Tanaka J, Sato T, Berezesky I K, Jones R T, Trump B F, Cowley R A
Adv Shock Res. 1983;9:219-32.
The effects of hypothermia on survival time and ECGs were investigated in hemorrhagic-shocked rats. Acute blood loss corresponding to LD84 was achieved within 1 min through cannulation of the carotid artery. Immediately following the hemorrhagic episode, extracorporeal cooling was performed by placing the animals, with ice packs attached to their lateral sides, in a cold water bath. Rewarming was achieved by removing the ice packs and resetting the temperature of the water bath to 37 degrees C. With this system, the survival time of the hemorrhagic rats was lengthened from 40 to 60 min without rewarming and to 123 min with rewarming. ECGs showed sinus bradycardia, prolonged PR and QRS intervals, AV block, and finally ventricular fibrillation in both the control and hemorrhagic groups during extracorporeal cooling. During rewarming, the above ECG changes returned to normal in the control group as did body temperature. In contrast, animals in the hemorrhagic group did not survive. Body temperature in this group began to rise toward normal, and above ECG changes showed slight but not complete improvement. It is concluded that extracorporeal cooling can lengthen the survival time of hemorrhagic-shocked rats and that recovery of the disturbed conduction system is a prerequisite for survival from severe hypothermia.
研究了低温对失血性休克大鼠存活时间和心电图的影响。通过颈动脉插管在1分钟内造成相当于84%致死剂量的急性失血。失血性发作后，立即将动物置于冷水浴中，在其身体两侧附上冰袋进行体外降温。通过移除冰袋并将水浴温度重新设定为37℃来实现复温。使用该系统，失血性大鼠在未复温时的存活时间从40分钟延长至60分钟，复温后延长至123分钟。在体外降温期间，对照组和失血性组的心电图均显示窦性心动过缓、PR和QRS间期延长、房室传导阻滞，最终出现心室颤动。在复温过程中，对照组的上述心电图变化以及体温均恢复正常。相比之下，失血性组的动物未能存活。该组体温开始向正常上升，上述心电图变化显示出轻微但未完全改善。结论是体外降温可延长失血性休克大鼠的存活时间，并且紊乱的传导系统恢复是严重低温下存活的先决条件。
