Airway pressures during positive-pressure ventilation with superimposed oscillations.

This study was undertaken to determine whether oscillations superimposed on a regular ventilatory pattern influence the arterial blood gases and pH and the airway pressures at adequate alveolar ventilation at the onset of inhibition of inspiratory activity. The peak, mean and end-expiratory airway pressures were therefore measured at inhibition of this activity with and without superimposition of oscillations on the ventilatory pattern. It was found that superimposed oscillations lowered the airway pressure only at a low ventilatory frequency, whereas inhibition occurred at almost equal arterial PCO2 and pH values with and without superimposed oscillations on the ventilatory pattern.