Experimental evaluation of the effects of high-dose administration of 25% human albumin solution on the vasospastic blood vessels and rCBF

The Authors evaluated the effects of high-dose administration of 25% albumin solution on the vasospastic basilar artery and rCBF in adult mongrel cats. A comparative analysis was made based upon the experiments done in the following 3 groups; Group I : Vasospasm was induced by infusion of hemolysate solution, and simultaneously, physiological saline (12 ml/kg) was administered intravenously in 2 hours. Group II : Vasospasm was induced by the same method as Group I, and simultaneously, 3 g/kg (12 ml/kg) of 25% human albumin solution was administered intravenously in 2 hours. Group III : Without inducing vasospasm, 25% human albumin solution was administered exactly the same way as in group II. General hemodynamic state, caliber of the basilar artery and rCBF in the thalamus were measured. In Group I, the basilar artery constricted throught its length following the infusion of hemolysate solution (Fig. 1) resulting in a decrease in rCBF in the thalamus (Fig. 2). During this period, no significant change was observed in general hemodynamic state (Fig. 3-6). In Group II, the basilar artery constricted to the same extent as that in Group I. However, despite the decrease in the caliber of the artery, rCBF in the thalamus significantly increased (Fig. 2). During this period, marked increase in cardiac output, increase in the central venous pressure, marked decrease in Hct and moderate increase in the mean systemic blood pressure were observed (Fig. 3-6). Group III showed mild vasodilation and significantly higher degree of increase in rCBF than the increase in Group II. (Fig. 2) Hemodynamic state was similar to that of Group II. (Fig. 3-6) The result indicates that : 1) High-dose albumin administration had no vasodilating effects on the spastic basilar artery; 2) Despite the decrease in the caliber of the cerebral blood vessel caused by vasospasm, high-dose albumin administration increased rCBF; 3) High-dose albumin administration produced a marked hyperhemodynamic state. As the cause of increase in rCBF following administration of human albumin under the condition of the vasospasm, following three mechanisms are being assumed since albumin was proved to have no influence on the caliber of the large artery which is in the state of vasospasm : 1) increase in flow through collateral vessels 2) increased blood flow through the spastic vessel caused by decreased viscosity of the blood. 3) mild increase in blood pressure.