Kim S H, Stezoski S W, Safar P, Tisherman S A
Safar Center for Resuscitation Research and the Department of Anesthesiology/Critical Care Medicine, University of Pittsburgh, Pennsylvania 15260, USA.
J Trauma. 1998 Mar;44(3):485-91. doi: 10.1097/00005373-199803000-00010.
To test the hypothesis that moderate hypothermia (Hth) (30 degrees C) or breathing 100% oxygen (best with both combined) would prolong survival during lethal uncontrolled hemorrhagic shock (UHS) compared with normothermia (38 degrees C) and breathing air.
Forty Sprague-Dawley rats were anesthetized with halothane during spontaneous breathing of N2O/O2 (50:50). UHS was induced by volume-controlled blood withdrawal of 3 mL/100 g over 15 minutes, followed by 75% tail amputation and randomization to one of four UHS treatment groups (10 rats each): group 1 (control) was maintained on room air and rectal temperature of 38 degrees C; group 2 (Hth) was maintained on air and 30 degrees C; group 3 (O2) was maintained on FiO2 100% (starting immediately after tail cut) and 38 degrees C; and group 4 (O2-Hth) was maintained on FiO2 100% and 30 degrees C. Rats were observed otherwise untreated until death (apnea and pulselessness) or for a maximum of 5 hours.
During the initial blood withdrawal, mean arterial pressure (MAP) decreased to an average of 24 mm Hg. Seventeen of 40 rats then showed an increase in MAP (attempted self-resuscitation). Induction of hypothermia increased MAP to around 35 mm Hg at 30 minutes but did not increase bleeding. Additional blood loss from the tail stump averaged 1.0, 2.3, 2.9, and 1.7 mL in groups 1, 2, 3, and 4, respectively (not significant). Breathing 100% oxygen did not affect MAP or blood loss. Survival time was a mean of 47 and 52 minutes in normothermic groups 1 and 3 versus 121 and 135 minutes in hypothermic groups 2 and 4, respectively (p < 0.001, Kaplan-Meier). Breathing FiO2 100% increased PaO2 but did not change MAP, blood loss, or survival time.
Moderate hypothermia, but not increased FiO2, prolonged survival time during untreated UHS in rats. The effect of hypothermia on survival after resuscitation from UHS needs to be determined.
验证以下假设，即与正常体温（38℃）并呼吸空气相比，中度低温（Hth，30℃）或呼吸100%氧气（两者联合使用效果最佳）可延长致死性非控制性失血性休克（UHS）期间的生存期。
40只Sprague-Dawley大鼠在吸入N2O/O2（50:50）自主呼吸时用氟烷麻醉。通过在15分钟内按容量控制抽取3 mL/100 g血液诱导UHS，随后进行75%尾部截肢，并随机分为四个UHS治疗组之一（每组10只）：第1组（对照组）维持在室温空气中，直肠温度为38℃；第2组（Hth组）维持在空气中，温度为30℃；第3组（O2组）维持吸入100%氧（尾部切断后立即开始），温度为38℃；第4组（O2-Hth组）维持吸入100%氧，温度为30℃。除不进行其他治疗外，观察大鼠直至死亡（呼吸停止和无脉搏）或最长观察5小时。
在最初的放血过程中，平均动脉压（MAP）降至平均24 mmHg。40只大鼠中有17只随后MAP升高（尝试自我复苏）。诱导低温使30分钟时MAP升高至约35 mmHg，但未增加出血量。第1、2、3和4组尾部残端的额外失血量分别平均为1.0、2.3、2.9和1.7 mL（无显著性差异）。呼吸100%氧气对MAP或失血量无影响。正常体温的第1组和第3组的平均生存时间分别为47分钟和52分钟，而低温的第2组和第4组分别为121分钟和135分钟（p<0.001，Kaplan-Meier法）。吸入100%氧可提高动脉血氧分压（PaO2），但不改变MAP、失血量或生存时间。
在未治疗的大鼠UHS期间，中度低温而非提高的FiO2可延长生存时间。低温对UHS复苏后生存的影响有待确定。
