Effect of different recumbent positions on postprandial gastroesophageal reflux in normal subjects

OBJECTIVE: Gastroesophageal reflux (GER) is increased in the right compared to the left recumbent position. Esophageal acid exposure is related to the acidity at the cardia, but the effect of body position on the acidity at t he cardia has not yet been investigated. We aimed to investigate the mechan isms underlying increased esophageal acid exposure in the right recumbent p osition. METHODS: On 2 separate days a 4-h combined esophageal and lower esophageal sphincter (LES) manometry and pH recording of esophagus, gastric cardia, an d corpus was performed in the right and left recumbent position after a hig h fat meal in 10 healthy subjects. RESULTS: In the right recumbent position a prolonged esophageal acid exposu re (7.0% vs 2.0%, p < 0.03), a higher incidence of reflux episodes (3.8 vs 0.9/h, p < 0.03), more transient LES relaxations (TLESRs) (6.5 vs 3.2/h, p < 0.03), and higher percentage TLESRs associated with reflux (57.0% vs 22.4 % p < 0.03) was recorded than in the left supine position. Acidity at gastr ic cardia and corpus was not affected by body position. CONCLUSIONS: Increased esophageal acid exposure in the right recumbent posi tion relative to the left recumbent position is the result of a higher inci dence of GER episodes caused by an increased incidence of TLESRs and higher percentage of TLESRs associated with GER. Body position does not affect th e acidity at the gastric cardia and corpus. (Am J Gastroenterol 2000;95:273 1-2736. (C) 2000 by Am. Coll. of Gastroenterology).