Upstream effect of esophageal distention: effect on airway.

The pharyngoesophageal segment of the foregut has an important function in steering clear of luminal contents from the airway, across the age spectrum from a premature neonate to an aging adult. This complex neuromuscular interaction between the esophagus and the airway is maintained by a variety of mechanisms mediated by the parasympathetic and sympathetic afferent and efferent outflows involving the myenteric plexus, glossopharyngeal and vagus cranial nerves, phrenic nerve, and brainstem nuclei. The esophageal provocation during gastroesophageal reflux events results in esophageal distention, followed by responses in the esophagus, the airway, or both. Studies involving esophageal provocation in human adults and animal models are beginning to illuminate the pathogenetic mechanisms associated with aerodigestive tract disease. However, studies pertinent to this topic in infants or children have been lacking. In this paper, we review recent advances concerning the motor responses of the esophagus and the airway ensuing upon esophageal distention. Recent advances in methods to evaluate aerodigestive responses in infants that have been validated are discussed.