METHOD AND APPARATUS FOR IMPROVED FLOW LIMITATION DETECTION OF OBSTRUCTIVE SLEEP APNEA

The present invention discloses an apparatus for detecting inspiratory and expiratory flow-time curves in an airflow, comprising: a flow detector configured to generate an airflow signal representing a respiratory airflow curve based on measurements of the airflow overtime, and a processor in communication with the flow detector, the processor configured to: process the airflow signal by: provisionally taking a start of inspiration as a time that the airflow exceeds a predetermined threshold, rejecting the start of inspiration if the airflow then falls below zero before a total volume inspired reaches a first predetermined value, provisionally taking a start of expiration as a time that the airflow falls below zero, and rejecting the start of expiration if the airflow then goes above a second predetermined value in an inspiratory direction before a total volume expired reaches a predetermined value; and adjust, based on the processed airflow signal, a treatment pressure provided to a patient.