Distinguishing closed and open respiratory airway apneas by complex admittance values

摘要

Methods and apparatus are disclosed for determining the occurrence of a closed or open apnea. Respiratory air flow from a patient is measured to give an air flow signal. The determination of an apnea is performed by applying an oscillatory pressure waveform of known frequency to a patient's airway, calculating a complex quantity representing a patient admittance (12) and comparing its value with ranges (14,16) indicative of open or closed apneas. The method distinguishes open from closed apneas even when the model used to calculate admittance is not based on details of the respiratory apparatus. In addition the patient admittance may be compared with admittance during normal breathing to avoid having to characterize the airway.

主权项

1. A method of classifying airway apneas of a patient as open and closed with a positive airway pressure respiratory apparatus connectable to a patient via an air delivery tube and a patient interface, the method comprising:
(i) controlling delivery of a pressure waveform to a patient from the respiratory apparatus via the air delivery tube; (ii) measuring a flow rate and pressure of air at the respiratory apparatus; (iii) determining a capacitive component of an air delivery tube impedance with a processor of the respiratory apparatus; (iv) determining a patient admittance from said measured flow and pressure of air and said capacitive component with the processor; and (v) classifying the airway apnea on a basis of said patient admittance with the processor.