Night-time Surgery versus Day-time Surgery: Does Circadian Timing Influence Outcomes in Emergency Laparotomies?

Background: Emergency laparotomy carries a high risk, and recent work suggests that outcomes may vary with surgical timing. Physiological stress, reduced staffing, and limited resources at night may contribute to poorer results. This study examined whether night-time emergency laparotomy is linked to higher 30-day mortality compared with day-time surgery after adjusting for baseline risk. Methods: This retrospective cohort included adults undergoing emergency midline laparotomy for nontraumatic general surgical indications at a tertiary center from January 2022 to December 2024. Operations were classified as day-time (08:00–19:59) or night-time (20:00–07:59). The primary outcome was 30-day all-cause mortality. Secondary outcomes were 7-day mortality, major complications (Clavien–Dindo ≥ III), reoperation, intensive care unit (ICU) admission, and hospital stay. Multivariable logistic regression adjusted for age, sex, American Society of Anesthesiologists grade, Physiological and Operative Severity Score for the enUmeration of Mortality (P-POSSUM) predicted mortality, indication, and consultant presence. Sensitivity analyses used propensity score matching and predefined subgroups. Results: Among 847 patients, 612 (72.3%) underwent day-time and 235 (27.7%) night-time surgery. Baseline characteristics were comparable, though delays to theater were longer at night (median 8.2 vs. 6.1 h, P = 0.003). Crude 30-day mortality was higher at night (14.9% vs. 10.3%, P = 0.067). After adjustment, night-time surgery was associated with increased 30-day mortality (adjusted odds ratio [aOR] 1.78, 95% confidence interval 1.12–2.84, P = 0.015), major complications (28.5% vs. 21.4%; aOR 1.52, P = 0.017), and ICU admission (45.1% vs. 35.6%; aOR 1.48, P = 0.016). Consultant presence was lower during night-time (61.7% vs. 78.4%, P < 0.001). P ro p ensity-matched results were consistent. Conclusion: Night-time emergency laparotomy is linked to higher adjusted mortality and morbidity. Strengthening consultant involvement and night-time staffing may help improve outcomes.