Comparison of Anesthesia Beginning at On-hours Versus Off-hours on Outcomes in Patients Undergoing Hip Surgery: A Retrospective, Propensity Score–matched Cohort Study

Abstract

Objective: To explore the impact of the begin time of anesthesia on in-hospital mortality and early prognosis of patients undergoing hip surgery.Methods: All patients who had hip surgery between January 1, 2015, and December 31, 2020, were evaluated in this retrospective cohort study. The primary outcome was in-hospital mortality. Secondary outcomes were: (1) postoperative hospital length of stay (postoperative LOS) and total LOS; (2) ICU admission; (3) the ratio of postoperative complications, including renal dysfunction, anemia, hypotension, deep vein thrombosis (DVT), arrhythmia, coronary artery disease (CAD) or heart failure, pulmonary infection, electrolyte disturbance, hyoxemia and delirium; (4) intraoperative outcomes, including blood loss, urine volume, concentrated red blood cells (CRBC), fresh frozen plasma (FFP), equilibrium liquid, colloidal solution, intraoperative sufentanil, and using vasoactive drugs. A propensity score–matched analysis was used to adjust for confounders to make baseline characteristics more similar within the cohort. Results: We identified 1,843 patients, of whom 1,727 had anesthesia begun at on-hours and 116 had anesthesia begun at off-hours. Before propensity score matching (PSM), in-hospital mortality (risk ratio, 19.85; 95% CI, 4.39-89.78; P <0.001), postoperative LOS (11 days [8-16] vs. 9 days [7-14]; P =0.001) and total LOS (16 days [12-25.3] vs. 14 days [12-19]; P =0.020), the proportion of ICU admission (risk ratio, 4.70; 95% CI, 1.84-12.01; P <0.001), hypotension (risk ratio, 5.96; 95% CI, 1.84-19.29; P =0.004), pulmonary infection (risk ratio, 4.74; 95% CI, 1.98-11.33; P <0.001) and hyoxemia (risk ratio, 5.32; 95% CI, 1.88-15.03; P <0.001) was higher in the off-hours group. Intraoperative CRBC (0 U [0-2] vs. 0 U [0-0]; P <0.001), FFP (0 mL [0-37.5] vs. 0 mL [0-0]; P <0.001) and the intraoperative dosage of sufentanil (24.5 vs. 19.3 μg; P =0.003) was higher in the off-hours group. After PSM, 110 patients in the on-hours group were matched to similar patients in the off-hours group. Intraoperative CRBC (0 U [0-2] vs. 0 U [0-0]; P =0.040) and FFP (0 mL [0-0] vs. 0 mL [0-0]; P =0.015) was higher in the off-hours group. And postoperative renal dysfunction (risk ratio, 1.67; 95% CI, 0.86-3.21; P =0.050) and hyoxemia (4.5% vs. 0%; P =0.060) had a tendency to be different.Conclusion: Off-hours anesthesia for hip surgery is associated with statistically significant increases in intraoperative CRBC, FFP, and possibly associated with higher ratio of postoperative renal dysfunction and hyoxemia. These findings suggest that off-hours anesthesia, possibly by affecting the anesthetist’s judgment and decision making, could cause potential risks for hip surgery patients, which requires further exploration.