Intraoperative awareness in a regional medical system: a review of 3 years' data

Intraoperative awareness in patients undergoing general anesthesia is an infrequent but well-described adverse outcome. The reported incidence of this phenomenon is between 0.1% and 0.9%.

With institutional review board approval, the authors reviewed continuous quality improvement data from 3 yr (2002-2004) at the locations where the physician group provided anesthesia. Board-certified anesthesiologists supervising certified registered nurse anesthetists in the anesthesia care team model of practice delivered all anesthetics. Brain function monitors were not used in the operating room setting. Patients were interviewed twice during a 48-h postoperative period and, as part of that process, underwent a modified Brice interview to determine intraoperative awareness. All cases that met the criteria for awareness were examined by the continuous quality improvement committee to modify anesthetic practice and were included in this study.

Data from 211,842 patients undergoing anesthesia were considered. Of these, the continuous quality improvement process followed up 177,468 (83.1%). Cases were not included in the study if the patient was younger than 18 yr, did not have a general anesthetic, or had a terminal event during the hospital course. By these criteria, a total of 87,361 patients followed by the continuous quality improvement process were at risk for awareness. Six patients reported instances of recall.

The incidence of intraoperative awareness in this large sample of patients from a regional medical center undergoing general anesthesia was 0.0068%, or 1 per 14,560 patients, substantially less than that reported in the recent literature.