Pulmonary artery wedge pressure may fail to reflect left ventricular end-diastolic pressure in dogs with oleic acid-induced pulmonary edema

We investigated the accuracy with which pulmonary artery wedge pressure (WP) reflected left ventricular end-diastolic pressure (LVEDP) in dogs with oleic acidinduced pulmonary edema. We compared hemodynamic variables before and during edema as measured from a pulmonary artery catheter placed before oleic acid (PA-1) and from a second catheter (PA-2) placed 2 h after oleic acid infusion. Oleic acid decreased arterial oxygen saturation and cardiac output and increased pulmonary vascular resistance and phasic pulmonary artery pressure. LVEDP did not change after oleic acid, although WP measured by both catheters was increased. In addition, WP measured by PA-2 (7.1 ± 0.7 mm Hg) was greater than that measured by PA-1 (5.6 ± 0.5 mm Hg) (p ± 0.037). Using PA-1, we found that WP increased in a linear manner with LVEDP both before and after pulmonary injury (r = 0.91, 0.68, respectively). There was no relationship between LVEDP and WP using PA-2 (r = 0.07). We conclude that oleic acid-induced pulmonary edema lessens the accuracy with which WP reflects LVEDP, and that WP from a catheter placed after edema less accurately reflects LVEDP than does WP from a catheter placed before edema.