Oates R K, Harvey D
Arch Dis Child. 1976 Jul;51(7):512-6. doi: 10.1136/adc.51.7.512.
Cooling is known to prolong survival in newborn animals when used before the onset of asphyxia. It has therefore been advocated as a treatment for birth asphyxia in humans. Since it is not possible to cool a human baby before the onset of birth asphyxia, experiments were designed to test the effect of cooling after asphyxia had already started. Newborn rabbits were asphyxiated in 100% nitrogen and were cooled either quickly (drop of 1 degree C in 45 s) or slowly (drop of 1 degree C in 2 min) at varying intervals after asphyxia had started. When compared with controls, there was an increase in survival only when fast cooling was used early in asphyxia. This fast rate of cooling is impossible to obtain in a human baby weighing from 30 to 60 times more than a newborn rabbit. Further litters of rabbits were asphyxiated in utero. After deliver they were placed in environmental temperatures of either 37 degrees C, 20 degrees C, or 0 degrees C and observed for spontaneous recovery. The animals who were cooled survived less often than those kept at 37 degrees C. The results of these experiments suggest that hypothermia has little to offer in the treatment of birth asphyxia in humans.
已知在新生动物窒息发作前进行降温可延长其存活时间。因此，有人主张将其作为人类出生窒息的一种治疗方法。由于不可能在人类婴儿出生窒息发作前进行降温，所以设计了实验来测试在窒息已经开始后进行降温的效果。将新生兔子置于100%氮气中使其窒息，并在窒息开始后的不同时间间隔进行快速降温（45秒内下降1摄氏度）或缓慢降温（2分钟内下降1摄氏度）。与对照组相比，只有在窒息早期采用快速降温时，存活率才会提高。对于体重比新生兔子重30至60倍的人类婴儿来说，不可能达到这种快速降温速度。进一步使多窝兔子在子宫内窒息。分娩后，将它们置于37摄氏度、20摄氏度或0摄氏度的环境温度下，并观察其自发恢复情况。与保持在37摄氏度的动物相比，接受降温的动物存活几率更低。这些实验结果表明，低温疗法对治疗人类出生窒息作用不大。
