Normal 24-hour ambulatory proximal and distal gastroesophageal reflux parameters in Chinese.

OBJECTIVE To quantify normal proximal and distal oesophageal acid parameters in healthy Chinese. DESIGN Observational study. SETTING University teaching hospital, Hong Kong. SUBJECTS AND METHODS Twenty healthy adults who were not on medication and were free from gastrointestinal symptoms were recruited by advertisement. Ambulatory oesophageal acid (pH<4) exposure parameters were recorded at distal and proximal sites, 5 and 20 cm, respectively above the lower oesophageal sphincter. RESULTS The 95th percentile for reflux parameters assessed in the distal/proximal oesophagus were: percent total time pH<4, 4.6/0.7%; percent upright time pH<4, 7.0/1.1%; percent supine time pH<4, 4.5/0.5%; number of reflux episodes, 73/12; number of reflux episodes with pH<4 for >5 minutes, 4/0; and the longest single acid exposure episode, 11.2/3.0 minutes. CONCLUSION Physiological gastroesophageal reflux occurs in healthy Chinese. These initial data provide a preliminary reference range that could be utilised by laboratories studying Chinese subjects.