Clinical importance of impedance measurements

Background: Because impedance changes have been shown to be a sensitive and reliable means to detect fluid or gas movement within the esophagus, numerous studies worldwide have addressed the potential for impedance determinations to provide a sensitive measure of either esophageal transit function or the presence and extent of gastroesophageal reflux. Using a catheter with multiple impedance measuring sites [multichannel intraluminal impedance (MII)] allows the opportunity to track fluid movement within the esophagus. Aim: To review the clinical importance of impedance measurements. Conclusions: Ambulatory MII-pH monitoring is a valuable tool in the assessment of reflux because it identifies not only acid reflux but overcomes the deficiency of simple pH monitoring by showing all reflux types, both acid and nonacid. It is our belief that MII-pH testing on proton pump inhibitor therapy has become the new gold standard for detection of reflux and for clarifying its relationship to symptoms.