Significant negative behavior change can occur in children after anesthesia. It is difficult to precisely predict in which children this will occur, however, some individual, family and procedural variables are associated with significant negative behavior change. If used, preparation should be considered according to level of surgical complexity.

Some simple preoperative questions can help identify children at risk of heightened anxiety at induction of anesthesia; however, it remains difficult to precisely predict which child will experience high anxiety.

During routine adult anesthesia, the risk of awareness is 0.1%-0.2%. No recent studies have reported the incidence in children. Altered pharmacology and differing anesthesia techniques suggest that the incidence may differ in children. In this prospective cohort study, we determined the incidence of awareness during anesthesia in children. Eight-hundred-sixty-four children aged 5-12 yr who had undergone general anesthesia at The Royal Children's Hospital were interviewed on 3 occasions to determine the incidence of awareness. The awareness assessment was nested within a larger study of behavior change after anesthesia. Reports of suspected awareness were sent to four independent adjudicators. If they all agreed, a case was classified as true awareness. Twenty-eight reports were generated. There were 7 cases of true awareness, for an incidence of 0.8% (95% confidence interval, 0.3%-1.7%). Only one aware child received neuromuscular blockers, compared with 12% in the nonaware group. No aware child reported distress, and no substantial difference was detected in behavior disturbance between aware (20%) and nonaware (16%) children. The data provide some evidence that, like adults, children are also at risk of intraoperative awareness. Although the cause remains unclear, anesthesiologists should be alerted to the possibility of awareness in children.

At equipotent concentrations of halothane and isoflurane BIS valves were significantly greater with halothane. At awakening the BIS values were equivalent for each agent. This finding is consistent with the BIS being more affected by the agent used at higher concentrations of anaesthetic. The BIS must be interpreted with caution when using halothane.