Normal esophageal high-resolution manometry and impedance values in the supine and sitting positions in the population of Northern China

The aim of this study was to investigate the normal high-resolution manometry and impedance (HRiM) values in the supine and sitting positions in the population of Northern China, and to investigate the influence of different body positions and bolus consistency on esophageal HRiM findings. In this study, healthy volunteers in the supine position underwent esophageal HRiM examination of 10 swallows of 5 mL normal saline solution and 10 swallows of 5 mL synthetic gel of known viscosity, and in the sitting position of an additional five swallows of a synthetic gel of known viscosity. Total bolus transit time (TBTT), complete bolus transit rate (CBTR), distal contractile integral (DCI), distal esophageal amplitude (DEA), and integrated relaxation pressure (IRP) were measured. Sixty-two healthy volunteers were examined in the supine position and 45 of these performed additional swallows of the viscous gel in the sitting position. In the supine position, normal values for swallowing the liquid and viscous boli were as follows: TBTT 6.9 +/- 0.9 and 8.0 +/- 1.2 s (P < 0.001), CBTR 90.3 +/- 14.0 and 77.9 +/- 20.3% (P < 0.001), DCI 1891.5 +/- 1131.9 and 1967.8 +/- 1140.1 mmHg.s.cm (P = 0.227), DEA 95.3 +/- 35.4 and 98.7 +/- 37.5 mmHg (P = 0.148), and IRP 10.4 +/- 4.9 and 9.0 +/- 4.2 mmHg (P < 0.001), respectively. For swallows of the viscous boli in the sitting position, TBTT, DCI, DEA, and IRP were significantly decreased, while CBTR was unchanged (P = 0.075). Normal HRiM values of the population of Northern China were established. Esophageal transit times of viscous boli were significantly slower, more often incomplete and produced less normal peristalsis in the supine position than swallows of liquid boli. Independent reference values for different manometric systems, body positions, and population need to be established before clinical application.