Pulmonary capillary pressure

Abstract

Pulmonary capillary pressure is a primary determinant of fluid flux across the pulmonary capillary wall [1]. Increasing pulmonary capillary pressure increases fluid flux out of the capillaries into the interstitium and in the extreme induces pulmonary edema. Pulmonary capillary pressure is itself determined by the mean pulmonary artery pressure, pulmonary vascular resistance, and total blood flow. The distribution of the pulmonary vascular resistance from precapillary arterial to postcapillary venous compartments varies. Accordingly, at any given blood flow rate the hydrostatic pressure in the pulmonary capillaries depends on the magnitude of the resistance to blood flow across the pulmonary circulation and its distribution between precapillary and postcapillary vessels. Since pulmonary capillary pressure cannot be directly measured, the presence and relevance of increased pulmonary capillary hydrostatic pressures to values in excess of pulmonary artery occlusion pressure are often overlooked. © 2009 Springer-Verlag Berlin Heidelberg.