Stimulation of the autonomic nervous system in colorectal surgery: a study protocol for a randomized controlled trial

ABSTRACT: BACKGROUND: Postoperative ileus is a well-known complication of abdominal surgery and is considered to be caused by a local inflammation in the gut. Previously it has been shown that both local and systemic inflammation can be reduced by stimulation of the autonomic nervous system via lipid rich nutrition. Stimulation of the autonomic nervous system releases acetylcholine from efferent vagal nerve endings that binds to nicotinic receptors located on the inflammatory cells leading to a decrease of pro-inflammatory markers . Possibly this mechanism may explain the attenuating effect of lipid enriched nutrition on postoperative ileus. Besides administration of nutrition there are other ways of stimulating the autonomic nervous system such as gum chewing. METHODS: This prospective, placebo-controlled randomized trial will include 120 patients undergoing colorectal surgery which are randomized for gum chewing in the perioperative phase or a placebo. Postoperative ileus will be assessed both clinically by time to first flatus and time to first defecation and by determination of gastric motility using ultrasound to measure dimensions of the antrum. Furthermore the inflammatory response is quantified by analysing pro-inflammatory mediators. Finally markers of gut barrier integrity will be measured as well as occurrence of postoperative complications. DISCUSSION: We hypothesize chewing gum preoperatively and direct postoperatively when undergoing a colorectal surgical procedure will dampen the inflammatory response, both locally and systematically, via stimulation of afferent vagal nerve fibres. By down-regulation of the inflammatory cascade POI will be ameliorated and patients' recovery will be enhanced.