Gastrointestinal sounds and migrating motor complex in fasted humans

Objective: We investigated the relationships among gastrointestinal sounds, gastrointestinal manometric findings, and small intestinal transit time in healthy fasted humans. Methods: Gastrointestinal sounds acquired with two microphones attached to the upper and lower abdominal walls of healthy subj ects were quantified with a computer-aided sound analysis program. Antroduo denal contractions were recorded by manometry. Small intestinal transit tim e was measured by breath hydrogen testing after intraduodenal administratio n of lactulose. Results: The sum of the gastrointestinal sound amplitudes ( sound index) in both the upper and lower abdomen changed with time, coincid ing with the gastric phases of the migrating motor complex. The sound indic es in the upper and lower abdomen were 59.0 +/- 24.8 and 98.1 +/- 21.6 mV/m in in phase 1, 95.5 +/- 27.9 and 127.4 +/- 34.9 mV/min in phase 2, and 132. 8 +/- 12.4 and 188.5 +/- 73.4 mV/min in phase 3, respectively. There were n o significant differences among motility phases in terms of the mean durati on or frequency of each sound event. Intravenous erythromycin induced phase 3 in the stomach and doubled the sound index. Somatostatin analogue induce d phase-3-like clustered contractions in the duodenum, but inhibited antral contractions and decreased the sound index. The small intestinal transit t ime was shorter and the sound index increased after intravenous metoclopram ide, compared with controls. Scopolamine delayed small intestinal transit t ime and decreased the sound index. Conclusions: This study is the first to document the relationships between gastrointestinal sounds and the migratin g motor complex. The chronological relation between antral motility and gas trointestinal sounds, and the dissimilar effects of erythromycin and somato statin, suggest that antral contractions increase gastrointestinal sounds, perhaps by supplying gas into the intestine. (Am J Gastroenterol 1999;94:37 4-381, (C) 1999 by Am. Cell. of Gastroenterology).