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Table 3 PaO2/FiO2 ratio and static respiratory system compliance responses after the first prone positioning session

From: Effect of prone positioning on oxygenation and static respiratory system compliance in COVID-19 ARDS vs. non-COVID ARDS

 

Entire group

PaO2/FiO2-matched

Compliance-matched

N = 168

P value

N = 46

P value

N = 46

P value

PaO2/FiO2 ratio

 Change at the end of the first prone positioning session, mmHg

  COVID-19 ARDS, median (IQR)

89.8 (35.3–135.2)

0.003

89.8 (35.3–135.2)

0.091

89.8 (35.3–135.2)

< 0.001

  Non-COVID ARDS, median (IQR)

40.1 (7.0–77.5)

48.7 (5.0–87.0)

21.1 (0.0–43.8)

 Regression coefficient (COVID vs. non-COVID)

  Unadjusted (95% CI)

46.7 (17.8–75.6)

0.002

32.5 (− 14.7–79.8)

0.172

69.7 (31.2–108.2)

0.001

  Adjusted (95% CI)a

39.3 (5.2–73.5)

0.024

4.0 (− 62.9–71.0)

0.903

58.4 (− 13.5–130.2)

0.108

Static respiratory system compliance

 Change at the end of the first prone positioning session, mL/cmH2O

  COVID-19 ARDS, median (IQR)

3.7 (− 1.0–7.3)

< 0.001

3.7 (− 1.0–7.3)

0.044

3.7 (− 1.0–7.3)

< 0.001

  Non-COVID ARDS, median (IQR)

− 0.3 (− 4.0–1.9)

0.4 (− 1.2–2.3)

− 2.3 (− 7.2–0.0)

 Regression coefficient (COVID vs. non-COVID)

  Unadjusted (95% CI)

4.2 (2.3–6.2)

< 0.001

2.7 (0.0–5.5)

0.047

6.6 (3.8–9.3)

< 0.001

  Adjusted (95% CI)a

3.4 (1.1–5.6)

0.003

0.3 (− 3.3–3.8)

0.883

2.2 (− 2.4–6.7)

0.340

  1. CI confidence interval, FiO2 fraction of inspired oxygen, IQR interquartile range, PaO2 partial pressure of oxygen
  2. aFor multivariable linear regression, the following variables were adjusted: age, sex, body mass index, duration of mechanical ventilation before initiation of prone positioning, sequential organ failure assessment (SOFA) score, Charlson comorbidity index (CCI), baseline setting of mechanical ventilator (positive end-expiratory pressure and tidal volume), and baseline respiratory mechanics before initiation of prone positioning (PaO2/FiO2, static compliance, and ventilatory ratio)