Esophagopharyngeal acid regurgitation: Dual pH monitoring criteria for its detection and insights into mechanisms

Background & Aims: A valid technique for the detection of esophagopharyngeal acid regurgitation would be valuable to evaluate suspected reflux-related otolaryngologic and respiratory disorders. The aim of this study was to derive pH criteria that optimally define esophagopharyngeal acid regurgitation and to examine patterns of regurgitation. Methods: In 19 healthy controls and 15 patients with suspected regurgitation, dual or quadruple pH sensors were used to monitor pharyngeal and esophageal pH. For each combination of the 2 variables, Delta pH and nadir pH, proportions of pH decreases that occurred during or independent of esophageal acidification were calculated to determine the likelihood that an individual pharyngeal pH decrease was a candidate regurgitation event or a definite artifact. Results: Overall, 92% of pharyngeal pH decreases of 1-2 pH units and 66% of pH decreases of this magnitude reaching a nadir pH of <4 were artifactual. Optimal criteria defining a pharyngeal acid regurgitation event were a pH decrease that occurred during esophageal acidification, had a Delta pH of >2 units, and reached a nadir of <4 units in less than 30 seconds. Regurgitation occurred move frequently in subjects in an upright (32 of 35) than in a supine (3 of 35 events; P less than or equal to 0.0001) position and was more frequently abrupt (synchronous with esophageal acidification) than delayed (P less than or equal to 0.05). Conclusions: Accepted criteria for gastroesophageal reflux are not applicable to the detection of esophagopharyngeal acid regurgitation, and most regurgitation occurs abruptly and in upright position.