Atarashi K, Ozaki M, Suzuki H
Department of Anesthesiology, Tokyo Women's Medical College.
Masui. 1996 Jul;45(7):818-23.
The core temperature triggering thermoregulatory arteriovenous shunt constriction is defined as the threshold for vasoconstriction. Vasoconstriction helps prevent further core hypothermia by decreasing cutaneous heat loss and constraining metabolic heat to the core thermal compartment. A previous study showed isoflurane inhibited thermoregulatory threshold. However there is no study to confirm whether sevoflurane perturb thermoregulatory vasoconstriction or not. Consequently we tested the hypothesis that 1.0 minimum alveolar concentration (MAC) sevoflurane and 1.0 MAC isoflurane would reduce the vasoconstriction threshold comparably. With institutional review board approval, we studied 20 patients, aged 20-60 yr, undergoing open abdominal surgery. No premedication was given. Ten patients each were anesthetized with 1.0 MAC sevoflurane (2.0%) alone or 1.0 MAC isoflurane (1.2%) alone. A forearm minus fingertip, skin temperature gradient 0 degree C was considered to demonstrate significant vasoconstriction; the esophageal temperature triggering vasoconstriction identified the threshold. Morphometric characteristics were comparable in each group. The threshold for vasoconstriction was 35.1 +/- 0.4 degrees C in the patients given 1.0 MAC sevoflurane, which was comparable that in those given 1.0 MAC isoflurane: 35.3 +/- 0.7 degrees C. We thus conclude that sevoflurane impairs thermoregulation comparably with isoflurane.
触发体温调节性动静脉分流收缩的核心温度被定义为血管收缩阈值。血管收缩通过减少皮肤热量散失并将代谢热限制在核心热腔室，有助于防止核心体温进一步降低。先前的一项研究表明异氟烷抑制体温调节阈值。然而，尚无研究证实七氟烷是否会干扰体温调节性血管收缩。因此，我们检验了以下假设：1.0 最低肺泡浓度（MAC）的七氟烷和 1.0 MAC 的异氟烷会同等程度地降低血管收缩阈值。经机构审查委员会批准，我们研究了 20 名年龄在 20 - 60 岁之间接受开腹手术的患者。未给予术前用药。每组 10 名患者分别单独使用 1.0 MAC 的七氟烷（2.0%）或 1.0 MAC 的异氟烷（1.2%）进行麻醉。前臂指尖皮肤温度梯度为 0℃被认为表明有明显的血管收缩；触发血管收缩的食管温度确定阈值。每组的形态学特征具有可比性。给予 1.0 MAC 七氟烷的患者血管收缩阈值为 35.1±0.4℃，与给予 1.0 MAC 异氟烷的患者相当：35.3±0.7℃。因此，我们得出结论，七氟烷与异氟烷对体温调节的损害程度相当。
