Background: The role of early postoperative enteral nutrition after gastrointestinal surgery is controversial. Traditional management consist of 'nil by mouth', where patients receive fluids followed by solids when tolerated. Although several trials have implicated lower incidence of septic complications and faster wound healing upon early enteral feeding, other trials have shown opposite results. The immediate advantage of caloric intake could be a faster recovery with fewer complications, to be evaluated systematically.
Objectives: To evaluate whether early commencement of postoperative enteral nutrition compared to traditional management (no nutritional supply) is associated with fewer complications in patients undergoing gastrointestinal surgery
Search strategy: We searched the Cochrane Central Register of Controlled Trials, PUBMED, EMBASE, and LILACS from 1979 (first RCT published) to March 2006. We manually scanned the references from the relevant articles, and consulted primary authors for additional information.
Selection criteria: We looked for randomised controlled trials (RCT's) comparing early commencement of feeding (within 24 hours) with no feeding in patients undergoing gastrointestinal surgery. Early enteral nutrition is defined as all oral intakes (i.e. registered oral intake, supplemented oral feeding) and any kind of tube feeding (gastric, duodenal or jejunal) containing caloric content. No feeding is traditional management, defined as none caloric oral intake or any kind of tube feeding before bowel function. The definition 'no nutrition' includes non caloric placebo and water.
Data collection and analysis: The three authors independently assessed the identified trials, and extracted the relevant data using a specifically developed data extraction sheet. Primary end points of interest were: Wound infections and intraabdominal abscesses, postoperative complications such as acute myocardial infarction, postoperative thrombosis or pneumonia, anastomotic leakages, mortality, length of hospital stay, and significant adverse effects. We combined data to estimate the common relative risk of postoperative complications, and calculated the associated 95% confidence intervals. For analysis, we used fixed effects model (risk ratios to summarise the treatment effect) whenever feasible. The treatment effect on length of stay was estimated using effect size (presented as mean +/- SD). Some outcomes were not analysed but presented in a descriptive way. We used a random effects model to estimate overall risk ratio and effect size.
Main results: We identified thirteen randomised controlled trials, with a total of 1173 patients, all undergoing gastrointestinal surgery. Individual clinical complications failed to reach statistical significance, but the direction of effect indicates that earlier feeding may reduce the risk of post surgical complications. Mortality was the only outcome showing a significant benefit, but not necessarily associated with early commencement of feeding, as the reported cause of death was anastomotic leakage, reoperation, and acute myocardial infarction.
Authors' conclusions: Although non-significant results, there is no obvious advantage in keeping patients 'nil by mouth' following gastrointestinal surgery, and this review support the notion on early commencement of enteral feeding.