If you're talking full-blown sleep study with all the sensors, then it's pretty easy. If you're attempting to breathe but no air goes in: it's obstructive. If y

If you're talking full-blown sleep study with all the sensors, then it's pretty easy. If you're attempting to breathe but no air goes in: it's obstructive. If you're not attempting to breathe, it's central. You can detect whether or not someone is trying to breathe by looking at the chest strap reading. The cause of central apneas isn't always clear, but at high CPAP pressures it can be caused by CPAP, because it can end up blowing off CO2, and breathing is done primarily in response to an increase in CO2.