Effect of Esophageal Emptying and Saliva on Clearance of Acid from the Esophagus

• Published in: The New England journal of medicine Vol. 310; no. 5; pp. 284 - 288
• Main Authors: Helm, James F, Dodds, Wylie J, Pelc, Lorie R, Palmer, David W, Hogan, Walter J, Teeter, Bruce C
• Format: Journal Article
• Language: English
• Published: Boston, MA Massachusetts Medical Society 02.02.1984
• Subjects: Accuracy; Acids - metabolism; Adult; Biological and medical sciences; Deglutition; Electrodes; Esophagus; Esophagus - diagnostic imaging; Esophagus - metabolism; Esophagus - physiology; Female; Fundamental and applied biological sciences. Psychology; Gastroenterology; Gastroesophageal reflux; Humans; Hydrochloric Acid; Hydrogen-Ion Concentration; Male; Manometry; Mouth. Exocrine and endocrine salivary glands. Teeth. Esophagus; Peristalsis; pH effects; Radionuclide Imaging; Saliva; Saliva - physiology; Sulfur; Technetium; Vertebrates: digestive system; Human; Acids; Digestive system; Muscle contraction; Saliva; Esophagus
• ISSN: 0028-4793; 1533-4406
• DOI: 10.1056/NEJM198402023100503

We studied clearance of acid from the esophagus and esophageal emptying in normal subjects. A 15-ml bolus of 0.1 N hydrochloric acid (pH 1.2) Radio-labeled with [ 99m Tc]sulfur colloid was injected into the esophagus, and the subject swallowed every 30 seconds. Concurrent manometry and radionuclide imaging showed nearly complete emptying of acid from the esophagus by an immediate secondary peristaltic sequence, although esophageal pH did not rise until the first swallow 30 seconds later. Esophageal pH then returned to normal by a series of step increases, each associated with a swallow-induced peristaltic sequence. Saliva stimulation by an oral lozenge shortened the time required for acid clearance, whereas aspiration of saliva from the mouth abolished acid clearance. Saliva stimulation or aspiration did not affect the virtually complete emptying of acid volume by the initial peristaltic sequence. We conclude that esophageal acid clearance normally occurs as a two-step process: (1) Virtually all acid volume is emptied from the esophagus by one or two peristaltic sequences, leaving a minimal residual amount that sustains a low pH, and (2) residual acid is neutralized by swallowed saliva. (N Engl J Med 1984; 310:284–8.) GASTROESOPHAGEAL reflux occurs commonly in asymptomatic subjects as well as in patients with reflux esophagitis. 1 After acid reflux, clearance of acid from the esophagus is an important defense against the development of esophagitis. 2 Esophageal acid clearance is the restoration of a normal intraluminal pH after acid reflux. A common notion ascribes such clearance to emptying of refluxed acid from the esophagus by peristalsis. 3 , 4 Recent findings, however, indicate that acid neutralization by swallowed saliva is responsible for the series of step increases in esophageal pH that occur during acid clearance. 5 The purpose of this study was to evaluate the role of . . .