Distinguish Obstructive and Central Sleep Apnea by Portable Peripheral Arterial Tonometry.

Sleep apnea has a very high prevalence in the general population. Sleep apnea can be the cause for cardiovascular disorders. An increased risk for suffering from hypertension, stroke, and myocardial infarction had been shown in large studies, like the Sleep Heart Health Study. Sleep related breathing disorders and sleep apnea had been diagnosed in sleep laboratories with polysomnography in the past. Today in view of the high prevalence of sleep disordered breathing, home sleep apnea testing (HSAT) has become the accepted test for the diagnosis of sleep apnea, if there are no other comorbidities, and if a high pretest probability was confirmed by a sleep physician. For home sleep apnea testing, the number of sensors needed should be reduced. Some methods use indirect means to derive features to detect sleep apnea and hypopnea events. A very well developed method is peripheral arterial tonometry (PAT). This method records the pulse wave on a finger and derives sleep and sleep apnea feature. The PAT method has been tested under many conditions. As an indirect method, it was long seen as a limitation that obstructive and central sleep apnea events could not be distinguished. A new multicenter trial was set up to develop algorithms, which could distinguish central and obstructive apnea events with sufficient accuracy.