Critical incidents associated with intraoperative exchanges of anesthesia personnel.

It is a common practice for anesthesia to substitute for one another, especially for short breaks during long surgical procedures. The assets and liabilities of this practice of relief have not been examined previously. In the course of gathering 1,089 reports of preventable errors and failures associated with anesthesia management, we identified 96 which involved a relief anesthetist. This subset was examined in search of common characteristics and patterns of cause and discovery of errors. In 28 incidents, the relief anesthetist discovered an error or the cause of an error. In 10 incidents, the process of relief was identified as having contributed to the commission of an error. Although 70 of the 1,089 incidents were associated with substantive negative outcomes, e.g., death, cardiac arrest, or extended ICU stay, none of those incidents was caused by a relieving anesthetist. There is a strong implication that relief is beneficial more often than not even aside from the presumed beneficial effect on the vigilance of the primary anesthetist (the latter effect was outside the scope of this study). From the descriptions of the causes and discoveries of errors in these relief-related incidents, guidance can be drawn for the safe and effective conduct of the intraoperative exchange of anesthesia personnel.