Transient inflammation and dysfunction of the eustachian tube secondary tomultiple exposures of simulated gastroesophageal refluxant

Gastroesophageal reflux is a common problem in the newborn and preschool pe riods. Recent research suggests that it may be related to eustachian tube d ysfunction and otitis media with effusion. The purpose of this experiment w as to investigate the relationship between simulated gastroesophageal reflu x and eustachian tube dysfunction. Rat middle ears were repeatedly exposed (trans tympan ic ally) to pepsin in hydrochloric acid or to phosphate-buffe red saline solution. Their eustachian tube function was evaluated by assess ing passive opening and passive closing pressures, and active clearance of positive and negative pressure. The passive pressure function tests showed variable results. The rats exposed to pepsin in hydrochloric acid had an im paired ability to clear positive and negative pressure from the middle ear as compared to the rats exposed only to phosphate-buffered saline solution. The results demonstrate that multiple middle ear exposures to pepsin in hy drochloric acid leads to eustachian tube dysfunction in rats.