Adults with obstructive sleep apnea benefit significantly from longer nightly use of continuous positive airway pressure (CPAP), a device to improve breathing during sleep, according to a new study supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health. This is the first study to identify the nightly duration of CPAP use needed to gain maximum benefit for daytime alertness and functioning.
Researchers at seven sleep centers in the United States and Canada studied 149 adults with sleep apnea to determine how long they routinely used CPAP each night. In addition, patients were evaluated for daytime symptoms such as excessive daytime sleepiness using two widely accepted assessment tools, and for daytime functioning using a standardized test before treatment and after three months of CPAP therapy. The findings suggest that most patients should use CPAP for at least 7.5 hours each night to realize the greatest possible benefits of therapy.
"Relationship Between Hours of CPAP Use and Achieving Normal Levels of Sleepiness and Daily Functioning," is published in the June issue of the journal SLEEP.
More than 12 million adult Americans are believed to have sleep apnea, a common disorder in which the upper airway is intermittently narrowed during sleep, causing breathing to be difficult or even completely blocked. The CPAP device is worn while the patient sleeps and works by blowing just enough air into the nose to keep the patient's throat open.
Because they often find the CPAP device cumbersome, many patients do not use it consistently or for long enough periods while sleeping. In the current study, for example, patients used CPAP on average about 5 hours a night. The researchers found that although daytime sleepiness could be improved after 4 hours to 6 hours a night, depending on the measurement used, functional status or quality-of-life improvements were maximized after 7.5 hours of use each night. Although individual patient response to CPAP therapy can vary, these latest findings provide a yardstick to help clinicians assess whether a patient's use is optimal.
In addition to NHLBI, support for the study was provided by Respironics, Inc., Nellcor Puritan Bennett Inc., DeVilbiss Health Care Inc., and Healthyne Technologies, Inc.
Michael J. Twery, PhD, director of the National Center on Sleep Disorders Research (NCSDR), is available to comment on this study. He can address the importance of diagnosing and treating sleep apnea (more than one-half of adults with sleep apnea remain undiagnosed). To schedule interviews, contact the NHLBI Communications Office at 301-496-4236.