WatchPAT as a diagnostic device for obstructive sleep apnoea in children

Obstructive sleep apnoea (OSA) affects 1-5% of otherwise healthy children and high rates of children with certain medical comorbidities such as Down Syndrome and obesity. The diagnosis is made by polysomnography (PSG), an expensive and time-consuming test that involves collection of many channels of physiological data overnight, most commonly in an inpatient sleep laboratory setting. Alternatives to PSG that are accurate and easy to perform are desirable, to enhance access to appropriate diagnosis and treatment for children with suspected OSA, in the interests of reducing the morbidity of the condition, especially cardiovascular, behavioural and cognitive/learning impacts. One such alternative to PSG is the WatchPAT device (Itamar Medical Ltd., Caesarea, Israel). WatchPAT is a small watch-like device attached to the patient’s wrist with a probe on the fingertip. It derives data based on a change of peripheral arterial tone (PAT). The PAT signal is a non-invasive measure of the arterial pulsatile volume changes at the fingertip: the signal reduction and the consequent accelerated pulse rate reflect sympathetic activation occurring with repetitive autonomic arousals typically seen in OSA. This device has been widely studied in adults and validated against in-laboratory polysomnography, but fewer studies involving small numbers have examined the WatchPAT in children. Given the limited and conflicting evidence base in children and an observed increase in use of WatchPAT as a diagnostic device in the community, we aim to validate the use of WatchPAT in children with suspected OSA against the gold standard of in-laboratory polysomnography (sleep studies).