AIRWAY PRESSURE RELEASE VENTILATION

Background: 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. Methods: 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. Results: 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 oxygen in arterial blood (791+/-9 vs 86+/-11 mm Hg) were essentially unchanged. Conclusions: 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.