Table 2.

Types of oxygen supplementation in the different groups at the admission.

Types of oxygen supplementation	Group 1		Group 2
	N	%	N	%
<15L (cannula or face mask)	170	73.9	196	69.5
HFNC	42	18.2	52	18.3
VNI	18	7.8	30	10.6
VM	0	0.0	3	1.0