Time of day and 30‐day mortality after emergency surgery

Tessler et al. did not find an association between the time of day and 30-day mortality after emergency surgery 1. Evaluating the factors associated with early postoperative mortality in emergency surgery may help the development of reasonable preventive measures to improve treatment planning, the consent process and postoperative outcome. The authors acknowledged some limitations of their study, including deficiencies in patient morbidity and time to surgery, but we would like to invite the authors to comment on further concerns that we have. Firstly, the authors adjusted the logistic regression for anaesthesia duration and type of surgery, but not other risk factors, such as ASA physical status. ASA physical status is a significant predictor of in-hospital mortality after emergency surgery 2, and increasing ASA physical status is associated with greater mortality within 48 h after both elective and emergency surgery 3. Five other pre-operative variables are involved in the American College of Surgeons National Surgical Quality Improvement Program 30-day mortality calculator following emergency general surgery: age; non-independent status; sepsis; renal function; and albumin 4. Do the authors think that these and/or other confounding variables might have affected their results? Secondly, it was not reported how long patients waited for surgery, but pre-operative delay results in higher postoperative morbidity and mortality 5. Although the authors assumed that staff fatigue would be similar between their three time periods (day, evening, night), as most would become similarly tired throughout their shift, this may not hold true for all staff, and surgeons’ performance may decline after more prolonged periods of sleep deprivation 6, 7. To what degree do the authors think that surgical and anaesthetic sleep deprivation may have been a factor affecting their results?