OBJECTIVEAim of this study was to investigate functions of lower esophageal sphincter (LES) barrier and esophageal clearance in fasting and postprandial stages in gastroesophageal reflux disease (GERD).

METHODSEight patients with confirmed GERD and 8 healthy subjects (HS) were observed in the study. The esophageal pH and manometry were recorded simultaneously for 1 h during fasting and 2 h after a meal (1,675 kJ) using pneumohydrolic capillary perfusion system.

RESULTS(1) The esophageal pH monitoring showed that median of percentage of pH < 4 at postprandial in HS and patients with GERD was 0.45% and 11.2%, respectively (P < 0.05). (2) Pressure of lower esophageal sphincter (LESP) significantly decreased after a test meal in GERD (P < 0.001) and in HS (P < 0.001). (3) The amplitude of post-LES relaxation related to swallow (post-LESRA) in GERD was much lower than in HS either during fasting or postprandial stage (P < 0.05). (4) The tension of crural diaphragm at resting (Dia-A0) in GERD was lower than in HS during fasting and postprandial stage(P < 0.05). (5) The tension of crural diaphragm at deep inspiration (dia-AM) in GERD and HS increased 3 or 4 times at pressure at gastroesophageal junction (GEJ). (6) The peristaltic amplitude of the distal esophagus in GERD were much lower than that in HS in both pre- and postprandial periods.

CONCLUSIONS(1) Impaired clearance of Post-LESRA and esophageal body, function of diaphragmatic crural play an important role in development of GERD. (2) The tension of crural diaphragm at deep inspiration can increase the pressure at GEJ.