Association Between Handover of Anesthesia Care and Adverse Postoperative Outcomes Among Patients Undergoing Major Surgery

Abstract

Importance: Handing over the care of a patient from one anesthesiologist to another occurs during some surgeries and might increase the risk of adverse outcomes.

Objective: To assess whether complete handover of intraoperative anesthesia care is associated with higher likelihood of mortality or major complications compared with no handover of care.

Design, setting, and participants: A retrospective population-based cohort study (April 1, 2009-March 31, 2015 set in the Canadian province of Ontario) of adult patients aged 18 years and older undergoing major surgeries expected to last at least 2 hours and requiring a hospital stay of at least 1 night.

Exposure: Complete intraoperative handover of anesthesia care from one physician anesthesiologist to another compared with no handover of anesthesia care.

Main outcomes and measures: The primary outcome was a composite of all-cause death, hospital readmission, or major postoperative complications, all within 30 postoperative days. Secondary outcomes were the individual components of the primary outcome. Inverse probability of exposure weighting based on the propensity score was used to estimate adjusted exposure effects.

Results: Of the 313 066 patients in the cohort, 56% were women; the mean (SD) age was 60 (16) years; 49% of surgeries were performed in academic centers; 72% of surgeries were elective; and the median duration of surgery was 182 minutes (interquartile [IQR] range, 124-255). A total of 5941 (1.9%) patients underwent surgery with complete handover of anesthesia care. The percentage of patients undergoing surgery with a handover of anesthesiology care progressively increased each year of the study, reaching 2.9% in 2015. In the unweighted sample, the primary outcome occurred in 44% of the complete handover group compared with 29% of the no handover group. After adjustment, complete handovers were statistically significantly associated with an increased risk of the primary outcome (adjusted risk difference [aRD], 6.8% [95% CI, 4.5% to 9.1%]; P < .001), all-cause death (aRD, 1.2% [95% CI, 0.5% to 2%]; P = .002), and major complications (aRD, 5.8% [95% CI, 3.6% to 7.9%]; P < .001), but not with hospital readmission within 30 days of surgery (aRD, 1.2% [95% CI, -0.3% to 2.7%]; P = .11).

Conclusions and relevance: Among adults undergoing major surgery, complete handover of intraoperative anesthesia care compared with no handover was associated with a higher risk of adverse postoperative outcomes. These findings may support limiting complete anesthesia handovers.

Figure 1.. Cohort Build and Missing Data for Surgeries With Complete Handover vs No Handover

^aBilling code for replacement anesthesiologist not used as intended (1 institution) refers to 1 Ontario institution which systematically billed the code used to define the main exposure in this study for an alternative purpose (ie, the postoperative care of patients with complicated medical needs in the postanesthetic care unit). Since it was not possible to positively determine which exposures among these patients were intraoperative vs postoperative, all patients who underwent surgery at this institution were excluded. ^bTo move from the complete case cohort (256 424 patients) to the subgroup analysis cohort (308 014 patients), 51 670 patients missing data on years since graduation for the primary anesthesiologist were added to the complete case cohort, and 80 patients were subtracted who also had missing data on duration of surgery.

Figure 2.. Risk of Adverse Outcomes (Complete Intraoperative Handover of Anesthesia Care vs no Handover Groups) in the Prespecified Subgroups

See Statistical Analysis for calculation methods of subgroup effects. Because of missing data, years since graduation for the primary anesthesiologist was excluded as a covariate in these analyses (Figure 1). ^aData were plotted in the year the fiscal year ended (end date, March 31). ^bSmall cell sizes (≤5) cannot be reported and were obscured to create ambiguity.