Standard protocol devised by the Japanese Pediatric Impedance Working Group for combined multichannel intraluminal impedance-pH measurements in children

Multichannel intraluminal impedance-pH measurements (MII-pH) are useful for evaluating acid and non-acid gastroesophageal reflux (GER). However, the use of MIH-pH is not yet established in Japan. The Japanese Pediatric Impedance Working Group (Japanese-PIG) convened to devise a standard protocol for MII-pH in Japanese children. The expert members of the Japanese-PIG collected data on pediatric MII-pH from the relevant literature in English, including the standard protocol of MII-pH presented by the European PIG, and the insights of international experts. The resultant consensus was included in the contents of the standard protocol of MII-pH. The standard protocol included standardization of the indication, methodology, and interpretation of MII-pH in Japanese children. The criteria for abnormal GER by MII-pH were defined using the Reflux Index and number of total reflux episodes independently in children aged < 1 year and those aged ≥ 1 year. Moreover, a significant relationship between GER and symptoms was identified using the symptom index and symptom association probability approach. We conclude that the current version of the protocol for MII-pH is tentative because it is not based on data from Japanese children. Further studies are needed to render this protocol clinically beneficial and expand its use in Japan.