WatchPAT™300 System
10
Operation Manual
2
OVERVIEW
Sleep apnea syndrome is considered a major public health problem. The prevalence of the
syndrome is estimated at 2% to 5% in the adult population. Obstructive sleep apnea is
characterized by recurrent events of complete or partial obstruction of the upper airways
during sleep with the presence of breathing effort, while Central Sleep apnea is
characterized by no respiratory effort. Both conditions often lead to hypoxemia, and/or
arousals associated with sympathetic nervous system activation. The diagnosis and
assessment of the sleep apnea patient is usually based on the apnea-hypopnea index (AHI –
the number of Apneas, and Hypopneas per hour of sleep) and / or the Respiratory
Disturbance Index (RDI) which is AHI plus Respiratory Effort Related Arousals (RERA),
along with sleep architecture. The common consequences of this sleep disruption are
daytime sleepiness, poor daytime performance and increased vulnerability to accidents.
Cardiovascular complications such as systemic/pulmonary hypertension, ischemic heart
disease and arrhythmias are the major sequel of sleep apnea in the adult population.
The WP300 is worn on the wrist and utilizes a plethysmographic based finger–mounted
probe that measures the PAT
®
(Peripheral Arterial Tone) signal. The PAT
®
signal is a
measurement of the pulsatile volume changes in the fingertip arteries which reflects the
relative state of the arterial vasomotor activity, and thus indirectly the level of sympathetic
activation. Peripheral arterial vasoconstriction, which mirrors sympathetic activation, is
shown as attenuation in the PAT
®
signal amplitude.
The same probe measures RED and IR channels used for the measurement of SpO2 signal.
The PAT
®
and SpO2 signals are recorded continuously and stored on an embedded flash
memory, together with data from a built-in actigraph (monitor for human rest/activity
cycles, embedded in the WP300). Snoring and Body Position signals are generated from the
SBP/RESBP integrated sensor (optional). The RESBP (Respiratory Effort Snoring and
Body Position) sensor records the subject’s chest movement signal in addition to the
snoring and body position signals that are included with the SBP sensor.
Following the sleep study, the recordings are automatically downloaded and analyzed in an
offline procedure using the proprietary zzzPAT software.
The zzzPAT algorithms use the WP300 channels for the detection of sleep related
breathing disorders and sleep staging (Rapid Eye Movement (REM), Light Sleep, Deep
Sleep and Wake). Further identification of central apnea the respiratory movement channel
generated from the RESBP sensor is used in the zzzPAT algorithm in addition to the other
channels. The zzzPAT uses WP300's snoring and body position channels to generate
snoring level and body position discrete states. The use of SBP/RESBP is optional and
according to physician preference.
The software issues comprehensive reports of the study, with statistics and graphic
presentation of the results. The whole night data can be viewed and the automatically
detected events can be revised manually.
