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The technology behind the Take-Home Sleep Testing Program is the Watch PAT 100 (WPAT). The Watch-PAT 100 offers physicians and the millions of undiagnosed sufferers of sleep apnea a new option for patient-friendly, first line diagnostic evaluation of sleep related breathing disorders and fulfills the important need for cost effective diagnosis and patient follow-up.
But what is the Watch PAT? The Watch-PAT 100 is a self-contained, battery-powered recording device that is worn on the wrist and uses a non-invasive finger mounted sensor called a pneu-optical probe to measure the “PAT” signal. The PAT signal has been used as a sensitive surrogate of sympathetic activation during sleep. Transient attenuation of the PAT signal, indicating vasoconstriction or increased sympathetic activation, accompanies SDB and tonic attenuation occurs with REM sleep stages. The two finger mounted sensors on the elastic wrist band assess blood oxygen levels as well as pulse rate and arousals from sleep.
The W-PAT is a finger plethysmograph coupled to a constant volume, variable pressure pneumatic system. They provide a uniform pressure field over the fingertip and prevent motion. Pulse is recorded as pressure signals. The device prevents venous pooling. The problem of venous distention distal to the cuff is avoided which could mask the response to sympathetic activation. The PAT avoids previous problems of inducing venous distention distal to the cuff. This avoids local reflex veno-arteriolar vasoconstriction which could mask sympathetic activation. Blood flow to the finger can vary dramatically and hence reactivity has a wide range. Several factors affect finger blood flow, including temperature changes in the finger as well as other body areas, and due to vasoconstriction from the startle response. The measure of pulsatile volume rather than flow has enabled us to observe beat-to-beat variations in blood flow, which has a better correlation to AHI than does pulse transit time.
The recorded signals are stored in a removable memory card in the device to be downloaded to a computer for automatic analysis utilizing proprietary algorithms. A complex equation (algorithm) combines these bits of information to assess wake, dream sleep and non-dream sleep, and the severity of sleep disordered breathing.
Significant research & references are available illustrating the advantages of utilizing this technology to simplify the testing process.
The recorded signals are stored in a removable memory card in the device to be downloaded to a computer for automatic analysis utilizing proprietary algorithms. A complex equation (algorithm) combines these bits of information to assess wake, dream sleep and non-dream sleep, and the severity of sleep disordered breathing.
Significant research & references are available illustrating the advantages of utilizing this technology to simplify the testing process.
The Watch-PAT 100 is manufactured by Itamar Medical Ltd.
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