SENSITIZATION OF ESOPHAGEAL MUCOSA BY PRIOR ACID INFUSION - EFFECT OFDECREASING INTERVALS BETWEEN INFUSIONS

Objective: To determine the effect of decreasing time intervals betwee n acid exposures on the sensitivity of the esophageal mucosa. Methods: Ten healthy subjects with no history of gastroesophageal reflux disea se who were symptomatic during a modified Bernstein acid infusion test were recruited for the study. Hydrochloric acid solutions of pH 3, 2, and 1 were sequentially tested. The weakest pH solution that was perc eived by the patient was used for the study. The same duration of acid infusions (9 ml/min for 5 min) were made but with decreasing time int ervals between each subsequent acid infusion (30-0 min). Esophageal se nsation during each of the infusions, the amount of distilled water re quired to raise intraesophageal pH > 4, and the duration of residual h eartburn after pH > 4 were recorded. Results: Seven of the 10 subjects (70%) were Bernstein-positive to pH 3, two to pH 2, and only one to p H 1 solution. The median time to initial heartburn was significantly r educed only between the initial infusion and the first subsequent acid exposure 30 min later (165 vs 51.5 s, p < 0.009). Subsequent reductio ns in the time interval between infusions did not significantly reduce the perception threshold. The water required to clear the esophagus t o pH > 4 and time required for the residual esophageal sensation to di sappear were not significantly altered throughout the study. Conclusio ns: These data suggest that some episodes of reflux may be felt sooner and perhaps more severely despite similar levels of acid burden in th e esophagus when sensitization by a prior reflux episode occurs.