Elevated airway pressures during mechanical ventilation are associated with hemodynamic compromise and pulmonary barotrauma. We studied the cardiopulmonary effects of a pressure-limited mode of ventilation (airway pressure release ventilation) in patients with the adult respiratory distress syndrome.
Fifteen patients requiring intermittent mandatory ventilation (IMV) and positive end-expiratory pressure (PEEP) were studied. Following measurement of hemodynamic and ventilatory data, all patients were placed on airway pressure release ventilation (APRV). Cardiorespiratory measurements were repeated after a 2-hour stabilization period.
During ventilatory support with APRV, peak inspiratory pressure (62±10 vs 30±4 cm H2O) and PEEP (11±4 vs 7±2 cm H2O) were reduced compared with IMV. Mean airway pressure was higher with APRV (18±5 vs 24±4 cm H2O) There were no statistically significant differences in gas exchange or hemodynamic variables. Both cardiac output (8.7±1.8 vs 8.4±2.0 L/min) and partial pressure of oxgen in arterial blood (79 ±9 vs 86±11 mm Hg) were essentially unchanged.
Our results suggest that while airway pressure release ventilation can provide similar oxygenation and ventilation at lower peak and end-expiratory pressures, this offers no hemodynamic advantages.(Arch Surg. 1993;128:1348-1352)