SPATIOTEMPORAL CHARACTERISTICS OF PHYSIOLOGICAL GASTROESOPHAGEAL REFLUX

Spatiotemporal characteristics of physiological gastroesophageal reflu x. Am. J. Physiol. 266 (Gastrointest. Liver physiol. 29): G357-G362, 1 994. - Recent technological developments have made it possible to meas ure intraluminal pH simultaneously at multiple sites using one single small-caliber catheter. The aim of this study was to investigate the d ynamics of physiological gastroesophageal reflux in eight ambulatory h ealthy volunteers (age 21-51 yr). Esophageal pH was recorded for 24 h at 3, 6, 9, 12, and 15 cm from the lower esophageal sphincter (LES), u sing an 8-Fr catheter containing five ion-sensitive field effect trans istor (ISFET) pH transducers and a digital data logger. Signals were s ampled at a rate of 4 Hz. Automated analysis included determination of the extent of the reflux (cm above LES) and calculation of the veloci ty of the advance of the pH front from the LES (ascending velocity), m inimum pH reached, and duration of all individual reflux episodes at d ifferent segments in the esophagus. The reflux time and the number of reflux episodes/24 h showed a gradual decrease from the distal to the proximal sensor (mean +/- SE:4.4 +/- 0.8 to 0.9 +/- 0.2% and 46 +/- 7. 6 to 11 +/- 1.9, respectively). Of all reflux episodes 23% did not rea ch the sensor at 6 cm above the LES, and only 25% reached the most pro ximal sensor. Characteristically, acid refluxed rapidly (velocity 0.4- 2.4 cm/s) and was cleared in a stepwise fashion. Reflux episodes of lo ng duration at the distal sensor reached high levels in the esophagus (P < 0.001). It was concluded that ambulatory multichannel esophageal pH monitoring using ISFET technology is a valuable tool for studies on the spatiotemporal characteristics of gastroesophageal reflux.