Optimal endexpiratory airway pressure for ventilated patients.

In patients ventilated for acute respiratory failure PEEP was changed either by gradual increase and decrease (5 cm H2O/min) or in steps of 5 cm H2O. The effects on gas exchange, pulmonary mechanics and pulmonary and systemic circulation were studied. Total compliance did not change uniformly and cardiac index decreased so much due to PEEP that the increase in PaO2 could not prevent the decrease of arterial oxygen transport. No variable was found helpful to predict the "best PEEP" in a clinical situation.