Hypnotic depth and the incidence of emergence agitation and negative postoperative behavioral changes.

BACKGROUND Emergence agitation (EA) and negative postoperative behavioral changes (NPOBC) are common in children, although the etiology remains unclear. We investigated whether longer times under deep hypnosis as measured by Bispectral Index (BIS) monitoring would positively correlate with a greater incidence of EA in the PACU and a greater occurrence of NPOBC in children after discharge. METHODS We enrolled 400 children, 1-12 years old, scheduled for dental procedures under general anesthesia. All children were induced with high concentration sevoflurane, and BIS monitoring was continuous from induction through recovery in the PACU. A BIS reading <45 was considered deep hypnosis. The presence of EA was assessed in the PACU using the Pediatric Anesthesia Emergence Delirium scale. NPOBC were assessed using the Post-Hospital Behavior Questionnaire, completed by parents 3-5 days postoperatively. Data were analyzed using logistic regression, with a P < 0.05 considered statistically significant. RESULTS The incidence of EA was 27% (99/369), and the incidence of NPOBC was 8.8% (28/318). No significant differences in the incidence of EA or NPOBC were seen with respect to length of time under deep hypnosis as measured by a BIS value of <45. CONCLUSION Our data revealed no significant correlation between the length of time under deep hypnosis (BIS < 45) and the incidence of EA or NPOBC. Within this population, these behavioral disturbances do not appear to be related to the length of time under a deep hypnotic state as measured by the BIS.