Explicit awareness during anaesthesia for general surgery has an incidence of <0.3% and may be associated with a lower frequency when using volatile inhaled anaesthesia.
How can awareness during anaesthesia be prevented in patients undergoing general surgery?
Awareness during anaesthesia is a rare (<0.3%) but severe adverse event that can be mitigated through proper preoperative assessment, equipment checks, and monitoring of anaesthetic depth.
Awareness during anaesthesia is a state of consciousness that is revealed by explicit or implicit memory of intraoperative events. Although large clinical surveys indicate an incidence of explicit awareness of < 0.3% during anaesthesia for general surgery, this adverse effect should be a great concern, because patients may be permanently disabled by the experience of being awake during surgery. Prevention of awareness during anaesthesia starts with an appropriate preoperative visit to the patient. The anaesthetic delivery machines must be properly checked before and during anaesthesia. The anaesthetic depth should be assessed by observation of movement responses, and consequently a minimum of muscle relaxants used. Because the anaesthetic depth can be controlled by determination of endtidal drug concentration, volatile inhaled anaesthesia may be associated with a lower frequency of awareness than other anaesthetic regimens.
Heier et al. (1996) conducted a review in Awareness during anaesthesia. Volatile inhaled anaesthesia vs. Other anaesthetic regimens was evaluated on Explicit awareness. Explicit awareness during anaesthesia for general surgery has an incidence of <0.3% and may be associated with a lower frequency when using volatile inhaled anaesthesia.