Gastro-oesophageal reflux and belching revisited

Abstract

In this thesis recent studies into the pathophysiology of gastro-oesophageal reflux disease and belching are described. The thesis is divided into four parts. Part I describes studies in which the technique of impedance monitoring is validated. With impedance monitoring reflux of liquid and gas can be studied independent of its acidity. The minimum sample frequency for impedance monitoring is determined and the reproducibility of this new technique is demonstrated. In part II the role of the anti-reflux barrier in the prevention and permission of gastro-oesophageal reflux is investigated, with in particular the role of transient lower oesophageal sphincter relaxations and spatial separation of the lower oesophageal sphincter and diaphragm such as occurs in a hiatal hernia. The most important conclusion of this part is that spatial separation of lower oesophageal sphincter and diaphragm results in a two-fold increase in gastro-oesophageal reflux. Part III describes studies in which the relationship between reflux symptoms and reflux episodes is investigated. It is concluded that besides acidity of the refluxate other factors such as proximal extent and pH drop are important in the generation of symptoms. Besides acid reflux episodes also non-acid reflux episodes can cause heartburn and regurgitation. Part IV describes the physiology and pathophysiology of belching and gas reflux. It is shown that patients with aerophagia exhibit gastro-oesophageal reflux of gas in similar frequencies as healthy subjects and that their excessive belching results from a particular gas transport pattern what we describe as supragastric belching. This is most likely a behavioural disorder. We furthermore describe that air swallowing and intragastric air result in gas reflux but not in acid reflux. This studies described in this thesis thus provide some new insights into the pathophysiology of gastro-oesophageal reflux and belching.