title: Acid and nonacid gastro-oesophageal reflux in neurologically impaired children: investigation with the multiple intraluminal impedance procedure.
abstract: OBJECTIVE
  The diagnosis of gastro-oesophageal reflux (GOR) is more difficult in children with neurological impairment because symptoms are often less interpretable and frequently go undetected. The use of combined pH and multiple intraluminal impedance allows for the detection of both acid (pH < 4) and nonacid (pH > 4) GOR episodes, in addition to the height of the refluxate and the total acid and bolus clearance time in this cohort.
  
  
  METHODS
  Sixteen neurologically impaired children (9 were fed nasogastrically, 7 were fed orally) underwent 12-hour combined pH and multiple intraluminal impedance.
  
  
  RESULTS
  There were a total of 425 reflux episodes during the study period, of which 239 (56.2%) were nonacid. The median of reflux episodes per hour was 1.8 (range, 0.2-6.3/h). The median height of the refluxate was 1.5 channels (range, 1.1-2.9); and 71.3% of reflux episodes reached the upper oesophagus, of which 52.4% were nonacid reflux events. On average there were more GOR events (both acid and nonacid) in the children who were fed via a nasogastric tube, and the median height of refluxate was also higher in this group. However, the median acid clearance time was longer (both proximal and distal) in the children who were fed orally (28.6 s vs 16.2 s proximally; 67.9 s vs 38.3 s distally). The median acid clearance time (21.7 s proximally; 39.5 s distally) was longer when compared with bolus clearance (14.9 s).
  
  
  CONCLUSIONS
  More than half of the reflux events in neurologically impaired children are nonacidic and would therefore go undetected by conventional pH metry. There are more reflux events in children fed nasogastrically than oral-fed children.
authors.affiliation: Centre for Paediatric Gastroenterology, Royal Free and University College Medical School, London, United Kingdom.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Del Buono
authors.forename: Tobias G
authors.initials: TG
authors.lastname: Wenzl
authors.forename: David
authors.initials: D
authors.lastname: Rawat
authors.forename: Mike
authors.initials: M
authors.lastname: Thomson
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D017097:Electric Impedance; D004566:Electrodes; D004750:Enteral Nutrition; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis* / Q000188:drug therapy; D041981:Gastrointestinal Tract / Q000294:innervation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D007441:Intubation, Gastrointestinal; D008297:Male; D009422:Nervous System Diseases / Q000150:complications*