Design and implementation of an ambulatory pH monitoring protocol in patients with suspected laryngopharyngeal reflux

OBJECTIVE/HYPOTHESIS: Adding a hypopharyngeal sensor to esophageal pH monitoring has been advocated for laryngopharyngeal reflux (LPR). However, selecting the proper pH catheter is problematic because esophageal lengths are variable among individuals. OBJECTIVE: To design and implement a new pH monitoring protocol for LPR. STUDY DESIGN/METHODS: Design parameters were defined prospectively: single-probe, triple-sensor pH catheter with sensors located in the hypopharynx (1-3 cm above upper esophageal sphincter) and in proximal and distal esophagus (20 cm and 5 cm above lower esophageal sphincter, respectively). Esophageal lengths were determined in a study population undergoing esophageal manometry. Optimal pH sensor spacings were determined using the least number of catheters to satisfy the design parameters. The protocol was implemented in consecutive subjects with suspected LPR. RESULTS: Distribution of esophageal lengths was determined in 1,043 subjects. In 92% of the study population, three pH catheters (3-15, 6-15, and 9-15 sensor-spacings) would satisfy the design criteria. Forty-one subjects with suspected LPR underwent the pH protocol. An abnormal pH test was found in 40 subjects (98%) with triple-sensor combination compared with 29 subjects (71%) if only dual esophageal sensors were used. CONCLUSIONS: Single-probe pH monitoring of the hypopharynx and esophagus was feasible. Adding a hypopharyngeal pH sensor increased the detection of abnormal acid reflux more often than traditional dual-sensor esophageal pH monitoring.