EFFECTS OF DOPAMINE ON CARDIOPULMONARY FUNCTION AND LEFT-VENTRICULAR VOLUMES IN PATIENTS WITH ACUTE RESPIRATORY-FAILURE

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Abstract
The cardiopulmonary effects of dopamine [DA] in patients with acute respiratory failure were investigated. Specifically, the hypothesis that left ventricular filling pressure (Pcwp) would increase when cardiac output (CO) increased with (DA) was tested. DA (range, 5.5-20 .mu.g/kg per min) increased blood pressure (BP) (P < 0.001) Pcwp, CO and stroke volume (SV) (P < 0.005). Mean Pcwp increased (P < 0.005) 45% with DA, from 11 to 16 mmHg. .ovrhdot.Qs/.ovrhdot.Qt increased with DA in association with an increase in mixed venous O2 tension, and arterial O2 tension remained constant. In 8 of these patients, left ventricular end-diastolic volume (LVEDV) and end-systolic volume (ESV) were measured using scintigraphic techniques. The LVEDV increased (P < 0.01) in each patient after the administration of DA, and the mean change was from 134 to 163 ml. Although BP and LV afterload increased in each patient, there was no consistent change in LVESV after DA administration, i.e., ESV decreased in 1 patient, remained constant in 3, and increased in 4. Accordingly, because afterload increased in all patients and ESV did not, DA probably increased contractility. Because EDV increased in all patients, the increase in SV with DA is explained by a combination of inotropic and peripheral vascular effects.