Variables

β

s x ¯

Wald χ2

P value

HR (95% CI)

Time of ECMO (h)

<24

−0.92

0.30

9.28

0.002

0.40 (0.22 - 0.72)

24 - 48

−0.89

0.28

10.26

0.001

0.41 (0.24 - 0.71)

≥48

1.00

Group

Intra-operative ECMO

1.00

Post-operative ECMO

0.84

0.36

5.62

0.018

2.33 (1.16 - 4.67)