Anesthesia & Analgesia: Nov 2015 Vol 121 issue 5 p 1194-1201
Authors: Bresson Julie MD et al
BACKGROUND: NeuroSENSE is a depth of anesthesia monitor that uses automated electroencephalogram quantification. The Wavelet-based Anesthetic Value for Central Nervous System (WAVCNS) index calculated by this monitor is based on wavelet analysis of a normalized electroencephalogram signal in the γ-frequency band. The aim of this study was to determine the extent of disagreement between the Bispectral Index (BIS) and the WAVCNSindex during propofol-based and sevoflurane-based maintenance of general anesthesia in a routine surgical population.
METHODS: Patients undergoing elective surgery were enrolled in the study and randomly assigned to receive either propofol or sevoflurane for the maintenance of anesthesia and remifentanil in both groups. Anesthesiologists were blinded to monitors in both groups. Discordance between the 2 monitors was assessed by the count of discrepancy in recommendation (DR) (type 1 defined as one parameter <40 and the other >60, or type 2 defined as BIS and WAVCNS values on different sides of a threshold [40 or 60]) and also by the proportion of agreement (P0) between WAVCNS and BIS, obtained every 5 seconds, in 3 categories of index (<40, 40–60, and >60).
RESULTS: The analyzed data set consisted of 22 patients (36,872 data pairs) in the propofol group and 24 patients (32,826 data pairs) in the sevoflurane group. The type 1 DR rarely occurred in both the groups (<1%); however, the median (interquartile range) type 2 DR was significantly more frequent in the propofol group (20.6% [7.0–36.9] vs 4.5% [2.3–12.4]; P = 0.0005). The median difference in P0 was 11.53% (95% confidence interval, 0.57–21.32). Major disagreement between WAVCNS index and BIS was related to the weight of burst suppression pattern for the index calculation.
CONCLUSIONS: Disagreement between BIS and NeuroSENSE during the maintenance of general anesthesia was worse in the propofol group than that in the sevoflurane groups. The disagreement increases during deep anesthesia or in the occurrence of burst suppression.