Shoenut J Patrick B.Sc.; Micflikier, Allan B. M.D.; Yaffe, Clifford S. M.D.; Den Boer, Barbara R.N.; Teskey, John M. M.D.Journal of Clinical Gastroenterology: January 1995 Clinical Studies: PDF Only Buy Abstract We made a prospective assessment of acid exposure in the distal esophagus in 48 consecutive untreated patients with achalasia using 24-h ambulatory esophageal pH studies. The majority of patients (38/48) experienced reflux that was within reported values for normal controls (total time pH<4.0, 1.8 ±1.9%). Approximately 20% (10/48), however, demonstrated abnormal acid exposure (total time pH<4.0, 18.8 ± 14.8%). The difference in reflux expressed by these two groups was not due to a significant difference in lower esophageal sphincter pressure (p>0.05) or retained food. An in vitro model of lactobacillus fermentation supported the contention that true acid reflux accounted for changes in esophageal pH. Repeat pH studies were obtained in 23 patients following treatment: 15 underwent pneumatic dilatation and 8 underwent limited myotomy. Although no significant differences were found between pre- and posttreatment reflux, some patients undergoing either treatment were found to demonstrate increased acid exposure. In conclusion, we believe that patients with achalasia should be tested by pH study both before and after treatment. Most of the patients who demonstrated significant pretreatment reflux were asymptomatic, and both methods that were used to decrease resting sphincter pressure were shown to be able to increase distal acid exposure. © Lippincott-Raven Publishers.