Piepgras A, Roth H, Schürer L, Tillmans R, Quintel M, Herrmann P, Schmiedek P
Department of Neurosurgery, Faculty of Clinical Medicine Mannheim, University of Heidelberg, Germany.
Neurosurgery. 1998 Feb;42(2):311-7; discussion 317-8. doi: 10.1097/00006123-199802000-00058.
Moderate hypothermia (32 degrees C) may limit postischemic neuronal damage and is increasingly used clinically in head injury and stroke. For the use of hypothermia as a neuroprotective agent in the prevention of ischemic damage, it is necessary to induce it as soon as possible after the insult and to keep it at the lowest safe level. Active core cooling using an extracorporeal heat exchanger may circumvent the rather slow induction speed and temperature drifts experienced with surface cooling techniques.
In eight patients with severe head injuries (Glasgow Coma Scale score, 4-5), a venovenous extracorporeal circulation was established via a percutaneously introduced double-lumen cannula in the femoral vein. A heat exchanger was connected via a pressure-controlled roller pump. In addition to standard parameters, brain white matter temperature was continuously recorded as the target temperature. Cooling was initiated as early as possible with an extracorporeal temperature of 30 degrees C and maintained at a 32 degrees C brain temperature for 48 hours, and then gradual rewarming for 24 hours.
Cooling was able to be initiated within 6 hours and 48 minutes +/- 3 hours and 47 minutes (mean +/- standard deviation) after trauma. A brain temperature of 32 degrees C was reached within 1 hour and 53 minutes +/- 1 hour and 21 minutes after induction of cooling with a cooling speed of 3.5 degrees C per hour. Brain temperature was able to be controlled within 0.1 degrees C intervals, which was especially helpful in gradual rewarming. No cardiac abnormalities or statistically significant changes in coagulation parameters occurred. Mean platelet count decreased to 89,614+/-42,090 on Day 3 after treatment. No clinical bleeding complications or problems resulting from extracorporeal circulation occurred. Moderate hypothermia was a helpful tool for managing increased intracranial pressure; however, five patients of this series died either of their intracranial abnormalities (n = 4) or of a delayed septic shock after pneumonia (n = 1) at various points in time during therapy. The three survivors experienced either an excellent or a good recovery.
The results of this investigation suggest that the use of an extracorporeal heat exchanger to achieve active core cooling is suitable for fast and accurately controllable induction, maintenance, and reversal of moderate hypothermia in emergency situations with reliable control of temperature. In this small series of highly selected patients with severe head injuries, we did not note a beneficial effect of hypothermic therapy on outcome.
亚低温（32℃）可能会限制缺血后神经元损伤，并且在颅脑损伤和中风的临床治疗中应用越来越广泛。为了将低温作为一种神经保护剂用于预防缺血性损伤，有必要在损伤后尽快诱导低温并将其维持在最低安全水平。使用体外热交换器进行主动核心降温可能会避免表面降温技术所经历的诱导速度较慢和温度漂移问题。
对8例重度颅脑损伤患者（格拉斯哥昏迷量表评分为4 - 5分），经皮在股静脉置入双腔导管建立静脉 - 静脉体外循环。通过压力控制滚压泵连接一个热交换器。除了标准参数外，持续记录脑白质温度作为目标温度。尽早开始降温，体外温度设定为30℃，将脑温维持在32℃达48小时，然后逐渐复温24小时。
创伤后6小时48分钟±3小时47分钟（平均值±标准差）内能够开始降温。开始降温后1小时53分钟±1小时21分钟内脑温达到32℃，降温速度为每小时3.5℃。脑温能够控制在0.1℃的区间内，这在逐渐复温过程中尤其有用。未出现心脏异常或凝血参数的统计学显著变化。治疗后第3天平均血小板计数降至89,614±42,090。未发生临床出血并发症或体外循环相关问题。亚低温是控制颅内压升高的一种有用手段；然而，该系列中的5例患者在治疗期间的不同时间点死于颅内病变（n = 4）或肺炎后延迟性感染性休克（n = 1）。3例幸存者恢复良好或极佳。
本研究结果表明，在紧急情况下，使用体外热交换器实现主动核心降温适用于快速、精确可控地诱导、维持和逆转亚低温，并能可靠地控制温度。在这一小系列经过严格挑选的重度颅脑损伤患者中，我们未发现低温治疗对预后有有益影响。
