Behind the (impedance) baseline in children

Abstract

Impedance baseline is a new parameter recently related to esophageal integrity. The aim of this study was to assess the effect of different factors on impedance baseline in pediatric patients. We analyzed the impedance baseline of 800 children with symptoms of gastroesophageal reflux. Mean impedance baseline was automatically calculated throughout 24-hour tracings. The presence of different age groups and of esophagitis was evaluated. Unpaired t-test, Spearman rank correlation, polynomial, and regression plot were used for statistical analysis. Age-related percentile curves were created. We considered a P-value<0.05 as statistically significant. Impedance baseline was significantly (P<0.001) lower in younger compared to older children up to 48 months. The mean increase of baseline per month was much higher in the first 36 months of life (47.5 vs. 2.9 Ohm in Channel 1 and 29.9 vs. 2.3 Ohm in Channel 6, respectively) than in older ages. Patients with esophagitis showed significantly decreased impedance baseline (P<0.05). Infants (especially in the first months of life) and young children present a significantly lower impedance baseline compared to older children both in proximal and distal esophagus. The presence of esophagitis may also determine a decreased impedance baseline regardless of the age of the patients.

Role of Intraluminal Esophageal Impedance Baseline in the Diagnosis of Esophagitis in Children

“…Salvatore, in a first investigation, and Zhong had also observed a negative correlation between EIB and signs of HiE due to GERD. 12,18 On the contrary, the results published by Borrelli and Salvatore, in a posterior different work, did not outline differences between children with HiE and those with normal biopsies. 19,20 Several facts might explain these disagreements.…”

“…The need to adjust EIB for age in pediatrics was suggested by an investigation that found an increase in EIB during the first 48 months of life. 12 In the present work, adjustment for age in the evaluation of global diagnostic performance was performed with logistic regression taking age as an effect modifier between EIB and esophagitis. Sensitivity and specificity values were defined separately for children younger or older than 4 years old with practical purposes, trying to avoid complex calculations.…”

“…10,11 Finally, some studies reported that children with histological findings of esophagitis or erosive GERD had significantly lower impedance baseline results. 12 Although previous investigations point toward a strong correlation between low EIB and esophagitis, available data do not generally provide particular values of EIB, which could be used to infer the existence or absence of esophagitis: there is scarce information about the capability of EIB to predict esophageal inflammation caused by GERD. Thus, the major aim of this investigation was to study the diagnostic performance of the impedance baseline for both endoscopic and histological esophagitis (HiE) in children.…”

The significance of different methods for detection of gastroesophageal reflux in children

“…BI represent the resistance to alternating current not related to swallowing or reflux, and serves to estimate the integrity of the esophageal mucosa (54,55). The presence of esophagitis reduces BI primarily in distal esophagus (56). There is a strong negative correlation between RI and BI (57).…”

An updated review on gastro-esophageal reflux in pediatrics

“…Infants and young children present a significantly lower impedance baseline compared to older children, both in the proximal and distal esophagus [70]. Baseline impedance is reported to be age dependent, which is likely to be related to the size of the esophagus [71,72]. Moreover, since esophagitis does decrease the baseline, and since the definition of impedance reflux is a decrease of impedance by more than 50%, severe esophagitis may have a normalizing effect on impedance.…”