Figure 3 .

Example tracing of intragastric pH recorded at the time of gastro-oesophageal reflux (GOR). Two reflux episodes are shown (shaded regions). During the first episode, oesophageal pH falls to a nadir that is lower than the pH recorded in the proximal stomach (G1) but greater than that in the mid and distal stomach (G2 and G3), suggesting that refluxate is originating from the mid and/or distal stomach. During the second reflux episode, expulsion of refluxate is followed by acidification of the proximal stomach indicating mixing of gastric contents.