Table 5 Univariable and multivariable analyses with Cox’s proportional hazards model for probability of circuit change within 72 h

 No line

–

–

–

–

–

–

 Single line

0.69

0.53–0.91

0.008

0.74

0.46–1.19

0.216

 Double line

0.29

0.23–0.37

< 0.001

0.39

0.25–0.60

< 0.001

 Venoarterial

–

–

–

–

–

–

 Venovenous

2.05

1.72–2.44

< 0.001

1.33

1.06–1.67

0.013

 Mixed

0.41

0.15–1.11

0.079

0.45

0.16–1.27

0.132

Size of drainage cannula, Fr

1.07

1.03–1.11

0.001

1.01

0.97–1.06

0.549

Size of return cannula, Fr

1.09

1.04–1.13

< 0.001

1.06

1.01–1.13

0.028

Use of unfractionated heparin

0.56

0.47–0.67

< 0.001

0.64

0.52–0.78

< 0.001

Metabolic acidosis

1.42

1.17–1.72

< 0.001

1.17

0.95–1.43

0.147

Access pressure, mmHg

1.001

1.000–1.002

0.027

1.000

0.998–1.002

0.957

Filter pressure, mmHg

0.995

0.994–0.996

< 0.001

1.006

1.002–1.010

0.007

Effluent pressure, mmHg

0.995

0.994–0.996

< 0.001

1.000

0.998–1.002

0.956

Return pressure, mmHg

0.994

0.993–0.995

< 0.001

0.994

0.990–0.998

0.005