Objective: Damage caused to oesophageal mucosa by bile constituents is pH dependent. The aim of this study was to evaluate the relationship between pH and duodeno-gastro-oesophageal reflux in gastro-oesophageal reflux disease at night in the supine position.
Design: A prospective study of 113 patients with reflux symptoms [63 without erosive oesophagitis (group 1), 23 with erosive oesophagitis (group 2), 27 Barrett's oesophagus (group 3)] and 15 controls.
Methods: All subjects underwent 24 h ambulatory oesophageal pH and bilirubin and gastric pH monitoring. For the supine period, oesophageal pH during episodes of bile reflux was calculated, and the temporal relationship between individual oesophageal and gastric alkaline shift and oesophageal bile reflux episodes was established. The supine period was divided into four equal segments and the temporal patterns of acid and bile reflux and alkaline shift in each of the four supine time segments were investigated.
Results: Both acid and bile reflux are severe in Barrett's oesophagus, particularly at night. Nocturnal oesophageal bile reflux occurs mostly between pH 4 and 7 in all groups: 67.6%, 76.5% and 41.4% of the supine period for groups 1, 2 and 3 respectively (P < 0.001 vs. pH < 4 or > 7). Individual oesophageal bile reflux and oesophageal or gastric alkaline shift episodes rarely coincide. Acid reflux predominates in the first half of the night (P < 0.001), oesophageal bile reflux and alkaline shift continue throughout the night, gastric alkaline shift increases towards the end of the night (P < 0.001).
Conclusion: Duodenal contents in the oesophagus exist at a wide pH range, and may have passed through an acid or an alkaline stomach. This has implications for the damage which individual constituents are able to cause.