LAUSR

Obstructive sleep apnea (OSA) is typically treated with positive airway pressure (PAP) therapy in symptomatic patients with ≥ 5 obstructive respiratory events (apneas, hypopneas or respiratory effort related arousals) per hour of sleep. In this case, we present a patient with severe OSA isolated to REM sleep who demonstrated significant symptomatic improvement on PAP therapy, despite an overall apnea-hypopnea index (AHI) of less than 5 events/hour. A 73-year-old obese male with history of SVT, hypertension, and diabetes presented with symptoms of snoring, witnessed apneas, non-restorative sleep, restless sleep, excessive daytime sleepiness, and fatigue. A baseline polysomnogram (PSG) demonstrated severe OSA exclusively in REM sleep (overall AHI 2.9, REM AHI of 37.3, minimum SpO2 of 84%). A subsequent PAP titration study tested CPAP 5-17 and BPAP 19/15 cm of water but was unable to identify an effective pressure during REM sleep. Pressures as low as CPAP 5 cm of water appeared effective in NREM sleep. Ultimately, as the patient was unwilling to undergo a re-titration study, empiric treatment with auto-BPAP (min EPAP 5, max IPAP 25, PS 4) was initiated. With excellent adherence to BPAP therapy, the patient experienced profound symptomatic benefit, with resolution of daytime symptoms, less restlessness during sleep, and more restorative sleep. This case highlights a gap, and potential pitfall, in current practice. Our patient 1) did not meet the overall AHI criteria for diagnosis of OSA yet had typical symptoms and high pretest probability for OSA; 2) had a PSG which showed severe OSA exclusively during REM sleep; and 3) experienced resolution of symptoms with PAP therapy. Presently, there is no consensus on whether REM-dependent OSA should be treated if the overall AHI is < 5 events/hour. In fact, there is no standardized definition for REM-dependent OSA. This patient with cardiovascular risk factors was able to receive PAP therapy through the Veterans’ Affairs, and access to PAP therapy changed the Veteran’s quality of life dramatically. Obtaining a PAP device for this patient through private payors would have been nearly impossible. More research is needed to understand the clinical implications of this condition.