Continuous Positive Airway Pressure machine, pronounced ceepap.
Essentially, it delivers air on demand, but at the end of expiration it keeps the pressure higher than 0, often at 12-15cm H20 pressure, therefore splinting the airways open. The airway is sealed and the pressure is maintained via a tight fitting face mask, preventing expiration pressure from falling to 0. That pressure is called Positive End Expiratory Pressure and is the preset prescribed pressure the machine will maintain.
For use in the community, it's usually prescribed for Obstructive Sleep Apnoea. That's a very common condition characterised by snoring, cessation of breathing (apnoea), restless/useless/no sleep and other consequential medical conditions like depression, cardiac failure....the list goes on.
Can it pump tyres up? Hmmm, they're a basic machine and I'm unsure if they have a continuous flow of air. The air is entrained from atmosphere by the machine, usually on demand. Some can be preset to time a breath, but they're a bit more sophisticated...expensive that is. If whilst it was connected to a tube, if you could trick the machine into thinking it was delivering a breath, then maybe it would. It's just a box of valves shunting air..