow direction in response to breathing cycle phase,or otherwise under control of the controller120. Optionally, the flow gate may be controlled to activate to a position that allows the splittingor mixing of the flow between the two paths. For e, based on the desired humidity and/orW0 2009/146484 temperature settings measured by one set of sensors in a combined tube, the controller mayadjust the flow gate to mix variable s of gas of two distinct flow paths at two differenthumidity and/or temperature settings, which may be separately controlled by readings from twoadditional and different sets of sensors. Another version of the flow gate that allows for mixingof flows is illustrated in with a controllable iris valve. Other mechanisms of generatingand mixing flows of different temperatures and humidities, such as dual blower supply, may beused.
By way of further e, by controlling the flow gate in conjunction with detectedchanges in the patient's atory cycle, a lower humidity and/or temperature gas may bedelivered during patient expiration and a higher humidity and/or temperature gas may bedelivered during patient inhalation. Alternatively, a higher humidity and/or ature gas maybe delivered during exhalation. Thus, such flow control of the humidity of the breathable gasdelivered to the patient can generate high temperature and/or humidity delivery only when thet requires such for eutic reasons, for example during an inhalation phase of abreathing cycle. This controlled delivery in turn may allow for a reduction in thepower and/orwater requirements of the apparatus over the duration of a therapy session. ion of thephases of the respiratory cycle of the t may be based on an analysis of data from anappropriate sensor such as the sensors discussed in more detail herein.
In one embodiment, shown in the delivery conduit 406A, 406B, 406C fromthe airway ent device may be formed with agas delivery channel that has a decreasingcross section or diameter. A ion in the cross section diameter can reduce the impedance ofthe delivery tube and may also reduce heat loss. For e, as illustrated in the embodimentof the delivery conduit of the open airway treatment device 402 of an internal airflowchannel GC ofthe delivery conduit decreases from at least one larger cross nalarea portionshown as delivery conduit 406A to at least one smaller cross sectional area n shown asconduit 406B to a yet smaller cross sectional area portion shown as delivery conduit 406Cproximate to the nasal cannula 408. In this way, for a given flow resistance, the tube diameterproximal to the patient can be smaller than with a constant diameter tube. Further, the tubesection 406A, and optionally 406B, may be heated (not shown) to control the breathabletemperature and/or humidity to a level that allows for the change in temperature of the breathablegas through 406C such that the delivered gas to the patient is within the desiredrange. The smalltube section of 406C reduces the heat transfer between the breathablegas and the environmentcompared with the larger sections of 406B or 406C.
The cross sectional area of any portion of the airflow channel would typically ber than the cross sectional area of the airflow channel of the upstream portion of theW0 2009/146484 delivery conduit. To avoid undesired flow restriction and/or noise, transitions between thesedifferent cross sectional portions of the delivery conduit may be made by gradual blending at ornear their intersections. Additional tube portions may be interposed n 406A and 406B toprovide for more gentle transitions in diameter.
In one embodiment, the end portion of the delivery conduit near the flow generatormay have an internal airflow l cross n diameter of about 8-15 mm. Such anembodiment may also end with an airflow channel having a cross sectional area er ofabout 3-6 mm proximate to the nasal cannula. Such a delivery conduit may optionally be formedas a foam silicone tube to provide improved thermal tion properties..3 SENSORS In some embodiments, the airway treatment delivery device may optionally includeone or more flow sensors 116. For example, flow through the nasal cannula 108 may bemeasured using a pneumotachograph and differential pressure transducer or similar device suchas one employing a bundle of tubes or ducts to derive a flow signal. Although the flow sensor israted in in a on proximate to the blower, the flow sensor may optionally belocated closer to the patient, such as in the patient interface or nasal cannula 108; The airway treatment device may also ally include one or more pressuresensors 114, 131, such as a pressure transducer. The pressure sensor(s) 114, 131 can beconfigured to e the pressure generated by the blower 104 and/or supplied at the nasalcannula or patient . In the illustrated embodiment, the pressure sensors 114, 131 areproximate to the blower and located downstream of the blower proximate to the patient interface.
For example, one or more pressure sensors may be located in theprongs or body of the nasalcannula. The pressure sensor(s) 114, 131 generates a pressure signa1(s) indicative. of themeasurement(s) ofpressure at its particular location. Such a signal(s) can be utilized in settingsor ations of the device. The pressure sensor 114 has only been shown symbolically in since it is understood that other configurations and other componentsmay be implemented tomeasure the pressure associated with the blower 104. For example, the pressure may be deducedfrom dge of the blower performance characteristics and the operating blower currentand/or voltage and/or rotational speed and/or flow rate. Optionally, different groups of sensorsmay be provided for a delivery tube associated with each nare of the nasal a. Forexample, a delivery tube for each nare may e a pressure sensor and/or flow sensor so thatindependent measurements offlow and/or pressure may be measured for each nare.
The airway ent device may also include one ormore temperature sensors aspreviously mentioned. For example, such sensors may be located to e the heater(s) 111,135, and/or the treatment gas at various locations in the delivery tube such as near the blowerW0 2009/146484 (e.g., before or after), after the humidifier and near the patient. Similarly, the treatment devicemay also e one or more humidity sensors as described above. Thus, humidity may bemeasured before and/or after the humidifier and near the patient. Additional such sensors maybe employed when multiple flow channels are utilized such as in the embodiments of FIGS. 2Aand 2B for more measuring of the conditions of the distinct portions of the tubes. Still furthersensors may also be configured to measure ambient humidity and ature..4 CONTROLLER The signals from the various sensors (when present) may be sent to a ller orprocessor 120. Optional analog-to-digital (A/D) converters/samplers (not shown separately) maybe utilized in the event that supplied signals from the sensors are not in digital form and thecontroller is a digital controller. Based on input signals from these sensors and/or other optionalsensors, the controller may in turn generate blower control signals. For example, the controllermay generate an RPM request signal to l the speed of the blower 104 by setting a desiredfrequency or rotational velocity set point and comparing it with the measured condition of afiequency or velocity sensor. atively, such changes may be based on ining adesired flow set point and comparing it with the measured condition of the flow sensor.lly, such changes to the motor speed are accomplished by sing or decreasingsupplied motor current with the servo based on determined differences between set and measuredconditions such as in a closed loop feedback n and ating the difference to current.
Thus, the processor 120 or controller may make controlled s to the flow delivered to thepatient interface by the blower 104. Optionally, such changes to flow may be implemented bycontrolling an t with a mechanical release valve (not shown) to increase or decrease thet while maintaining a relatively constant blower speed.
The controller or processor 120 is typically configured and adapted to implementparticular l methodology such as the methods described in‘more detail herein. Thus, thecontroller may include integrated chips, a memory and/or other control instruction, data orinformation storage medium. For example, prograrmned instructions encompassing such acontrol methodology may be coded on integrated chips in the tsor memory of the device orsuch instructions may be loaded as sofiware or firmware usingan riate medium. Withsuch a controller or processor, the apparatus can be used for many different open airwaytreatment therapies, such as the flow treatments previously mentioned, by adjusting a flowdelivery equation that is used to set the speed of the blower or the exhaust venting by an optionalrelease valve (not shown). Thus, flow may be set to desired levels as set by the es of thedevice and optionally increased inresponse to detected respiratory conditions such as an apnea,hypopnea, or airway resistance. The flow rate may be kept substantially constant over the phasesW0 2009/146484 of respiration. In some embodiments, the generated flow may be kept generally constant overthe respiratory cycle and provide some end expiratory relief. Altemately, in some mentsthe flow may be varied smoothly to replicate the patient's detected respiration cycle.
In another example embodiment of the device, indications of upper airwayobstruction determined by the controller are servo-controlled by varying the flow rate and/orlevel of humidification and/or temperature. For example, a device in accordance with thetechnology rs the patient for signs of partial or complete upper airway obstruction. Upondetection of partial upper airway obstruction, and according to the severity and frequency of suchevents, the level of fication is increased. In some embodiments, if the partial airwayobstruction is eliminated, or not detected, the level of humidification may be reduced. rly,ifpartial airway obstruction is detected, flow may be further increased.
In one embodiment of the technology, indications of the need to vary treatment arederived from a pressure signal that is in turn used to infer patient flow in the controller 120. Theinferred flow estimate is applied to automatic pressure control algorithms such as those describedin US. Patent No. 5,704,345, the entire contents of which are hereby expressly incorporated byreference. The output of the automatic pressure algorithms is however, in onement, used to control the flow rate and/or level ofhumidification and/or temperature.
In other forms, pressure is used directly by the controller to determine thepresence ofpartial or complete airway obstruction. In other forms, other non-pressure, non-flow baseddiagnostic techniques are used, such as movement of the suprasternal notch, patient movement,sympathetic nervous system activation (e.g. sweating, skin ance, heart rate), pulse try,EEG and ECG. Such additional diagnostic devices may be configured with the apparatus toprovide measurement data to the controller.
In one ment, the controller may determine a tidal volume or inspired volumeof air or gas by the patient during treatment. Such a determination may be used for setting thepressure or flow and/or analyzing conditions of the patient‘s airway or ation. In view of theventing or unsealed nature of the patient interface that permits the external flow, the tidal volume(Vp) may be determined by measuring the volume of air delivered by the blower 0/0) andmeasuring or determining the volume of leak air (VL) ated with the nasal a andsubtracting the latter from the former (e.g., V0 — VL é Vp). In some embodiments, the patientinterface may seal with the t nares but have a pre-determined venting characteristic,or onethat may change as a function of thepressure or flow rate setting of the flow generator. Thus,the volume of leak may be determined by a p tableor calculation by the controller 120based on the gs of the flow generator.
W0 2009/146484 .5 OTHER ASPECTS OF THE APPARATUS In other embodiments of the technology, the apparatus can be combined withadditional components like accessories, which may be attached to pre-defined interfaces or usingthe shape of the ment, gs, screw holes, or other ng methods or prominentareas of the apparatus to attach. These accessories can be for example additional filters, or sounddampening mechanisms, or data g electronics, which may have for example either amechanical, pneumatic, magnetic and/or electrical connection to the apparatus. The connectionand interaction may also be wired so that the accessories work together with the tus from adistance.
One example is a able battery pack as illustrated in The airwaytreatment device of this embodiment may be implemented with a DC battery sufficient to permitat least a use for a single sleep session without connection to an AC power outlet. A dock 333,such as a cradle with a docking port charger that may be releasably coupled with a charging portof the respiratory treatment device 302, provides a ient way to charge the battery of therespiratory ent device 302.
Other accessories can add additional features to the devices or modify the existingfeature set, for example by using a new method for motor control to reduce noise. For example,a noise sensor or microphone may be provided to detect levels of noise generated by the bloweror the patient interface. Noise measurements may be made and an increase in ambient noise(e.g., a level of sound afier filtering out frequencies such as the fiequencies that may beassociated with snoring) may be responded to by the controller 120 changing a motor speed inattempt to reduce the noise. However, the controller may further reject such s to theextent that any change would prevent a minimum desired level of treatment from beinggenerated by the flow generator for the patient..6 WARM-UP METHODOLOGY One practical consideration in the design and ion of the apparatus describedherein is that the humidification apparatusmay comprise an arrangement whereby a mass ofwater is required to be increased or decreased in temperature. This, in turn, may result in somedelay between the change in the heater state and the humidity and/or temperature of thebreathable gas delivered. When such a delay prevents the desired combination of flow,temperature and humidity to be met in the delivered gas, it may be desirable to prioritize theties that are to be met for therapeutic, comfort or functional reasons. For example, it maybe desirable to ensure that humidity is within the preferredrange as the first ty, temperatureis within the red range as the second priority, and flow is within thepreferred range as thethird priority.
W0 2009/146484 Such prioritizing can be accomplished by the logic sequence described in The flow rate Fmin is a small flow of about 5% - 35% of the desired therapy flow — sufficientlylarge to transport the breathable gas to allow sensing and control, but sufficiently small to ensurethat the patient does not suffer any fort as a consequence of the delivered sub-Optimalbreathable gas.
Optionally, this sequence may be initiated conditionally upon, and/or triggered by,detection of a patient connected to the apparatus. Such detection may be by observation ordetection of fluctuations in pressure and/or flow signal(s) and other techniques such as thosedescribed in US. Patent No. 6,240,921 (ResMed Limited), the contents of which are herebyexpressly incorporated herein by cross-reference.
In addition to control of the flow to meet the desired delivered breathable gasproperty ranges, it may also be ble for the t to l the flow of the apparatus in amanner that allows the flow rate to increase in accordance with a selected rate. Such l mayoffer ages in acceptance and compliance of such therapy because the patient is able tobecome accustomed to the therapy over a longer time than would be the case without such ratecontrol.
This start-up strategy may be applied for a cold-start or a warm-startiAs shown in an example algorithm monitors the temperature and humidity delivered at the patientinterface r directly or calculated from other inputs), for example by means of temperatureand humidity sensors 132 and 134, and rampsup the temperature as quickly as le to thedesired range (while maintaining relative humidity (RH) within the desired range). Then theflow rate is increased from the initial value to the desired value in accordance with theuser rampg such that the red temperature and humidity are maintained within the desiredranges.
The algorithm of may be further described as follows. At 502 of FIGS, thestart-up procedure determines if the apparatus is in a cool-down mode. If the result isaffirmative, the flow rate is ined in 504. Otherwise, a minimum flow rate will be set in506. Process moves to 510 where the flow of the apparatus is controlled to meet the targetor setpoint. The method then proceeds to 512 where the relative ty (RH) is measured andcompared to a d range or deviation of the target or set point for relative humidity, If theresult in 512 is negative then the process proceeds to 514 to control the humidity relatedts of the apparatus to the set point or target for relative humidity. The process thenadvances to 510 to l the breathablegas flow rate. If the result is affirmative in 512 thenprocess advances to 516. In 516, the breathable gas temperature is checked tosee if it is within adesired range or deviation from the target or set point value. If the result in 516 is negative thenW0 2009/146484 2009/000671the process proceeds to 518 to control the temperature related elements of the tus to the setpoint or target for temperature. The process then advances to 510 to control the breathable gasflow rate.
If the result in 516 is affirmative, then the process proceeds to 520. In 520, the flowrate is checked to see if it is below a desired range or acceptable deviation from the therapytarget flow rate. If, in 520, the result is negative then the s is complete. If, in 520, theresult is affirmative then the process advances to 522. In 522, the flow rate is measured orcalculated to determine if a step increase in the rate is appropriate for g up of the flowrate. If the step increase would raise the flow rate above the therapy target, then process flows to524 and 510 without an increase in the target set point of the flow rate for the warm-up process.
If in 522 a step increase would not raise the flow rate above the therapy target, the target setpoint is incremented to increase or ramp up the flow rate in 526 and then controlled in 510 at thenew stepped~up flow rate. In this way, the ramping of flow rate may be governed withoutallowing the humidity or temperature to deviate from their desired or target set—points.
Another example start-up procedure algorithm is illustrated in At 602 thestart up procedure begins. In 604, the temperature (and/or ty) of one or more gelements (e.g., fier heating element) is set and allowed to raise to the desired set point asdetermined by a temperature and/or ve humidity sensor. Once the set temperature and/orhumidity setting has been reached, at 606, a ramp-up procedure for the flow generator begins inwhich an incremental increase in the flow rate will be set over toward a maximum, suchas bysetting an incremental increase in the RPM set point of the blower every several minutes. At608, the temperature and/or humidity levels are checked with the appropriate sensors todetermineif the temperature and humidity is within an acceptable deviation margin of the setpoint after an increase in the blower flow rate. If the margins are acceptable (e.g., a margin of+/- 1, 2, 3, 4 or 5 degrees of the temperature setting or +/— l, 2, 3, 4 or 5% ve humidity ofthe humidity setting) the process will flow to 609 to check if theramp-up of flow has reached thetarget therapy level for the treatment session. If not, then the process returns to 606 to againincrement the flow generator according to thep procedure and its time ment period.
If, in 609, the therapy level has been reached, the warm-up process is te and the ysession protocol may begin.[007 9] However, in 608, if the levels are not within a predetermined margin ofthe set points,the measurement/comparison process flows to .610 to waita period of time. Process then returnsto the comparison process of 608 to again check the temperature and/or humidity sensorscompliance with the deviation margin. In this way, the flow rate of the apparatusmay ramp upW0 46484 2009/000671in a comfortable fashion to the therapy flow rate g while maintaining the desired set pointsfor the humidity and/or temperature of the gas delivered by the apparatus..6.1 RE-RAMP METHODOLOGY In some situations, during the course of therapy with the apparatus a patient maydesire a temporary decrease in the flow rate to permit the patient to more comfortably fall asleepwith a lower flow rate before the flow rate would then return to a higher prescription ortherapeutic level during sleep. Thus, in some embodiments of the apparatus, a re—rampmethodology may be implemented by the controller. The apparatus may permit the user toactivate the re-ramp procedure by a switch, button, knob or other user interface of the apparatus.
Thus, upon activation of the procedure, the tus would lower the flow rate for apredetermined period of time. The period of time may optionally be adjustable by the user withan input device of the tus. At the conclusion of the period of time the flow rate may thenreturn to the therapeutic level. Alternatively, it may gradually return to the therapeutic level overthe period of time or after a period of time. However, in the event that humidification ,is alsoprovided during the particular therapy session, additional elements of the control of the re—rampprocedure may be implemented as a on of the presence of humidification and/or heating soas to assist with avoiding rainout or condensation.
For example, in a typical embodiment, the re-ramp algorithm or methodology of theapparatus may only permit the re-ramp feature to be activated after the apparatus has achieved awarmed—up state, such as if the apparatus has already ted the warm-up procedurepreviously described. Similarly, in an embodiment, the re-ramp feature may be ed if theapparatus has achieved a cool down state such as at a time after completing a cool-downmethodology or when the apparatus is performing a cool-down methodology as bed inmore detail herein. Thus, the methodology of the re-ramp feature may be implemented as afunction of humidification and/or temperature or a humidification state and/or temperature stateof the apparatus. In the event that a cool-down state has been achieved, such as with theing described cool-down methodology, and/or the re—ramp feature is disabled, theapparatus may then be re-activated by execution of the warm-up methodology previouslydescribed rather than the re-ramp ure.
In some embodiments, the selection of the rate for the reduced flow duringtheramp ure may be user adjusted or selected with an input device or user ace of theapparatus. onally, in some embodiments the reduced flow rate may be a fimction ofhumidity and/or temperature such that the reduced flow rate selection is at least partially set in amanner that prevents condensation from forming in the patient interface and/or delivery tube.
For example, the thm may monitor the temperature and humidity internaland/or external toW0 2009/146484 the apparatus, for example by means of ature and ty sensors, and thenautomatically select a reduced flow rate, such as from a look-up table based on the atureand/or humidity information.[0 083] In some embodiments, the reduced flow may be implemented without a blower speedchange by the flow generator. In such an embodiment, an exhaust vent or release valve, whichmay be a mechanical valve that is controlled by a processor or controller of the apparatus, maybe opened to vent part of a humidified gas supply from the blower so that only a n of thefied flow generated by the flow generator is directed to the patient interface. In this way,a lower humidified flow rate may be red to the patient for the re-ramp procedure. The ventor e valve may then close, such as gradually over a period of time that is typically longerthan several breaths, to return the humidified flow to the therapeutic rate. Although not shown in such a release valve or exhaust vent may, for e, be positioned to exhaust gas flowgenerated by the blower 104 at a position in the air deliver circuit after the humidifier 112..7 COOL-DOWN METHODOLOGY Another consequence of the practical eration described above is that theimmediate power-down of the tus may lead to condensation in the apparatus — particularlythe tube — because the heated water mass will continue to emitvapor and so the regions wherethe breathable gas path is in thermal contact with the environment, for example the tube walls,may cool rapidly. The presence of condensation in the apparatus will adversely affect thecomfort and/or'function ofthe apparatus at a subsequent start-up, because dropletsmay be blowndown the tube to the patient interface causing patient discomfort, and/or thepresence of water inthe heated tube may lead to additional humidification in the breathable gas delivered to thepatient or otherwise affect the ability of the system to control the breathable gas delivery at thepatient interface within the desired ranges.
An aspect of the current technology is a control methodology thatmay be optionallyused with the apparatus to control the rate of cooling of the apparatus— especially the tube— todiminish the likelihood of significant condensation forming duringapparatus power—down.
Such a strategy es enting asequence ofapparatus states or tions topromote the maintenance of the temperature of the breathable gas in the system above the localdew-point temperature. Optionally, this sequence may be initiated ionally upon, and/ortn'ggered by, detection of the absence of a patient connected to the apparatus. Such detectionmay be by detection of fluctuations in pressure and/or flow signa1(s). The initiation of thissequence may be delayed by a predetermined period, which may be t-selectable, followingsuch triggering, to allow for temporary disconnection and reconnection of theapparatus. Thepredetermined period may be about 1 - 30 minutes.
W0 2009/146484 This strategy can be accomplished by the example logic described in Theflow rate Fminl may be about 50% - 150% of the typical therapy flow. The flow rate needs tobe sufficiently high to promote cooling of the water mass but not so high so as to teobtrusive noise. This flow rate may be a fixed value, a value that is directly or indirectly selectedby the user, for example should a rapid cool-down be desired, and/or a le value thatfollows a profile with time, or with a sensed breathable gas property value such as humidity.
The flow rate Fmin2 is a small flow of about 5% - 35% of the typical therapy flow —sufficiently large to transport the breathable gas to allow sensing and control, but sufficientlysmall that the humidification of the breathable gas is low and does not cause condensation whenthe apparatus is uently powered-down. The transition in flow rate from Fminl to Fmin2may be controlled to a predetermined profile. Fmin2 may be a fixed value, a value that isdirectly or indirectly selected by the user, for example should a rapid cool-down be desired,and/or a variable value that follows a profile with time, or with a sensed breathablegas propertyvalue such as humidity.
This cool-down strategy applies to any mode or phase of operation of the apparatus.
Optionally, a pause to therapy may be requested by the user such that the breathable gasconditions are maintained for a short , for example 1 — 30 minutes, and if therapy is notrestarted within this period, either-manually or by the detection method above, then the cool-down strategy will be initiated. As shown in the algorithm monitors the temperature andhumidity delivered at the patient interface (either directly or calculated from other inputs), forexample by means of temperature and ty sensors 132 and 134, and ramps down thehumidity as quickly as le until such time as the system humidity is stable, whilstmaintaining an acceptable int margin, for e about a 2-5°C . The margincan be determined from the Saturation Vapour Pressure at the flow temperature, for exampleusing the formulas in ISO Standard 8185 2007. The flow rate is decreased from the initial valueto the Fmin2 in a manner that allows the maintenance of the dew-point . The apparatusmay then be powered-down.
The algorithm of may be summarized as follows. In 702, after the enttherapy controlled by the apparatus is stopped, humidity generation with the humidifier isd. In 704, the flow rate generated by the flow generator is controlled to the Fminltargetvalue. In 706, one or more of the g elements are controlled to in a targettemperature in the delivery tube of the patient interface. In 708, a dew-point temperature ischecked to assess if it has stabilized. If it has not, process flow returns to 704. If it has, processflows to 710. In 710, the flow rate of the flow generator is then controlledto the target Fmin2value. In 712, one or more of the heating elements are controlled to maintain a targetW0 2009/146484 temperature in the delivery tube of the patient ace. In 714, a dew-point ature ischecked to assess if it has ized. If it has not, process flow returns to 710. If it has, processflow ofthe cool-down procedure is complete..8 ATIONS OF METHOD AND APPARATUS A user will be titrated to determine the optimal flow rate and temperature for treatingthe user’s sleep disordered breathing (SDB). The l settings for flow rate and temperatureare those that maximize efficacy of the therapy as well as user comfort. For example, thetemperature will be set to the highest value within the range capable by the device that is deemedcomfortable by the user. The temperature may also be changed to compensate for any droplets ofwater that may form in the air ry tube or user interface, for example nasal cannula. Thetemperature may also be changed to maximize the efficacy of the therapy. For flow, an examplewould be for the rate of flow to start at the lowest le by the device. When the user isasleep and SDB events are detected, such as by the controller of the device, the flow rate wouldbe incrementally increased in response to the SDB events (for example, apneas, hypopneas, flowlimitation and snoring) to prevent them from repeating and hence maximizing the efficacy of thetherapy. Another method would be to set the flow rate to the highest rate that is table forthe user when awake. When the user is asleep, the necessary s in flow ratemay be madein response to the SDB events, again to maximize the efficacy of the therapy.
Changes to flow rates and temperature may be done manually, by an observer of theuser when they are asleep. For example, by a sleep technologist observing the user usingpolysomnography (PSG). I Changes to flow rate, gas temperature and/or humidity levels may also occurautomatically in response to the SDB events detected by the apparatus. This would be based onan algorithm that incrementally increases the flow rate, gas temperature and/or humidity levels inresponse to the SDB events. The magnitude of the increase would be governed by the type ofthe SDB event. For example, the increase in flow rate, gas ature and/or humidity levelswould be greater for an apnea compared to flow limitation which in turn would begreater thanthe response to snore. Alternatively, incremental decreases in the flow rate, gas temperatureand/or humidity levels would occur in response to an absence of detected SDBevents after acertain period of time.[0 094] The gs of flow rate, ty and/or aturemay be increased or decreasedby the device with some step value by simply detecting whether any one or more of these SDBevents occur. er, such adjustments may be a fimction of the measure of the detectedSDB event. For example, a measure of partial obstruction may be a varying index from 0 to 1where 1 is fully obstructed, 0 is not obstructed and 0.5 if half obstructed. The change in any ofW0 2009/146484 the flow rate, humidity and/or temperature may then be a fimction of the degree of partialobstruction, such as, a function that generates a greater ment when there is a larger degreeof obstruction and a lesser adjustment when there is a smaller degree of obstruction. In someembodiments, a degree of partial obstruction may be assessed by a flattening analysis of arespiratory flow , a roundness analysis of a respiratory flow signal and/or other partialobstruction methodology for assessing of the patient's upper airway.
To assist in the treatment of SDB, in some embodiments the ratio of the outerdiameter of the nasal prongs of the patient interface to the surface area of user’s nares may beincreased or decreased. These changes would be to increase the efficacy and comfort of thetherapy.[009 6] Once titration has been effected, optionally, the patient may alter the therapy settingsmanually within a restricted range to improve comfort according to personal choice..9 CYCLING In some embodiments of the logy, the flow and or humidification of airdelivered to each nare is individually controlled. For example, a higher flow and/or morehumidification may be delivered on one side compared to the other. In one form, each of the airflow & fication may be individually cycled in a nare. For example, a flow rate may beadjusted in one nare while maintaining a fairly constant flow rate or ty in the other nare.
By way of further example, a high flow rate may alternate between the lefi nare and a right naresuch that when a high rate is directed at one nare, a low rate is directed at the other. In anotherform changes in flow and/or humidification of air red to one nare are synchronized withchanges in flow and or humidification of air delivered to the other nare.
The delivery of a higher flow to one nare compared to the other may be tocompensate for a user with unilateral nasal obstruction. In one embodiment, the higher flow ratewould be delivered to the nare that was not obstructed. This would maximize the efficacy of thetherapy. Alternatively, a higher rate may be delivered to the obstructed mate as an t todecrease the obstruction. Obstruction may be ined by automatic method of ingpartial obstruction, for example, by analysis of a respiratory flow signal. Such an analysis maybe independent for the respiratory flow signal associated with each nare. Alternatively,unilateral l obstruction may be detected by an increase ina measure of re from are sensor associated with one nare with respect to a measure of pressure of anotherpressure sensor ated with the other nare.
The delivery of more humidification to one nare compared to the other mightbe tocompensate for the higher flow being delivered to one nare because it is less obstructed.
Alternatively, more humidification may be delivered to the nare with higher nasal resistance toW0 2009/146484 reduce this resistance. Optionally, while this is occurring, 3 higher flow may be delivered to theother nare. After the higher nasal resistance is reduced, by more humidification and/era higherflow rate, and the resistance is equal between the two nares, the humidification and air flow maythen be returned to equal delivery to each of the nares. This may be tested by analysis of theve pressures of the sensors associated with each nare. For example, the flows directed ateach nare may be set to be equal and the two pressures associated with the nares may then bed and compared for substantial equality, which may indicate that there is no unilateralobstruction.
This delivery of different flow can be achieved, for example, by the use of twomotors within the device. One motor for each of the two nares with a controller linking bothmotors. Alternatively, a single motor blower might be used with lled venting valves in theflow paths for each nare. In such a case, the blower may be set to a desired rate for the highestflow desired for either nare. The flow at the high rate may be delivered to one nare withoutsubstantial venting while the blower flow rate to the other nare may be reduced by venting someof the flow of the flow path of the other nare without delivering all of it to that nare. This maybe achieved by separately lling the diameter of an re associated with a venting valveof each delivery tube associated with each nare by the controller. Alternatively, one or morevariably controlled gate valves may split a single supply tube from a blower into a y-junction.
For example, mechanical gate valves, near a y-junction,may then be set to position(s) to. gate aportion of the flow to one delivery tube directed at one nare and a portion of flow into anotherdelivery tube directed at the other nare. For example, 60% of the flow may be directed to onemare and 40% ofthe flow may be directed at the other nare. The gate valvemay be controlled todivide the supply rate by other tages (e.g., 50%/50%, O%/100% etc.) Essentially, thecontroller can set the gate valve to divide the flow between the nares byany desired on oraperture g. An example of suitable gate valves may be comparable to the gate valvesillustrated in Figs. 2A or 2B but with the flows traveling in the opposite ion from thatillustrated in those figures. Optionally, additional tubes and gate valves may also be added tothen adjust the humidity levels directed to each nare tube as previously described with regard and 2B.[ 0 101] Still fiirther, the delivery of different levels of humidificationcan be achieved, forexample, by altering the proportion of air being delivered that comes fiom the humidifiercompared to that from the environment. By increasing the proportion of air fi'om theenvironment the lower the amount of fication being red to thepatient. In such acase, ambient humidification and ature sensors may be utilized to provide the controllerW0 2009/146484 with data concerning these ambient conditions. Alternatively, there may be two humidificationsystems. One for each nare of the user with a ller linking both humidifiers..10 DUAL RATE OPERATION In one embodiment of the technology, a dual rate mode of operation may beemployed. In this mode, the device is triggered by the inspirational flow of a user, in particularby the flow rate provided at the beginning of inspiration. This flow rate may be detected bynce from the pressure signal, or otherwise, and compared to a predetermined threshold. Thethreshold may be set to different sensitivities, e.g. high, medium and low. Once a trigger event isdetected, a first flow rate is provided. When the inspirational flow of a user, in particular by theflow rate provided at the end of inspiration, falls below another threshold, the device cycles to asecond flow rate. The flow rate may be ed as described above. Again, the thresholds forcycling may be set to different sensitivities, e.g. high, medium and low.
In one form of this dual rate operation, the inspiration flow rate is higher than the’ expiration flowrate. This is a form of expiration flow relief that may improve the comfort of thetherapy.
In another form of this dual rate operation, the tion flow rate is higher thanthe inspiration flow rate. This may assist in further increasing the end expiratorypressure (EEP)in the upper airway of the user. By increasing the EEP, the efficacy of the therapy may beimproved.
As previously mentioned, such triggering may also be utilized to implement firstand second ct humidification levels or first and second distinct breathablegas temperaturesaccording to the detected phases of the patient's respiratory cycle. Thus, the controller may setdifferent gas temperatures and/or different humidification levels depending on the phase ofrespiration..11 ALTERNATIVE THERAPY The therapeutic mode described herein,may be implemented in a device alsocapable of delivering CPAP or APAP therapy. In this case, the mode apy delivered by thedevice may be changed through a button, dial, menu or other control. A change of therapeuticmode might also be associated with changing the air-delivery circuitto that appropriate to thetherapeutic mode.
The device may have an indicator, for examplean LED, which will illuminatewhen the device believes it is not satisfactorily treating the SDB of the user based on datag. For example, the LED would be nated when the device recordedSDB eventswere above a ermined threshold at the end ofa session. This threshold could be set basedon the requirements of the ng physician. An e ofa threshold would be an apnea andW0 2009/146484 hypopnea index (AHI) r than 5 per hour of use. The illumination of this indicator based onSDB events would indicate a change to an ative y from that described in this patentto conventional continuous positive airway pressure (CPAP) or automatic positive airwaypressure (APAP).
The indicator described above in one case may result in the device of the userbeing changed to a PAP device. In another case, it may indicate that the mode oftherapy being delivered by the device he switched, manually, to CPAP/APAP mode. For this thedevice would be capable of delivering both types of y (i.e., that described in this documentand CPAP/APAP). In another case, the indicator may lead to an automatic change of therapymode and the device which is e of delivering both types of therapy automatically makesthe change. The indicator in this instance would be to notify the user that the change had.12 DISLODGEMENT AVOIDANCE AND DETECTION The relatively high flow rates of the devices and systems may give rise toadditional ms relating to patients experiencing problems wherein the nasal cannulaaccidently dislodged during operation. These problems may include potential damage to' the eyesor face of the patient n the high flow rates of air are accidently directed to sensitive partsof the face.
The preferred system and device may also detect accidental dislodgement,wherein the dislodgement is ed by at least one of the aforementioned preferredsensors.
When the dislodgement is detected, the system or devicemay be automatically shut off toprevent or limit potential damage from the high flow rates being accidentally directed tosensitive parts of the patient’s face. Alternatively or in on to the shut off, the dislodgmentdetection may automatically open a mechanical vent valve controlled by the llerto ventthe air at or near the controller or flow tor in a manner that more immediatelydepressurizes the supply tube to the cannula. One example dislodgement sensormay be apressure transducer that detects a change in pressure as an indication of dislodgement. In anotherexample, a clip with electrical contacts 1210A, 1210B, such as that illustrated in or 13,may serve as a dislodgment sensor by sending an electrical switch signal to the controller.
During use, the clip may be attached to a portion of the nares, such as at the base of the nose. Alight spring force used to hold the clip in place may also be utilized to te the sensorupondislodgment. Upon removal or dislodgment, the clip may be configured to spring closed (oropen depending on its desired configuration). The closing of the contacts (or opening thereofdepending on the configuration of the switch and the spring action) may then be detectedelectrically by the controller as a dislodgment. The clip may even be combined with the otherW0 2009/146484 components of the patient interface such as the nasal dilators previously discussed (e.g., thedilator of FIGS. 8 or 11), and may even also serve to maintain the cannula in place as describedfurther herein.
In this regard, the chance or likelihood of accidental dislodgement may also bezed by attaching a specialized clip 1310 onto the nasal cannula. The clip may beconstructed of flexible and resilient material ding polyermic materials) and may attach andsecure the nares of the patient to the nasal a with a retaining force, and may still maintaina non-sealed relationship between the nose and nasal cannula.
Also in some embodiments, the end of the nasal a that may be ed intothe nose during operation may include an air diffuser such as the example diffuser with radialfins 1440 on the prong 880 illustrated in . Preferably, the air er may prevent orlimit the flow of air in a single direction but increases the dispersion of air g the nasalcannula. This may serve as an additional safety feature, wherein the nasal cannula areaccidentally dislodged from their position in nares. If the dislodgement occurs, the air diffuserreduces the risk that relatively high flow air will directed into a sensitive region of the patient’sface such as the eyes. Even if the air is accidentally ed into theeyes of the patient, theattachment of the air diffuser may significantly reduce the overall flow of air directed into theeyes and thereby increase safety ofthe device and reduce the overall risks.
In situations where the nasal cannala is dislodged while in operation, and this isdetected by sensors attached to the system, the system or devicemay include a controller thatsounds and/or displays an alarm to alert a patient or clinician to the dislodgement..13 A DESIGN MODIFICATION[ 0114] The nasal a previously described for use withany of the aforementionedembodiments may further include noise limiting features. These noise ng features mayreduce the l noise heard by the patient and people around the patient, whereinthe systemor device is operational.
In some embodiments, these noise limiting features may include specializedbaffles mounted on or in the nasal cannula orprongs to disperse or diffuse any noise emitted bythe nasal cannala. This may be particularly true when the nasal cannulaare ring relativelyhigh flow rates when compared to standard closed CPAP devices.
The noise baffle may be ucted of a foam insert,a maze-like structuremounted on or proximal to the end of nasal cannula engaging thenares of the patient. Ane, baffle 1550 about a prong 880 is illustrated in .
In the foregoing description and in the accompanying drawings, specificterminology, equations and drawing symbols are set forth to provide a thoroughunderstanding ofW0 2009/146484 the present technology. In some instances, the terminology and symbols may imply cdetails that are not required to practice the technology. Moreover, although the technologyherein has been described with reference to particular embodiments, it is to be understood thatthese embodiments are merely illustrative ofthe principles and applications of the logy. Itis therefore to be understood that numerous modifications may be made to the illustrativeembodiments and that other arrangements may be d without departing from the spirit andscope of the technology. For example, a device in accordance with the present technology couldprovide nasal CPAP. In one form ofthe technology, drug delivery is provided with the supply ofbreathable gas, for e in the form of a nebulised drug. For example, the present systemmay be used for ent of COPD or Cystic Fibrosis and accompanied with appropriate drugsfor the respective diseases.