Background and aims The mechanism underlying symptoms in gastroesophageal reflux disease remain to be fully elucidated. Weakly acid reflux and the presence of gas in the refluxing could be relevant in the pathogenesis of symptoms. We aimed to evaluate the role of gas reflux in children evaluated with pH-metry associated with multichannel intraluminal impedance (MII-pH) and analyse there clinical and therapeutical implications.

Methods We performed a retrospective study. We examined all our recording of patients referred for suspected gastroesophageal reflux disease evaluated with MII-pH and selected the registrations with pathological gas reflux. The limit value for pathological gas reflux was 72.

Results Thirty two children (18 male) were selected for the study, according to protocol, aged between 4 months and 16 years (average age was 3 years and 5 months). Predisposing conditions for gaseous reflux were identified in 24 children: 20 children were diagnosed with alimentary allergies (17 non IgE mediated) and four children with small intestinal bacterial overgrowth detected by determining the level of expired hydrogen, after glucose ingestion. 11 patients were treated with proton pump inhibitors for acid RGE.

Conclusions Combining impedance and pH monitoring improves the detection and characterisation of GER. The majority of children with gaseous reflux were allergic (62.5%), 6.25% of them suffered from constipation. For 31,25% we have not found predisposing conditions causes.