A Validation Study of the Dx-pH Probe in Children for the Detection of Extra-oesophageal Reflux

Inclusion Criteria: * All children between the age of 1 year old and 16 years old consecutively referred for outpatient 24 hour oesophageal pH / impedance monitoring will be invited to participate in the study. This is regardless of the underlying diagnosis, aetiology and manifestation of symptoms. Exclusion Criteria: * Children under the age of 1 year old. Children under 1 year old will be excluded due to the technical difficulty of placing both the pH / impedance monitoring probe and the Dx-pH probe into the same nostril. Firstly, this is due to the size restriction of placing 2 probes into one nostril. Secondly, the non-pathologic high incidence of regurgitation and positing in below the age of 1 will make data difficult to interpret. * Children with an nasogastric feeding tube in situ will be excluded. Firstly due to the difficulty in placing and securing the nasogastric, oesophageal pH and Dx-pH probe (3 tubes / probes) through the nostrils, with resultant bilateral nasal obstruction. Secondly, the nasogastric tube causes increased iatrogenic reflux within the pharynx, making data more difficult to interpret and creating artificial reflux events. * Children with cleft palate prior to surgical repair will be excluded as the Dx-pH probe will be difficult to locate in the oropharynx and may displace into the oral cavity. * Children requiring pH monitoring as inpatients during an acute medical admission. Children will be excluded from the study if their condition has nece…