xPAP use actually increases CO2 elimination, which is why it can lead to Treatment-Emergent Central Sleep Apnea. You'd have to fall asleep with the device off

xPAP use actually increases CO2 elimination, which is why it can lead to Treatment-Emergent Central Sleep Apnea. You'd have to fall asleep with the device off to get meaningful CO2 rebreathing, which is neither an easy feat nor particularly different whether you've been prescribed or not.