Objectives: Belching and gastroesophageal reflux share a common physiological mechanism. The aim of this study was to investigate whether air swallowing leads to both belching and reflux.
Methods: Esophageal impedance, pH, and pressure were measured during two 20-min recording periods in 12 controls and 12 patients with gastroesophageal reflux disease (GERD), before and after intragastric inflation of 600 mL of air. This was repeated after a meal. Subsequently, ambulatory 24-h impedance-pH measurement was performed.
Results: During the 24-h study, patients showed a higher incidence of air swallows (287 +/- 45 vs 176 +/- 24, p < 0.05), belches (52.4 +/- 6.6 vs 32.7, p < 0.01), and acid reflux (42.3 +/- 7.6 vs 19.1 +/- 2.8, p < 0.01) than controls. After air infusion the incidence of gas reflux episodes was increased, both in patients (0.58 +/- 0.36 vs 3.50 +/- 0.61, p < 0.01) and in controls (0.75 +/- 0.67 vs 4.08 +/- 0.59, p < 0.01). In contrast, the incidence of acid and weakly acidic reflux episodes was not increased after air infusion, neither in patients (acid: 1.25 +/- 0.37 vs 1.20 +/- 0.33, weakly acidic: 1.08 +/- 0.40 vs 0.80 +/- 0.23) nor in controls (acid: 0.72 +/- 0.34 vs 0.50 +/- 0.23, weakly acidic: 0.80 +/- 0.35 vs 0.33 +/- 0.19). Air infusion increased transient lower esophageal sphincter relaxations (TLESR) frequency in patients and controls, but this was entirely because of an increase in gas reflux-associated TLESRs.
Conclusions: Patients with GERD swallow air more frequently and belch more frequently than healthy subjects. However, air swallowing is not the cause of their increase in reflux.