Tu1443 The Optimum Acceptable Swallowing Rate During 2 Hour Basal Esophageal Impedance Measurement for Diagnosis of GERD in Patients With Typical Refluxes Symptoms and No Esophagitis Using a Commercially Available Intraluminal Impedance Monitoring System

Abstract

Previous studies demonstrated that 2 hours esophageal basal impedance measurement is promising diagnostic tool for GERD. Saliva swallowingmay affect basal esophageal impedance and accuracy of the basal esophageal impedance for diagnosis of GERD. To demonstrate whether saliva swallowing rate affect the accuracy of the diagnosis of non-erosive gastroesophageal reflux disease (NERD) using the 2 hour basal esophageal impedance measurement, 61 consecutive patients with typical reflux symptoms and no esophagitis were included. All patients underwent 24 hr esophageal impedance pH monitoring during off treatment using the VersaFlex® Z pH impedance catheter and the Omega® MMS data recording system. Basal impedance levels were mean basal impedance values evaluated at the most distal impedance channels every 5 minute during first 2 hours after catheter insertion. Impedance tracing periods with artifacts from swallows, belching and gastroesophageal refluxes were excluded. Rate of swallows was also evaluated during the same periods. Result : 29 and 32 patients had positive pH test [defined as the % time pH 4.5% (15F,age 50 ±14 yr, BMI 26.4±5.0 kg/m2)] and negative pH test (18F, age 55±13, BMI 23.2±3.6 kg/m2), respectively.The mean basal impedance during the 2hr study period was significant lower in patients with positive vs. negative pH test (1831±452 vs. 3386±883 , p 0.05). The basal impedance levels had a significantly positive correlation with swallowing rate (r=0.46, p 10, 11, 12, 13, 14 and 15 times/hour, the sensitivity, specificity and accuracy for diagnosis of GERD was very high and not significantly different among each swallowing cut point rate. But when the poor impedance tracing was defined as the swallowing rate >16 times/hr, the specificity and accuracy was decreased (see table). Conclusion: This study demonstrated that using swallowing rate < 15 times/hr to define the good impedance tracing quality provides higher sensitivity, specificity and accuracy for diagnosis of GERD compared to using higher swallowing cut point rate. This data provide an insight into the role of control swallowing rate during basal esophageal impedance measurement to diagnosis of GERD.