Methodological factors affecting esophageal clearance

To define some methodological factors that could affect the measurement of the esophageal clearance, we used three different protocols, on 41 healthy control subjects. In 20 subjects, we studied the influence of a naso-esophageal probe on the frequency of swallowing. We observed a significant (44 +/- 5%) decrease in the frequency of spontaneous swallows 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 exponential relationship between the esophageal clearance (C) expressed in minutes and the initial pH of the lumen contents: C = 43.3 exp (-0.54 pH) In 10 other subjects, we studied the influence of the volume of the esophageal contents on esophageal clearance. We found no influence for volumes less than 30 ml and a significant increase of clearance for volumes greater than 30 ml. In summary, this study of the effects of methodological factors on esophageal clearance: Gives new information about the "accommodation phase" of the esophagus after distension by a naso-gastric probe; Allows us to propose a new quantitative method for evaluation of esophageal clearance Shows the small importance of the ingested volume.