Effects of Esophageal Acid Perfusion on Airway Hyperresponsiveness in Patients With Bronchial Asthma

Airway responses to esophageal acidification

“…Numerous prior studies have found that esophageal acidification caused a variety of changes in the airways (1,2,7,13,17,23,32,47,53,59). These include increased tracheal pressure (2,23) or airway resistance (decreased compliance; Refs.…”

“…mucociliary transport; gastroesophageal reflux; apocrine gland secretion; airway resistance THE ESOPHAGUS HAS BEEN IMPLICATED as a source of receptors for reflex-induced airway disorders including gastroesophageal reflux-induced asthma (10,18,33,47) and chronic cough (11,22,39); however, the role of the esophagus in airway disorders is unclear. Studies have found that stimulation of the esophagus using HCl (1,2,13,23,32,47,53,59) or mechanical distension (2, 32) caused increased airway resistance (decreased compliance) or tracheal pressure; however, the mechanisms of these responses remain unclear. In all of these studies but one (13), the esophagus was not ligated to prevent esophago-pharyngeal or esophago-laryngeal reflux of the applied acid.…”

“…1,2,13,23,32,47,53,59) and sometimes nonexistent (2, 30), but these measures of airway function may not accurately reflect the total response. Airway resistance is a relatively insensitive measure and tracheal pressure is a very limited measure of changes in airway function.…”

“…Studies have found that stimulation of the esophagus using HCl (1,2,13,23,32,47,53,59) or mechanical distension (2,32) caused increased airway resistance (decreased compliance) or tracheal pressure; however, the mechanisms of these responses remain unclear. In all of these studies but one (13), the esophagus was not ligated to prevent esophago-pharyngeal or esophago-laryngeal reflux of the applied acid.…”

“…In all of these studies but one (13), the esophagus was not ligated to prevent esophago-pharyngeal or esophago-laryngeal reflux of the applied acid. Considering that stimulation of the larynx with HCl (23) causes a much greater response of the airways than esophageal stimulation (250 vs. 15% increase in tracheal pressure), it is possible that the airway effects due to esophageal acidification observed in prior studies (1,2,23,39,47,53,59) were due to laryngeal rather than esophageal stimulation. In the one study (13) in which esophago-laryngeal reflux was prevented, the investigators used HCl concentrations (0.3-3.0 N HCl) far above the physiological range, and the effect on airway resistance was small (ϳ10%) and inconsistent.…”