An intraoperative transfer of care from one anesthesia provider to another, or handover, may result in information loss and contribute to adverse patient outcomes. In 2019 we undertook a quality improvement effort to increase the use of a structured intraoperative handover tool incorporated in the electronic medical record. We hypothesized that intraoperative handovers of anesthesia care would be associated with adverse patient outcomes, and that increased use of a structured tool would attenuate this effect.


This study included adult patients undergoing non-cardiac surgery of at least 1-hour duration performed during the period 2016-2021. Cases with a handover were identified if either there was a change of attending anesthesiologist or change of nurse anesthetist or resident for > 35 minutes. Our primary outcome was the occurrence of a composite of postoperative mortality and major postoperative morbidity. The effect of the intervention was analyzed by examining the quarterly change in odds ratio for the primary outcome for cases with and without a handover.


A total of 121,077 cases, 40.4% of which had a handover, were included. After weighting, the composite outcome was statistically associated with handovers (3517/48,986 [7.2%] in handover cases, vs. 4470/72,091 [6.2%] in non-handover cases, odds ratio 1.08, 95% CI: 1.04, 1.12). Time series analysis showed a marked increase in usage of the structured tool following the initial intervention. The odds ratio for the composite outcome showed a significant decrease over time following the initial intervention (t = -3.97, p < 0.001), with the slope of the OR vs. time curve decreasing from 0.002 (95% CI: 0.001, 0.004; P=0.018) to -0.011 (-0.01, -0.018; P < 0.001).


Intraoperative handovers are significantly associated with adverse outcomes even after controlling for multiple confounding variables. Use of a structured handover tool during anesthesia care may attenuate the adverse effect.