APPARATUS FOR DISTINGUISHING BETWEEN CLOSED AND OPEN RESPIRATORY AIRWAY APNEAS BY COMPLEX ADMITTANCE VALUES

摘要

The present invention relates to a patency detection system for determining patency of an airway of a patient, the system comprising, a controller means for controlling a flow generator to generate airflow in an oscillatory pressure waveform at known frequency and magnitude for delivery to the patient's airway calculating complex admittance values (12) of respiratory air flow of the patient from said airway in response to the oscillatory pressure waveform and determining the patency of the airway by determining whether the complex admittance values are in a region of complex values characteristic of patency (14, 16).