Value of esophageal impedance monitoring in clinical diagnostics

Introduction: pH-monitoring is the standard diagnostic tool for proving acid regurgitation in gastroesophageal reflux disease (GERD) patients. Multichannel intraluminal impedance (MII) is a new technique for the evaluation of non-acid, volume, liquid or gas reflux, regardless of its acidic content, or combined with pH-metry (pH-MII). Impedance measurement is used to show the bolus transit in the esopahgus (without X-ray). Aims, methods and result: Diagnostic and therapeutic values of pH-MII method were investigated in 2 (F) patients suffering from non-erosive form of GERD (NERD), with atypical extraesophageal symptoms, and resistant to previous adequate proton-pump inhibitor (PPI) therapy. Single channel pH-metry (Digitrapper Deta 4 instrument) was performed in all cases both, before and after PPI-therapy. The diagnosis of GERD was confirmed with the result of pH-metry (before the treatment). Clinical symptoms were not significantly reduced by adequate PPI treatment. The repeated pH-metry (during standard PPI-therapy) did not show pH values over 4.0. Esophageal impedance was measured by Sleuth GER Monitoring Recorder, using ZAN-S61CO1E Single use multichannel (6+1) impedance – pH probe. Non-acidic reflux was confirmed in both cases in the background of clinical symptoms. The symptom index was positive in all cases. Two characteristic case reports will be presented in details. Conclusion: Esophageal impedance monitoring is a very sophisticated diagnostic method, which can detect reflux with a pH above 4 (weakly acid reflux or non-acid reflux), is reserved for clinically complicated cases approving the indication of antireflux surgery. Up until now more than 32 patients were investigated this way, and our general estimation is that MII must not be included into the routine esophageal diagnostic procedure, but it might be mandatory in cases with unexplainable PPI treatment resistance.