The importance of multichannel intraluminal impedance in the evaluation of children with persistent respiratory symptoms

OBJECTIVES: Previous evidence suggests an association between gastroesophageal reflux disease and chronic respiratory disease in children. Despite antisecretory antacid therapy, respiratory symptoms often persist supporting a role for nonacid reflux. The aim of this study was to determine whether nonacid reflux occurs in children with chronic respiratory disease. METHODS: Twenty-eight children (mean age: 6.5 +/- 5.6 yr) with persistent respiratory symptoms on antacid medications underwent 24 h pH/multichannel intraluminal impedance (pH/MII) recording. The symptom index (SI) and the symptom sensitivity index (SSI) were calculated for each patient. Logistic regression was performed to determine which reflux characteristics were associated with a high degree of symptom correlation present during the occurrence of symptoms. RESULTS: A total of 1,822 reflux episodes were detected by pH/MII, 45% of which were nonacidic. The mean SI increased using pH/MII (35.7 +/- 28.5) compared to pH probe alone (14.6 +/- 18.9; p = 0.002); no differences in the mean SSI using pH/MII compared to pH probe alone were identified. Significantly more patients had a positive SI using pH/MII than pH probe alone (p = 0.035); there was no difference in the number of patients with a positive SSI using pH/MII compared to pH probe alone. Multivariate analysis revealed that symptoms occurred more frequently when the reflux was nonacidic, mixed, and full column. Also, younger children were more likely to have the simultaneous occurrence of symptoms and reflux. CONCLUSIONS: Nonacid reflux may be an important predictor of respiratory symptoms. pH/MII provided important information in the evaluation of children with intractable respiratory symptoms.