Block S M, Pixley J E, Wray A H, Ray D, Barnes K D, Engstrom P C, Rose J C
Department of Pediatrics, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27103.
Am J Physiol. 1989 Sep;257(3 Pt 2):R647-52. doi: 10.1152/ajpregu.1989.257.3.R647.
Blood volume restitution after hemorrhage was investigated in lambs in the first week of life. Two groups of nonsplenectomized lambs were bled 10 and 20% of their blood volume at 2%/min while being suspended horizontally in a sling with their legs dependent, and a third group was bled 20% while lying down. Blood pressure fell 8% in the lambs bled both 10 and 20% while lying down and 44% in those bled 20% while being suspended. Blood volume was completely restored in all three groups by 5 h after the hemorrhage, the rate of restitution being equal among the groups. The initial phase of restitution was slower when the lambs were bled while lying down. Vasopressin levels were increased only in the lambs bled 20% of their blood volume while being suspended. Plasma renin activity increased similarly in all groups. Hemorrhage increased plasma glucose but did not change plasma protein and serum osmolality. We conclude that lambs bled up to 20% of blood volume restitute relatively quickly at a rate independent of the volume shed. The position of the animal affects the degree of hypotension, the levels of vasopressin, and the rate of the initial phase of volume restoration.
对出生第一周的羔羊出血后的血容量恢复情况进行了研究。两组未切除脾脏的羔羊在水平悬吊于吊床、腿部下垂的状态下，以每分钟2%的速度放血，放血量分别为其血容量的10%和20%，第三组羔羊则在躺卧状态下放血20%。躺卧状态下被放血10%和20%的羔羊血压下降8%，而悬吊状态下被放血20%的羔羊血压下降44%。出血后5小时，所有三组的血容量均完全恢复，各组的恢复速度相同。躺卧状态下放血时，恢复的初始阶段较慢。仅在悬吊状态下被放血达其血容量20%的羔羊中，血管加压素水平升高。所有组的血浆肾素活性均有类似增加。出血使血浆葡萄糖升高，但未改变血浆蛋白和血清渗透压。我们得出结论，放血量达血容量20%的羔羊能以与放血量无关的速度相对快速地恢复血容量。动物的体位影响低血压程度、血管加压素水平以及血容量恢复初始阶段的速度。
