Neither - it is size does matter.
To some people size does matter, to others it doesn't. It all depends on the person.
Room air is 20%. 0ne Liter increases the FIO2 4%. So 1L =24%, 2L=28% and so on to 6L=44%, do not use a cannula above 6 lmp. Becomes uncomfortable and dries out the nares and can cause bloody noses...
oh it sure does!!!
Yes it matters what size the condom is. It has to fit properly. If it is too small, there is chance it will break. If it is too big, it may come off.