Background: OSA-patients with persistent excessive daytime sleepiness (EDS) despite CPAP treatment are challenging in daily clinical life. To rule out residual sleep-disordered breathing (SDB), CPAP device-derived data are used in outpatient setting. In case of no pathological finding, a more intensive work-up with is necessary. 6-channel portable monitoring (6Ch-PM) is frequently used to exclude residual SDB. Peripheral arterial tonometry (PAT), as embodied in the WatchPAT device, represents an alternative technique for detecting SDB based on changes in autonomic tone. We wanted to investigate whether PAT might be a useful tool to improve diagnostic work-up in this specific patient group by better identifying residual SDB due to insufficient CPAP-adjustment.
Methods: Forty-nine OSA patients (39 male, 10 female) with sufficient CPAP treatment according to device-derived data were consecutively recruited. EDS was assessed by Epworth Sleepiness Scale (ESS). All patients underwent home-based CPAP therapy control by 6Ch-PM and portable monitoring using PAT technology on two consecutive nights. A sequence of both types of monitoring was randomized to prevent possible first night effect bias.
Results: Twelve out of 49 patients showed persistent EDS according to ESS (ESS > 10 points). 6Ch-PM showed a residually increased AHI under CPAP-treatment in 2 of those 12 subjects (positive predictive value, PPV = 16.7%). PAT-PM revealed 5 patients of those 12 with residual SDB (PPV = 41.7%).
Conclusion: PAT could detect significantly more residual SDB under CPAP treatment than 6Ch-PM. Diagnostic work-up of CPAP-treated OSA patients with persistent EDS might be optimized, as insufficient pressure level adjustments could be recognized more precisely in time, possibly preventing more resource-consuming procedures, and potentially increased morbidity.
Clinical trial registration: DRKS00007705.
Keywords: CPAP; Excessive daytime sleepiness; Obstructive sleep apnea; PAT.