Continuous versus intermittent acid exposure in production of esophagitis in feline model

Our morphometric feline model of acid-induced esophageal damage histologically resembles human reflux esophagitis. The histologic scoring system includes intensity and linear extent of basal cell hyperplasia, intraepithelial and subepithelial segmented leukocytes, and ulcers. Each of these four categories is scored from 0 to 4, for a potential total score of 16. Some reports have indicated that the long-duration acid exposure episodes during recumbent nighttime reflux are apt to be associated with greater injury than shorter episodes during daytime upright exposure. We tested the hypothesis that longer single exposures to acid would incite greater morphologic damage in the cat than would multiple, shorter acid exposures. To study the influence of continuous versus intermittent hydrochloric acid exposure, groups of six cats each were infused continuously (single infusion) for 15, 20, or 30 min, and compared with cats infused for 2-min acid infusion times. Our studies indicate that total acid exposure and mucosal damage are more likely to be greater after multiple episodes of the same total duration with adequate clearing (ie, awake upright reflux) than after single long episodes of acid exposure that are poorly cleared (ie, sleeping).