Is it possible that the cpap device be a cause of subcutaneous emphysema?

Yes: We have to be careful with the pressures from the CPAP in people with blebs or bullae in that it can actually cause them to pop, cause pneumothorax and yes subcutaneous emphysema, rare but can happen. Sometimes when patients fight the pressure there is also increased esophageal pressure and may actually cause rupture (boorhave's), fortunately also rare.