Impedance-pH monitoring: new standard for measuring gastro-oesophageal reflux.

Impedance monitoring is a new technique that can be used to detect the flow of fluids and gas through hollow viscera. With impedance monitoring gastro-oesophageal reflux can be detected independent of its acidity by differences in electrical impedance between the mucosal surface, fluids and gas that surround the catheter. Clinically, it is used in combination with oesophageal pH monitoring, and the combination of impedance-pH monitoring allows recognition of both acidic and weakly acidic reflux episodes. Studies have shown that impedance-pH monitoring is useful in the evaluation of patients with proton pump inhibitor-resistant typical reflux symptoms, as it provides a higher yield in detecting reflux as the cause of a patient's symptoms compared to pH monitoring alone. It is therefore likely that impedance-pH monitoring will largely replace pH monitoring in the next 5 years and it will become the standard for reflux detection.