Central Sleep Apnea; Sleep Quality; Ramp - ResMed S9 Series Clinical Manual

Central sleep apnea

The S9 AutoSet and S9 Elite detect both obstructive and central sleep apneas (CSA). CSA detection
uses the Forced Oscillation Technique (FOT) to determine the state of the patient's airway during an
apnea. When an apnea has been detected, small oscillations in pressure (1 cm H
4 Hz) are added to the current device pressure. The CSA algorithm uses the resulting flow and pressure
(determined at the mask) to measure the airway patency.
Note: The S9 Escape and S9 Escape Auto do not differentiate between different types of apneas.
Respiratory flow

Sleep quality

Designed to promote compliance, the Sleep Quality indicator allows the patient to actively engage in
their own therapy by identifying leak, usage and AHI information. This information can be set to:
• Usage—where only usage hours are displayed
• On—where usage, leak and AHI information are displayed.

Ramp

Designed to make the beginning of treatment more comfortable, ramp is available in CPAP , AutoSet or
APAP modes.
In CPAP mode during ramp time, the pressure increases from a low pressure to the prescribed
treatment pressure.
In AutoSet and APAP modes, ramp time defines the period during which the pressure gradually
increases from a lower more comfortable start pressure to the minimum treatment pressure before the
auto-adjusting algorithm commences. In previous products in the AutoSet range, settling was the period
where the device was at a minimum treatment pressure until the auto-adjusting algorithm commenced.
20
16
Settling
8
4
Start
0
10 sec
4 sec 6 sec
delay
CSA detector
(respiratory
begins
pause)
Time
O peak-to-peak at
2
Apnea type
detected -
Central or
Obstructive
Max
Min
9
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