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Table 3 Electrical impedance tomography and pressure-volume curve data

From: Variation of poorly ventilated lung units (silent spaces) measured by electrical impedance tomography to dynamically assess recruitment

Variable

PEEP 5 incremental phase

PEEP 10 incremental phase

PEEP 15

PEEP 10 decremental phase

PEEP 5 decremental phase

Friedman test p value

Nondependent silent spaces, %

0.4 [0–3.3]

1.3 [0–3.9]

1.4 [0.4–4.3]

1.7 [0.5–3.0]

0.7 [0.1–2.2]

0.109

Dependent silent spaces, %

16.3 [11.7–17.9]

12.3 [9.2–15.2]a

8.7 [6.2–11.1]a,b

10.4 [8.0–12.7]a,c

13.6 [9.1–16.2]a,c,d

< 0.001

Center of ventilation ventral-dorsal, %

41.9 [38.1–48.8]

46.3 [41.8–50.8]a

49.4 [46.9–54.8]a,b

47.7 [44.3–52.3]a,c

43.2 [40.9–50.9]a,c,d

< 0.001

Regional compliance (ROI 4), ml/cmH2O

3.09 [1.21–4.95]

4.32 [2.92–6.03]a

5.90 [4.63–6.8]a,b

6.01 [4.53–6.53]a,b

4.27 [2.64–5.34]c,d

< 0.001

Regional compliance (ROI 3), ml/cmH2O

10.52 [7.74–12.27]

12.32 [8.64–14.03]a

13.12 [10.41–14.96]a,b

13.10 [10.77–17.35]a,b

11.25 [9.11–14.5]a,d

< 0.001

Regional compliance (ROI 2), ml/cmH2O

13.9 [12.24–18.97]

13.55 [12.82–17.06]

13.09 [11.07–15.93]b

14.95 [12.59–19.32]b,c

14.74 [11.38–20.21]

0.026

Regional compliance (ROI 1), ml/cmH2O

10.53 [7.51–13.27]

7.89 [5.93–9.73]

6.15 [4.63–8.15]a,b

7.68[6.95–10.96]c

10.98 [6.26–12.58]c

< 0.001

Tidal distribution index

1.9 [1.4–2.9]

1.3 [0.8–1.7]a

1.0 [0.7–1.2]a,b

1.3 [1.1–1.7]a,c

1.8 [1.4–2.2]a,c

< 0.001

Regional compliance dependent lung, ml/cmH2O

11.9 [10.4–16.7]

17.7 [12.3–19.2]a

19.1 [14.2–21.3]a,b

18.9 [15.7–22.8]a,b

16.0 [12.3–19.8]a,d

< 0.001

Regional compliance nondependent lung, ml/cmH2O

25.3 [21.3–30.4]

22.7 [19.5–25.8]

20.0 [16.6–22.8]b

24.3 [18.7–28.5]c

26.4 [17.5–30.7]

< 0.001

∆EELV, ml

170 [132–242]

495 [411–565]a

800 [638–943]a,b

435 [336–574]a,c

190 [133–262]b,c,d

< 0.001

∆EELI, ml

170 [105–260]

559 [404–716]a

1190 [903–1378]a,b

777 [500–930] a,b,c

270 [191–410]a,b,c,d

< 0.001

Recruitment

P-V curve, ml

Baseline

87.60 [32.20–119.00]

114.50 [71.50–171.00]

−82.20 [−164.70 to 3.00]

−101.20 [−158.50 to −28.00]

 

Recruitment

P-V curve, ml/kg IBW

Baseline

1.32 [0.66–2.18]

2.09 [1.05–3.22]

−1.61 [−3.26 to 0.04]

−1.65 [−2.22 to −0.59]

 
  1. Abbreviations: PEEP Positive end-expiratory pressure, RM Recruitment maneuver, ROI Region of interest, ∆EELV Change in end-expiratory lung volume, ∆EELI Change in end-expiratory lung impedance, P-V Pressure-volume, IBW Ideal body weight
  2. Data are expressed as median [IQR]
  3. Wilcoxon post-hoc analysis for couples: aStatistically significant difference from PEEP 5 incremental phase; bStatistically significant difference from PEEP 10 incremental phase; cStatistically significant difference from PEEP 15; dStatistically significant difference from PEEP 10 decremental phase