Table 2. Type of procedures, procedure time, changes of oxygenation parameters.

	NIV group	Control group	P value
Type of procedures
Apc	12	10	0.68
Cryotherapy	13	10	0.39
Balloon Dilation	5	4	1.00
Electrocautery	2	3	0.65
Procedure time (min)	60.5 ± 4.2	67.8 ± 5.6	0.31
Success rate (%)	100.0	100.0	1.00
Lowest SPO2 during procedure	92.4 ± 0.7	92.9 ± 0.5	0.53
PaO2
before procedure	66.7 ± 1.9	67.3 ± 1.8	0.83
after procedure	79.9 ± 2.1	80.3 ± 2.3	0.90