Determination of apnea/hypopnea during CPAP treatment through calculating an average respiratory airflow over a comparative short and long term interval

摘要

An apparatus for detecting the occurrence of apnea and/or hypopnea events in a patient, and corresponding method is disclosed. The apparatus includes a sensor for sensing respiratory flow, first and second filters to iteratively calculate a first and second average respiratory airflow over a first and second time interval; the second time interval being shorter than the first time interval. The apparatus also includes a controller in communication with the sensor and the first and second filters. The controller is programmed to iteratively calculate a predetermined fraction of the first average respiratory airflow and compare this value with the second average respiratory airflow such that the comparison can determine an apnea or hypopnea event. The controller then continues to calculate the second average respiratory airflow and compare this value to the predetermined fraction of the first average respiratory airflow to confirm the occurrence of the apnea or hypopnea event. Upon determining the apnea or a hypopnea event, the calculation of the first average respiratory airflow is stopped until the apnea or the hypopnea ends.