Mason D G, Higgins D, Boyd S G, Lloyd-Thomas A R
Department of Anaesthetics, Hospital for Sick Children, London.
Br J Anaesth. 1992 Dec;69(6):567-9. doi: 10.1093/bja/69.6.567.
We have used sequential measurements of median nerve somatosensory evoked potentials (mnSSEP) in 10 children to estimate the equilibration time of an inhalation anaesthetic agent between alveolar gas, arterial blood and brain. MnSSEP were obtained sequentially every 90-180 s. After control measurements in the absence of isoflurane, the end-tidal concentration was increased stepwise (0.25, 0.5 and 0.75 MAC). Each isoflurane concentration was maintained for 15 min. The point at which the N20 latency reached stability was determined; the mean time between reaching a stable end-tidal isoflurane concentration and this point varied between 5 min 16 s and 7 min 37 s. This technique may be useful in circumstances in which a "steady state" of anaesthesia is important, such as in the determination of MAC or during intraoperative monitoring of evoked potentials.
我们对10名儿童进行了正中神经体感诱发电位（mnSSEP）的连续测量，以估算吸入麻醉剂在肺泡气、动脉血和脑之间的平衡时间。每90 - 180秒连续获取一次mnSSEP。在无异氟烷的情况下进行对照测量后，呼气末浓度逐步增加（0.25、0.5和0.75 MAC）。每种异氟烷浓度维持15分钟。确定N20潜伏期达到稳定的时间点；从呼气末异氟烷浓度达到稳定到该时间点的平均时间在5分16秒至7分37秒之间变化。该技术在麻醉“稳态”很重要的情况下可能有用，例如在确定MAC或术中诱发电位监测期间。
