LUNG VENTILATORS

A lung ventilator particularly adapted for use in weaning patients from dependence thereupon and includes an exhalation conduit through which the gas exhaled by the patient is passed. Both the rate of flow of gas passing through the exhalation conduit during each individual exhalation phase, and the minute volume of exhaled gases are monitored. If, during any given exhalation phase, the minute volume of exhaled gases should fall below a chosen threshold, indicating that the patient fails to breathe adequately, the ventilator is triggered to perform a mandatory ventilation cycle. The ventilator is inhibited from delivering mandatory breaths, however, until the rate of flow of exhaled gas in a given exhalation phase has reduced to the point which indicates that exhalation has ceased.