Prediction of EEG-Derived Wavelet Index for End-Tidal Sevoflurane in Pediatric Anesthesia: A Prospective, Single-Blind Study.

Background: Processed electroencephalogram is able to assess the depth of anesthesia. EEG-derived wavelet index (WLi) is a novel indicator derived from EEG on the basis of wavelet analysis.

Aims: We primarily tested whether WLi can reflect changes in end-tidal sevoflurane (sevo_ET) in pediatric patients, especially during the transition from awake status to 0.6 MAC. We then explored the concentration-effect relationship between sevo_ET and WLi and tested the effect of age on WLi.

Methods: This prospective, single-blind study was performed at a tertiary care hospital affiliated with Shanghai Jiao Tong University School of Medicine, China. WLi and BIS were measured in 40 pediatric patients aged 6 months to 6 years who underwent elective surgeries after sevo_ET was maintained at 2.0, 1.3, and 0.6 age-adjusted MAC in stepwise decrements.

Results: WLi and BIS had comparable performance in predicting the transition of anesthesia status from awake to sevo_ET at 0.6 MAC and from 1.3 to 2.0 MAC. In contrast to BIS, WLi exhibited a plateau effect and failed to predict the transition from 0.6 to 1.3 MAC. The indicator-specific performance of prediction was supported by their concentration-effect relationships, with EC₅₀ of 0.38 MAC for WLi and 0.95 MAC for BIS. Further, we found that the WLi values between individuals were independent of age.

Conclusions: WLi can reflect the transition of anesthesia status from light to moderate sedation, and the plateau effect might indicate adequate depth of anesthesia during deeper sedation and general anesthesia.