Bringing Sleep, Heart Health Together
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Doctors usually use what are called polysomnographic measures to evaluate patients with obstructive sleep apnea. This requires an overnight stay in a sleep lab while connected to multiple leads that monitor heart, respiratory, muscle, and brain functions.
But the FDA in January approved a new technology to make diagnosing sleep apnea much easier. Using a system called "Watch PAT100," a device is worn on the wrist and a noninvasive finger probe measures the patient's body functions during sleep. It is manufactured by Itamar Medical Co., based in Israel.
The device detects changes in peripheral arterial tone, or PAT. PAT is a newly identified physiological signal that reports changes in arterial volume in the fingertip from pulsing blood. These changes have been shown in clinical trials to be a reliable indicator of sleep-related breathing disorders. The device records signals and stores them in a removable memory card. The data are downloaded to a computer for analysis to detect sleep-related breathing disorders.
"The PAT is a sensitive indicator of sympathetic activity induced by acute periods of airflow obstruction, such as associated with OSA," says White.
The manufacturers of the Watch PAT100 expect the device to be commercially available in early 2002, but Gottlieb says that traditional ways of diagnosing sleep disorders aren't going to change that quickly.
"There have been a number of simplified tests for sleep apnea," he says. "Although the PAT is promising, it is unlikely that the PAT or any other such simplified test for sleep apnea will replace standard polysomnography in the near future."
Notwithstanding Gottlieb's reservations, with FDA approval, the PAT may well help more people get simpler, faster diagnoses -- and treatment -- of this common and dangerous sleep disorder.