Glass and antimony electrodes for oesophageal pH monitoring in distressed infants: how different are they?

Esophageal pH-impedance monitoring in children: position paper on indications, methodology and interpretation by the SIGENP working group

Multichannel intraluminal impedance pH (MII-pH) monitoring currently represents the gold standard diagnostic technique for the detection of gastro-esophageal reflux (GER), since it allows to quantify and characterize all reflux events and their possible relation with symptoms. Over the last ten years, thanks to its strengths and along with the publication of several clinical studies, its worldwide use has gradually increased, particularly in infants and children. Nevertheless, factors such as the limited pediatric reference values and limited therapeutic options still weaken its current clinical impact. Through an up-to-date review of the available scientific evidence, our aim was to produce a position paper on behalf of the working group on neurogastroenterology and acid-related disorders of the Italian Society of Pediatric Gastroenterology, Hepatology and Nutrition (SIGENP) on MII-pH monitoring technique, indications and interpretation in pediatric age, in order to standardise its use and to help clinicians in the diagnostic approach to children with GER symptoms.

Challenges in the diagnosis of gastroesophageal reflux disease in infants and children

INTRODUCTION

The diagnosis of gastroesophageal reflux disease (GERD) is challenging. The wide variation in symptoms is a major reason for the controversies. Since the expression of GERD varies from nonerosive reflux disease over Barrett's esophagus to chronic respiratory disease, it is clear that not one investigation technique will provide an answer in all situations.

AREAS COVERED

Relevant literature published in PubMed and CINAHL and recent guidelines were collected and reviewed. Diagnostic tests were evaluated by the following criteria: ability to confirm a diagnosis, to exclude other diagnoses with similar presentation, to detect complications, to predict disease severity.

EXPERT OPINION

Multiple intraluminal impedance (MII) is extensively evaluated in recent years, but other new techniques and measurements were also developed, mainly to diagnose extra-esophageal symptoms. Although evidence for a "relation" between GER and extra-esophageal symptoms is demonstrated, the "causality" between both is not proven. MII measures in a reliable reproducible way non-acid or weakly acid reflux. However, as long as medical therapeutic options are limited to anti-acid medications, MII lacks therapeutic implications, and therefore clinical impact. Since investigations for GER are invasive or cause irradiation, normal ranges cannot be established. As a consequence, the "old" techniques remain the standard diagnostic tools: barium meal for anatomy, endoscopy for esophagitis, and pH monitoring to demonstrate a time relation between (acid) GER and symptoms. MII provides more information than pH monitoring, but is more expensive and has limited therapeutic impact as long as drugs are mainly "anti-acid."

Can acid (pH) refluxes predict multichannel intraluminal impedance refluxes? A correlation study

BACKGROUND AND AIM

The present study aims to explore if and when acid (pH) refluxes can predict refluxes detected by multichannel intraluminal impedance (MII) studies. This correlation may indicate whether pH probe-only and MII-pH studies are interchangeable.

METHODS

Prospective observational cross sectional study of symptomatic children (below 18 years) who had MII-pH studies done for gastroesophageal reflux. Clinical data were extracted from patient records. Non-parametric tests, Pearson's rho and receiver operating characteristic (ROC) curves were used for data analysis.

RESULTS

A total of 153 children were included in the study and 62% were on acid suppression. Indices for acid and MII refluxes correlated with each other only in those without acid suppression. This correlation was lost in children on acid suppression. There was no statistically significant difference in acid or MII reflux indices in children with or without acid suppression. Like acid reflux, indices for MII refluxes had good correlation with each other irrespective of acid suppression. Liquid and mixed MII refluxes showed excellent correlation with respective types of proximally migrating refluxes. The values for MII reflux indices derived from our patient population were in broad agreement with available pediatric and adult data.

CONCLUSIONS

A pH probe-only study in patients without acid suppression may reflect both acid and volume (MII) reflux activities adequately and can substitute for MII-pH study. The observed excellent correlation between acid and MII refluxes with proximal migration may justify using pH probe-only studies for extra esophageal symptoms in patients without acid suppression.