Postoperative diet advancement: surgical dogma vs evidence-based medicine

Postoperative ileus is a natural part of recovery following abdominal and intestinal surgery. Research in the laboratory and clinical arenas has challenged the long-held belief that enteral nutrition (EN) should not be administered until bowel function has resumed, which is typically judged by a subjective bowel function assessment. Traditional postoperative management begins with clinical monitoring of return of bowel function, followed by a clear liquid diet that is advanced to regular solid food as tolerated. Studies have consistently demonstrated that early EN is safe and well tolerated, showing a reduction in wound morbidity and healing, fewer septic complications, diminished weight loss, and improved protein kinetics in patients administered early EN. Barriers to early enteral feeding include fear of GI morbidity, anastomotic disruption or leak but have not been proven valid in clinical or experimental trials. A clear liquid diet is the most frequently ordered first postoperative meal regardless of early or delayed administration. Although generally well tolerated, this diet fails to provide adequate nutrients to the postsurgical patient. In contrast, advancement to a regular diet as the initial meal has been shown to be well tolerated and provides significantly more nutrients than a clear liquid diet. This article reviews basic GI physiology, including motility, nutrient absorption, and the changes that occur in regulation and function of the GI tract following surgery, as well as clinical data regarding postoperative GI function and diet advancement. This will be applied to the clinical practices of postoperative dietary advancement to discuss the timing and choice of initial feeding in the postoperative patient.