Accuracy of index of consciousness in monitoring depth of anesthesia with sevoflurane inhalation in children: a comparison with bispectral index

Abstract

Objective To evaluate the accuracy of the index of consciousness (IoC) in monitoring the depth of anesthesia with sevoflurane inhalation in children,by comparing it with the bispectral index (BIS).Methods Forty-two ASA physical status Ⅰ or Ⅱ children,aged 8-12 yr,scheduled for elective abdominal surgery under general anesthesia,were studied.Anesthesia was induced with sevoflurane inhalation.The patients were endotracheally intubated.The concentration of sevoflurane was then adjusted to maintain the end-tidal concentration of sevoflurane (CETSev) at 1.6％,2.1％,2.6％,3.1％,3.6％,4.1％ and 4.6％ for5 min.The IoC and BIS values were recorded simultaneously.Results When CETSev ＜ 3.1％,CETSev was negatively correlated with IoC and BIS values,and the correlation coefficients between CETSev and IoC and BIS values were-0.927 (r1) and -0.869 (r2),respectively (P ＜ 0.01).When 3.1％ ≤ CETSev ≤ 4.6 ％,CET Sev was negatively correlated with IoC and BIS values,and the correlation coefficients between CETSev and IoC and BIS values were-0.808 (r3,P＜ 0.01) and-0.430 (r4,P ＜ 0.05),respectively.Comparison of the absolute value of correlation coefficients:there was no significant difference between r1,r2 and r3 (P ＞ 0.05) ; r1,r2 and r3 were significantly larger than r4 (P ＜ 0.01).Conclusion IoC can accurately reflect the depth of anesthesia with sevoflurane inhalation in children and when 3.1％ ≤ CET Sev ≤ 4.6 ％,the accuracy of IoC in monitoring the depth of anesthesia is superior to that of BIS. Key words: Monitoring, intraoperative; Anesthetics, inhalation; Electrical trace technique; Children