Immediate hemodynamic effects of high-dose furosemide in normovolemic and hypovolemic dogs

We investigated whether the large dose (7 mg/kg) of iv furosemide often recommended for patients with oliguric acute renal failure impaired hemodynamic function in dogs. Six normovolemic and six hypovolemic animals were anesthetized, intubated, and ventilated. Femoral and pulmonary artery catheters were inserted. After a stable baseline period, the animals received 7 mg/kg of iv furosemide over 30 sec. Mean systemic artery pressure (MAP), mean pulmonary artery pressure (MPAP), CVP, and ECG were continuously monitored. Cardiac output and mean pulmonary arterial occlusion (wedge) pressures (WP) were recorded 2, 6, 12, 18, 24, 30, and 46 min after injection. Neither group demonstrated significant immediate changes in MAP, CVP, MPAP, heart rate (HR), cardiac output, or systemic and pulmonary vascular resistances (SVR and PVR, respectively). Later in the observation period, cardiac output decreased and SVR and PVR increased significantly. The changes were probably associated with decreased plasma volume causing compensatory increases in baroreceptor activity and vascular tone.