Changes in small bowel myoelectrical activity following laparotomy.

Recordings of the myoelectrical activity have been obtained from the small intestine of 4 dogs by means of serosally implanted electrodes. The occurrence of the activity front (phase III) of the migrating myoelectrical cycle (MMC) in the recordings obtained each day after abdominal surgery have been compared. No activity fronts were seen on postoperative days 1 and 2. From days 3 to 6 there was a slightly reduced incidence, but from day 7 onwards an activity front was observed in each recording. It is concluded that the normal pattern of cyclic myoelectrical activity in the small intestine is disrupted for at least 2 days following a laparotomy, and the view that small bowel motility returns to normal soon after routine abdominal surgery may be inaccurate.