RESUMEN
In order to study the characteristics of the early cardiovascular responses after oleic acid induced lung damage, oleic acid (OA) 0.1ml/kg body weight was infused intravenously into 11 anesthetized and artificially ventilated dogs, and the effects were observed for 3 hours. After OA infusion, PaO2 decreased progressively to a fairly low level with a coincident increase of the alveolar-arterial PO2 gradient and decrease of the oxygen delivery. Cardiac index gradually decreased and reached only 49% of the baseline value at 180 minutes after OA injection. Mean systemic arterial pressure decreased transiently at 60 minutes after OA injection without concomitant increase of the pulmonary arterial pressure. The left ventricular stroke work, +dp/dtmax and - dp/dtmax, and the impedance contractility index were inhibited throughout the experiment. The postmortem lung-body ratio was significantly increased.These results suggest that the dogs following OA injection exhibit severe hypoxemia, reduced cardiae output, suboptimal cardiac performance and reduced oxygen delivery; the reduced cardiac outpur is associated with early and sustained inhibition of the myocardial contractility; and the pulmonary arterial pressure does not change significantly in the whole course of the experiment, so the edema formation does not result from the increase of the capillary hydrostatic pressure.