NOCTURNAL NASAL CONTINUOUS POSITIVE AIRWAY PRESSURE IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE - INFLUENCE ON WAKING RESPIRATORY MUSCLE FUNCTION

Patients with COPD often have reduced inspiratory muscle strength and endurance as well as poor exercise tolerance. Increased inspiratory wo rk during sleep (probably due to increased upper airway resistance) ma y further strain these compromised respiratory muscles in COPD patient s. We hypothesized that nasal continuous positive airway pressure (CPA P) might reduce respiratory work during sleep in COPD patients and the reby improve waking inspiratory muscle function. To test this hypothes is, eight male COPD patients were treated with sustained nocturnal nas al CPAP. Inspiratory muscle strength (maximum inspiratory pressure) an d endurance (sustained inspiratory pressure) as well as clinical perfo rmance (12-min walk) were assessed before and after therapy. We observ ed that compared with matched controls, COPD patients treated with noc turnal nasal CPAP had significant and substantial improvement in inspi ratory muscle strength and endurance as well as functional ability as assessed by the le-min walk. In addition, CPAP did not significantly a lter sleep quality or oxygenation in the patients studied. We conclude that nocturnal nasal CPAP improves inspiratory muscle performance dur ing wakefulness in COPD patients, which is very likely a product of th e reduced work of breathing during sleep while these individuals recei ved CPAP.