Table 2 Gas exchange and respiratory monitoring parameters in NIV success and NIV failure groups during 14 days of NIV

Gas exchange

 PaO₂, mmHg

S

94.0** [73.0–134.0]

87.0^§ [79.0–121.0]

76.5 [65.8–85.0]

89.0 [67.5–127.0]

74.0 [66.0–78.0]

77.0 [66.5–95.3]

84.0^§ [75.0–107.0]

F

73.0 [65.0–96.5]

66.0 [59.0–78.5]

69.5 [62.0–80.5]

69.0 [61.0–85.0]

66.0 [61.0–80.0]

67.0 [51.5–87.5]

68.0 [58.5–81.0]

 FiO₂, %

S

75 [50–95]*

60 [45–70]^§

60 [34–78]^§

60 [45–73]**

45 [43–75]**

48 [34–50]*

45 [35–50]^§

F

85 [78–100]

85 [75–100]

83 [74–100]

80 [70–95]

100 [75–100]

70 [65–93]

80 [70–95]

 PaO₂/FiO₂, mmHg

S

130.8^§ [92.0–230.0]

145.5^§ [112.9–280.0]

135.8* [82.9–236.4]

148.3* [96.7–244.2]

137.8* [106.6–169.7]

172.2 [142.6–252.5]

231.1^§ [162.2–280.0]

F

90.0 [69.9–120.1]

77.5 [62.6–102.1]

82.4 [71.8–103.4]

86.3 [69.4–128.3]

66.0 [62.0–100.0]

78.8 [61.4–133.1]

73.0 [60.9–103.9]

 SpO₂, %

S

98 [96–99]^§

97 [95–99]^§

95 [94–97]

96 [94–98]

95 [94–98]*

96 [95–98]

97 [95–98]^§

F

95 [92–96]

93 [91–95]

95 [92–96]

95 [92–98]

93 [88–94]

94 [93–95]

94 [91–96]

 SpO₂/FiO₂, %

S

128.0** [104.2–198.0]

166.7^§ [135.7–220.0]

151.7** [115.9–233.1]

161.7** [129.8–211.1]

208.9** [132.0–225.4

203.6* [193.0–290.3]

218.9^§ [192–256.1]

F

109.4 [95.5–123.1]

109.4 [93.0–124.7]

114.0 [95.0–125.5]

118.8 [104.2–135.7]

94.0 [90.0–117.3]

135.7 [101.7–146.1]

95.0 [91.0–116.3]

 RR, min-1

S

27.0 [24.0–33.0]

25.0^§ [19.0–27.0]

24.5 [18.5–28.3]

21.0 [19.0–25.5]

24.0 [22.5–29.0]

24.0 [18.5–29.5]

23.0^§ [19.0–25.0]

F

28.0 [24.0–31.0]

30.0 [25.0–32.0]

27.5 [24.0–30.0]

27.0 [24.0–28.0]

30.0 [21.0–35.0]

24.0 [18.5–28.0]

28.0 [25.0–33.5]

 ROX index, units

S

4.75* [3.80–6.62]

7.05^§ [5.61–10.76]

6.44^§ [4.87–9.11]

8.08** [5.33–9.72]

7.62** [5.08–9.51]

9.60* [7.03–13.21]

10.16^§ [7.60–12.36]

F

4.08 [3.42–4.96]

3.79 [2.92–4.65]

4.12 [3.57–5.52]

4.40 [3.86–5.89]

3.35 [2.67–4.56]

5.76 [4.42–6.75]

2.79 [3.52–4.63]

 P_ETCO₂, mmHg

S

25.0^§ [18.0–29.0]

25.0^§ [21.0–27.0]

23.5* [18.0–27.3]

22.0 [15.0–25.5]

20.0* [16.5–23.5]

21.5 [16.5–24.3]

25.0^§ [21.0–27.0]

F

17.0 [14.0–21.5]

15.5 [14.0–20.7]

18.0 [12.5–20.5]

19.0 [13.0–24.0]

14.0 [11.0–18.0]

17.0 [12.0–17.5]

15.0 [13.0–18.0]

 PaCO₂, mmHg

S

37.0* [34.0–40.0]

39.0* [35.0–43.0]

39.0 [36.0–40.0]

37.0 [34.5–40.0]

39.0 [31.0–44.5]

37.8 [30.1–42.8]

39.0 [37.0–42.0]

F

35.0 [32.0–38.0]

35.5 [33.0–38.0]

38.0 [32.0–41.3]

37.0 [37.0–39.0]

34.0 [32.0–40.0]

42.0 [29.8–51.0]

36.0 [33.0–41.0]

 VDalv/VT

S

0.36^§ [0.28–0.47]

0.39^§ [0.28–0.47]

0.42 [0.38–0.52]

0.45 [0.34–0.57]

0.51 [0.38–0.53]

0.44* [0.38–0.49]

0.39^§ [0.36–0.43]

F

0.52 [0.41–0.61]

0.55 [0.41–0.64]

0.51 [0.41–0.67]

0.50 [0.37–0.62]

0.57 [0.50–0.66]

0.57 [0.53–0.69]

0.57 [0.51–0.65]

 VR, units

S

2.91 [2.03–3.76]

2.26 [1.86–3.10]

2.48 [1.94–3.35]

2.04 [1.62–2.68]

2.58 [2.21–3.26]

2.64 [2.07–3.00]

2.13** [1.79–2.96]

F

2.58 [2.17–3.26]

2.89 [2.33–3.59]

2.73 [1.74–3.05]

2.48 [2.10–3.13]

2.96 [1.91–3.55]

2.81 [1.56–3.64]

2.99 [2.33–3.88]

Noninvasive ventilation monitoring parameters

 Pressure support above PEEP, cmH₂O

S

10.0 [7.0–10.0]

8.0* [6.0–10.0]

9.5 [7.5–11.3]

9.0 [6.0–11.0]

9.0 [4.0–12.0]

6.5 [6.0–7.8]

7.0^§ [5.0–9.0]

F

10.0 [9.0–12.0]

10.0 [8.0–12.0]

9.0 [8.0–10.3]

10.0 [8.0–12.0]

11.0 [8.0–14.0]

10.0 [7.5–10.5]

11.0 [8.0–12.0]

 VTe max, ml/kg IBW

S

9.7 [8.2–13.4]

9.8 [8.7–11.1]

11.3 [8.6–12.9

9.3 [7.7–11.2]

10.6 [8.8–12.7]

9.6 [8.5–12.6]

10.7 [8.2–13.5]

F

10.1 [8.2–12.4]

10.1 [8.0–13.2]

10.4 [8.1–13.0]

9.8 [8.2–11.3]

10.8 [8.2–14.6]

9.6 [8.5–12.6]

10.7 [8.2–13.5]

 VTe mean, ml/kg IBW

S

7.2 [5.8–9.4]

7.6 [6.4–9.0]

7.0 [5.7–8.4]

8.1 [6.5–9.5]

8.6 [7.0–10.1]

8.4 [6.6–10.3]

7.5 [6.1–9.0]

F

8.2 [6.7–10.0]

7.5 [6.6–10.2]

7.8 [7.1–11.5]

8.1 [6.3–9.0]

10.3 [7.4–13.0]

7.3 [6.9–11.7]

7.8 [6.6–11.3]

 Leak mean, l/min

S

28 [21-40]

32 [22–43]

34 [27-40]

37 [25–50]

31 [27-34]

34 [28–44]

28 [23-39]

F

30 [13-37]

30 [18-38]

27 [21-34]

29 [13–44]

32 [28-39]

30 [24–44]

32 [21-39]

 PIF mean, l/min

S

58 [39–82]

43 [36–63]

44 [37–56]*

39 [36–49]

50 [41–56]

51 [38–73]

45 [35–56]^§

F

60 [47–86]

63 [49–85]

56 [47–85]

54 [40–69]

60 [47–79]

59 [34–63]

63 [51–92]

 MV mean, l/min

S

17.5 [13.8–21.1]

14.1** [11.3–15.8]

12.4 [10.5–19.6]

12.6* [11.1–13.9]

16.8 [14.5–18.9]

15.3 [10.6–20.6]

13.4^§ [10.8–15.8]

F

17.2 [14.1–21.7]

19.3 [14.1–22.8]

17.0 [14.3–23.5]

15.3 [13.7–20.2]

19.6 [14.6–26.5]

17.6 [11.3–20.4]

19.4 [14.3–26.3]

 Ti max, s

S

0.94 [0.82–1.24]

1.04** [0.92–1.36]

1.09* [0.91–1.59]

1.15 [1.00–1.24]

1.00 [0.90–1.23]

1.12 [0.82–1.56]

1.13^§ [0.98–1.26]

F

0.89 [0.79–1.06]

0.89 [0.77–1.00]

0.93 [0.78–1.05]

0.96 [0.82–1.30]

0.82 [0.73–1.20]

1.32 [1.04–1.45]

0.82 [0.70–1.02]

 Ti min, s

S

0.76 [0.67–0.98]

0.86** [0.80–1.13]

0.92 [0.70–1.11]

1.00 [0.86–1.07]

0.79 [0.73–0.93]

0.90 [0.70–1.26]

0.93^§ [0.72–1.08]

F

0.78 [0.69–0.94]

0.76 [0.61–0.89]

0.78 [0.62–0.90]

0.90 [0.63–1.12]

0.73 [0.69–1.19]

1.13 [0.98–1.25]

0.69 [0.60–0.90]

 I/E

S

0.71 [0.67–0.78]

0.67 [0.56–0.77]

0.71 [0.58–0.91]

0.63 [0.62–0.67]

0.69 [0.66–0.71]

0.67 [0.58–0.76]

0.67 [0.56–0.77]

F

0.71 [0.59–0.77]

0.71 [0.59–0.83]

0.67 [0.58–0.77]

0.67 [0.63–0.83]

0.71 [0.63–0.83]

0.67 [0.63–0.91]

0.67 [0.59–0.77]

Accessory respiratory muscles

 Patrick scale, points

S

1.0 [0.0–2.0]^§

0.0 [0.0–1.0]^§

1.0 [0.0–2.0]^§

0.0 [0.0–2.0]^*

1.0 [0.0–1.5]^**

0.5 [0.0–1.8]^*

0.0 [0.0–0.0]^§

F

2.0 [2.0–3.0]

2.0 [2.0–3.0]

2.0 [1.8–3.0]

2.0 [1.0–2.0]

2.0 [2.0–3.0]

2.0 [2.0–3.5]

3.0 [2.0–4.0]

Patients remaining on NIV

 n (%)

S

23 (100.0)

23 (100.0)

14 (60.8)

9 (39.1)

5 (21.7)

4 (17.4)

23

F

57 (100.0)

41 (71.9)

26 (45.6)

15 (26.3)

11 (19.3)

5 (8.8)

57

Organ dysfunction before intubation

 SOFA before intubation

F

-

-

-

-

-

-

5.0 (4.5–7.0)

 Non-respiratory SOFA before intubation

F

-

-

-

-

-

-

1.0 (0.5–3.0)