Esophageal emptying and acid neutralization in patients with symptoms of esophageal reflux.

Clearance of refluxed acid from the distal esophagus is due to bolus emptying and salivary neutralization of acid. We compared results of 24-hour pH monitoring with acid clearance tests (ACT) and radioisotope swallows (RIS) in 26 symptomatic patients to determine which of the components of acid clearance is better correlated with gastroesophageal acid reflux (GER). Seven of eight patients with GER had delayed esophageal emptying on RIS. Abnormal salivary clearance of acid was present in nine of 18 patients without GER, accounting for a high false-positive rate of ACT. Delayed esophageal bolus emptying, not deficient acid neutralization by saliva, is the predominant component of abnormal acid clearance in patients with GER. RIS is superior to ACT as part of the evaluation of reflux symptoms, and may prove to be a valuable screening test for this condition.