Comparison of the effects of hypothermia at 33°C or 35°C after cardiac arrest in rats
Comparison of the effects of hypothermia at 33°C or 35°C after cardiac arrest in rats
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DOI：
10.1197/j.aem.2006.10.097
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发表时间：
2007-04-01
影响因子：
4.4
通讯作者：
Callaway, Clifton W.
中科院分区：
文献类型：
--
作者：
Logue, Eric S.;McMichael, Melissa J.;Callaway, Clifton W.
目的：心脏骤停复苏后32℃~34℃的低温可促进神经功能恢复，但最佳降温深度尚不清楚。使用大鼠模型，作者检验了这一假设，即在复苏后I小时至24小时内冷却至35摄氏度可改善神经系统预后，与冷却至33摄氏度一样。方法：氟烷麻醉的大鼠(n=38)经历了8分钟的窒息心脏骤停和复苏。在被逮捕之前、期间和之后，头骨温度都保持在37摄氏度。在复苏后1至24小时内，使用计算机控制的冷却风扇和加热灯将颅温维持在33摄氏度、35摄氏度或37摄氏度。每天测量神经学评分，第14天处死大鼠进行组织学分析。结果：14天后，12只大鼠(100%)降温至33℃，11只(92%)降温至35℃，14只大鼠(71%)降温至37℃，10只(71%)存活，降温至37℃组大鼠死亡风险大于联合低温组。降温至37℃组大鼠在第1、2、3天的神经学评分均低于低温组，而存活神经元数在降温至33℃组和35℃组之间相似，高于降温至37℃组。结论：复苏后第1天降温35℃或33℃可改善大鼠心脏骤停后的神经学评分和神经元存活率。诱导降温35摄氏度的益处似乎与33摄氏度的益处相似。
Objectives: Hypothermia of 32 degrees C-34 degrees C induced after resuscitation from cardiac arrest improves neurologic recovery, but the optimal depth of cooling is unknown. Using a rat model, the authors tested the hypothesis that cooling to 35 degrees C between hours I and 24 after resuscitation would improve neurologic outcome as much as cooling to 33 degrees C.Methods: Halothane-anesthetized rats (n = 38) underwent 8 minutes of asphyxial cardiac arrest and resuscitation. Cranial temperature was maintained at 37 degrees C before, during, and after arrest. Between one and 24 hours after resuscitation, cranial temperature was maintained at 33 degrees C, 35 degrees C, or 37 degrees C using computer-controlled cooling fans and heating lamps. Neurologic scores were measured daily, and rats were killed at 14 days for histologic analysis. Neurons per high-powered held were counted in the CA1 region of the anterior hippocampus using neuronal nuclear antigen staining.Results: After 14 days, 12 of 12 rats (100%) cooled to 33 degrees C, 11 of 12 rats (92%) cooled to 35 degrees C, and ten of 14 rats (71%) cooled to 37 degrees C survived, with hazard of death greater in the rats cooled to 37 degrees C than in the combined hypothermia groups. Neurologic scores were worse in the rats cooled to 37 degrees C than in the hypothermia groups on days 1, 2, and 3. Numbers of surviving neurons were similar between the groups cooled to 33 degrees C and 35 degrees C and were higher than in the group cooled to 37 degrees C.Conclusions: These data illustrate that hypothermia of 35 degrees C or 33 degrees C over the first day of recovery improves neurologic scores and neuronal survival after cardiac arrest in rats. The benefit of induced hypothermia of 35 degrees C appears to be similar to the benefit of 33 degrees C.