Mechanisms of gastroesophageal reflux in children.

We studied the lower esophageal sphincter in 29 children with known or suspected gastroesophageal reflux using a sleeve sensor and micro pH electrode. Mean lower esophageal sphincter pressure for a ten-minute monitoring period was 19 +/- 13 mm Hg; however, considerable temporal variation occurred in each child. Gastroesophageal reflex was infrequently associated with a low basal sphincter pressure (< 5 mm Hg) but usually associated with an increase in intra-abdominal pressure or with transient inappropriate relaxation of the lower esophageal sphincter.