Table 4.

Logistic regression analysis of the predictors of severity

	B	S.E.	Wald	P value	OR (95% C.I. for OR)
Pneumothorax	2.325	1.128	4.250	0.039	10.231 (1.121 to 93.341)
Ventilator-associated pneumonia	3.469	0.886	15.345	0.000	32.111 (5.660 to 182.176)
Days of mechanical ventilation before 1st extubation	0.740	0.229	10.479	0.001	2.096 (1.339 to 3.281)
Intubation attempts	2.378	0.760	9.795	0.002	10.789 (2.433 to 47.847)
Time elapsed	2.471	0.720	11.796	0.001	11.836 (2.889 to 48.490)