Comparison of an Oropharyngeal pH Probe and a Standard Dual pH Probe for Diagnosis of Laryngopharyngeal Reflux

Abstract

We compared the ability of an oropharyngeal (OP) aerosol-detecting pH probe and a standard dual pH probe in measuring laryngopharyngeal reflux (LPR). Fifteen subjects with LPR symptoms had 24-hour simultaneous placement of the OP probe and a standard dual pH probe. Acid exposure was defined as a 10% pH decrease below baseline for the OP probe or a pH of less than 4 at the upper esophageal sphincter (UES) probe of the dual pH probe. The mean duration of acid exposure was 650 seconds (SD, 619) or 0.75% of the total time for the OP probe and 438 seconds (SD, 511) or 0.51% of the total time for the UES probe. When we excluded meals and sleep, the mean duration of acid exposure was 271 seconds (SD, 356) or 0.31% of the total time for the OP probe and 271 seconds (SD, 359) or 0.31% of the total time for the UES probe. The correlation coefficient (R) between the two probes for measurement of the duration of acid exposure was 0.50 (p < 0.05). When we excluded meals and the supine position, the R was notably higher, at 0.95 (p < 0.0001). The OP probe reliably documented LPR events when meals and sleep were eliminated and was better tolerated than the standard dual probe.