Figure 3: While decreasing the gradient for the venous return, PEEP also increases the systemic circulatory pressure which may counter the decrease in the gradient for the venous return. Increasing right ventricular afterload may compromise LV filling. Volume status is a major determinant of PEEP effects on preload. Decrease in cardiac output explains decrease in splanchnic and renal blood flows. Decreased LV afterload is due to an increase in ITP by PEEP. See text for greater detail.SBP; systolic blood pressure, ITP; intrathoracic pressure, RV; right ventricle, LV; left ventricle, ↓; decrease.