Adaptive servo-ventilation (ASV)

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Adaptive servo-ventilation (ASV) modes of therapy have been developed to manage this central sleep apnea and complex sleep apnea. ASV machines are expensive and insurance will require extensive evidence of medical necessity to approve the purchase and use of ASV. See Justifying ASV backup Info.

Studies have demonstrated marginally superior performance of the adaptive servo ventilators in treating Cheyne-Stokes respiration. Adaptive-servo ventilation adapt to the patient’s ventilatory needs on a breath-by-breath basis, automatically calculating a target ventilation and adjusts the pressure support to achieve it.

Here is a chart posted by a forum member and it shows how the Auto ASV changes pressure to prevent events. In this chart the red pressure line is the pressure the machine is delivering, the blue chart is mask pressure and the flow rate line in black shows the user's breathing flow rate. You can see the machine is set to EPAP min of 6.0, which is the bottom of those pressure charts. The minimum pressure support looks to be 3.0 and that is what is delivered most of the time. The machine frequently increases IPAP pressure to prevent hypopnea and central apnea. In this case there are no events recorded, but the machine is intercepting them by providing as much pressure as is needed to maintain respiratory volume and timing, without getting in the way when that is not needed. In this case the user had limited his maximum pressure support to about 8.0 which was not enough for certain events. The purpose of showing this chart is to show how the ASV adapts to changing needs through the night and on a breath by breath basis.

ASV Working.png

User Review of the Philips Respironics Dreamstation BiPAP Auto SV

User review of the Resmed Aircurve 10 ASV