Table 2.

Comparison of the specified blood parameters between the two groups before and after treatment.

	Treatment	HFNC Group	NIPPV group
pH	Before	7.21 ± 0.03	7.23 ± 0.03
	After	7.38 ± 0.04a	7.34 ± 0.03a
PaCO2	Before	63.97 ± 4.79	63.68 ± 4.81
	After	51.63 ± 3.32b,c	55.61 ± 3.47b
PaO2	Before	54.15 ± 2.74	54.22 ± 2.69
	After	77.94 ± 3.51b,c	68.24 ± 2.67b
PaO2/FiO2	Before	158.21 ± 20.89	158.38 ± 21.46
	After	254.97 ± 18.45b	249.98 ± 17.14b
${\text{HCO}}_3^{-}$	Before	33.06 ± 5.17	30.88 ± 4.87
	After	26.81 ± 4.35a,c	26.49 ± 4.24a
Intubation rate (%)		2.78	2.78

Data are mean ± SD. n = 36. Comparison with before treatment: ^aP < 0.05; ^bP < 0.01 (paired t-test); comparison with the control group: ^cP < 0.05; ^dP < 0.01 (unpaired t-test).

HFNC, high-flow nasal cannula; non-invasive positive-pressure ventilator.