Nakahara Toshiyuki, Yasumoto Satoshi, Jinnouchi Yuka, Hano Kimitaka
Department of Anesthesia, Tokushima Municipal Hospital, Tokushima 770-0812.
Masui. 2002 Jan;51(1):7-13.
The minimum alveolar concentration of an anesthetic that blocks the skin vasomotor reflex to surgical incision (MACBVR) for sevoflurane was determined in 37 patients aged 30-60 years scheduled for laparotomies with or without nitrous oxide. Thirty seven patients were randomly allocated to one of the two groups: a sevoflurane group and a sevoflurane/N2O (50 vol%) group. The skin blood flow of the finger tip was measured using a laser Doppler flowmeter. Anesthesia was induced with sevoflurane and N2O and tracheal intubation was facilitated with vecuronium 0.1 mg.kg-1. Predetermined end tidal concentrations of sevoflurane and N2O were maintained for at least 15 min before incision. The MACBVR values of sevoflurane in O2 and in the presence of 50% N2O were 3.07% and 1.63%, respectively. The MACBVR level in the total anesthetic MAC multiple was 1.75 MAC for sevoflurane alone and the value decreased to 1.43 MAC when 50% N2O was used. There were no relations between the amplitude of the reduction in skin blood flow and the changes of hemodynamic variables in each group. However, the changes in SBP and HR at incision were significantly suppressed by addition of N2O (changes in SBP and HR: 41.6 +/- 20.4 mmHg and 35.4 +/- 12.5 bpm in the sevoflurane group vs. 24.6 +/- 10.2 mmHg and 18.1 +/- 9.5 bpm in the sevoflurane/N2O group, P < 0.01). The results suggest that N2O is useful to suppress adrenergic responses to a surgical stimulus during sevoflurane anesthesia.
在37例年龄30至60岁、计划接受或不接受氧化亚氮的剖腹手术患者中，测定了七氟醚阻断皮肤血管运动对手术切口反射（MACBVR）的最低肺泡浓度。37例患者被随机分为两组之一：七氟醚组和七氟醚/氧化亚氮（50体积%）组。使用激光多普勒血流仪测量指尖皮肤血流。用七氟醚和氧化亚氮诱导麻醉，并用0.1mg·kg-1维库溴铵辅助气管插管。在切口前，将七氟醚和氧化亚氮的预定呼气末浓度维持至少15分钟。七氟醚在纯氧中和存在50%氧化亚氮时的MACBVR值分别为3.07%和1.63%。单独使用七氟醚时，总麻醉MAC倍数中的MACBVR水平为1.75MAC，当使用50%氧化亚氮时，该值降至1.43MAC。每组中皮肤血流减少幅度与血流动力学变量变化之间无相关性。然而，添加氧化亚氮可显著抑制切口时收缩压和心率的变化（收缩压和心率变化：七氟醚组为41.6±20.4mmHg和35.4±12.5次/分钟，七氟醚/氧化亚氮组为24.6±10.2mmHg和18.1±9.5次/分钟，P<0.01）。结果表明，氧化亚氮有助于抑制七氟醚麻醉期间对手术刺激的肾上腺素能反应。
