Department of Anaesthesia and Intensive Care, Lund University Hospital, Lund, Sweden.
Acta Anaesthesiol Scand. 2009 Nov;53(10):1233-8. doi: 10.1111/j.1399-6576.2009.02074.x. Epub 2009 Aug 13.
Hypothermia is shown to be beneficial for the outcome after a transient global brain ischaemia through its neuroprotective effect. Whether this is also the case after focal ischaemia, such as following a severe traumatic brain injury (TBI), has been investigated in numerous studies, some of which have shown a tendency towards an improved outcome, whereas others have not been able to demonstrate any beneficial effect. A Cochrane report concluded that the majority of the trials that have already been published have been of low quality, with unclear allocation concealment. If only high-quality trials are considered, TBI patients treated with active cooling were more likely to die, a conclusion supported by a recent high-quality Canadian trial on children. Still, there is a belief that a modified protocol with a shorter time from the accident to the start of active cooling, longer cooling and rewarming time and better control of blood pressure and intracranial pressure would be beneficial for TBI patients. This belief has led to the instigation of new trials in adults and in children, including these types of protocol adjustments. The present review provides a short summary of our present knowledge of the use of active cooling in TBI patients, and presents some tentative explanations as to why active cooling has not been shown to be effective for outcome after TBI. We focus particularly on the compromised circulation of the penumbra zone, which may be further reduced by the stress caused by the difference in thermostat and body temperature and by the hypothermia-induced more frequent use of vasoconstrictors, and by the increased risk of contusional bleedings under hypothermia. We suggest that high fever should be reduced pharmacologically.
体温过低通过其神经保护作用被证明对短暂全脑缺血后的结果有益。这种情况是否也适用于局灶性缺血，例如严重创伤性脑损伤 (TBI) 后，已经在许多研究中进行了调查，其中一些研究表明结果有改善的趋势，而其他研究则未能证明任何有益效果。一项 Cochrane 报告得出结论，已发表的大多数试验质量较低，分配隐匿性不明确。如果只考虑高质量的试验，接受主动降温治疗的 TBI 患者更有可能死亡，最近一项针对儿童的高质量加拿大试验支持了这一结论。尽管如此，人们仍然相信，如果修改方案，将从事故到开始主动降温的时间缩短、冷却和复温时间延长、更好地控制血压和颅内压，将有利于 TBI 患者。这种信念促使人们在成人和儿童中开展了新的试验，包括这些类型的方案调整。本综述简要总结了我们目前对 TBI 患者使用主动降温的认识，并就主动降温为何未显示对 TBI 后结果有效提出了一些初步解释。我们特别关注半影区的循环受损，体温调定点和体温之间的差异引起的压力以及低温诱导的更频繁使用血管收缩剂，以及低温下挫伤性出血的风险增加，可能会进一步降低半影区的循环。我们建议通过药理学降低高热。
