Automatic Positive Airway Pressure Therapy through the Nose or Mouth for Treatment of Sleep Apnea and Other Respiratory Disorders

• US 20090095297A1
• Filed: 08/28/2007
• Published: 04/16/2009
• Est. Priority Date: 09/01/2006
• Status: Active Grant

• Current Assignee: Ventific Holdings Pty., Ltd.
• Original Assignee: Ventific Holdings Pty., Ltd.
• Inventors: Hallett, Michael David
• Granted Patent: US 8,316,847 B2
• Time in Patent Office: Days
• US Class Current: 128/204.18
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2205/3331 Pressure; Flow

Abstract

The method describes a means of automatic determination of required pressure levels of a breathable gas for treating sleep apnea or other respiratory disorder such as sleep hypoventilation or chronic obstructive pulmonary disease. The method makes use of a face mask nasal prongs or similar means with venting system for elimination of expired gas to atmosphere, gas delivery tubing, and a computer controlled fan or blower or other similar source of pressurised breathable gas.

Claims

1. A method of providing ventilatory support or treatment of sleep disordered breathing comprising an electrically operated and computer controlled fan or blower or other similar source of pressurised breathable gas, a gas delivery tube, and an atmospherically vented face mask, nasal prongs or similar means and over a single respiratory cycle comprising the steps of:

Cycling administered pressure between and including an upper pressure and a lower pressure to a user'"'"'s airway, such lower pressure being not less than atmospheric pressure and maintained only for as long as is required to allow the immediately prior administered gas volume to be at least substantially or completely expelled from a user'"'"'s respiratory system by its elastic recoil, a lower pressure thereafter automatically being returned to an upper pressure;

Sensing either flow or pressure to detect a user'"'"'s need to initiate lung emptying and thereby initiating a transition from an upper pressure to a lower pressure, or initiating such change in response to a minimum background time dependent rate;

Automatically determining a target level of a lower pressure and an upper pressure.

Applying target pressures from said pressure source of breathable gas to the patient'"'"'s airway where target pressures will vary between an upper and lower pressure;

2. The method contained in claim 1 wherein the rate at which the immediately prior administered gas volume is at least substantially or completely expelled from a user'"'"'s respiratory system by its elastic recoil may be servo regulated by a computer controlled pressure source

3. The method contained in claim 1 wherein the form of administered pressure and volume with time from the lower to upper pressure may be servo regulated by a computer controlled pressure source

4. The method in claim 1 wherein the minimum lower pressure level may be set to maintain the airways unrestricted or unobstructed or between such minimum pressure level and atmospheric pressure or at a level sufficient to reasonably minimise rebreathing of residual carbon dioxide remaining within the mask and gas delivery tube

5. The method in claim 4 wherein a lower and an upper pressure can be incrementally adjusted simultaneously but independently in regards to degree and direction and administered to provide a required level of supported instantaneous minute ventilation

6. The method in claim 5 wherein the degree of supported ventilation can be increased or decreased to ensure that over a single respiratory cycle the total ventilation being equal to the level of supported ventilation and user'"'"'s own effort is targeted to provide a time average equivalence with a moving average of the user'"'"'s past minute ventilation

7. The method in claim 6 wherein the calculated difference between level of an upper pressure and lower pressure when added to a lower pressure or subtracted from a upper pressure will always yield values that are not less than a minimum required for respective lower or upper pressures

8. The method in claim 7 wherein upper and lower pressures may be progressively decreased after a period of stability

9. The method in claim 8 wherein the automatic trigger from a lower pressure to an upper pressure may be pre-empted by a user'"'"'s spontaneous inspiratory effort.

10. The method in claim 8 wherein a minimum upper pressure may be set at a level to minimise or eliminate patient inspiratory effort.

11. The method in claim 8 wherein a minimum upper pressure is set to provide a level of support less than or equal to a moving average of the user'"'"'s past minute ventilation and the user provides additional effort to fulfil ventilatory requirements as required.

12. The method in claim 11 wherein the upper pressure may be further adjusted to eliminate inspiratory flow abnormalities including but not limited to snoring and flow limitation as indicated by shape of the flow time curve during voluntary efforts

13. The method in claim 12 wherein the rate of pressure rise to an upper pressure from a lower pressure is set to ensure that an upper pressure is reached concomitantly with a user beginning an inspiratory effort.

14. The method in claim 13 wherein the rate of pressure increase to an upper pressure from a lower pressure may be linear such as a half square wave or ramp.

15. The method in claim 14 wherein the rate of pressure rise will further be defined by a combination of the shape of the inflow time curve at the commencement of user effort, the magnitude of difference between a lower and an upper pressure and the duration of the total respiratory cycle time.