Relationships between cecoileal reflux and ileal motor patterns in conscious pigs

Abstract

Ileal infusion of cecocolonic contents, used to mimick reflux, enhanced terminal ileal motility, increasing the frequencies of prolonged propagated contractions (PPC) and discrete clustered contractions (DCC). Because the reflux rate in dogs and humans is marginal, the relationship of these motor patterns to reflux remained putative. In six conscious pigs, the ileal pH, used to indicate reflux event, was measured 10 and 5 cm proximal to the ileocecal sphincter (ICS). Ileal motility was evaluated with three strain gauges 15, 10, and 5 cm proximal to the ICS. Ileal pH dips were observed about eight times per hour in the fasting or fed state, and 46% of the pH dips were preceded by a retrograde contraction. During pH dips, frequency of ileal contractions not classified as PPC or DCC was significantly increased. Of the PPC 52% occurred immediately after the start of the dip and might act as a clearance mechanism because dips associated with PPC were of smaller amplitude and duration than those not associated with PPC. Most DCC also occurred during pH dips but their delay to the onset of the dip was longer. The pig presents frequent cecoileal reflux events associated with ileal motor patterns, some of them might facilitate reflux, whereas others act as a clearance mechanism.