Insights from PAT on Sleep Disorders and Heart Problems

New studies show that sleep apnea, sleep fragmentation, and abnormal respiratory patterns associated with congestive heart failure are all reflected by changes in peripheral arterial tone (PAT). This physiologic signal reflects arterial pulsatile volume changes in the fingertip, mirroring changes or anomalies in autonomic nervous system activity. The PAT signal can be measured by using a noninvasive finger-mounted optical sensor and is analyzed with specialized signal processing. The studies were presented at the annual meeting of the Associated Professional Sleep Societies in Chicago (IL, USA).

The PAT signal may help to improve diagnosis and management of obstructive sleep apnea (OSA), according to a study conducted by Alan R. Schwartz, M.D., associate professor of pulmonary medicine and co-director of the Sleep Disorders Center at Johns Hopkins School of Medicine (Baltimore, MD, USA). "Our study showed that the PAT is a sensitive indicator of arousal induced by acute periods of airflow obstruction, such as associated with OSA.”

Other studies found that PAT could be useful in screening for autonomic arousals during sleep and may be better at predicting subjective and objective sleepiness than polysomnographic (PSG) measures such as respiratory and electroencephalographic monitoring. One researcher noted that PAT seemed to provide more subtle data than other tools and thus may offer useful new information about the impact of sleep disorders on waking function. Still another study on advanced congestive heart failure (CHF) found that the PAT signal was a sensitive (90%) and specific (87%) marker of Cheyne-Stokes breathing (CSB) when compared to current techniques. Thus, ambulatory screening for CSB in CHF patients could become routine using the convenient PAT technology.

Professor Peretz Lavie and researchers at the Technion-Israel Institute of Technology found that the PAT signal also provided insights into REM sleep, suggesting that PAT data could be used to develop algorithms to automatically identify episodes of REM. "This next step will allow us to examine, by using PAT, whether the early morning peak in REM-related sympathetic activation is related to the early morning peak in cardiovascular events,” said Dr. Lavie. The PAT technology was developed by Itamar Medical (Caesarea, Israel).




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