Figure 1 Characteristics of asymptomatic and symptomatic liquid reflux episodes in the upright position in 20 patients with gastro‐oesophageal reflux disease. (A) Median nadir pH. (B) Median pH drop. (C) Median extent of the reflux episodes. Horizontal lines indicate group medians. Comparisons were performed using the Wilcoxon signed rank test. LOS, lower oesophageal sphincter.