Failure of a ventilator alarm to detect patient disconnection.

An East Ventilator pressure monitor, Model VPM, used with an East Radcliffe PNA I Ventilator, failed to detect a patient disconnection at the distal end of the catheter mount. An investigation was undertaken to show why this system failed by measuring pressure and flow whilst using a variety of catheter mounts. It was concluded that the use of the East Ventilarm pressure monitor in conjunction with a pressure generator ventilator is unsuitable for detecting disconnections at the distal end of the catheter mount, the most frequent site of disconnection. Possible alternative methods of detecting this type of disconnection are suggested.