Clifton G L, Allen S, Berry J, Koch S M
Department of Surgery, University of Texas Health Science Center, Medical School, Houston.
J Neurotrauma. 1992 May;9 Suppl 2:S487-95.
An extensive literature suggests that there are minimal complications of systemic hypothermia in humans at and above 30 degrees C for periods of several days. Intracranial hemorrhage has been found to complicate profound hypothermia (10-15 degrees C), and ventricular arrhythmias occur at temperatures below 30 degrees C. Our initial clinical studies were with 21 patients undergoing elective craniotomy cooled to 30-32 degrees C for 1-8 h (mean 4 h). Hypothermia was induced by surface cooling with water blankets. No complications were found. Among 11 patients with severe brain injury, cooling to levels below 32 degrees C was associated with ventricular arrhythmias in 1 patient and atrioventricular block in 1 patient. Asymptomatic hypokalemia was found routinely and treated with potassium replacement. No intracranial hemorrhage or other complications were found. With surface cooling, intravascular temperature dropped at 1.6 degrees C/h. Based on the safety of surface cooling to a core temperature of 32 degrees C for 48 h, we are conducting a randomized study of this level of hypothermia in patients with severe brain injury, cooled within 6 h of injury.
大量文献表明，人体体温在30摄氏度及以上并持续数天时，全身性低温的并发症极少。已发现颅内出血会使深度低温（10 - 15摄氏度）情况复杂化，且体温低于30摄氏度时会出现室性心律失常。我们最初的临床研究针对21例接受择期开颅手术的患者，将体温降至30 - 32摄氏度，持续1 - 8小时（平均4小时）。通过用水毯进行体表降温诱导低温。未发现并发症。在11例重型脑损伤患者中，体温降至32摄氏度以下时，1例出现室性心律失常，1例出现房室传导阻滞。常规发现无症状性低钾血症，并进行补钾治疗。未发现颅内出血或其他并发症。采用体表降温时，血管内温度以每小时1.6摄氏度的速度下降。基于将体表温度降至32摄氏度并持续48小时的安全性，我们正在对重型脑损伤患者在损伤后6小时内进行该水平低温治疗的随机研究。
