초록

A method and apparatus for delivering breathable gas to a user includes a humidifying unit that is controllable to humidify the gas in accordance with a variable humidity profile such that the gas is delivered to the user at variable humidity levels, e.g., during a treatment session.

대표청구항 ▼

1. A humidifying system configured to humidify pressurized breathable gas, the humidifying system comprising: a housing configured to couple to a blower that is adapted to supply pressurized breathable gas to provide continuous positive airway pressure (CPAP) treatment to a patient;a tub adapted to

1. A humidifying system configured to humidify pressurized breathable gas, the humidifying system comprising: a housing configured to couple to a blower that is adapted to supply pressurized breathable gas to provide continuous positive airway pressure (CPAP) treatment to a patient;a tub adapted to hold a volume of water;a heater element to heat the volume of water;a temperature sensor to sense the ambient temperature;and a controller, wherein the controller is configured to control the heater element to provide a humidity profile during a treatment session, and a set point of the humidity profile is modified over at least a portion of the treatment session to maintain efficient use of the volume of water throughout the treatment session, wherein the set point of the humidity profile is modified as a function of the sensed ambient temperature and a measure of time. 2. A humidifying system according to claim 1, wherein the humidity profile includes cycling the heater element on and off for predetermined periods of time during the treatment session. 3. A humidifying system according to claim 1, wherein the humidity profile includes delaying turning on the heater element for a predetermined period of time at the beginning of the treatment session. 4. A humidifying system according to claim 3, wherein the predetermined time is one hour. 5. A humidifying system according to claim 1, wherein the humidity profile reduces the humidity level during the treatment session and the initial humidity level is determined based on the ambient temperature and the measure of time. 6. A humidifying system according to claim 1, wherein the ambient temperature is sensed over a plurality of treatment sessions to determine the humidity profile. 7. A humidifying system according to claim 1, wherein the humidity profile is determined from the sensed ambient temperature from one or more previous treatment sessions. 8. A humidifying system according to claim 1, wherein the humidity profile is varied in response to the sensed ambient temperature of the current treatment session and the measure of time. 9. A humidifying system according to claim 1, wherein time is measured over the entire treatment session. 10. A humidifying system according to claim 1, wherein the measure of time counts down from a predetermined time value at the beginning of each treatment session. 11. A humidifying system according to claim 10, wherein the predetermined time value is an average length of time of a treatment session. 12. A humidifying system according to claim 11, wherein the average length of time of a treatment session is determined from a plurality of previous treatment sessions. 13. A humidifying system according to claim 1, wherein the humidity profile is determined so that the humidity profile does not require a volume of water equal to or more than the volume of water available in the tub during a treatment session. 14. An apparatus for providing continuous positive airway pressure (CPAP) treatment to a patient comprising: a blower adapted to provide a supply of pressurized breathable gas;a patient interface configured to deliver the supply of pressurized breathable gas to the patient;an air delivery conduit between the blower and the patient interface; anda humidifier unit comprising a humidifying system according to claim 1;wherein the humidifier unit includes at least one conduit in communication with the blower, the humidifier unit being configured to provide humidity to the pressurized breathable gas according to the humidity profile, andthe humidity profile comprises a setting that causes the humidity to vary during the treatment session. 15. An apparatus according to claim 14, further comprising a control panel to allow the humidity profile to be selected from a menu. 16. An apparatus according to claim 15, wherein the menu includes at least one of a sinusoidal wave humidity profile, a square wave humidity profile and a combination thereof. 17. An apparatus according to claim 14, wherein the humidity profile is configured to vary the humidity in response to changes in ambient environmental conditions. 18. An apparatus according to claim 17, wherein the ambient environmental conditions include at least one of temperature and humidity. 19. An apparatus according to claim 14, wherein the humidity profile is configured to cycle between switching the humidifier unit on and off during the treatment session. 20. An apparatus according to claim 19, wherein the on and off cycles are configured to occur regularly throughout the treatment session. 21. An apparatus according to claim 19, wherein the on and off cycles are configured to occur irregularly throughout the treatment session. 22. An apparatus according to claim 19, wherein the off cycle is a period when the level of humidity provided is reduced compared to the level of humidity provided during the on cycle. 23. An apparatus according to claim 14, wherein the humidity profile is configured to delay the supply of humidity for a predetermined period at the beginning of the treatment session. 24. An apparatus according to claim 14, wherein the humidity profile is configured to reduce the level of humidity provided over time throughout the treatment session. 25. An apparatus according to claim 14, wherein the humidity profile is configured to provide humidity for only a predetermined period of time of the treatment session. 26. An apparatus according to claim 14, wherein the humidifier unit comprises two conduits in communication with the blower, one conduit adapted to supply the pressurised breathable gas to the humidifier and the other conduit adapted to supply the humidified pressurized breathable gas back to the blower for delivery to the air delivery conduit. 27. An apparatus according to claim 26, wherein the blower further includes a diverting means to divert the path of the pressurized breathable gas to a by-pass means of the humidifier unit. 28. An apparatus according to claim 27, wherein the diverting means includes a pair of valves to shut off the two conduits of the humidifier to prevent the pressurized breathable gas from entering the humidifier unit. 29. An apparatus according to claim 14, wherein the patient interface further comprises a sensor configured to detect condensation. 30. An apparatus according to claim 29, wherein the sensor includes at least one of an infrared emitter and a detector. 31. An apparatus according to claim 29, wherein the humidity profile is configured to adjust the temperature of the breathable gas in response to a level of condensation sensed by the sensor. 32. An apparatus according to claim 14, wherein the tub has a capacity in the range of 20 ml to 400 ml. 33. An apparatus according to claim 32, wherein the tub has a capacity in the range of 50 ml to 200 ml. 34. A humidifying system according to claim 1, wherein the humidity profile is modified as a function of a predicted ambient condition based on the measure of time. 35. A humidifying system according to claim 1, wherein the humidity profile is modified as a function of a predicted humidification need of the patient based on the measure of time. 36. A humidifying system configured to humidify pressurized breathable gas, the humidifying system comprising: a housing configured to couple to a blower that is adapted to supply pressurized breathable gas to provide continuous positive airway pressure (CPAP) treatment to a patient;a tub adapted to hold a volume of water;a heater element to heat the volume of water;a temperature sensor to sense the ambient temperature;anda controller configured to control the heater element based on a humidity profile that sets a target humidity level during the treatment session, the controller being further configured to modify the target humidity level of the humidity profile as a function of the sensed ambient temperature and a time monitored over at least a portion of a treatment session. 37. A humidifying system according to claim 36, wherein the monitored time corresponds to at least one of: an amount of time that has elapsed since an initiation of the treatment session,time of day, anda time of year. 38. A humidifying system according to claim 37, wherein the controller is configured to modify the humidity profile according to a change in the sensed ambient temperature over the course of the treatment session. 39. A humidifying system according to claim 37, wherein a target humidity level of the humidity profile forms a sinusoidal wave over the course of the treatment session. 40. A humidifying system according to claim 39, wherein the sinusoidal wave is symmetrical. 41. A humidifying system according to claim 39, wherein the sinusoidal wave is asymmetrical. 42. A humidifying system according to claim 37, wherein a target humidity level of the humidity profile forms a square wave over the course of the treatment session. 43. A humidifying system according to claim 42, wherein the square wave is symmetrical. 44. A humidifying system according to claim 42, wherein the square wave is asymmetrical. 45. A humidifying system according to claim 37, wherein a target humidity level of the humidity profile forms a combination of at least two of a wave, a curve and a step over the course of the treatment session. 46. A humidifying system according to claim 37, wherein the controller is configured to modify the humidity profile to reduce the humidity level during the treatment session and an initial target humidity level is determined based on the ambient temperature and the current time.