BILE AND ACID IN THE GULLET

While we all experience gastro-oesophageal reflux, exposure of the oesophagus to gastric contents is normally rapidly terminated by peristalsis, a process known as volume clearance. Gastric acid is also neutralised by bicarbonate, both locally secreted and from swallowed saliva, so called “chemical clearance”. However it is well recognised that bile is a very important component of refluxate, and that in patient studies, episodes of reflux containing bile appear to clear less rapidly than those containing only acid. The study from Leuven compared volume and chemical clearance rates using a combination of scintigraphy, pH and bile detecting probes. They found that peristaltic clearance of citric acid solutions or duodenal contents instilled into the lower oesophagus in normal subjects was no different. Somewhat unexpectedly bilirubin in the duodenal contents, as detected by the Bilitec^R monitor, was cleared faster than acid. The authors speculate that this may be because lipophilic bile contents penetrate oesophageal mucus less well than protons and hence are cleared more easily. …