應用畢氏腦波指數監測，比較Propofol與Isoflurane在選擇性剖腹產婦身上之差異

Effects on the Bispectral Index during Elective Caesarean Section: A Comparison of Propofol and Isoflurane

背景：全身麻醉在剖腹產手術，常因其手術的特殊性，使得甦醒機率較其他手術為高。畢氏腦波監測器，是利用數位化腦波分析，來量化病人的意識狀態。方法：報告中收集24位進行選擇性剖腹產手術的產婦，給與全身麻醉。所有產婦在胎兒娩出前，所給予的處置皆相同；胎兒娩出後，將產婦隨機分成兩組，一組給予propofol 8 mg/kg/h，一組給予isoflurane 0.5最低有效肺泡濃度(MAC)，來維持麻醉深度。整個麻醉過程皆用畢氏腦 波監測器監測，藉以比較兩者在鎮靜效果上，是否有臨床應用的價值；再者，比較兩者在統計上或臨床上，是否有效果上的差異。結果：Isoflurane與propofol這兩組，在畢氏腦波指數監測下，發現皆有良好效果，甦醒機率低。結論：雖然兩組在臨床上或統計學上皆無明顯差異，但isoflurane這組因宮縮不佳而需處理的機率，較propofol這組為高。

Background: Awareness during general anesthesia has been a particular problem during caesarean section. About 7 percent of patients undergoing elective caesarean section have reported dreaming or recall of voices during the procedure. The bispectral index (BIS), a value derived from the electroencephalogram (EEG), has been shown to be useful in monitoring the depth of anesthesia. Supplementation of propofol or isoflurane for maintenance of anesthesia has been shown to effectively reduce the incidence of awareness. However, the effects of propofol or isoflurane on the BIS index have not been fully investigated. We therefore designed this study to compare the effects of isoflurane or propofol supplementation on the BIS index in 24 healthy parturients undergoing elective caesarean section. Methods: All patients had induction of anesthesia and orotracheal intubation in rapid sequence made possible by 1 MAC isoflurane with 50% N20-50% O2 as conveyer and atracurium. After delivery, patients were randomly assigned to either of two groups (isoflurane or propofol). Patients in the Isoflurane group (n = 12) received 0.5 MAC isoflurane in 67% N20-33% O2 and fentanyl + droperidol. Patients in the propofol group (n = 12) received propofol (8 mg/kg/h) infusion combined with 67% N20-33% O2 and fentanyl + droperidol. Results: There was no difference between the two groups in total operation time, maternal blood loss, fetal Apgar scores. No differences between the two groups in heart rate, blood pressure or BIS index values were found throughout the surgery. No patient from either group reported recall of the operative procedure. However, 25% of patients (3 of 12) in the isoflurane group had poor uterine contraction, suggestive of doubtful appropriateness of the use of isoflurane for maintenance of anesthesia in delivery. Conclusions: We therefore concluded that supplementation of isoflurane or propofol for maintenance of anesthesia can satisfactorily decrease the BIS index and minimize the incidence of awareness in patients undergoing caesarean section under general anesthesia. The BIS index is a reliable monitor of the hypnotic component of anesthesia.