Although nasal continuous positive airway pressure (NCPAP) is the most commonly used treatment for obstructive sleep apnea, the therapeutic effects of NCPAP have not been evaluated in a controlled clinical trial. Jenkinson and colleagues conducted a trial of the effects of therapeutic and subtherapeutic NCPAP on reducing daytime sleepiness and improving well-being and function among men with obstructive sleep apnea.
The 107 patients in the four-week study were 30 to 75 years of age and had more than 10 documented episodes per hour of obstructive sleep apnea that produced a drop of at least 4 percent in the arterial oxygen saturation (Sao2). In addition, each patient reported excessive daytime sleepiness and had a score of more than 10 on a standardized sleepiness test.
Patients were randomly assigned to receive therapeutic (52 patients) or subtherapeutic (49 patients) NCPAP. They received instructions on the use of the equipment and stayed overnight in the sleep unit to gain experience in using the equipment. With therapeutic NCPAP, the equipment was set to maintain an open pharynx during sleep. The equipment used by the subtherapeutic NCPAP group was identical to that used by the therapeutic group but was not set to maintain an open pharynx during sleep.
The two groups were comparable, including their use of the equipment during the trial. The mean daytime sleepiness score in the therapeutic group improved from 15.5 to 7.0 after four weeks of NCPAP therapy. In contrast, the mean daytime sleepiness score in the subtherapeutic group changed from 15.0 at baseline to 13.0 at the end of the study. Patients who received therapeutic NCPAP showed significantly greater improvement in daytime wakefulness, Sao2 levels and all other outcome measures, including self-report of vitality and energy.
The authors conclude that therapeutic NCPAP reduces daytime sleepiness and improves well-being in patients with obstructive sleep apnea. According to this study, the effects are great and confirm clinical observations and previous trials that used an oral placebo.