Upper airway reflexes in response to gastric reflux.

Gastric reflux, and especially laryngopharyngeal reflux, occur several times a day in every infant. Most often, this does not pose any problem. However, in certain conditions, the contact between the refluxate and the upper airway mucosa can trigger several reflexes leading to cardiorespiratory inhibition. This is especially true for the laryngeal chemoreflexes, which are triggered by laryngeal penetration of gastric refluxate. The laryngeal chemoreflexes are held responsible for a subset of apnoeas of prematurity, many apparent life-threatening events, and probably some cases of sudden infant death syndrome. Although a number of experiments in newborn animals, as well as a few clinical studies in human infants, have been performed in the last 40 years to evaluate laryngeal chemoreflexes, their true role in neonatal cardiorespiratory events is still highly debated. In addition, many uncertainties persist with regard to treatment and prevention of their potentially dramatic consequences.