COLONIC SECRETORY EFFECT IN RESPONSE TO ENTERAL FEEDING IN HUMANS

Diarrhoea complicating enteral feeding is a common clinical problem af fecting up to 25% of patients. Its pathogenesis remains unknown. A new technique of human in vivo segmental colonic perfusion was used to in vestigate colonic water and electrolyte movement in response to entera l feeding. Four groups of studies were performed in which low and high load polymeric enteral diet infusions were undertaken, either intraga strically or intraduodenally (n=6 each group). Net absorption of sodiu m, chloride, and water occurred during fasting throughout the colon in all groups. There was a significant net secretion of sodium, chloride , and water in the ascending colon during low load (sodium: -42 mmol/h ; 95% confidence limits -52 to -19, Chloride: -18 mmol/h; -50 to +16, water: -174 ml/h; -348 to -30) and high load (sodium: -24 mmol/h; -60 to +8, chloride: -18 mmol/h; -31 to +16, water: -120 ml/h; -246 to +6) gastric feeding, and during high load duodenal feeding (sodium: -12 m mol/h; -22 to -6, chloride; -6 mmol/h; -16 to +3, water: -72 ml/h; -14 4 to -6). Net secretion persisted in the distal colon only during high load gastric feeding. In the other three groups there was a net absor ption in the distal colon. This study identified a significant colonic secretory response to enteral feeding, which is related to the site a nd load of the diet infusion. This response may play an important part in the pathogenesis of enteral feeding related diarrhoea.