Objective: To explore the diagnostic characteristics of 24 hours multichannel intraluminal impedance-pH (MII-pH) monitoring in patients with laryngopharyngeal reflux (LPR).
Methods: Patients who were suspected to have laryngopharyngeal reflux (LRP) between February and December 2014 were included. The frequency of pH < 4 waveform, artifacts, numbers of acid reflux events, weakly acidic reflux events, weakly alkaline reflux events, time of acid exposure, time of acid clearance, acid reflux events in upright position and supine position, reflux symptom index(RSI) and reflux findings score (RFS) were analyzed.
Results: Forty-five times pH < 4 reflux waveform were identified according to software analysis.140 pH drops of 4 were observed according to manual analysis, in which 78 times were caused by reflux and 62 artifacts. The consistency of manual analysis and software automatically analysis was general (κ = 0.234). The positive rate of 60 patients was 28.3% (17/60). In the 17 LPR patients, the median number [P25, P75] of acid reflux events was 5.0 [4.0, 8.8], weakly acidic reflux events was 6.5 [5.3, 10.3], weakly alkaline reflux events was 1.0 [0.0, 2.0], time of acid exposure was 3.8 [2.3, 7.2] min, time of acid clearance was 36.0 [21.5, 57.6] s, acid reflux events in upright position was 4.0[3.0, 4.8] and in supine position was 1.5 [0.0, 2.3]. All the data were approximately identical with the domestic and foreign literature. 24 hours MII-pH monitoring and RSI + RFS had medium consistency (κ = 0.590).
Conclusions: 24 hours MII-pH monitoring has ideal repeatability, but false positive and false negative can not be avoided completely. The diagnosis of laryngopharyngeal reflux should be combined with medical history and laryngoscopy.