Doufas Anthony G, Wadhwa Anupama, Lin Chun-Ming, Shah Yunus M, Hanni Keith, Sessler Daniel I
Outcomes Research Institute, Department of Anesthesiology, University of Louisville, Louisville, KY, USA.
Stroke. 2003 Jul;34(7):1736-40. doi: 10.1161/01.STR.0000077014.47422.DB. Epub 2003 May 29.
Hand warming and face warming, combined with inhalation of heated air, are reported to suppress shivering. However, hand or face temperature contributes only a few percent to control of shivering. Thus, it seems unlikely that manipulating hand or facial skin temperature alone would be sufficient to permit induction of therapeutic hypothermia. We tested the hypothesis that focal arm (forearm and hand) warming or lower facial warming, combined with inhalation of heated and humidified gas, only minimally reduces the shivering threshold (triggering core temperature).
We studied 8 healthy male volunteers (18 to 40 years of age) on 3 days: (1) control (no warming), (2) arm warming with forced air at approximately 43 degrees C, and (3) face warming with 21 L/min of air at approximately 42 degrees C at a relative humidity of 100%. Fluid at approximately 4 degrees C was infused via a central venous catheter to decrease tympanic membrane temperature 1 degrees C/h to 2 degrees C/h; mean skin temperature was maintained at 31 degrees C. A sustained increase in oxygen consumption quantified the shivering threshold.
Shivering thresholds did not differ significantly between the control (36.7+/-0.1 degrees C), arm-warming (36.5+/-0.3 degrees C), or face-warming (36.5+/-0.3 degrees C; analysis of variance, P=0.34) day. The study was powered to have a 95% probability of detecting a difference of 0.5+/-0.5 degrees C (mean+/-SD) between control and either of the 2 treatments at alpha=0.05.
Focal arm or face warming did not substantially reduce the shivering threshold in unanesthetized volunteers. It thus seems unlikely that these nonpharmacological modalities will substantially facilitate induction of therapeutic hypothermia.
据报道，手部保暖、面部保暖以及吸入热空气可抑制寒战。然而，手部或面部温度对寒战控制的贡献仅为百分之几。因此，仅通过控制手部或面部皮肤温度似乎不太可能足以诱导治疗性低温。我们检验了这样一个假设，即局部手臂（前臂和手部）保暖或面部下部保暖，结合吸入加热加湿的气体，只会轻微降低寒战阈值（触发核心温度）。
我们在3天内对8名健康男性志愿者（18至40岁）进行了研究：（1）对照（不保暖），（2）用约43摄氏度的强制空气进行手臂保暖，（3）用约42摄氏度、相对湿度为100%、流速为21升/分钟的空气进行面部保暖。通过中心静脉导管输注约4摄氏度的液体，以使鼓膜温度以每小时1摄氏度至2摄氏度的速度下降；平均皮肤温度维持在31摄氏度。通过氧气消耗量的持续增加来量化寒战阈值。
对照日（36.7±0.1摄氏度）、手臂保暖日（36.5±0.3摄氏度）或面部保暖日（36.5±0.3摄氏度；方差分析，P = 0.34）的寒战阈值之间无显著差异。该研究的检验效能为在α = 0.05时，有95%的概率检测到对照与两种治疗中任一种之间0.5±0.5摄氏度（均值±标准差）的差异。
局部手臂或面部保暖并未显著降低未麻醉志愿者的寒战阈值。因此，这些非药物方法似乎不太可能显著促进治疗性低温的诱导。
