초록 ▼

A low-cost CPAP apparatus in which, upon detection of the transition from inhalation to exhalation, the blower motor is de-energized to allow it to freewheel. When the pressure in the patient mask (or whatever interface is utilized) reaches a minimum pressure level during exhalation, the motor is re

A low-cost CPAP apparatus in which, upon detection of the transition from inhalation to exhalation, the blower motor is de-energized to allow it to freewheel. When the pressure in the patient mask (or whatever interface is utilized) reaches a minimum pressure level during exhalation, the motor is re-energized and its speed is controlled so to maintain the pressure at a level suitable for exhalation. Upon detection of the transition from exhalation to inhalation, the motor speed is increased to provide higher pressures in the patient mask suitable for inhalation.

대표청구항 ▼

1. A method of controlling a pressure of air delivery by a CPAP apparatus; wherein said CPAP apparatus includes an electric motor, an impeller driven by the motor for delivering air to a patient interface, a sensor for determining the pressure in the patient interface, and a controller (1) to contro

1. A method of controlling a pressure of air delivery by a CPAP apparatus; wherein said CPAP apparatus includes an electric motor, an impeller driven by the motor for delivering air to a patient interface, a sensor for determining the pressure in the patient interface, and a controller (1) to control the pressure of air delivery to the patient interface and (2) to detect transitions between inhalation and exhalation of a respiratory cycle of a patient, comprising the steps of: (i) operating said electric motor, thereby driving said impeller for delivering air to said patient interface at a pressure above atmospheric;(ii) upon detection of the transition from inhalation to exhalation, ceasing driving said impeller and causing said impeller to freewheel;(iii) upon the sensor sensing that the pressure in the patient interface reaches a minimum pressure level during exhalation, re-starting driving said impeller to maintain the pressure at a level suitable for exhalation; and(iv) upon detection of the transition from exhalation to inhalation, increasing driving said impeller to provide an increased pressure in the patient interface suitable for inhalation. 2. The method of claim 1 wherein in step (iii) the impeller speed is controlled so as to maintain the pressure at said minimum level. 3. The method of claim 1 further comprising the step of applying braking to the impeller for a portion of time between detection of the transition from inhalation to exhalation and sensing that the pressure in the patient interface reaches a minimum pressure level. 4. The method of claim 3 wherein the step of applying braking to the impeller for the portion of time occurs when the impeller first begins to slow. 5. The method of claim 4 wherein detection of the transition from inhalation to exhalation or exhalation to inhalation comprises the sub-steps of: (v) monitoring an air flow to the patient; and(vi) comparing the air flow to a threshold. 6. The method of claim 5 wherein said threshold is adjustable and when the air flow is smaller than said threshold, a transition is determined to have occurred, the threshold permitting an adjustment of a phase delay between the pressure and the air flow, the larger the threshold, the greater the confidence that a transition has been determined reliably at the expense of increased uncertainty in when the transition occurred, potentially leading to a phase delay and reduced synchronicity. 7. The method of claim 6 wherein said minimum pressure level during exhalation is adjustable to vary the patient's comfort level. 8. The method of claim 1 wherein detection of the transition from inhalation to exhalation or exhalation to inhalation comprises the sub-steps of: (vii) monitoring an air flow to the patient; and (viii) comparing the air flow to a threshold. 9. The method of claim 8 wherein said threshold is adjustable and when the air flow is smaller than said threshold, a transition is determined to have occurred, the threshold causing an adjustment of a phase delay between the pressure and the air flow, the larger the threshold, the greater the confidence that a transition has been determined reliably at the expense of increased uncertainty in when the transition occurred, potentially leading to a phase delay and reduced synchronicity. 10. The method of claim 9 wherein said minimum pressure level during exhalation is adjustable to vary the patient's comfort level. 11. The method of claim 1 wherein said minimum Pressure level during exhalation is adjustable to vary the patient's comfort level. 12. The method of claim 1 further comprising the step of braking the impeller in short bursts for a portion of time that the impeller freewheels. 13. The method of claim 12 wherein braking of the impeller occurs when the impeller first begins to slow during a breathing cycle. 14. A method of operating a CPAP apparatus in which a motor-driven rotating impeller delivers air at a desired pressure to a patient interface, comprising the steps of: (i) detecting a transition from inhalation to exhalation and in response thereto ceasing driving said impeller allowing the impeller to freewheel for an amount of time;(ii) detecting when the pressure in the patient interface reaches a minimum pressure level during exhalation and in response thereto re-starting driving the impeller and controlling the impeller speed so as to maintain the pressure at a level suitable for exhalation; and(iii) detecting a transition from exhalation to inhalation and in response thereto causing the motor to control the impeller to operate at a higher speed to provide higher pressures in the patient interlace suitable for inhalation. 15. The method of claim 14 further comprising the step at applying braking to the impeller for a portion of time between detection of the transition from inhalation to exhalation and sensing that the pressure in the patient interface reaches a minimum pressure level. 16. The method of claim 15 wherein said braking is applied to the impeller upon detecting the transition from inhalation to exhalation. 17. The method of claim 14 wherein detection of the transition from inhalation to exhalation or exhalation to inhalation comprises the sub-steps of: (iv) monitoring an air flow to the patient; and (v) comparing the air flow to a threshold. 18. The method of claim 17 wherein said threshold is adjustable and a transition is detected when the air flow is smaller than said threshold, the threshold causing an adjustment of a phase delay between the pressure and the air flow, the larger the threshold, the greater the confidence that a transition has been detected reliably at the expense of increased uncertainty in when the transition occurred, potentially leading to a phase delay and reduced synchronicity. 19. The method of claim 14 wherein said minimum pressure level during exhalation is adjustable to vary a patient's comfort level. 20. The method of claim 14 further comprising the step of braking the impeller in short bursts for a portion of time between detection of the transition from inhalation to exhalation and sensing that the pressure in the patient interface reaches a minimum pressure level. 21. A CPAP apparatus for treatment of sleep disordered breathing comprising: a blower, driven by a motor, which provides air at a desired pressure at the airway of a patient; anda controller coupled to the motor, the controller adapted to detect transitions between inhalation and exhalation and to control a reduction in the pressure during exhalation from a high level to a low level by controlling the blower to freewheel, wherein the reduction in pressure during exhalation occurs during a pretreatment phase of use of the CPAP apparatus. 22. A CPAP apparatus of claim 21 where said pretreatment phase of use is a ramp phase. 23. A CPAP apparatus of claim 21 where said pretreatment phase of use is settling time. 24. A CPAP apparatus comprising a motor-driven impeller, a sensor to sense pressure at a patient interface, and a controller to control said motor, said apparatus having two modes of operation including: a) a first mode where the pressure during exhalation is reduced by ceasing to drive the impeller, sensing that the pressure at the patient interface reaches a minimum pressure during exhalation, and then re-starting driving the impeller to maintain said minimum pressure, andb) a second mode where the pressure at the patient interface remains substantially constant during a cycle of inhalation and exhalation;wherein said controller is adapted to detect the presence of an apnea and to switch the CPAP apparatus from the first mode of operation to the second mode of operation upon detection of the presence of an apnea. 25. A CPAP apparatus of claim 24 where the controller is further adapted to detect a resumption of normal breathing and to switch from the second mode of operation to the first mode of operation upon the detection of the resumption of normal breathing. 26. A CPAP apparatus of claim 24 where the controller is further adapted to switch from the second mode of operation to the first mode of operation upon an expiration of a predetermined period of time. 27. A method of operating a CPAP apparatus comprising a motor-driven impeller, a sensor to sense pressure at a patient interface, and a controller to control said impeller; the CPAP apparatus having two modes of operation: (a) a first mode where the pressure during exhalation is reduced by ceasing to drive the impeller, sensing that the pressure reaches a minimum pressure during exhalation, and then re-starting driving the impeller to maintain said minimum pressure, and(b) a second mode where the pressure remains substantially constant during a cycle of inhalation and exhalation;the method comprising:detecting the presence of an apnea; andswitching the CPAP apparatus from the first mode of operation to the second mode at operation when the presence of an apnea is detected. 28. A method of operating a CPAP apparatus as claimed in claim 27 further comprising: detecting resumption of normal breathing; andswitching from the second mode of operation to the first mode of operation when the resumption of normal breathing is detected. 29. A method of operating a CPAP apparatus as claimed in claim 27 wherein switching from the second mode of operation to the first mode of operation is performed when a predetermined period of time has expired. 30. A method of controlling pressure in a patient interface of a CPAP apparatus during a sequence of respiratory cycles, wherein said CPAP apparatus further includes an electric motor, an impeller driven by the motor for delivering air from the impeller to the patient interface, a mechanism for determining the pressure in the patient interface, and a controller (1) to control the pressure of air delivery to the patient interface, and (2) to detect transitions between inhalation and exhalation of a respiratory cycle of a patient, comprising the steps of: (i) operating said electric motor, thereby driving said impeller for delivering air to said patient interface at a pressure above atmospheric;(ii) upon detection of the transition from inhalation to exhalation, ceasing driving said impeller to allow it to freewheel;(iii) upon the mechanism determining that the pressure in the patient interface reaches a minimum pressure during exhalation, re-starting driving the impeller to maintain the pressure at a level suitable for exhalation; and(iv) upon detection of the transition from exhalation to inhalation, increasing driving said impeller to provide an increased pressure in the patient interface suitable for inhalation. 31. The method of claim 30 wherein during a ramp phase the motor speed is controlled in step (iv) so as to increase the pressure over successive respiratory cycles. 32. The method of claim 31 wherein during said ramp phase the impeller speed is controlled in step (iv) so as to provide a substantially constant pressure during any single respiratory cycle while increasing the substantially constant pressure over successive respiratory cycles. 33. The method of claim 32 wherein at least one of ceasing driving the impeller in step (ii) and increasing driving the impeller in step (iv) is controlled so as to decrease a pressure differential between inhalation and exhalation during the two steps over successive respiratory cycles. 34. The method of claim 33 wherein the cycles occur during a ramp phase. 35. The method of claim 34 wherein the ramp phase takes place while the patient is trying to fall asleep so that increased comfort is obtained during the ramp phase following which during patient therapy the pressure is more constant throughout a respiratory cycle.