Nuwayhid B, Vaughn D, Brinkman C R, Assali N S
Am J Obstet Gynecol. 1978 Nov 15;132(6):658-66.
Hemodynamic responses to hypovolemia were investigated in unanesthetized, unstressed fetal lambs and in acute fetal and neonatal preparations. The unstressed fetus tolerated twice the amount of blood loss of the acutely studied fetus or newborn lamb and with a lesser hypotension. Hemodynamic behavior of the newborn lamb and fetus anesthetized with pentobarbital during hypovolemia was markedly different from that of the fetus studied under spinal anesthesia or chronically. Besides tolerating greater blood loss, the unstressed fetus reversed the state of hypovolemic shock rapidly as contrasted to the stressed fetus which was unable to do so even with total blood reinfusion. All animals exhibited bradycardia in response to hypovolemia. The following conclusions were drawn: (a) cardiovascular response to hypovolemia in the perinatal period depends on the initial status of the animal, (b) the fetus tolerates a greater degree of blood loss than a newborn or adult animal, and (c) anesthesia and stress of surgery modify considerably circulatory behavior during blood loss.
在未麻醉、未受应激的胎羊以及急性胎儿和新生儿实验制剂中研究了对血容量减少的血流动力学反应。未受应激的胎儿耐受的失血量是急性研究的胎儿或新生羔羊的两倍，且低血压程度较轻。戊巴比妥麻醉的新生羔羊和胎儿在血容量减少期间的血流动力学行为与脊髓麻醉或长期研究的胎儿明显不同。除了耐受更大的失血量外，未受应激的胎儿能迅速逆转低血容量休克状态，而受应激的胎儿即使完全回输血液也无法做到。所有动物对血容量减少均表现出心动过缓。得出以下结论：(a)围产期对血容量减少的心血管反应取决于动物的初始状态，(b)胎儿比新生动物或成年动物耐受更大程度的失血，(c)麻醉和手术应激会显著改变失血期间的循环行为。
