Table 3 Arterial blood gases values on admission to the ICU and after the first hour of NIV in patients with NIV success and failure

APACHE II score, median(IQR)

14 (12–16)

20 (17–23)

0.001

GCS, median(IQR)

15 (14–15)

14 (10–15)

0.002

Respiratory rate, median(IQR) [bpm]

25 (22–31)

26 (19–37)

0.58

ABGs on admission to the ICU, median(IQR)

pH

7.37 (7.30-4.40)

7.28 (7.26-7.32)

0.005

paCO₂, mmHg

69.0 (61.2-78.6)

81.6 (72.5-93.2)

0.015

PaO₂/FiO₂

201 (149–274)

161 (137–191)

0.12

HCO₃, mmol

37.7 (33.2-41.2)

38.9 (33.1 -41.1)

0.74

First control ABGs after NIV, median(IQR)

pH

7.38 (7.34-7.42)

7.29 (2.25-7.40)

0.026

paCO₂, mmHg

62.9 (55.6-77.7)

77.0 (57.8-90.6)

0.07

PaO₂/FiO₂

234 (202–293)

193 (137–219)

0.015

HCO₃, mmol

35.4 (33.0-40.0)

36.4 (32.5-39.8)

0.74