Symptoms and Physiological Parameters of Obstructive Sleep Apnoea Patients Diagnosed with a Portable Sleep Monitor: Implications and Challenges.

Abstract

Background: Obstructive sleep apnoea is a chronic, debilitating condition that if left undiagnosed and untreated is associated with adverse clinical events. The WatchPAT® is a portable wrist-worn sleep study device that uses peripheral arterial tonometry with pulse oximetry and actigraphy to assess respiratory disturbances. Unlike other level 111 sleep monitors, it measures actual sleep time, distinguishes between REM and Non-REM sleep stages, and thus generates actual apnoea-hypopnoea index.

Objectives: The study was done to assess symptoms of obstructive sleep apnoea, evaluate physiological parameters recorded by the sleep monitor and highlight changes encountered in deploying the monitor for diagnosis of sleep apnoeas.

Methods: It was a cross-sectional study. A structured Questionnaire was administered to all patients to obtain data regarding their symptoms, co-morbidities and socio demographics. Sleep study was conducted using a Watch-PAT® portable monitor. Data were entered first on Microsoft excel sheet and analysed using SPSS version 25.

Results: Thirty-eight participants, mean age 49±14 years (17 to76 years) were studied (females, 73.7%). Thirty-four (89.5%) of them were diagnosed with OSA. Sixteen (47.0%), 9 (26.5%) and 9 (26.5%) had severe, moderate and mild OSA respectively. Commonest symptoms were snoring (85.7%), abrupt awakening accompanied by gasping/choking at night (65.8%) and non-refreshing sleep (60.5%). Memory loss occurred significantly among those with severe OSA compared with mild and moderate OSA (X2=9.920, p=0.007). Seventeen participants (44%) had excessive daytime somnolence (EPSS > 10). Those with severe OSA recorded the lowest minimum pulse (median 42.5, IQR 39.3-51.8), highest maximum pulse (median 130bpm, IQR 114-138), and lowest minimum SPO2 (median 70%, IQR 64.3-80.3). Severe OSA was associated with reduced mean percentage of REM sleep (14.6%) compared to moderate (25.1%) and mild (16.1%) OSA.

Conclusion: Diagnosing OSA objectively using a portable sleep monitor such as WatchPAT® is feasible. Snoring (85.7%) was the commonest symptom among those diagnosed with OSA. Physiological parameters obtained from the monitor provide the clinician the requisite information with which to persuade patients of a need for intervention. However, cost of CPAP machine and mandibular advancement device delayed immediate intervention.