七氟醚吸入麻醉对喉返神经监控下甲状腺手术的影响

Effects of sevoflurane inhalation in different concentrations on thyroid operation under real-time monitoring of the recurrent laryngeal nerve

目的研究吸入不同浓度的七氟醚对甲状腺手术中的喉返神经实时监控下喉返神经肌电活动的影响。方法20例择期在全麻下行甲状腺部分切除手术的患者,气管插管后采用单纯七氟醚吸入麻醉,将七氟醚呼气末浓度调整为0.4、0.6、0.8、1.0、1.2、1.4、1.6最低肺泡有效浓度(MAC)时,观察并记录收缩压、舒张压、心率及喉返神经肌电活动波形的振幅变化(振幅大于100μV时监测有效),同时记录脑电双频指数(BIS)的变化。结果喉返神经肌电活动振幅随七氟醚呼气末浓度的增高而逐渐降低(P<0.05),但均大于140μV,在整个手术、麻醉过程中全组患者的喉返神经实时监控均未中断。七氟醚呼气末浓度低于1.0MAC时,大多数患者的BIS值为43～61;当七氟醚呼气末浓度高于1.0MAC、低于1.4MAC时,全组患者血压、心率与麻醉前相比均有轻度下降(P<0.05),BIS值为44～46。当七氟醚呼气末浓度高于1.6MAC时,全组患者血压、心率进一步下降,BIS值降至36左右,喉返神经肌电活动波形的振幅均大于140μV;当七氟醚呼气末浓度低于0.1±0.1MAC,BIS值为90～94时,全组患者清醒。结论静脉快速诱导、单纯七氟醚吸入全麻不会影响喉返神经功能监控的连续性,不但能维持甲状腺手术时血压、心率的平稳,而且苏醒迅速、完全,可在喉返神经监控手术中推广使用。

Objective To study the effects of sevoflurane inhalation in different concentrations on the thyroid operation under realtime monitoring of the recurrent laryngeal nerve （RLN）. Methods 20 ASA Ⅰ-Ⅱ patients underwent thyroid operation were given different concentrations of sevoflurane inhalation after intubation. BP, HR and real-time monitoring of RLN were recorded （the amplitude should be above 100μV） when the sevoflurane inhalation were at 0. 4, 0. 6, 0.8, 1. 0, 1.2, 1.4 and 1, 6 MAC.. Meanwhile the bispectral analysis （BIS） was monitored. Results The amplitude of RLN decreased continuously （all of the amplitude 〉140μV） when the end tidal concentration of sevoflurane increased during the operation. The BIS were between 43-61 when the end tidal concentration of sevuflnrane was lower than 1.0 MAC. The BP and HR in the group decreased （P〈0. 05） and the BIS were between 44--46 when the end tidal concentration of sevuflnrane was higher than 1.0 MAC and lower than 1.4 MAC compared with pre-anesthesia during the operation. The potential of RLN could still be recorded when the end tidal concentration of sevoflurane was higher than 1.6 MAC and the BIS was 36 at the same time. All of the cases awoke when the end tidal concentrations of sevoflurane were lower than 0.1 MAC and BIS were between 90- 94. Conclusion Intravenous induction and sevoflurane inhalation can not only inhibit the action potential of RLN, but also decrease effectively the cardiovascular reaction, and all the patients awake quickly. This method can be used in operation with nerve monitoring.