The primary study objective is to investigate sensitivity and specificity of a wrist sensor pulse oximeter (the Oxitone Medical Oxitone 1000M device) to screen for obstructive sleep apnoea. This study will involve thirty participants attending a sleep centre suspected of suffering from obstructive sleep apnoea (case finding screening). The secondary objective is to assess patient convenience with the screening procedure.

This is an observational study to assess the sensitivity and specificity of a wrist sensor pulse oximeter (Oxitone Medical Oxitone 1000M) to identify obstructive sleep apnoea cases in patients referred to the London Sleep Centre (case finding screening, or case only study). The wrist sensor pulse oximeter streams data (pulse rate, heart rate variability (HRV), blood oxygen saturation levels (SPO2), actigraphy data and skin temperature data) to a software application using bluetooth connectivity to be stored in a securely encrypted database cloud for analysis. The investigators at the sleep centre will be masked when analysing the data from the wrist sensor pulse oximeter when deciding on diagnosis of obstructive sleep apnoea. Data from the wrist sensor oximeter device will be statistically compared with the data from a conventional PPG fingertip oximeter and Peripheral Arterial Tonometry device currently in use. The study outcome will be whether the wrist sensor pulse oximeter device could be used in patients to screen reliably for obstructive sleep apnoea. The study also will include patient feedback on convenience of the screening procedure. The study will not affect routine patient medical management and care for patients assessed at the sleep centre.

Inclusion Criteria:

• Thirty consecutive patients referred to the sleep Centre for screening for sleep apnoea that consented to involvement in the study.

Exclusion Criteria:

• Patients who are unable to give written informed consent.
• anaemia or dysfunctional hemoglobin
• upper limb complaints affecting the ability to wear the watch like wrist sensor device such as tenderness, deformity or swelling, skin complaints such as ulceration, swelling or skin breaks
• impairment in circulation in the left upper limb (active Raynauds or other vascular impairment)
• neurological conditions such as tremor or convulsions
• Medical conditions likely to affect the blood oxygen such as chronic obstructive pulmonary disease (COPD) and chronic asthma
• Neurological conditions likely to affect breathing such as stroke
• Conditions likely to affect autonomic nervous system such as diabetes mellitus

Thirty consecutive patients referred to the sleep Centre for screening for sleep apnoea that consented to involvement in the study.

All IPD that underlie results in a publication will be shared with other researchers.

Personal identifiable data will not be shared with other researchers.

Three months

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