ASV waveform
ResMed’s Adaptive Servo-Ventilation (ASV) mode is the most proven treatment on the market for Cheyne-Stokes respiration (CSR), periodic breathing and central and/or mixed apnea. It has been the subject of more published papers than any other therapy and used for more than 10 years to treat patients with these conditions.
How it works
EPAP is set to manage the patient's upper airway when OSA presents simultaneously with periodic breathing. ASV also helps to reduce dyspnea, excessive preload and pulmonary congestion in such patients.
Pressure support is automatically titrated to compensate for fluctuations in the patient's respiratory drive.
Patient conditions
The VPAP Adapt provides noninvasive ventilatory support to patients (over 30kg) suffering from OSA and respiratory insufficiency caused by CSR, periodic breathing and central and/or mixed apneas.
CSR is a common breathing disorder in certain patient groups. With its unique ASV algorithm, the AutoSet CS device has been specifically designed to provide a rapid response to CSR, providing ventilatory support when it is needed.
Extensively researched, clinical evidence confirms the proven benefits of ASV therapy in these patient groups.
Ventilation to a moving target
To determine the degree of pressure support needed, the ASV algorithm continuously calculates a target ventilation. The target is 90% of the patient's recent average ventilation—changes in ventilation over the course of the night are well-supported.
Patient comfort
VPAP Adapt enhances patient comfort by delivering the Easy-Breathe waveform (in ASV mode) and also by optimising patient–device synchronisation.
The Easy-Breathe waveform offers a gentle increase and decrease in line with natural breathing to offer maximum comfort to the patient.
To optimise patient–device synchrony, the device tracks the patient's breath rate as well as the shape and timing of the patient's inspiration. Information about the patient's breathing, which is learnt during each breath, is used to deliver the desired pressure profile for subsequent breaths.
When a central apnea/hypopnea occurs, support quickly responds to compensate for the drop in patient respiratory drive. The VPAP Adapt provides backup breaths at the patient's recently learnt respiratory rate. If the apnea/hypopnea persists, the timing of support transitions to the default backup respiratory rate of 15 bpm.
Minimal support during stable breathing
The ASV algorithm starts working even before the CSR cycle begins, from the moment the patient lies down, puts on the mask, and switches on the VPAP Adapt device.
The underlying expiratory positive airway pressure (EPAP) is adjustable from 4–15 cm H2O and helps reduce dyspnea, excessive preload and pulmonary congestion, while preventing obstructive apneas.
The level of pressure support adjusts to the minimum required to ensure ventilation is at or above the target. The default minimum value of 3 cm H2O is small enough to ensure the patient keeps spontaneously breathing, while providing just enough support for extra comfort.
Support when it is needed
When a central hypopnea/apnea occurs and ventilation suddenly drops below the target, pressure support rapidly increases over a few breaths to maintain ventilation.