The gastro-oesophageal common cavity revisited

The manometric common cavity phenomenon has been used as indicator of gastro-oesophageal reflux of liquid or gaseous substances. Using combined pH and impedance recording as reference standard the value of a common cavity as indicator of gastro-oesophageal reflux was tested. Ten healthy male subjects underwent combined stationary pressure, pH and impedance recording for 4.5 h. After 1.15 h of recording, a reflux-eliciting meal was consumed. The chi-squared and Kolmogorov-Smirnov tests were used for the statistical analysis. A common cavity was found in 95 (43%) of the 223 reflux events detected by impedance, while seven common cavities were unrelated to a reflux episode. In 54% of the reflux events detected by impedance without a common cavity, a possible common cavity was obscured by either contractile activity or artefacts of various origin. The types of reflux associated with a common cavity (liquid 60%, mixed 31%, gas 9%) and without a common cavity (liquid 59%, mixed 29%, gas 12%) did not differ, or did the acidity of the reflux episodes (with common cavity: acid 67%; without common cavity: acid 58%). The common cavity is a specific but not a sensitive marker of gastro-oesophageal reflux. Furthermore, common cavities are not specific for a particular type of reflux.