Gastroesophageal Reflux Due to Hiatal Incompetence—Influence of the Viscosity of the Gastric Content

The lower esophageal sphincter provides important protection against gastroesophageal reflux [1]. Some authors have also stressed the importance of the hiatal mechanism in preventing reflux [2–6]. On contraction of the diaphragm, the muscles around the hiatus also contract and thereby pinch the esophagogastric tract. When the pressure difference across the diaphragm increases, the stomach wall and/or other viscera are forced towards and into the hiatal channel. In this way, the folds of the mucous membrane can be compressed so that the gastric contents cannot pass into a herniated part of the stomach or into the esophagus, making the hiatus competent. If the hiatal channel is wider, the gastric contents can pass the folds which means that the hiatus is incompetent. If the sphincter is also forced, reflux will occur. Earlier investigations have shown that substances with a high viscosity increase hiatal competence and decrease reflux. This observation provided the background for the invention of Gaviscon [3, 7]. The aim of the present study was to investigate the effect of varying the viscosity of gastric content on intraluminal pressures in patients with hiatal incompetence and incompetent sphincter.