EFFECTS OF ONE NIGHT WITHOUT NASAL CPAP TREATMENT ON SLEEP AND SLEEPINESS IN PATIENTS WITH OBSTRUCTIVE SLEEP-APNEA

Nasal continuous positive airway pressure (CPAP) has become the nonsur gical treatment of choice for obstructive sleep apnea syndrome (OSAS). Recent evidence suggests that intermittent use of CPAP by patients is more common than nightly compliance. To determine the consequences of intermittent CPAP use, in terms of a return of sleep-disordered breat hing and daytime hypersomnolence, 15 OSAS subjects were evaluated at t hree times: (1) before CPAP treatment (pretreatment), (2) after 30 to 237 days post-treatment during a night of CPAP use (on CPAP), and (3) during a night without CPAP (off CPAP). Evaluations of sleep-disordere d breathing and three domains of hypersomnolence, physiologic sleep te ndency, subjective sleepiness, and performance, were accomplished with the respiratory disturbance index (RDI), multiple sleep latency test (MSLT), Stanford sleepiness scale (SSS), and psychomotor vigilance tas k (PVT), respectively. CPAP use was encouraged and monitored from pret reatment to post-treatment by daily diaries for most subjects and an e lectronic device for a subset of subjects. As expected, CPAP eliminate d apneas and hypopneas, and following the on CPAP night, there were st atistically significant improvements in objective measures of sleepine ss (MSLT and PVT). Subjective measures of sleepiness and fatigue also showed improvement. Sleeping without CPAP for one night reversed virtu ally all of the sleep and daytime alertness gains derived from sleepin g with CPAP This occurred despite a statistically significant reductio n in the RDI on the night off CPAP (M = 36.8, SD = 28.0 events/h) rela tive to the pretreatment night (M = 56.6, SD = 24.8 events/h), which m ay be due to a lessening of the edema of the upper airway following CP AP use. The results of the study suggest that failure to use CPAP for even a single night can result in reappearance of pretreatment levels of nocturnal sleep disturbance and daytime hypersomnolence, even thoug h the rate of respiratory events may be lessened.