The effects of early enteral nutrition on mortality after major emergency abdominal surgery: a systematic review and meta-analysis with Trial Sequential Analysis

Summary Background Early oral or enteral nutrition (EEN) has been proven safe, tolerable, and beneficial in elective surgery. In emergency abdominal surgery no consensus exists regarding postoperative nutrition standard regimens. This review aimed to assess the safety and clinical outcomes of EEN compared to standard care after emergency abdominal surgery. Methods The review protocol was performed according to the Cochrane Handbook and reported according to PRISMA. Clinical outcomes included mortality, specific complication rates, length of stay, and serious adverse events. Risk of bias was assessed by Cochrane risk of bias tool and Downs and Black. GRADE assessment of each outcome was performed, and Trial Sequential Analysis was completed to obtain the Required Information Size (RIS) of each outcome. Results From a total of 4741 records screened, a total of five randomized controlled trials and two non-randomized controlled trials were included covering 1309 patients. The included studies reported no safety issues regarding the use of EEN. A significant reduction in the mortality rate of EEN compared with standard care was seen (OR 0.59 (CI 95% 0.34-1.00), I2 = 0%). Meta-analyses on sepsis and postoperative pulmonary complications showed non-significant tendencies in favor of EEN compared with standard care. GRADE assessment of all outcomes was evaluated ‘low’ or ‘very low’. Trial Sequential Analysis revealed that all outcomes had insufficient RIS to confirm the effects of EEN. Conclusion EEN after major emergency surgery is correlated with reduced mortality, however, more high-quality data regarding the optimal timing and composition of nutrition are needed before final conclusions regarding the effects of EEN can be made.