Multichannel intraluminal impedance 7 and pH monitoring (pH-MII) in infants and children

The application of combined pH and multichannel intraluminal impedance (pH-MII) monitoring has enhanced the recognition and characterization of gastro-oesophageal reflux disease (GORD). Its main advantages over traditional pH monitoring lie in the additional ability to detect non-acid gastro-oesophageal reflux (GOR), to discern between liquid and gas GOR and to determine the proximal extent of a GOR episode. When conducted in combination with manometry, it reveals information on the relationship between oesophageal pressures and oesophageal bolus flow, enhancing the evaluation of oesophageal function testing in terms of assessment of mechanisms of oesophageal bolus clearance. The measurement of mean impedance baseline has also provided novel insights into oesophageal mucosal integrity changes as an indicator of oesophageal inflammation. However, a few clinical and technical shortcomings, of which some are specific to the paediatric population, must be considered when interpreting study results and limit the diagnostic value of pH-MII monitoring in children. In this chapter, the technical aspects of pH-MII monitoring will therefore first be addressed, and, second, the current clinical benefits and limitations of oesophageal pH-MII in children will be highlighted.