Hemodynamic effects of positive end-expiratory pressure

The hemodynamic effects of positive endexpiratory pressure (PEEP) may limit its use in improving oxygenation and pulmonary recruitment in patients receiving mechanical ventilation. Usually, PEEP has no significant effect on the heart rate, but it may reduce the left ventricle (LV) ejection volume, mainly through the alteration of the right ventricle (RV) preload and/or afterload. Consistently, PEEP may reduce the RV preload mainly through a decrease in the venous return conductance. Moreover, PEEP can, depending on its level, increase the RV afterload as a consequence of the increased transpulmonary pressure. The latter effect can result in RV dysfunction with cor pulmonale. The preponderance of RV preload or afterload depends on the hemodynamic and respiratory characteristics of each patient. Volume expansion can in most cases correct the alterations of the RV preload. Correction of the RV afterload alteration is complex and requires the adaptation of ventilatory settings in order to reduce the RV afterload and relieve pulmonary vascular dysfunction.