Thermoregulatory thresholds for vasoconstriction in patients anesthetized with various 1-minimum alveolar concentration combinations of xenon, nitrous oxide, and isoflurane
Thermoregulatory thresholds for vasoconstriction in patients anesthetized with various 1-minimum alveolar concentration combinations of xenon, nitrous oxide, and isoflurane
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DOI：
10.1097/00000542-199909000-00011
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发表时间：
1999-09-01
期刊：
影响因子：
8.8
通讯作者：
Morita, S
中科院分区：
文献类型：
--
作者：
Goto, T;Matsukawa, T;Morita, S
背景资料：一氧化二氮限制了术中低温，因为一氧化二氮的血管收缩阈值高于七氟烷或异氟烷的等最低肺泡浓度，可能是因为其对交感神经系统的刺激作用。相比之下，氙气不会引起交感神经激活。因此，作者测试的假设，氙-异氟烷麻醉过程中的血管收缩阈值是小于在一氧化二氮-异氟烷麻醉或isofluranes.Methods：15例。被随机分配到三种1最小肺泡浓度麻醉方案之一：（1）氙，43%（最小肺泡浓度0.6）和异氟烷，0.5%（最小肺泡浓度0.4）;（2）一氧化二氮，63%（最小肺泡浓度0.6）和异氟烷0.5%;或（3）异氟烷，1.2%。环境温度保持在23 ℃附近，患者未主动保暖。使用前臂减去指尖，皮肤温度梯度评价温度调节性血管收缩。梯度超过0摄氏度表明显著的血管收缩。核心温度阈值，将已观察到，如果皮肤一直保持在33摄氏度计算从平均皮肤和远端食管温度时的vascorption.Results：患者的人口统计学变量，preinduction核心温度，手术室环境温度和液体平衡之间的三组是可比的。氙麻醉时的心率明显低于一氧化二氮。氙气组计算的血管收缩阈值最低（34.6 +/- 0.8 ℃，平均值+/- SD），异氟烷单药组居中（35.1 +/- 0.6 ℃），一氧化二氮组最高（35.7 +/- 0.6 ℃）。每个阈值不同显着。结论：氙气抑制体温调节控制比异氟烷，而一氧化二氮是最有效的在这方面。
Background: Nitrous oxide limits intraoperative hypothermia because the vasoconstriction threshold with nitrous oxide is higher than with equi-minimum alveolar concentrations of sevoflurane or isoflurane, presumably because of its stimulating actions on the sympathetic nervous system. Xenon, in contrast, does not cause sympathetic activation. Therefore, the authors tested the hypothesis that the vasoconstriction threshold during xenon-isoflurane anesthesia is less than during nitrous oxide-isoflurane anesthesia or isoflurane alone.Methods: Fifteen patients each. were randomly assigned to one of three 1-minimum alveolar concentration anesthetic regimens: (1) xenon, 43% (0.6 minimum alveolar concentration) and isoflurane, 0.5% (0.4 minimum alveolar concentration); (2) nitrous oxide, 63% (0.6 minimum alveolar concentration) and isoflurane 0.5%; or (3) isoflurane, 1.2%. Ambient temperature was maintained near 23 degrees C and the patients were not actively warmed. Thermoregulatory vasoconstriction was evaluated using forearm-minus-fingertip, skin temperature gradients. A gradient exceeding 0 degrees C indicated significant vasoconstriction. The core-temperature threshold that would have been observed if skin had been maintained at 33 degrees C was calculated from mean skin and distal esophageal temperatures at the time of vasoconstriction.Results: The patients' demographic variables, preinduction core temperatures, ambient operating room temperatures, and fluid balance were comparable among the three groups. heart rates were significantly less during xenon anesthesia than with nitrous oxide. The calculated vasoconstriction threshold was lowest with xenon (34.6 +/- 0.8 degrees C, mean +/- SD), intermediate with isoflurane alone (35.1 +/- 0.6 degrees C), and highest with nitrous oxide (35.7 +/- 0.6 degrees C). Each of the thresholds differed significantly.Conclusions: Xenon inhibits thermoregulatory control more than isoflurane, whereas nitrous oxide is the least effective in this respect.