Hemodynamic effects of nitroprusside and furosemide in left ventricular failure

Abstract

Nitroprusside and furosemide are both used to treat acute left ventricular failure, but their hemodynamic effects have not been compared in the same patients. In 13 patients with acutely decompensated chronic left ventricular failure, we infused nitroprusside to reduce pulmonary wedge pressure to normal without inducing hypotension. When hemodynamics returned to control after stopping nitroprusside, furosemide was given ase a 200-mg rapid infusion. Control hemodynamic values before each drug were in the same range. Mean arterial pressure fell from 99.9 +/- 16.7(SD) to 74.8 +/- 10.5 mm Hg on nitroprusside (P less than 0.001) and was unchanged after furosemide. Nitroprusside reduced pulmonary wedge pressure from 30.5 +/- 6.9 to 15.9 to 6.0 mm Hg (P less than 0.001), while furosemide reduced it to 27.5 +/- 8.5 mm Hg (P less than 0.05). Cardiac index rose from 2.33 +/- 0.78 l/min/m2 to 3.62 +/- 0.93 l/min/m2 (P less than 0.001) on nitroprusside and remained unchanged at 2.32 +/- 0.64 l/min/m2 after furosemide. At the same pulmonary wedge pressure on each drug (24 mg Hg), cardiac index was increased by nitroprusside (+0.6 +/- 0.5 l/min/m2, P less than 0.01) and unchanged by furosemide. Thus, furosemide reduces only preload without changing cardiac output in patients with left heart failure, whereas nitroprusside at similar or lower preload in the same patients reduces afterload and raises cardiac output and improves left ventricular performance. Nitroprusside appears preferable for the immediate treatment of left ventricular failure.