Value of esophageal baseline impedance questioned

Last Updated: 2015-01-23

By Reuters Staff

NEW YORK (Reuters Health) - A new study questions the added benefit of baseline esophageal impedance (BI) measurement in children with esophageal motility trouble and gastric reflux.

The study team found that, along the length of esophagus, both bolus transit variables and gastric reflux significantly affect BI.

This suggests that BI measurement "is merely an innocent bystander" that can't replace impedance and manometric variables currently available evaluating gastroesophageal reflux disease (GERD) and esophageal motility disorders, say Dr. Osvaldo Borrelli and colleagues from the Department of Pediatric Gastroenterology, Great Ormond Street Hospital for Children in London.

In a paper online January 5 in the Journal of Pediatric Gastroenterology and Nutrition, they note that multichannel intraluminal impedance monitoring has become the gold standard for assessing gastroesophogeal reflux (GER)in both children and adults, and it can evaluate the esophageal transit by measuring the clearance of a swallowed bolus.

"The measurement of baseline impedance has been suggested to be useful in predicting the integrity of the esophageal mucosa. A clear relationship has been shown between the degree of esophageal acid exposure and the values of baseline impedance," they explain.

Yet, the clinical relevance of BI remains an open question.

Dr. Borrelli and colleagues explored the influence of GERD and esophageal dysmotility on BI in a prospective study involving 18 children with esophageal atresia (EA), 26 with GERD, and 17 healthy children. All participants underwent esophagogastroduodenoscopy and pH-impedance monitoring, and the researchers measured BI in both proximal and distal esophagus.

They found that the presence of esophageal motor abnormalities and/or excessive acid reflux was highly predictive of low BI values in both the proximal and distal esophagus.

This suggests, they say, that baseline impedance "mirrors phenomena occurring within the esophageal lumen or wall, limiting its value as a discrete clinical entity to replace variables already used for assessing both GERD and esophageal dysmotility."

"However, baseline impedance assessment may help the clinician in decision making about which patient would benefit from further investigations, such as upper gastrointestinal endoscopy and esophageal manometry," they say.

The study had no commercial funding and the authors have no conflicts of interest. They did not respond immediately to request for comment.

SOURCE: http://bit.ly/1zDG7mo

J Pediatr Gastroenterol Nutr 2015.