T. K. Woleston1,3, R. S. Chamberlain1,2,3 1Saint Barnabas Medical Center,Department Of Surgery,Livingston, NJ, USA 2Rutgers Univsersity,Department Of Surgery,Newark, NJ, USA 3St. George’s University School Of Medicine,St. George’s, ST. GEORGE’S, Grenada
Introduction: Preoperative fasting is an accepted precaution for patients undergoing surgery and is intended to prevent aspiration of gastric contents while under anesthesia. Surgery while in a fasting state can lead to increased metabolic stress and increased morbidity and mortality. Preoperative oral carbohydrate (OCH) supplementation has been proposed to decrease postoperative complications and improve clinical outcomes, however studies to date have produced inconsistent findings. This meta-analysis critically analyzes existing randomized controlled trials (RCTs) to establish an evidence-based perspective on preoperative OCH supplementation and its effect on length of stay, postoperative nausea/vomiting, insulin resistance, and post-operative complications.
Methods: A comprehensive search of PubMed, Google Scholar, and both the Cochrane and NIH Central Registry of Controlled Trials was completed (1990 – 2014). 15 RCTs were identified involving non-diabetic adult subjects undergoing elective surgery receiving a preoperative OCH dose greater than 25g or placebo/no therapy. Length of stay (LOS), postoperative nausea/vomiting, insulin resistance, and postoperative complications (including infection, wound dehiscence, anastomotic leak, atrial fibrillation, pneumonia, and ileus) were the outcomes assessed.
Results: 15 RCTs involving 1,380 patients were included in this meta-analysis. 605 subjects received preoperative OCH supplementation and 775 received traditional preoperative fasting or calorie-free placebo. OCH use decreased LOS by 1.8 days (6.9 vs. 8.7 days, p=0.026). There was no significant decrease in the risk of postoperative complications (p=0.157), or postoperative nausea/vomiting (p=0.485). The homeostatic model assessment for insulin resistance (HOMA-IR) value was 4.8% higher (2.44 vs. 2.30, p=0.009) in the OCH group than the control group preoperatively, however the postoperative day 1 values were not significantly different (p=0.6665).
Conclusions: Preoperative OCH supplementation is associated with a significant decrease in LOS when compared to fasting, and is comparable regarding postoperative complications. Preoperative caloric loading should be considered in all patients undergoing prolonged surgical procedures and may be superior to current practice. Additional well-designed large scale RCTs are required to evaluate ideal dose and timing of OCH, associated risks, and which procedures are most likely to benefit from OCH loading.
