In order for us to ship a Z2 Auto set in APAP mode, we must have a prescription on file for an APAP device. If you have already been prescribed CPAP at a fixed pressure setting, then all you need is for your doctor to write a new prescription with the pressure range settings that are required to program the Z2 Auto in APAP mode. You doctor will need to know that the full pressure range of the Z2 Auto is from 4 to 20 cmH2O. So the minimum pressure will be at least 4 and the maximum will be at most 20.