Pharyngeal reflux episodes at pH 5 in healthy volunteers

The clinically used cut-off limit in reflux disease is pH 4. Yet, earlier studies have shown a poor correlation between pharyngeal reflux episodes and symptoms or laryngeal findings, and treatment results have been suboptimal. Moreover, recent data suggest that pepsin is still active at pH 5. The aim of this study was to evaluate the occurrence of pharyngeal pH 5 reflux episodes in healthy controls and to correlate these to the pH monitoring results with a cut-off limit of pH 4.

The results of double-probe 24-h pH monitoring from 35 healthy controls were reanalysed concerning the occurrence of pH decreases to pH 5.

Pharyngeal pH 5 reflux episodes occurred in 32 healthy controls (91%). The median number of pharyngeal reflux episodes at pH 5 was 4.0. The vast majority of these reflux episodes (92%) occurred in the upright position, especially in the postprandial period. The median time pH < 5 in the pharynx was 0.1% while the upper limit of normality was 1.5%. Pharyngeal pH 5 reflux episodes were 5 times more common than pH 4 reflux episodes. There was a significant positive correlation between hypopharyngeal and oesophageal acid exposure time at both pH 4 and 5 (p<0.01).

Pharyngeal pH 5 reflux episodes are present in most healthy adults, mainly in upright position and in the postprandial period. The importance of these episodes for the occurrence of laryngeal symptoms and signs and for treatment response needs to be prospectively assessed.