Breathing gas delivery method and apparatus
AssigneeRIC Investments, LLC
InventorsRonald J. Zdrojkowski, Mark H. Sanders, Mark Estes
Life of this patent
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Abstract
An improved methodology and systems for delivery of breathing gas such as for the treatment of obstructive sleep apnea through application of alternating high and low level positive airway pressure within the airway of the patient with the high and low airway pressure being coordinated with the spontaneous respiration of the patient, and improved methods and apparatus for triggering and for leak management in such systems.
Claims9
A method of detecting changes in the respiratory state of a patient between inspiration and expiration comprising the steps of:
- monitoring the respiratory gas flow of such a patient;
- from said monitoring, determining a patient respiratory gas flow characteristic at selected time intervals;
- comparing selected pairs of said respiratory gas flow characteristics;
- and
- from said comparing, identifying changes in the patient's respiratory state between inspiration and expiration.
A method of determining the leak component of gas flow in a respiratory gas supply system for supplying respiratory gas to a patient comprising the steps of:
- determining the beginning and end of an integral number of patient breaths;
- integrating patient respiratory gas flow rate throughout at least some of said patient breaths to determine total respiratory gas volume for said at least some of said patient breaths;
- and
- dividing said total respiratory gas volume for said at least some of said patient breaths by the time duration of the respective patien breaths to determine a leakage rate for said at least some of said patient breaths.
A method of determining the rate of leakage from a respiratory gas supply system which supplies respiratory gas flow to a patient at specified flow rates and pressures comprising the steps of determining said rate of leakage as a leak which is proportional to the square root of pressure by a constant of proportionality K, where
- 2 K = ∫ 0 T ( total flow ) ⅆ t ∫ 0 T ( Pressure ) ⅆ t , eq . 1
- the numerator of eq. 1 representing average leak flow and the denominator of eq. 1 representing the relationship between the leak rate and pressure.
Dependencies are inferred from the claim text.