276 Gastroesophageal Reflux Disease in Infant: Relationship Between Multichannel Intraluminal Impedanceph Monitoring and Clinical Outcome

Background and aims: combined multichannel intraluminal impedance and pH-monitoring (MII/pH) is a new technique identifying refluxes irrespective of acidity and detecting their duration, proximal extent and pH. These features are important when studying gastroesophageal-reflux-disease (GERD) in infants, in which weakly acid refluxes are prevalent. Clinical application of MII/pH is uncommon yet, owing to lack of reference values and difficult interpretation of the variables obtained. Aim of the present study was to investigate the relationship between MII-pH results and clinical outcome on a sample of GERD infants. Methods: infants (age: 0-3 months) with GERD symptoms were studied with MII/pH and submitted to a follow-up consisting in clinical examinations and structured interviews to parents at 3-6-9-12-18-24-36 months to evaluate the presence of symptoms and the therapy effects. Results: 54 patients completed the follow-up (32M; age 33.69±21.78 days; weight 3465.13±791.08 gr.; length 52.08±3.55 cm). 22 and 15 patients were still symptomatic at the age of 6 and 9 months, without difference in MII/pH values between symptomatic and non symptomatic infants. The 12 infants that were still symptomatic at the age of 12 months showed a higher bolus exposure index (BEI) with respect to the healed patients (2.63±1.72% vs 1.72±1.05; p=0.029). Conclusions: MII-pH in first months of life could be useful to identify patients with high risk of presenting GER symptoms for more than 1 year. BEI is a pH independent variable with a significant relationship with symptoms duration. Our data highlight the clinical relevance of MII/pH-detected weakly acidic refluxes in GERD infant.