METHODOLOGICAL FACTORS AFFECTING ESOPHAGEAL CLEARANCE

To define some methodological factors that could affect the measuremen t of the esophageal clearance, we used three different protocols, on 4 1 healthy control subjects. In 20 subjects, we studied the influence o f a naso-esophageal probe on the frequency of swallowing. We observed a significant (44 +/- 5%) decrease in the frequency of spontaneous swa llows after 15 minutes, with stabilization after this 15 minute period of adaptation. In 11 subjects, we studied the influence of the pH of the esophageal content on esophageal clearance. We found an exponentia l relationship between the esophageal clearance (C) expressed in minut es and the initial pH of the lumen contents: C = 43.3 exp (-0.54 pH) I n 10 other subjects, we studied the influence of the volume of the eso phageal contents on esophageal clearance. We found no influence for vo lumes less than 30 ml and a significant increase of clearance for volu mes greater than 30 mi.In summary, this study of the effects of method ological factors on esophageal clearance: Gives new information about the ''accommodation phase'' of the esophagus after distension by a nas o-gastric probe; Allows us to propose a new quantitative method for ev aluation of esophageal clearance Shows the small importance of the ing ested volume.