The Effect of Peep-ventilation on Cardiac Function in Closed Chest Pigs

Abstract

Objective: Does ventilation with positive end-expiratory pressure (PEEP) depress myocardial contractility?

Design: Ten piglets were anaesthetized and prepared for the measurement of cardiac output (SV) and right (MRAPtm) and left (MLAPtm) mean transmural atrial pressure, the latter serving as indices of preload. 500 ml of autologous blood was re-transfused during intermittent positive pressure ventilation without PEEP (IPPV) and continuous positive pressure ventilation with 15 cm H₂O PEEP (CPPV).

Measurements and results: Right and left ventricular function curves were drawn by plotting MRAPtm and MLAPtm respectively versus the corresponding strokevolumes before and after re-transfusion. Similar inclinations were obtained during IPPV and CPPV on either side of the heart.

Conclusions: Although the ventricular function curves during IPPV and CPPV covered partially different preload levels, the results suggest that CPPV i.e. PEEP does not affect myocardial contractility.