Watanabe Y, Kawaura Y, Iwa T
Jpn J Surg. 1982;12(1):61-70. doi: 10.1007/BF02469017.
Histopathological and succinic acid dehydrogenase (SAD) activity changes, and the electron spin resonance (ESR) were examined in the brains of dogs exposed to various hypothermic conditions. A simple hypothermic cardiac arrest of 5 min duration occurred in the group subjected to 28 degrees C, and normal SAD activity was noted in dogs exposed 1-hour extracorporeal circulation under normothermia. In cases of a hypothermia below 28 degrees C, a decrease in enzyme activity, marked histopathological changes and the disappearance of the ESR signal were observed. In dogs killed immediately after induction of 20 degrees C hypothermia, the histopathological changes were primarily ischemic in nature, while in dogs killed at 1-12 month intervals after the experiments, irreversible gliosis was dominant. Our findings suggest that, to avoid brain damage under conditions of deep hypothermic circulatory arrest, the critical range is between 26-28 degrees C for rectal, and approximately 28-30 degrees C for brain temperature.
在暴露于各种低温条件下的犬类大脑中，检查了组织病理学和琥珀酸脱氢酶（SAD）活性变化以及电子自旋共振（ESR）。在28摄氏度的组中发生了持续5分钟的简单低温心脏骤停，并且在正常体温下进行1小时体外循环的犬类中观察到正常的SAD活性。在体温低于28摄氏度的情况下，观察到酶活性降低、明显的组织病理学变化以及ESR信号消失。在诱导20摄氏度低温后立即处死的犬类中，组织病理学变化主要是缺血性的，而在实验后间隔1 - 12个月处死的犬类中，不可逆的胶质增生占主导。我们的研究结果表明，为避免在深度低温循环骤停条件下的脑损伤，直肠温度的临界范围在26 - 28摄氏度之间，大脑温度约为28 - 30摄氏度。
