A Hazard of Pressure Support Ventilation

Many of the newer models of mechanical ventilators include the pressure support (PS) mode of ventilation as a standard feature. The mechanism for the termination of a pressure support breath varies considerably among the various ventilators. The potential for the sudden inadvertent application of a high, unremitting pressure support breath or continuous positive airway pressure (CPAP) clearly exists with some ventilators and is illustrated in two cases. The potentially adverse consequences of high levels of CPAP are predictable and have been well described. Standard ventilator monitoring systems which do not include mean airway pressure monitoring may not detect this problem before significant adverse consequences have occurred. Even when detected, this unfamiliar complication may be difficult to recognize by the uninitiated. Physicians utilizing this mode of ventilation must be familiar with the terminating mechanism of their particular ventilator and choose appropriate monitoring.