Measurement of Pulmonary Capillary Pressure and Hemodynamics in a Canine Model of Endotoxin - induced ARDS

Choi, Kyu Taek; Kim, Yon Kyu; Chung, Jung Kil; Cheun, Jae Kyu

Abstract

Gram-negative sepsis is the most common setting in which the constellation of abnormalities in lung function, is clinically called the adult respiratory distress syndrome(ARDS). There is a considerable clinical interest in measuring pulmonary microvascular filtration pressure in patients with acute respiratory failure. Pulmonary capillary pressure(Pc) influences the rate of edema formation in the injured lung, and an understanding of how Pc is altered by the disease is important to improve our treatment of acute respiratory failure, We infuesd E. Coli endotox-in, 3 mg/kg, intravenously into anesthetized dogs and measured the hemodynamics and pulmonary capillary pressure, which was derived from the pressure transient recorded while the pulmonary artery catheter was rapidly wedged. Dogs were given fluids to restore cardiac filling pressure to baseline levels. This resulted in a low resistance shock in all animals. 3 hours after the endotxin infusion experimental ARDS developed. The data report that mean pulomanary artery pressure, pulmonary capillary pressure, and pulmonary vascular resistance(PVR) are increased in experimental ARDS(P<0.1), and there is uneuqal, variable partitoning of the PVR. The Gaar estimation of Pc and measured Pc were highly correlated(r=0.915). These data suggest that measuring Pc will alow the clinician to learn if vasoactive agents infused in the management of acute respiratory failure can reduce the microvascular filtration pressure. In this manner, clinicians may directly reduce the rate of edema formation in the acutely injured lung.