The proximal probe in esophageal pH monitoring: Development of a normative database

Abstract

Healthy volunteers without symptoms of either gastroesophageal reflux or laryngopharyngeal reflux and without abnormalities on laryngologic examination were recruited for esophageal pH monitoring. Thirty subjects underwent ambulatory 24-hour double-channel pH probe monitoring to establish normative data for the upper probe, which was positioned just above the upper esophageal sphincter. Data were analyzed excluding meal periods plus 2 minutes of postprandial time. The mean, standard deviation, median, and 95th percentile were calculated for various reflux parameters for the following intervals: total study duration, upright time, supine time, and postprandial time. Normal subjects display physiologic reflux above the upper esophageal sphincter (median one event, 95th percentile 6.9 events), and 80.4% of these events occur in the upright position. The reflux area index (RAI) appears to be the most useful parameter to measure laryngopharyngeal reflux severity.