[Multiple Intraluminal Impedance measurement in the esophagus. Experience with the first 100 Danish patients]

Symptoms of gastroesophageal reflux are common in the Western world. Multiple Intraluminal Impedance (MII) measurement in the esophagus is a new diagnostic method for the evaluation of patients with suspected gastroesophageal reflux disease (GERD). Multiple pairs of impedance electrodes on a pH probe enable the detection of retrograde bolus movement in the esophagus. The acidity of the bolus can be detected by the pH probe.

100 patients referred to our motility laboratory with symptoms of GERD were monitored with MII for 24 hours. Impedance was measured at 6 levels (3, 5, 7,9,15 and 17 cm above LES) and pH was measured 5 cm above the manometrically defined LES. The total number and the number of acid and non-acid reflux episodes were detected by the combination of MII and pH.

97 of the 100 patients completed at least 20 hours of registration. 9 of the 100 investigated patients exhibited pathological volume reflux despite a normal index for acid reflux. 46 of the 97 investigated patients had a normal reflux index. In 9 (20%) patients pathological volume reflux was found by means of MII.

Combined MII and pH measurements provide new insight into the pathophysiology of GERD. It enables detection of volume reflux and a division into acid and non-acid reflux episodes. In the present study we found that 20% of patients with a normal reflux index had volume reflux.