Detection of gastroesophageal reflux in children using combined multichannel intraluminal impedance and pH measurement: data from the German Pediatric Impedance Group.

OBJECTIVE: To validate the use of combined multichannel intraluminal impedance (MII)-pH (MII-pH) monitoring for detecting gastroesophageal reflux (GER) in children in daily clinical practice. STUDY DESIGN: The patients were divided into 3 symptom groups based on the main indication for the procedure. MII-pH monitoring was performed in 700 children presenting with symptoms suggestive of GER, including 329 children with pulmonary symptoms, 325 with gastrointestinal symptoms, and 46 with neurologic symptoms. The MII-pH results were compared with pH monitoring alone, and retrograde bolus movements, symptom index, and symptom association probability were compared. RESULTS: Overall, 270 measurements were abnormal: 101 (37%) showed abnormal MII-pH study, 49 (18%) showed only pathological pH measurements and 120 measurements (45%) had an abnormal MII recording only. Extraintestinal symptoms of GER were seen more often in younger children and were more often related to a normal pH study but an abnormal MII study. Infants had a significantly higher number of retrograde bolus movements than older children. Symptom index and symptom association probability showed moderate agreement (Cohen kappa, 0.54). CONCLUSIONS: From this large systematically standardized data collection of MII-pH measurements in children, we conclude that 45% of the patients with abnormal GER would not have been recognized by 24-hour pH measurement alone. Our findings confirm that MII-pH is superior to pH monitoring alone in detecting GER.

Inter- and intraobserver agreement in 24-hour combined multiple intraluminal impedance and pH measurement in children.

OBJECTIVES: Assessment of intra- and interobserver agreement in multiple intraluminal impedance (MII) measurement between investigators from different institutions. METHODS: Twenty-four 18- to 24-hour MII tracings were randomly chosen from 4 different institutions (6 per center). Software-aided automatic analysis was performed. Each result was validated by 2 independent investigators from the 4 different centers (4 investigator combinations). For intraobserver agreement, 6 measurements were analyzed twice by the same investigator. Agreement between investigators was calculated using the Cohen kappa coefficient. RESULTS: Interobserver agreement: 13 measurements showed a perfect agreement (kappa > 0.8); 9 had a substantial (kappa 0.61-0.8), 1 a moderate (kappa coefficient 0.41 to 0.6), and 1 a fair agreement (kappa coefficient 0.11-0.4). Median kappa value was 0.83. Intraobserver agreement: 5 tracings showed perfect and 1 showed a substantial agreement. The median kappa value was 0.88. CONCLUSIONS: Most measurements showed substantial to perfect intra- and interobserver agreement. Still, we found a few outliers presumably caused by poorer signal quality in some tracings rather than being observer dependent. An improvement of analysis results may be achieved by using a standard analysis protocol, a standardized method for judging tracing quality, better training options for method users, and more interaction between investigators from different institutions.

Influence of gestational age, cesarean section, and type of feeding on fecal human beta-defensin 2 and tumor necrosis factor-alpha.

OBJECTIVE: : Development of the mucosal immune system is essential for controlling antigenic response. External factors are known to influence the immune system, such as breast-feeding or the mode of delivery. The aim of the present study was to investigate maturation of the enteric immune system. PATIENTS AND METHODS: : In stool samples of 59 preterm and term-born infants we measured the concentration of human beta-defensin 2 (HBD 2), an endogenous antimicrobial peptide, and tumor necrosis factor-alpha (TNF-alpha), a cytokine playing a central role in mucosal inflammation, by enzyme-linked immunosorbent assay. RESULTS: : Mode of delivery as well as nutrition (breast-feeding or formula) had no influence on the fecal concentration of HBD-2 or TNF-alpha, but there was a significant increase in the concentration of HBD-2 in correlation with gestational age. TNF-alpha showed no change in concentration. CONCLUSIONS: : Low fecal HBD-2 may be a risk factor in preterm infants to develop neonatal enteric disease, such as necrotizing enterocolitis.

Combined esophageal multichannel intraluminal impedance and pH monitoring after repair of esophageal atresia.

OBJECTIVE: Gastroesophageal reflux disease and impaired esophageal motility is a frequent problem after repair of esophageal atresia (EA). Combined multichannel intraluminal impedance (MII) and pH measurement identifies acidic and weakly acidic esophageal bolus movements. Our aim was to evaluate gastroesophageal reflux and its association with gastrointestinal or extraintestinal symptoms using combined MII-pH measurement. PATIENTS AND METHODS: In all, 24 patients (4 months-23 years; 17 male, 7 female) with repaired EA were included in this study. A single catheter with 6 impedance channels and 1 pH channel was used to perform the 24-hour MII-pH study. Symptoms were recorded during the study as events and with a standardized questionnaire. In a subgroup of patients, an impedance swallowing test evaluating liquid and viscous bolus movements was performed. RESULTS: We detected a total of 911 episodes of retrograde bolus movement, 379 acidic and 532 weakly acidic bolus movements. In all, 201 symptom events were recorded. Of these events, 42% were associated with retrograde bolus movements. More symptom events were associated with weakly acidic reflux (26%) than with acid reflux episodes (16%). There was a poor correlation between symptoms and MII-pH study findings. In comparison with patients without esophageal surgery, EA patients showed significantly fewer complete swallows of liquid (42% vs 98%) and viscous material (18% vs 87%). CONCLUSIONS: In patients with corrected EA, half of the reflux events could be detected only by MII. We also demonstrated that weakly acidic reflux can be responsible for the patients' symptoms. However, patients may have few or no symptoms despite poor esophageal function and extensive gastroesophageal reflux disease.