Titre de l'article sujet de la Lecture critique Althoff FC1, Wachtendorf LJ1, Rostin P1, Santer P1, Schaefer MS1, Xu X1, Grabitz SD1, Chitilian H2, Houle TT2, Brat GA3, Akeju O2, Eikermann M1. Effects of night surgery on postoperative mortality and morbidity: a multicentre cohort study. BMJ Qual Saf 2020;30(8):678-688. Doi : 10.1136/bmjqs-2020-011684. 1-Anesthesia, critical care and pain medicine – Beth Israel Deaconess Medical Center – Boston – Massachusetts – United States of America (USA) – E-mail : firstname.lastname@example.org. 2-Anesthesia, critical care and pain medicine – Massachusetts General Hospital – Boston – Massachusetts – USA 3-Surgery – Beth Israel Deaconess Medical Center – Boston – Massachusetts – USA
Background. Surgery at night (incision time 17:00 to 07:00 hours) may lead to increased postoperative mortality and morbidity. Mechanisms explaining this association remain unclear. Methods. We conducted a multicentre retrospective cohort study of adult patients undergoing non-cardiac surgery with general anaesthesia at two major, competing tertiary care hospital networks. In primary analysis, we imputed missing data and determined whether exposure to night surgery affects 30-day mortality using a mixed-effects model with individual anaesthesia and surgical providers as random effects. Secondary outcomes were 30-day morbidity and the mediating effect of blood transfusion rates and provider handovers on the effect of night surgery on outcomes. We further tested for effect modification by surgical setting. Results. Among 350 235 participants in the primary imputed cohort, the mortality rate was 0.9% (n=2804/322 327) after day and 3.4% (n=940/27 908) after night surgery. Night surgery was associated with an increased risk of mortality (ORadj 1.26, 95% CI 1.15 to 1.38, p<0.001). In secondary analyses, night surgery was associated with increased morbidity (ORadj 1.41, 95% CI 1.33 to 1.48, p<0.001). The proportion of patients receiving intraoperative blood transfusion and anaesthesia handovers were higher during night-time, mediating 9.4% (95% CI 4.7% to 14.2%, p<0.001) of the effect of night surgery on 30-day mortality and 8.4% (95% CI 6.7% to 10.1%, p<0.001) of its effect on morbidity. The primary association was modified by the surgical setting (p-for-interaction<0.001), towards a greater effect in patients undergoing ambulatory/same-day surgery (ORadj 1.81, 95% CI 1.39 to 2.35) compared with inpatients (ORadj 1.17, 95% CI 1.02 to 1.34). Conclusions. Night surgery was associated with an increased risk of postoperative mortality and morbidity. The effect was independent of case acuity and was mediated by potentially preventable factors: higher blood transfusion rates and more frequent provider handovers.