Effect of a catecholamine-induced increase in cardiac output on extravascular lung water

Objective: To determine the influence of dopamine- and dobutamine-induced i ncreases in cardiac output on the extravascular lung water in an experiment al model of pulmonary edema. Design: Animal experimental study. Setting: Animal experimental laboratory of a tertiary hospital. Subjects: Mixed-race pigs (n = 20) weighing 28-32 kg, Interventions: After the animals were anesthetized and tracheotomized, they were injected with 0.1 mL/kg of oleic acid, producing a pulmonary edema by increased permeability, The animals then were randomized into two groups: Group I (n = 10) received no medication to alter cardiac output and remaine d on mechanical, ventilation during the 240 mins of the experiment; group I I (n = 10) received a continuous infusion of dopamine and dobutamine to pro duce a cardiac output increase of greater than or equal to 30% the basal va lue and underwent the same mechanical ventilation regimen as group I. Measurements and Main Results: Hemodynamic and respiratory variables were m easured at 0 (baseline) and 30, 60, 120, 180, and 240 mins after the infusi on of oleic acid. At 30 mins, the cardiac output of group II (5.40 +/- 0.94 L/min) was significantly (p < .005) higher than that of group I (3.65 <plu s/minus> 1.02 L/min), and a similar significant increase was recorded at al l measurement times until the end of the experiment. The mean pulmonary art erial pressure was similar in both groups except that at 240 mins it was si gnificantly higher in group I (normal cardiac output) than in group II (hig h cardiac output; 34.9 +/- 7.9 mm Hg vs. 27.2 +/- 3.8 mm Hg, p = .01), The extravascular lung water was calculated by gravimetric method after the dea th of the animal. The extravascular lung water of group I (13.8 +/- 3.6 mL/ kg) did not significantly differ from that of group II (11.5 +/- 4.0 mL/kg) . Conclusions: An increase in cardiac output experimentally produced by the i nfusion of dopamine acid dobutamine does not modify the amount of extravasc ular lung water.