ASV therapy
Available in: ASV and ASVAuto modes.
ResMed's ASV therapy targets the patient’s own recent Minute Ventilation (MV). It treats central sleep apnea and/or mixed apnea and periodic breathing by automatically adjusting the pressure support (PS) in a defined pressure range to maintain Minute Ventilation at the target.
In ASV mode, the expiratory positive airway pressure (EPAP) is fixed and can be manually adjusted to eliminate obstructive events. The Pressure Support (PS) varies between the Min PS and the Max PS to answer to the patient's need. Mandatory breaths are delivered at the patient’s recent spontaneous breath rate, ie, the timed backup rate is automatically calculated to match the patient’s needs and is applied appropriately in the case of an event.
In addition to the functionality of the ASV mode, the device in ASVAuto mode automatically adjusts the expiratory pressure in order to provide only the amount of pressure (EPAP) required to maintain upper airway patency. The device analyzes the state of the patient’s upper airway on a breath-by-breath basis and delivers expiratory pressure within the allowed range (Min EPAP and Max EPAP) according to the degree of obstruction. EPAP is automatically adjusted depending on three parameters: inspiratory flow limitation, snore, and obstructive apnea.
Pressure Support
Pressure Support (PS) is defined as the difference between the peak pressure at the end of inspiration, and the minimum pressure at the end of expiration (ie, the amplitude of the pressure waveform delivered).
The AirCurve 11 VPAP Tx pressure support (Inspiration:Expiration and Expiration:Inspiration) trigger points are set automatically based on measurement of the patient respiratory flow. The AirCurve 11 VPAP Tx ASV algorithm will automatically adjust pressure delivery to keep the patient’s respiratory flow even.
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ResMed recommends that the Max PS should be set to 15 cm H2O (15 hPa).
Backup rate
The AirCurve 11 VPAP Tx device uses breath phase mapping to provide a timed backup rate that is synchronized with the patient’s own breathing. When the patient deviates from the ventilatory target, the AirCurve 11 VPAP Tx device aims to stabilize the patient by adjusting Pressure Support. If necessary, it will adjust the timed backup rate from one that matches the patient’s own recent rate towards the built-in default 15 BPM backup rate.
Leak management with VSync
Using ResMed's VSync algorithm, the AirCurve 11 VPAP Tx device monitors and compensates for leak by continuously and automatically adjusting the baseline flow. This enables reliable delivery of therapy pressure while maintaining patient-device synchrony.