Lack of adverse hemodynamic effects of PEEP in patients with acute respiratory failure.

The hemodynamic effects of PEEP ventilation were studied in 6 patients with adult respiratory distress syndrome (ARDS). Cardiac index (CI), blood pressure (BP), heart rate (HR), left cardiac work index (LCWI), and left ventricular stroke work index (LVSWI) were evaluated in each patient at 0, 5, 10, 15, and 20 cm H2O of PEEP. All patients were able to tolerate even the highest level of PEEP without evident clinical sequelae. BP did not change significantly. HR fell significantly at 20 cm H2O of PEEP. LCWI and CI fell at 20 cm H2O of PEEP but the mean fall in CI was only 6% (from 3.47 to 3.27 L/min . M2). LVSWI did not change significantly. PEEP did not produce clinically significant hemodynamic changes. We believe that the avoidance of hypovolemia, limited use of sedative and paralytic drugs, and use of assisted ventilation in the management of our patients contributed substantially to these results though other possible factors cannot be excluded.