초록 ▼

Methods and apparatus for determining leak and respiratory airflow are disclosed. A pressure sensor (34) and a differential pressure sensor (32) have connection with a pneumotach (24) to derive instantaneous mask pressure and airflow respectively. A microcontroller (38) estimates a non-linear conduc

Methods and apparatus for determining leak and respiratory airflow are disclosed. A pressure sensor (34) and a differential pressure sensor (32) have connection with a pneumotach (24) to derive instantaneous mask pressure and airflow respectively. A microcontroller (38) estimates a non-linear conductance of any leak path occurring at a mask (12) as being the low pass filtered instantaneous airflow divided by the low pass filtered square root of the instantaneous pressure. The instantaneous leak flow is then the conductance multiplied by the square root of the instantaneous pressure, and the respiratory airflow is calculated as being the instantaneous airflow minus the instantaneous leak flow. The time constants for the low pass filtering performed by the microcontroller (38) can be dynamically adjusted dependent upon sudden changes in the instantaneous leak flow.

대표청구항 ▼

[ I claim:] [1.] A method for determining instantaneous leak flow at a mask having a leak path during mechanical ventilation, the method comprising the steps of:(a) determining instantaneous airflow at the mask;(b) determining instantaneous pressure at the mask;(c) estimating non-linear instantaneou

[ I claim:] [1.] A method for determining instantaneous leak flow at a mask having a leak path during mechanical ventilation, the method comprising the steps of:(a) determining instantaneous airflow at the mask;(b) determining instantaneous pressure at the mask;(c) estimating non-linear instantaneous conductance of said leak path as the low-pass filtered instantaneous airflow divided by the low-pass filtered square root of the instantaneous pressure; and(d) determining said instantaneous leak flow to be said conductance multiplied by the square root of the said instantaneous pressure.