Table 2

 Characteristics of pure gas reflux episodes

AsymptomaticSymptomaticp Value
Values are median (interquartile range).
pH drop0.0 (0.0–0.5)1.3 (0.5–2.8)0.03
Nadir pH6.2 (5.3–6.4)4.7 (2.6–6.9)0.04
Proximal extent (cm)18 (18–18)18 (15–18)0.7
Ascending velocity (cm/s)57 (25–90)37 (17–170)0.6
Acid clearance (s)10.5 (6.5–21.0)9.5 (2.2–19.0)0.6