Measurement of Esophageal Nocturnal Baseline Impedance: A Simplified Method
Yoshimasa Hoshikawa, Akinari Sawada, Shirley Sonmez, Kornilia Nikaki, Philip Woodland, Etsuro Yazaki, Daniel Sifrim
Abstract
BACKGROUND/AIMS: Mean nocturnal baseline impedance (MNBI) during multichannel intraluminal impedance pH-monitoring (MII-pH) reflects the status of esophageal mucosal integrity. MNBI is suggested as an adjunctive method to distinguish patients with true gastroesophageal reflux disease (GERD) from functional heartburn (FH) and might predict outcomes for anti-reflux treatment. However, current methodology for calculation of MNBI is time-consuming and subject to operator-dependent selection bias. We aim to simplify and provide a more objective method to calculate MNBI. METHODS: We retrospectively analyzed 100 MII-pH tracings from 20 patients with erosive reflux disease, 20 with non-erosive reflux disease (NERD), 20 with reflux hypersensitivity, 20 with functional heartburn (FH), and 20 healthy asymptomatic volunteers. We compared the current "conventional" MNBI analysis with our "simple" MNBI analysis measured by selecting the whole supine period using the impedance average calculation function in the MII-pH software. RESULTS: < 0.001). With a cutoff value of 1785 ohms, simple MNBI can discriminate patients with GERD from those with reflux hypersensitivity and FH (sensitivity 80.0% and specificity 89.7%). CONCLUSION: Simple MNBI analysis provides very similar values and has an excellent correlation with conventional MNBI analysis.