To determine the proportion of acid and nonacid reflux events in children with asthma suspected to have gastroesophageal reflux (GER) using combined impedance–pH monitoring, and to determine the symptom index (SI) for nonacid and acid reflux events.

This was a prospective study of children with asthma (age 5 months to 6 years) referred for evaluation of GER. Exclusion criteria were congenital anomalies, cerebral palsy, mental retardation, and cardiac disease. The children underwent a 20-hour multichannel intraluminal impedance (MII)-pH study.

A total of 24 children (17 male; mean age, 33 months) were enrolled from March 2004 to February 2005. MII-pH detected 1184 reflux events, versus 419 reflux events by pH alone; 51% (605 events) were nonacid. The proportion of nonacid reflux events decreased with time elapsed from last meal (P < .0001 by Pearson’s χ² test). A total of 555 symptoms were recorded, including 331 cases of cough, 243 of which (73.4%) were not associated with a reflux event. The SI for MII-pH was significantly different than that for the pH probe (37% vs 0%; P = .008).

Acid and nonacid reflux occurs with equal frequency in children with asthma. Most symptoms occur in the absence of a reflux event.