Effects of Posture and Swallow Volume on Esophageal Motility Morphology and Probability of Bolus Clearance A Study Using High-Resolution Impedance Manometry

The Chicago classification diagnostic criteria of esophageal motility disorders are based on 5-ml water swallows in the supine position and have not been analyzed for the correlation between the morphology and bolus transit in the upright position and larger volume swallow conditions. This study aimed to evaluate the effect of posture and swallow volume on peristaltic morphology and the probability of bolus clearance in patients with nonspecific esophageal disorder. A total of 139 patients (4,214 swallows) were included for high-resolution impedance manometry analysis in the right lateral recumbent and upright positions, as well as 5- and 10-ml liquid swallows. Intact peristalses were more frequent in the right lateral recumbent position than in the upright position. No difference was reported on failed peristalsis between both positions. Breaks were more frequent in the upright position. A 20 mmHg isobaric contour (compared with 30 mmHg) was associated with decreased bolus clearance. Bolus clearance probability with 10-ml swallows is greater than that with 5-ml swallows. There was no significant difference in the total bolus clearance comparing between the right lateral recumbent and upright positions. The right lateral recumbent position was associated with a higher intact peristalsis. The volume of swallow did not affect the integrality of esophageal peristalsis but did improve the bolus clearance.