The optimal position for pH electrode placement in the diagnosis of gastroesophageal reflux disease (GERD) is unknown.
Dr Jörgen Wenner and colleagues from Sweden evaluated the discriminatory power of targeted pH recording immediately above the squamocolumnar junction.
The research team compared the results with those obtained by simultaneous recording at the conventional level for pH monitoring.
The team assessed 62 patients with typical reflux symptoms, and 49 asymptomatic volunteers.
The patients and volunteers underwent 48-hour simultaneous wireless pH monitoring with 2 endoscopically placed pH recording capsules.
|pH less than 4 for a 48-hour period distinguished GERD patients from controls|
|The American Journal of Gastroenterology
The first recording capsule was placed immediately above the squamocolumnar junction, and the other at the traditional position, 6 cm above the squamocolumnar junction.
The team analyzed the diagnostic accuracy, sensitivity, and specificity of pH monitoring at the 2 levels, using receiver operating characteristics curves.
The researchers found that of the 62 patients, 32 had erosive esophagitis and 30 had no endoscopic evidence of mucosal injury.
Analysis of the area under the receiver operating characteristics curve indicated that the total percent time with pH less than 4 for the entire 48-hour period was the parameter that best distinguished GERD patients from controls.
pH monitoring performed directly above the squamocolumnar junction increased the number of patients correctly classified with GERD compared to standard electrode placement.
With a predefined test specificity of 90%, pH monitoring immediately above the squamocolumnar junction increased the sensitivity of the test from 63% to 86% in all patients.
The team noted that pH monitoring immediately above the squamocolumnar junction increased the sensitivity from 78% to 97% in patients with esophagi is, and from 47% to 73% in patients with no esophagitis.
Dr Wenner’s team concluded, “Compared to standard electrode placement, wireless pH recording immediately above the squamocolumnar junction improved the diagnostic performance of esophageal pH monitoring in patients with GERD.”