Esophageal stimulation tests

Abstract

Both pharmacological and mechanical stimulation tests are used to evaluate the motor function of the esophagus and its sphincters. The stimulation of the esophagus allows not only evaluation of basal motor parameters but gives also information about the capability of the organ to respond to defined stimuli. Pentagastrin and edrophonium have been used to stimulate the esophageal motor function mainly with the intension of revealing abnormal motility patterns. In the esophageal body, the administration of the compounds allows detection of motor abnormalities. In contrast to a pharmacological stimulation test, the response of the lower esophageal sphincter to mechanical stimulation with an increase in abdominal pressure-applied by leg raising or using an abdominal beltremains a controversials field. The conflict is due to the fact that some investigators postulate an atropine-sensitive or vagally mediated reflex, whereas others suggest a purely mechanical extrinsic compression of the intraabdominal portion of the esophagus. The latter explanation seems to be wrong due to the fact that during mechanical stimulation with “intermittend abdominal compression” the change in pressure in the LES exceeds the time of the mechanical stimulation. The results were obtained in healthy persons and in patients with different esophageal motility disorders. It was concluded, therefore, that an increase in abdominal pressure results in an adaptive pressure rise in the LES, which can be used to evaluate the lower esophageal sphincter in a more detailed and functional way. In the esophageal body abnormal motility patterns can be more distinctly provoked by inducing swallowing with a defined bolus. Wet swallows more frequently allow detection of esophageal motor dysfunction than dry swallows. The inflation of a balloon in the esophageal body is sometimes helpful in patients with noncardiac chest pain to correlate mechanical stress with esophageal related symptoms.