Table 2. Subjects’ outcomes between the two groups ($\overline{x}\pm s$).

Group	Standard group (n=74)	HFNC group (n=77)	t/χ2/U	P
NIV treatment duration (days)	5.93±4.02	4.22±2.12	−3.253	0.002
Length of stay in the ICU (days)	9.89±6.87	10.34±11.27	−0.292	0.771
Total length of hospital stay (days)	18.41±14.42	20.27±18.73	−0.679	0.498
Invasive ventilation duration (days)	2.70±5.97	2.35±10.74	0.247	0.805
Hospitalization expenses (yuan)	92,867.76±83,518.55	91,848.42±95,841.43	0.066	0.947
ROX index	3.79±0.41	4.63±0.59	10.190	<0.001
VAS	3.24±0.48	5.67±0.83	21.910	<0.001

HFNC, high-flow nasal cannula; NIV, non-invasive ventilation; ICU, intensive care unit; ROX, rate-oxygenation index; VAS, visual analogue scale.