Table 2.

Secondary outcome measures.

Variable	Era I	Era II	Era III	p	p for trend
	1999–2000	2001–2006	2007–2013
	2,146 pts	2,572 pts	2,899 pts
Operated patients (%)	82.3	82.3	83.0	0.7462	0.5062
Oxygen dependency at 30 days (%)	40.2	42.7	44.4	0.0365	0.0106
Length of mechanical ventilation (days)	19.0 (0.8)	19.7 (0.7)	19.7 (0.4)	0.6588	0.4087
Length of hospital stay (days)	44.9 (1.3)	50.3 (1.2)	53.2 (1.2)	<0.0001	<0.0001

Results are mean (SE) or prevalence, as appropriate.

Pts, patients.

Sydak-adjusted p-value <0.0027 was considered significant.