AutoSet devices adjust pressure on a breath-by-breath basis to suit patient needs as they change throughout the night. As a result, patients receive the minimum pressure required for effective therapy. The lower average pressures improve comfort, reduce pressure-related side effects, and lead to more consistent use of therapy.
After you fall asleep and your pressure needs begin to vary, your AutoSet device responds to three separate parameters: inspiratory flow limitation, snore, and apnea. AutoSet devices act pre-emptively by increasing pressure in response to inspiratory flow limitation and snore, both of which typically precede obstructive apneas. The AutoSet device calculates the pressure you need based on the severity of the event. This early intervention prevents obstructive apneas and reduces respiratory arousals.
AutoSet devices respond to obstructive hypopnea events when they are associated with flow limitation or snoring. Hypopneas that are central in origin (related to your central nervous system, not physical obstruction) should not be treated with increased pressure.
This is a more difficult question to answer. The short answer is that all masks have different physical characteristics and an AutoSet device needs to know the specific characteristics of a mask for best performance. AutoSet devices respond to conditions like leak, snore, and inspiratory flow limitation. To properly treat a person with obstructive sleep apnea (OSA), an AutoSet device needs to know exactly how much of the conditions it detects come from the mask. All masks have some degree of leak to ensure users get fresh air. All masks also have some degree of resistance by virtue of their materials, contours, and leak. So using a mask that is "unknown" to the AutoSet device won't let it do its job properly.
Actually, the opposite is true. According to a recent study, AutoSet technology provides the greatest benefits for people on 10 cm H2O or more.
The AutoSet algorithm has been clinically validated in numerous third-party tests and peer-reviewed journals over the past 11 years.
AutoSet devices evaluate flow limitation on a breath-by-breath basis and adjust pressure according to a five-breath average.