The impact and safety of preoperative oral or intravenous carbohydrate administration versus fasting in colorectal surgery - a randomized controlled trial

BACKGROUND AND AIMS: Increasing evidence suggests that preoperative fasting, as was the clinical practice for many decades, might be associated with untoward consequences and that a standardized preoperative intake of nutrients might be advantageous; this is a component of the enhanced recovery after surgery (ERAS) concept. Thus, in a randomized controlled trial we compared preoperative fasting with preoperative preparation with either oral or intravenous intake of carbohydrates, minerals and water. Biochemical, psychosomatic, echocardiographic and muscle-power parameters were assessed in surgical patients with colorectal diseases during the short-term perioperative period. We also assessed the safety of peroral intake shortly before surgery. METHODS: A total of 221 elective colorectal surgery patients in this bicentric, randomized, prospective and blinded clinical trial were divided into three groups: A - patients fasting from midnight (control group); B - patients supported preoperatively by glucose, magnesium and potassium administered intravenously; C - patients supported preoperatively by oral consumption of a specifically composed solution (potion). RESULTS: The general perioperative clinical status of patients in groups C and B was significantly better than those in group A. Psychosomatic conditions postoperatively were found to be best in group C (P < 0.029). The rise in the index of insulin resistance (QUICKI) from the preoperative to the postoperative state was significant in group A (P < 0.05). The systolic and diastolic function of the left ventricle improved postoperatively in group C vs. group A (P < 0.04), and the ejection fraction was also significantly higher postoperatively in group C vs. group A (P < 0.03). The gastric residual volume was 5 ml and the pH of stomach juice was 3.5-5 in all groups without statistically significant difference. No difference was found in the length of hospital stay or the rate of complications. CONCLUSIONS: Preoperative fasting does not confer any benefit or advantage for surgical patients. In contrast, consumption of an appropriate potion composed of water, minerals and carbohydrates offers some protection against surgical trauma in terms of metabolic status, cardiac function and psychosomatic status. Peroral intake shortly before surgery did not increase gastric residual volume and was not associated with any risk.