Echocardiographic analysis of cardiac function during high PEEP ventilation

Does positive end-expiratory pressure ventilation (PEEP) deteriorate cardiac contractility By means of echocardiography nine piglets were studies during ventilation with 0, 15 and 25 cmH2O (PEEP). Recordings were made before and after 500ml of 6% dextran 70. Right and left ventricular enddiastolic diameters were plotted against the stroke volume determined by the thermodilution technique. By combining observations made before and after volume expansion during the different ventilation modes, a ventricular function curve was obtained. The slopes of the curves were similar during all three ventilation modes, both on the left and on the right side. This study indicates undisturbed myocardial contractility during PEEP ventilation. We infer that the cardiac output deterioration in the intact animal is caused entirely by impairment of venous return.