Esophageal function and gastroesophageal reflux during sleep and waking in patients with chronic obstructive pulmonary disease.

This study was conducted to assess esophageal function and pulmonary resistance changes with esophageal acidification in patients with COPD. Twelve patients with COPD and a mean age of 55.6 years were studied. Each patient underwent standard esophageal manometry, 24-h ambulatory pH testing, esophageal acid clearance evaluation during sleep, and an assessment of pulmonary resistance with and without esophageal acid perfusion. Neither airway resistance nor conductance was altered by the esophageal acid infusion; LES pressures were normal and esophageal contractile pressures were mildly decreased. Acid exposure in the upright and supine positions was within normal limits. Acid clearance during sleep was similar to that in normal subjects; however, acid clearance during waking appeared to be somewhat prolonged in the COPD patients. We conclude that patients with COPD do not have a bronchoconstrictive reflex to distal esophageal acidification, and esophageal function in these patients appears to be relatively normal.

Persistent hypoxemia and excessive daytime sleepiness in chronic obstructive pulmonary disease (COPD).

Fourteen patients with chronic obstructive pulmonary disease (COPD) and chronic hypoxemia were studied to evaluate the relationship between hypoxemia and objective and subjective daytime sleepiness. Patients were selected with a waking PaO2 of less than 70 mm Hg and less than 50 percent predicted FEV1. Clinically, none of these patients had complaints of significant daytime sleepiness. Each patient underwent standard all-night polysomnographic evaluation followed by a multiple sleep latency test (MSLT). There was no significant correlation between the mean sleep onset latency for the MSLT and the waking PaO2, PCO2, FEV1, or spontaneous desaturations during sleep. Patients with COPD exhibited a mean MSLT that was within normal limits, despite a short total sleep time and numerous arousals from sleep. We conclude that there appears to be no relationship between chronic daytime hypoxemia and subjective reports and objective measures of daytime sleepiness.