Objective: Our aim was to assess the efficacy and mechanism of solid bolus transit through the esophagus.
Methods: Eight healthy volunteers were studied with concurrent manometry and videofluoroscopy while swallowing 5 ml liquid barium, a 5-6 mm diameter bread ball, and 4 g chewed bread in both a supine and upright posture. As many as four successive swallows were performed until clearance was achieved.
Results: The esophageal clearance of liquid barium was 100% with the first swallow. Clearance of the unchewed bread ball occurred with the first swallow in only 6.7% of trials in the upright posture and 5.9% in the supine posture. After four swallows, clearance was 100% and 52.9% in the upright and supine postures, respectively. Chewed bread was more readily cleared than unchewed bread, with 100% clearance after two swallows in the upright posture and 91% clearance after four swallows in the supine posture. The most common locus of bread stasis was at the aortic arch and carina. The bread boluses were noted to move more effectively when localized in the head as opposed to the tail of the bolus composite. Nonocclusive contractions often occurred at the bolus tail despite the increased peristaltic amplitude seen with the chewed bread. Failed peristalsis, a frequent cause for solid clearance failure, was observed during 30% of all bread swallows. This usually occurred distal to the stopping point of the bolus, suggesting it to be the result rather than the cause of impaired transit.
Conclusions: Although infrequently perceived by these normal subjects and in contradistinction to liquid clearance, bread is rarely cleared from the esophagus with a single swallow. Mastication and an upright posture facilitate the esophageal transport of solids. Bolus composition and impaired bolus transit alter the amplitude and conductance of peristalsis. Manometric data pertaining to liquid clearance through the esophagus do not readily apply to bread.