Gastro-oesophageal reflux occurs frequently during the first months of life. Infants receive frequent milk feeds, and because milk is a potent buffer of gastric acidity, oesophageal impedance should detect more reflux than pH recording. Indeed, impedance has the advantage over pH monitoring of being independent of pH, and as a consequence, of being better adapted to measure reflux during postprandial periods when reflux is buffered and to detect symptoms associated with non-acid or weakly acid reflux episodes. Numerous episodes are detected by one of these techniques (pH monitoring or impedance) in children. Most studies using the impedance technique consider very small numbers of patients, and there are few reports linking data from diagnostic impedance procedures to clinical outcome in symptomatic patients. Data suggesting that impedance does offer a clear-cut benefit in paediatric clinical practice are missing. The high cost of the material and the investment in time necessary for interpretation of the recording, remains a handicap. It is mandatory, despite ethical difficulties, to obtain normal ranges for intraluminal impedance monitoring.
Conclusion: As pH monitoring is part of impedance technology, it is likely that the latter will replace pH monitoring despite the current lack of scientific evidence demonstrating a relation between symptoms, oesophageal damage or response to reflux treatment and impedance-pH results.