Correlation between Narcotrend index and depth of anesthesia during inhalation anesthesia with sevoflurane: a comparison with BIS values / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the correlation between Narcotrend index (NI) and the depth of anesthesia during inhalation anesthesia with sevoflurane and compare NI with BIS values in patients.Methods Sixtytwo ASA physical status Ⅰ or Ⅱ patients,aged 25-60 yr,weighing 44-100kg,scheduled for elective surgeries under general anesthesia,were enrolled in the study.Sevoflurane inhalation was started at 5 min after endotracheal intubation.When the end-tidal concentration of sevoflurane (ETsevo) reached 0.6％,0.9％,1.3％,1.6％,2.1％,2.4％,2.9％,3.2％,3.8％ and 4.2％,NI and BIS values were recorded simultaneously.Results The correlation coefficients between ETsevo and NI and BIS values were-0.627 (r1) and-0.669 (r2) respectively when ETsevo ＜ 2.9％,and-0.608 (r3) and-0.230 (r4) respectively when 2.9％ ≤ ETsevo ≤4.2％ (P ＜ 0.01).Comparison of the absolute value of correlation coefficientsno significant difference was found between r1,r2 and r3 (P ＞ 0.05) ; r1,r2 and r3 were significantly greater than r4 (P ＜ 0.01).Conclusion When ETsevo 4.2％,NI values can accurately reflect the depth of anesthesia; when 2.9％ ≤ ETsevo ≤4.2％,the accuracy of NI values in monitoring the depth of anesthesia is superior to that of BIS values.