Reflux Characteristics Detected by 24-Hour Esophageal pH-Impedance Monitoring in GERD Patients Presenting with Chronic Cough

Background:When combined with 24-hour esophageal pH monitoring,intraluminal impedance technique can detect various types of gastroesophageal reflux events and determine the physical and pH properties of the refluxate.Aims:To study the reflux characteristics of gastroesophageal reflux disease(GERD) patients presenting with chronic cough by 24-hour esophageal pH-impedance monitoring.Methods:Seventy-three consecutive chronic cough patients with normal chest radiography and without typical gastroesophageal reflux symptoms were enrolled.Among them,those with normal endoscopic findings and fulfilling the GERD criteria by pH-impedance monitoring were defined as GERD-chronic cough group.Twenty-one healthy volunteers were recruited as normal controls.The parameters of pH-impedance monitoring were compared between the two groups.Results:Using pH monitoring only,17 patients were diagnosed as GERD;however,26 patients were diagnosed as GERD when pH-impedance monitoring was used.The GERD-chronic cough group was characterized by gas/liquid mixed reflux(46.3%) and weakly acidic reflux(59.9%),while normal control group was characterized by gas reflux (68.9%) and weakly acidic reflux(59.1%).Parameters including DeMeester score and episodes of gas reflux,acid reflux and proximal reflux etc.were significantly different between the two groups(P0.05).Conclusions:Gas/liquid mixed reflux and weakly acidic reflux are predominant in GERD patients presenting with chronic cough.Pathological refluxes are commonly seen in both upright and supine positions,and proximal reflux is more frequent than that in healthy adult.24-hour esophageal pH-impedance monitoring is of important diagnostic value in chronic cough patients with suspected GERD.