The Hemodynamic Effects of Prolonged Albumin Administration in Beagle Dogs Exposed to Experimental Subarachnoid Hemorrhage

The hemodynamic effects of hyperdynamic hemodilution induced by prolonged (for 1 week) intravenous albumin or low-molecular-weight dextran administration were studied in the beagle two-hemorrhage model. Drug infusion was started immediately after the induction of a subarachnoid hemorrhage and continued for 7 days thereafter, according to the following treatment schedule: Group 1 (physiological saline); Group 2 (10% low-molecular-weight dextran, 0.8 g/kg per day); Groups 3, 4, and 5 (25% albumin, 1, 2, and 3 g/kg per day, respectively). On Day 0 (before subarachnoid hemorrhage) and Day 7, the cardiopulmonary parameters and the blood flow of the vertebral artery (VAF) were measured by the use of the Swan-Ganz catheter and an electromagnetic flowmeter, respectively. Cerebral angiography was carried out on Days 0 and 7. Only the albumin-treated groups showed a significant increase in plasma osmotic pressure, cardiac output, and VAF, as well as a decrease in the hematocrit on Day 7. The increase in cardiac output and VAF was maximal in Group 4. In Group 5, signs of pulmonary edema in the chest roentgenogram were noted in two of the four animals. The angiographic spasm of the basilar artery on Day 7 was not significantly ameliorated by either albumin or dextran. In the albumin-treated groups, the VAF was shown to increase in parallel with the increase of the cardiac output, within the range between 50 and 150%. Thus, this study indicates that the hemodynamic changes induced by prolonged albumin administration improve the cerebral circulation hindered by chronic vasospasm, whereas the increase in cardiac output is considered to be the most reliable indicator regarding the determination of the optimal dosage of albumin.