S8 Compact at CPAP-Supply.com

EPR^TM (expiratory pressure relief) is the most advanced compliance booster available for continuous positive airway pressure (CPAP) therapy. EPR provides you with a way to improve patient comfort and compliance without compromising therapy effectiveness.

EPR is an effective alternative to CPAP therapy. However, unlike other leading CPAP alternatives, EPR features several options that enable you to reliably and predictably control patient therapy while delivering a higher level of patient comfort. EPR is only available on the new S8^TM flow generators, for a complete and versatile therapy solution.

When the patient exhales, the S8 flow generator detects the beginning of exhalation and reduces motor speed to drop pressure. The patient or clinician chooses one of three comfort levels to determine the degree by which pressure will drop.

EPR offers built-in controls so you can reliably and predictably manage patient therapy while delivering a higher level of patient comfort.

EPR ramp enables clinicians to control a patient�s access to EPR, restricting its use during the ramp period only. Patients experience the comfort of EPR during the early stages of sleep when they are alert and breathing against CPAP pressure is most difficult. When the Ramp period expires, pressure reverts to set CPAP. Likewise, EPR can also be set to run full-time, providing more comfort throughout the night.

The Event Detection Circuit is a backup feature of the EPR algorithm. Changes in a patient's sleeping position or sleep stage (ie, REM sleep) may cause sudden, unpredictable events to occur without the typical preceding flow limitation or snoring. When such an event is detected, EPR immediately suspends, and the treatment pressure reverts to set CPAP. EPR remains suspended until the event concludes and normal breathing resumes.

AutoSet� Technology

The amount of pressure required for effective CPAP therapy varies according to sleep stage, sleep position, and other factors. Insufficient pressure results in ineffective therapy while too much pressure can lead to discomfort, non-compliance, and pressure-related side effects.

ResMed�s AutoSet Spirit^TM is an automatic titration system for the treatment of obstructive sleep apnea (OSA). AutoSet devices adjust pressure on a breath-by-breath basis to suit patient needs as they vary throughout the night. As a result, the patient receives the minimum pressure required for effective therapy. The lower pressures may improve patient comfort, reduce pressure-related side effects, and lead to increased patient compliance.

The AutoSet algorithm responds to three key respiratory parameters:

Inspiratory flow limitation
Snore
Apnea

Additionally, AutoSet devices maintain pressure by compensating for mask leak.

Preemptive Response

AutoSet devices act preemptively by increasing pressure in response to inspiratory flow limitation, which typically precedes snore and obstruction. This early intervention prevents snoring and obstructive apneas, thereby reducing respiratory arousals.

Sudden Apnea Response

Apneas may occur suddenly, without being preceded by flow limitation or snore. These sudden apneas are generally associated with sleep onset, change in body position, or REM onset. Following a sudden apnea, AutoSet devices will increase pressure relative to the severity of the event. If no further events occur, AutoSet devices reduce the pressure back to a minimum level.

The AutoSet Algorithm

The efficacy of the AutoSet algorithm is due to its ability to increase pressure in response to the severity of the three parameters (flow limitation, snore, and apnea):

The greater the flow limitation, the more pressure delivered
The louder the snoring, the more pressure delivered
The longer the apnea, the greater the increase in pressure

By responding to these three separate parameters, AutoSet devices effectively normalize sleep while delivering a mean pressure typically 37% lower than fixed pressure therapy.¹

Upper Airway Status and Flow Curves

The most effective way to assess flow limitation is through analyzing the shape of the inspiratory flow-time curve, as shown in the diagrams below. A rounded inspiratory flow contour is the monitoring event that best predicts upper airway patency and a transition to deeper sleep stages without arousals. Studies recommend that this inspiratory flow contour characteristic be routinely used to achieve an optimal pressure level and is preferable to responding to apneas and hypopneas directly. ^2,3

The rounded inspiratory flow curve in the left diagram indicates a normal breath. If the upper airway begins to narrow, causing flow limitation and upper airway resistance, the shape of the curve will flatten as shown in the right diagram. The AutoSet Spirit adjusts the pressure according to the extent of flattening, in order to maintain airflow and restore the curve to normal.

Best Therapy at Lowest Pressures

AutoSet technology has been clinically validated in numerous peer-reviewed journals. Its combined measurement and response to flow limitation, snore, and apnea is unique within the field of sleep-disordered breathing therapy. The AutoSet advantage enables physicians to provide their patients with the best sleep therapy at the lowest possible pressures.

Provides effective therapy at the lowest mean pressure, typically 37% lower than fixed pressure therapy
Adapts to patients� changing pressure needs on a short- and long-term basis
Responds to flow limitation, snore, apneas, and mask leak
Provides greater breathing comfort through smooth, quiet pressure delivery
Provides visual display for quality of mask fit; optional alert tone in presence of significant leaks

EPR (expiratory pressure relief)

AutoSet� Technology