First Direct Comparison of Pharyngeal pH Monitoring With Combined pH/Impedance Monitoring in Patients With Suspected Laryngopharyngeal Reflux

Abstract

Background The origin of laryngopharyngeal reflux (LPR) is unclear. It might be caused by pharyngeal acid exposure and it is thought to be associated with Gastroesophageal Reflux Disease (GERD). To objectify atypical symptoms of GERD currently the combination of pHmetry and impedance monitoring (pH/MII) seems to be the most sensitive method. However, a recently developed method using a pH measurement system probe which is placed in the oropharynx without passing the upper sphincter of the esophagus (Dx-pH Catheter, Restech, San Diego, USA) allows to measure pH values in the aerosolized environment of the nasopharynx. The aim of this study was primarily to measure the reproducibility of the new DxpH device and secondly to compare it with pH/MII in patients with suspected LPR for the first time. Methods In a total of 20 patients with oropharyngeal symptoms suspicious for an atypical GERD Proton Pump Inhibitors were stopped for at least 7 days. All patients were examined by using a reflux finding score (RFS). Thereafter pH/MII and a pharyngeal ph monitoring were applied simultaneously. After removal of the 2 probes the next day a single DxpH-measurement was performed. All functional tests lasted for at least 22 hours. pH/MII was regarded as pathological if pH dropped below 4 inmore than >4% of the recorded time and/or >73 mixed reflux episodes occurred. DxpH-measurement was pathological if the Ryan Score was <9.4 in an upright position or <6.8 in a supine position. Patients and results All patients had pathological findings in RFS. The results of the 1st DxpH-measurement were verified in the following pharyngeal pH-metry in 14/20 (70%) patients. Hence, at 2 consecutive days, pharyngeal measurement had a good concordance in the same patient. However, 11/20 (55%) patients had pathological values derived from DxpH, whereas pH/ MII showed pathological findings in only 5/20 (20%) patients. Overall only 6/20 (30%) results matched with findings in pH/MII. Conclusion DxpH-measurement showed satisfying reproducibility on two consecutive days. However, the pathological results of pharyngeal ph monitoring acquired in this case series were not connected to pathological reflux episodes of GERD in most cases. Potentially, other acid producing or acid retaining factors despite from GERD are accountable for atypical reflux symptoms. This should be subject of further studies.