Outcomes after endoscopic retrograde cholangiopancreatography with general anaesthesia versus sedation

Background: We tested the primary hypothesis that use of general anaesthesia vs sedation increases vulnerability to adverse discharge (in-hospital mortality or new discharge to a nursing facility) after endoscopic retrograde cholangiopancreatography (ERCP). Methods: In this retrospective cohort study, adult patients undergoing ERCP with general anaesthesia or sedation at a tertiary care hospital were included. We calculated adjusted absolute risk differences between patients receiving general anaesthesia vs sedation using provider preference-based instrumental variable analysis. We also used mediation analysis to determine whether intraoperative hypotension during general anaesthesia mediated its effect on adverse discharge. Results: Among 17 538 patients undergoing ERCP from 2007 through 2018, 16 238 received sedation and 1300 received GA. Rates of adverse discharge were 5.8% (n=938) after sedation and 16.2% (n=210) after general anaesthesia. Providers' adjusted mean predicted probabilities of using general anaesthesia for ERCP ranged from 0.2% to 63.2% of individual caseloads. Utilising provider-related variability in the use of general anaesthesia for instrumental variable analysis resulted in an 8.6% risk increase (95% confidence interval, 4.5-12.6%; P<0.001) in adverse discharge among patients receiving general anaesthesia vs sedation. Intraoperative hypotensive events occurred more often during general anaesthesia and mediated 23.8% (95% confidence interval, 3.9-43.7%: P=0.019) of the primary association. Conclusions: These results suggest that use of sedation during ERCP facilitates reduced adverse discharge for patients for whom general anaesthesia is not clearly indicated. Intraoperative hypotension during general anaesthesia for ERCP partly mediates the increased vulnerability to adverse discharge.