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Table 3 Comparison of gas exchange and mechanical properties of the respiratory system in different phases of the study in patients with lower or higher respiratory system compliance at enrolment

From: Chest wall loading during supine and prone position in patients with COVID-19 ARDS: effects on respiratory mechanics and gas exchange

 

Lower Crs

N = 16

Higher Crs

N = 24

P Crs

P Phase

P Crs*Phase

pH

  

 < 0.0001

 < 0.0001

 < 0.0001

Supine

7.33 ± 0.02#

7.38 ± 0.02

   

Supine + weight

7.34 ± 0.02#

7.38 ± 0.02

   

Prone

7.34 ± 0.02#

7.39 ± 0.02

   

Prone + weight

7.35 ± 0.02°#

7.39 ± 0.02

   

PaO2 (mmHg)

  

0.0425

 < 0.0001

 < 0.0001

Supine

67.9 ± 5.5

69.6 ± 3.8

   

Supine + weight

76.1 ± 6.8°#

62.3 ± 2.4

   

Prone

91.8 ± 9.4°*#

107 ± 15.2°*

   

Prone + weight

100 ± 12.2°*§#

87.1 ± 9.5°*

   

PaCO2 (mmHg)

  

 < 0.0001

 < 0.0001

 < 0.0001

Supine

57.6 ± 4.10#

43.0 ± 2.88

   

Supine + weight

56 ± 4.20#

43.8 ± 2.98

   

Prone

55.8 ± 4.07°#

42.4 ± 3.12

   

Prone + weight

55 ± 4.53°#

43.5 ± 3.04

   

PaO2/FiO2 (mmHg)

  

 < 0.0001

 < 0.0001

 < 0.0001

Supine

107 ± 15.4#

129 ± 15.3

   

Supine + weight

120 ± 18.5°

116 ± 13.1

   

Prone

146 ± 27.0°*#

198 ± 34.9°*

   

Prone + weight

159 ± 30.4°*§

162 ± 25.1°*

   

EtCO2 (mmHg)

  

 < 0.0001

 < 0.0001

 < 0.0001

Supine

42.4 ± 2.58#

36.9 ± 1.65

   

Supine + weight

43.1 ± 2.78#

36.7 ± 1.58

   

Prone

43.4 ± 2.92#

36.8 ± 1.76

   

Prone + weight

44.1 ± 2.98°#

36.5 ± 1.61

   

Ventilatory ratio

  

 < 0.0001

 < 0.0001

 < 0.0001

Supine

2.12 ± 0.28#

1.45 ± 0.22

   

Supine + weight

2.07 ± 0.27°#

1.48 ± 0.23

   

Prone

2.06 ± 0.28°#

1.43 ± 0.23

   

Prone + weight

2.03 ± 0.27°*§#

1.47 ± 0.22

   

Alveolar dead space (%)

  

 < 0.0001

 < 0.0001

 < 0.0001

Supine

26.4 ± 2.45#

14.1 ± 3.13

   

Supine + weight

22.9 ± 3.10°#

16.2 ± 3.27

   

Prone

21.9 ± 3.51°#

16.9 ± 1.14

   

Prone + weight

19.8 ± 4.34°*§#

15.8 ± 3.68

   

Airway plateau pressure (cmH2O)

  

 < 0.0001

 < 0.0001

 < 0.0001

Supine

27.1 ± 1.8#

17.4 ± 1.2

   

Supine + weight

23.4 ± 2.2°#

20.6 ± 1.1°

   

Prone

23.3 ± 2.1°#

16.9 ± 1.1*

   

Prone + weight

21.4 ± 2.8°*§#

19.9 ± 1.1§

   

Airway driving pressure (cmH2O)

  

 < 0.0001

 < 0.0001

 < 0.0001

Supine

16.8 ± 1.8#

8.67 ± 1.3

   

Supine + weight

13.2 ± 2.4°#

11.9 ± 1.0°

   

Prone

13.1 ± 2.4°#

8.17 ± 1.2*

   

Prone + weight

11.1 ± 3.3°*§#

11.1 ± 1.2§

   

Respiratory system compliance (ml/cmH2O)

  

 < 0.0001

 < 0.0001

 < 0.0001

Supine

23.9 ± 3.56#

64.8 ± 10.0

   

Supine + weight

30.9 ± 5.7°#

46.8 ± 4.8°

   

Prone

31.1 ± 5.7°#

68.9 ± 11.4*

   

Prone + weight

37.8 ± 8.7°*§#

50.0 ± 6.2§

   
  1. Crs: respiratory system compliance
  2. The analysis was performed by factorial analysis of variance for repeated measurements, with the phase of the study as a within-subject factor, and the lower or higher respiratory system compliance at enrolment as a fixed, between-subject factor. The interaction effect between respiratory system compliance on the phase of the study was included in the model. The statistical significance of the within-subject factors was corrected with the Greenhouse–Geisser method. In the case of statistically significant interactions, pairwise post hoc multiple interaction comparisons have been carried out, according to Tukey honestly significant difference method for multiple comparison. Adjusted p values are reported where appropriate and are expressed as the statistical significance of the between-group comparison (PCrs), the statistical significance of the within-group comparison (PPhase) and the statistical significance of the interaction between baseline compliance and the phase of the study (PCrs*Phase). Two-tailed p values < 0.05 were considered statistically significant
  3. °p < 0.05 versus supine; *p < 0.05 versus supine + weight; §p < 0.05 versus prone; #p < 0.05 versus normal Crs
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Critical Care

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