The role of baseline impedance as a marker of mucosal integrity in children with gastro esophageal reflux disease

Objectives. Diagnosis of gastro esophageal reflux disease (GERD) in children is challenging. 24-h-pH-multichannel-intraluminal-impedance measurement (pH-MII) is the best diagnostic tool to display gastro esophageal reflux whereas esophageal endoscopy indicates mucosal lesions. The aim of this study was to compare esophageal endoscopy results with reflux parameters such as acid exposure time (reflux index RI), bolus exposure time (bolus index BI), baseline impedance level (BIL) detected by pH-MII in children with suspected GERD. Methods. Analysis of data from 285 children (38 infants) referred to our hospital with suspected GERD. Division into three 'reflux esophagitis' (RE)-stages depending on the severity of endoscopic and histological findings and comparison with reflux parameters in these stages. Further categorization into four groups based on the pH-MII-results. Results. Children with high-grade esophagitis had a significantly lower BIL; otherwise there was no significant association between elevated reflux parameters and esophagitis. Pathological pH-MII results (RI and BI) were associated with lower BIL in the distal impedance channel. The BIL was significantly lower in infants compared to children >1 year regardless of the RI or BI. The main difference between these groups regarding reflux parameters was a longer BI and a higher number of retrograde bolus movements. Conclusion. Pathologic pH-MII results are not predictive for an erosive esophagitis and vice versa. Therefore, these two procedures cannot replace each other. A lower BIL is associated with esophagitis >= LA-grade B and may be caused by longer acid but also by longer bolus exposure and thus may be another useful parameter in GERD monitoring.