Intraoperative Awareness in a Regional Medical System: A Review of 3 Years' Data
Richard J. Pollard, Joseph P. Coyle, Richard L. Gilbert, and Janet E. Beck
(Anesthesiology, 106:269-274, 2007)
Southeast Anesthesiology Consultants, Charlotte, NC.
Intraoperative awareness occurs in 0.1% to 0.9% of cases, but this incidence has not been prospectively confirmed in a large community-based population of patients undergoing general anesthesia in the United States. The authors reviewed quality improvement data collected from 2002 to 2004 from a regional health care system where the physician group provided anesthesia. The physician group uses a continuous quality improvement (CQI) system to monitor and improve performance and outcomes.
Data were collected at 8 of the locations where anesthesia services are provided by board-certified anesthesiologists supervising registered nurse anesthetists in an anesthesia care team model of practice. Brain function monitors are not used in the operating room setting. Within 24 to 48 hours after their anesthetic, patients were interviewed and asked about the anesthesia experience and the possibility of awareness. The recall questions were based on a modified Brice interview. Cases that met the criteria for awareness were examined by the CQI committee to modify anesthetic practice.
From the 211,842 anesthetics delivered during the study period, 177, 468 (83.12%) were followed by the CQI process, with a total of 87,361 patients being at risk for awareness by meeting the criteria of being older than 18 years, undergoing a general anesthetic, and surviving the immediate postoperative period. Six cases were identified as "awareness" or "recall," for an incidence of 0.0068%, well below that reported in recent literature. Four patients had cardiac surgery; the incidence of awareness in cardiac cases was 0.12%, that is, 4 in 3208 cases. Those with recall were older (55.5 years vs. 46 years), had higher American Society of Anesthesiologists physical status (3.67 vs. 2.37), and were involved in longer anesthetics (340.7 minutes vs. 126 minutes) than the general population. All awareness instances were in patients in whom neuromuscular blocking agents were used. The level I trauma and teaching hospital in the region had 5 cases of recall of 52,751 cases (incidence of 0.0095%). The other institutions had a combined instance of 0.003% (1case in 34,610 cases). The difference was not statistically significant. The investigators concluded that use of an outcome-driven CQI process can provide mechanisms by which the incidence of recall during anesthesia can be lowered compared with previously reported rates.