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Table 4 Variables and diagnostic accuracy (for HFNC outcomes) at different time points during HFNC therapy initiated after a planned extubation

From: Early prediction of high flow nasal cannula therapy outcomes using a modified ROX index incorporating heart rate

 

Patients with HFNC success (n = 30)

Patients with HFNC failure (n = 16)

P value

AUROC

Number of patients who remain on HFNC

HFNC success

Number of patients free of mechanical ventilation

HFNC failure

ROX index

Before initiation

30

9.22 (7.61–12.46)

16

10.30 (7.62–12.47)

0.670

0.461 (0.286–0.637)

1 h

30

8.23 (6.58–11.44)

15

6.55 (5.61–8.91)

0.040

0.685 (0.522–0.849)

2 h

30

8.73 (7.18–10.94)

15

7.46 (6.17–9.40)

0.177

0.626 (0.448–0.805)

4 h

30

8.52 (6.67–962)

15

7.20 (5.81–8.18)

0.137

0.647 (0.472–0.821)

6 h

28

8.86 (6.97–11.10)

13

6.60 (5.62–8.00)

0.015

0.754 (0.598–0.911)

8 h

28

8.10 (7.12–11.79)

12

7.52 (5.42–8.36)

0.075

0.687 (0.514–0.860)

10 h

28

9.06 (7.64–11.79)

12

6.43 (5.42–8.51)

0.010

0.773 (0.617–0.928)

12 h

28

8.45 (7.70–10.27)

12

6.55 (5.42–7.42)

0.001

0.860 (0.728–0.992)

18 h

25

9.60 (7.54–11.79)

11

7.84 (5.71–9.78)

0.137

0.665 (0.468–0.863)

24 h

20

7.84 (6.68–10.62)

10

5.93 (5.27–7.17)

0.019

0.775 (0.561–0.990)

48 h

12

5.82 (5.43–11.81)

7

4.86 (3.88–7.92)

0.128

0.764 (0.452–1.000)

Before termination*

NA

12.12 (10.34–14.29)

NA

5.17 (4.21–6.40)

< 0.001

NA

Heart rate (beats/min)

Before initiation

30

90 (74–99)

16

93 (79–113)

0.299

0.594 (0.419–0.769)

1 h

30

87 (77–95)

15

94 (77–111)

0.350

0.584 (0.397–0.771)

2 h

30

82 (70–95)

15

95 (84–106)

0.039

0.693 (0.529–0.856)

4 h

30

83 (72–100)

15

94 (83–115)

0.043

0.699 (0.518–0.881)

6 h

28

81 (73–95)

13

91 (82–110)

0.182

0.640 (0.429–0.851)

8 h

28

84 (68–96)

12

90 (86–106)

0.093

0.677 (0.497–0.856)

10 h

28

83 (69–98)

12

90 (82–115)

0.084

0.682 (0.504–0.860)

12 h

28

78 (70–94)

12

95 (71–119)

0.096

0.676 (0.464–0.889)

18 h

25

80 (71–94)

11

90 (78–112)

0.142

0.663 (0.453–0.873)

24 h

20

80 (73–100)

10

80 (74–112)

0.667

0.550 (0.320–0.781)

48 h

12

74 (70–116)

7

90 (74–103)

0.574

0.575 (0.253–0.941)

Before termination*

NA

80 (69–91)

NA

104 (68–119)

0.033

NA

ROX-HR index

Before initiation

30

11.54 (7.94–15.94)

16

9.96 (9.05–14.90)

0.549

0.554 (0.380–0.728)

1 h

30

9.14 (7.72–14.56)

15

7.83 (5.90–10.98)

0.045

0.681 (0.518–0.845)

2 h

30

10.52 (8.62–13.76)

15

8.70 (7.17–10.42)

0.041

0.690 (0.532–0.849)

4 h

30

9.47 (7.14–12.13)

15

7.66 (5.05–10.48)

0.050

0.692 (0.512–0.873)

6 h

28

10.05 (7.93–13.94)

13

6.87 (6.19–10.03)

0.021

0.741 (0.572–0.909)

8 h

28

10.91 (8.03–14.70)

12

7.74 (5.42–9.30)

0.028

0.731 (0.567–0.894)

10 h

28

10.58 (9.00–15.11)

12

7.22 (5.36–9.83)

0.004

0.804 (0.660–0.948)

12 h

28

12.00 (8.60–13.54)

12

6.89 (5.98–7.41)

< 0.001

0.884 (0.738–1.000)

18 h

25

11.10 (9.42–14.85)

11

8.53 (6.18–10.62)

0.034

0.735 (0.549–0.921)

24 h

20

10.32 (7.48–13.45)

10

6.77 (5.32–8.98)

0.025

0.762 (0.547–0.977)

48 h

12

7.89 (4.56–17.00)

7

5.63 (4.699.30)

0.423

0.639 (0.296–0.982)

Before termination*

NA

15.79 (11.71–18.64)

NA

5.23 (4.63–7.26)

< 0.001

NA

  1. HFNC High flow nasal cannula therapy, AUROC area under the receiver operating characteristic curve, NA not applicable
  2. *Successful or failed termination of HFNC