The pathophysiology of gastric electrical activity and emptying.

A good understanding of upper gastrointestinal physiology is required to properly understand the pathophysiological events in various diseases or after operations on the upper gastrointestinal tract. It is evident that the electrical activity in infancy does not have the orderly pattern of that in adults and that severe disorder of this activity may produce abnormalities of gastric emptying. Surgical procedures on the gastrointestinal tract can cause alterations in the electrical and motility patterns of the stomach. The influence of various surgical manoeuvres on upper gastrointestinal motility indicates that the mere destruction of the pylorus does not in itself produce a gross distortion of the emptying of liquids or solids from the stomach, but that only when a vagotomy or antrectomy is added, do we find rapid gastric emptying of liquids and incontinence of solids. The effect of this, coupled with rapid small bowel transit, may be responsible for the nutritional disturbances sometimes seen after vagotomy or gastrectomy. These phenomena may partly account for some of the symptoms of the dumping syndrome. The gastric incontinence seen after distal gastrectomy can be corrected by the interposition of jejunal loops, but the direction of peristalsis within these loops is immaterial in that both iso- and retro-peristaltic loops are able to correct the disordered emptying pattern. Clinicians should not take for granted that which might seem obvious after gastric surgical procedures without careful testing and evaluation both in experimental animals and where possible in man. Failing this, incorrect clinical and therapeutic decisions might be taken.