DETECTION OF GASTROESOPHAGEAL REFLUX BY ELECTRICAL-IMPEDANCE TOMOGRAPHY

In children with vomiting, dyspepsia, and feeding problems, gastroesop hageal reflux (GOR) and altered gastric emptying are common. We have u sed electrical impedance tomography (EIT) to study children with suspe cted gastric emptying disorders. Abnormalities of the gastric emptying curve suggestive of GOR were seen in some, with marked negative or po sitive shifts related to sharp increases or decreases in intragastric resistance. These findings could represent fluid leaving or entering t he stomach, as might occur in GOR. To confirm the origin of the abnorm al EIT curves, we devised and in vitro tank test system, and we perfor med simultaneous 2-h EIT and intraoesophageal pH monitoring after a gl ucose meal on six patients. In vitro, reflux of greater than or equal to 25 ml produced clearly detectable changes on the emptying curves. I n vivo, the overall correlation between the times of 42 GOR episodes l asting greater than or equal to 1 min detected by pH study and the tim es of 38 negative peaks due to greater than or equal to 15% changes of the maximum intragastric resistivity detected by simultaneous EIT was significant; the correlation was highly significant in four of six pa tients. When the peaks were used to define GOR episodes on EIT gastric emptying curves, the two methods still showed good agreement. Retrosp ective examination of 50 patients who had undergone both EIT and 24-h intraoesophageal pH study during their diagnostic workup showed that E IT had a sensitivity of 94.6% and a specificity of 76.9% (with positiv e and negative predictive values of 0.92 and 0.83, respectively) for t he detection of pathological GOR. We have shown, for the first time th at EIT not only allows gastric emptying to be measured but can also de tect GOR. Therefore, EIT can be used as a noninvasive screening test i n patients with vomiting, dyspepsia, and feeding problems.