One of the newest PAP (positive airway pressure) machines on the market is Adaptive Servo Ventilation (ASV) which is a non-invasive therapy and created especially for treating adults suffering from obstructive sleep apnea and central/complex sleep apnea.
This ventilatory treatment unit can control and adjust to the patient’s issue continuously. Based on the input from the patient, the ASV adjusts the pressure which means that it doesn’t require a fixed value but rather adjusts to the patient’s needs.
Namely, this is what makes ASV so much different from CPAP (continuous positive airway pressure) therapy which is considered the number one therapy for treating obstructive sleep apnea.
How do ASV Units Work?
We’ve already mentioned that it works according to the input of the patients. But, how exactly does it work? To be more precise, the ASV unit identifies abnormalities in the patient’s breathing patterns and intervenes with as much as needed to keep breathing at 90% of the patient’s normal breathing, i.e. before the sudden breathing change. Once the OSA episode finishes, the ASV adjusts to the usual breathing pattern of the patient.
Once the breathing becomes stable, the ASV machine provides just enough support to provide about a 50% reduction in the patient’s work of breathing. This is mainly the reason why the ASV machine is considered as the most comfortable treatment option for obstructive sleep apnea.
Adaptive Servo Ventilation VS Other PAP Options
Before ASV was created, there were three main PAP (positive airway pressure) machines sleep technologists worked with. The most common is probably CPAP (continuous positive airway pressure) therapy, in which the patient is treated with the same pre-set pressure continuously. Second, the BPAP (bilevel positive airway pressure) machine detects when the patient is exhaling and lowers the pressure to make it easier to exhale. Last, BPAP with IMV (intermittent mandatory ventilation, is similar to the previous since it also identifies when the patient is exhaling and provides support based on a pre-set pressure and rate.
In general, these are all beneficial in treating obstructive sleep apnea, however, patients complain about the discomfort it causes and the time it takes to get used to using the machine. Luckily, the new ASV machines take advantage of high-end technology and smartly adapt to the patient’s needs, not the other way around.
Who Can Use the Adaptive Servo Ventilation Therapy?
Generally speaking, all patients suffering from complex sleep apnea, central apnea already treated with CPAP or BPAP therapy, are suitable candidates for using Adaptive Servo Ventilation therapy.
But, before even considering ASV, ensure you do not fit in some of the following since these patients shouldn’t use ASV:
- Patients with chronic and profound hypoventilation
- Patients suffering from neuromuscular disease or have restrictive thoracic
- Patients who have chronic obstructive lung disease, moderate to severe
- Patients with a chronic high partial pressure of carbon dioxide (>45 mm Hg) on arterial blood gas (ABG)
Furthermore, ASV therapy isn’t a suitable treatment option for those who have symptomatic chronic heart failure and lowered LVEF </=45%. Also, patients with moderate to severe predominant central sleep apnea should better choose another therapy rather than ASV.
In short, the ASV therapy is extremely beneficial for treating obstructive sleep apnea when used by the right type of patients. And, what’s probably most convenient about this therapy is the fact that it adjusts to the patient’s needs, not vice versa.