[quote Hollyhobbi]@Passmeabottlemrjones a Cpap machine only needs an electrical source not oxygen. It uses ambient room air, the same air we all breathe in. My dad uses a Cpap machine at night and it probably saved his life back in March after he caught Covid.[/quote]
I'm sorry, but this is misleading.
For sleep apnoea, the breathing problem is caused by the tissues at the back of the mouth collapsing when they relax, so the throat gets blocked. CPAP uses ambient air and supplies just enough pressure to keep the throat open.
For covid, where the lungs aren't working properly and the patient is starved of oxygen, a slightly different CPAP machine basically blows high pressure oxygen into the lungs. It uses oxygen - lots of oxygen - much more than ventilation, because it's a very leaky system.
With ventilation, the patient is sedated and a tube put down into their airway. The tube is connected to a ventilator which breathes for them. This also uses oxygen, but less than the CPAP, because there aren't so many leaks.
More info at coronavirusexplained.ukri.org/en/article/vdt0008/