The esophageal propulsive force: esophageal response to acute obstruction.

The response of the normal human esophagus to an obstructing intraluminal bolus was investigated and compared to the response evoked by transient intraluminal distention. A balloon, immobilized within the esophagus by external attachment to a force transducer, was inflated with from 3 to 25 ml of air for from 3 to 210 sec. Pressure phenomena occurring in the esophagus were simultaneously recorded from the body of the esophagus above and below the balloon. Transient distention (5 sec or less) with small volumes (5 ml or less) often evoked a secondary peristaltic wave in the esophagus distal to the balloon, but infrequently resulted in the registration of any force exerted upon the balloon to drive it downward. Conversely, distentions of longer duration and with greater volume elicited an esophageal propulsive force exerted upon the balloon oriented to propel it aborally, and much less often evoked a propagated wave of secondary peristalsis. The propulsive force, obviously resulting from esophageal muscular contraction, occurred promptly, and once initiated, was sustained until deflation of the balloon. It varied widely in magnitude, from 4 to 200 g, and was associated with no motor phenomena recorded from the body of the esophagus proximal or distal to the balloon which could account for its presence, onset, magnitude, or duration. The force was inhibited by deglutition, but arrival of the primary peristaltic wave at the bolus resulted in augmentation of the force. When the obstructing balloon was freed from its attachment, the persistent, stationary force was converted to a propagated one that propelled the balloon before it. It the balloon was arrested before entering the stomach, the moving contraction was also arrested and the persistent propulsive force acting upon the balloon was maintained. The velocity of the moving contraction wave was determined in great part by the resistance offered by the bolus. Unrestrained, the balloon was propelled aborally at 4-8 cm/sec by the esophageal propulsive force; when restrained by 50 g, the rate of passage was reduced to 0.2-0.8 cm/sec. The esophageal response to intraluminal distention is thus not limited to the uninterrupted wave of secondary peristalsis but is versatile and is determined by the nature of the distending bolus. Transient distention by a mobile or collapsible bolus elicits the propagated secondary peristaltic wave.