실혈시의 혈압강하와 복부장기 혈액유통의 관계

Abstract

On 22 rabbits stepwise bleedings were performed in order to elucidate the relationships among the bleeding amount, hypotension and the deterioration of the blood flow in the splanchnic area. Inital bleeding amount was 20ml and the following bleeding was mostly 5ml each time. In a few cases larger amount, 10 ml was drawn. Visceral blood flow change was detected by the alteration in the electrical conductivity, that was rheographically, between two electrodes. One electrode was placed on the liver surface and the other, which was grounded, was buried beneath the skin of the thigh. As the bleeding amount increased the mean arterial pressure and the visceral blood flow decreased, rapidly at first and slowly later on. The changes in the visceral flow manifested more varieties. When the shed blood was retransfused the blood pressure rose promptly. However, there were two different patterns in the response of visceral blood flow, showing the complete restoration on the one hand and the irrecoverable sluggishness on the other hand. These multiple patterns suggest the heterogeneity of the response in maintaining the homeostasis in the acute hemorrhage. The results obtained were as follows: 1. By bleeding of 20ml, that was approximately 1% of the body weight, the mean arterial blood pressure dropped down to 72% of the control value obtained before the bleeding. And successive bleedings brought the figures; by bleeding of 25mI the pressure was 63%, by 30mI pressure dropped to 51%, then followed by 42% when 35 ml of blood was shed. By the retransfusion of 10 ml of the shed blood the blood pressure recovered to 73%, and successive two increments of blood volume, 10 ml each time. resulted in 89 % and 93% of the control value. By the transfusion of 40ml in total, the pressure overpassed the control value, showing the persistence of the pressor response even when blood was retransfused. 2. The responses in the visceral blood flow after the bleeding were; decreased to 57% by bleeding of 20ml, and showed a fluctuation between 24 to 47 % on further bleedings. By the retransfusion of the shed blood two different kinds of manifestation were revealed. In 12 cases, 60% of the total number, there were nice recoveries by transfusion, but in 8 cases, 40% of the total, no restroations were attained, showing irreversible deteriorations. 3. Between the two groups, of reversible and irreversible visceral blood flow, no clear difference was noticed in the physiological parameters, except the pressor effect of transfusion. In the irreversible group the animals responded more sharply than the others. It suggested the persistent peripheral vascular constriction in the irreversible group and the possibility of occurrence of the irreversible hemorrhagic shock seemed to be probable. 4. If the irreversible deterioration in the visceral blood flow relates, in some way or other, to the onset of the irreversible hemorrhagic shock, some detectable measure for the onset of shock would be expected.