Pulmonary extravascular and intravascular fluid volumes in resting patients

Abstract

Pulmonary extravascular and intravascular fluid volumes were measured in 29 patients at rest during cardiac catheterization. Increased extravascular fluid volume was clearly related to increased left atrial and pulmonary arterial pressures. It was not related to flow, resistance or intravascular volume. Extravascular water volumes 3 times “normal” were observed without clinical signs of alveolar pulmonary edema. This probably represents increased interstitial volume or edema. Pulmonary intravascular volume (pulmonary blood volume) was observed to act as a rigid compartment, changing little with intravascular pressure, whereas the extravascular volume was very compliant or distensible. A possible feedback relationship between the pulmonary extravascular and intravascular volumes is discussed. Increases in pulmonary extravascular volume described here correlated well with functional capacity and dyspnea as evaluated by the New York Heart Association classification. Individuals with the greatest extravascular volume were most incapacitated. Chest roentgenograms showing pulmonary congestion and interstitial edema were also related to increased pulmonary extravascular volumes.