BIS guide for clinicians

Using BIS Monitoring to Reduce Intraoperative Awareness
Using BIS Monitoring To Reduce
Intraoperative Awareness
Despite best intentions, a small percentage of patients
undergoing general anesthesia regain consciousness
unexpectedly and are able to form sufficient memory to
recall portions of their intraoperative experience. This
section discusses the role that BIS monitoring can play in
decreasing the incidence of this adverse event.
Intraoperative Awareness During Anesthesia
In several large-scale prospective investigations, the incidence
of intraoperative awareness has been measured to occur
37, 38, 39
during general anesthesia in 0.1 to 0.2% of patients.
In 2004, the Joint Commission’s Sentinel Event Alert #32
noted that each year, 20,000 to 40,000 patients may become
cognizant and have recall of events during surgery. 40
An overview of various perioperative factors that put patients at
increased risk for awareness is presented in Table 6. Presence
of some of these risk factors has been reported to increase the
relative risk for awareness to nearly 1% of patients.
25