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Table 2 Ventilator settings, airway pressure variables and mechanical power

From: Continuous external negative pressure improves oxygenation and respiratory mechanics in Experimental Lung Injury in Pigs – A pilot proof-of-concept trial

Parameter PEEP [cmH2O] Position CENP [cmH2O] ANOVA (P-values)
    0 -10 -20 -30 -40 Position CENP PEEP Mixed
Tidal volume
VT (mL/kg)
        0.801 0.081 0.694 0.997
0 abdomen 5.77±0.4 5.71±0.4 5.67±0.3 5.65±0.4 5.76±0.4 0.070 0.708   0.620
thorax 5.79±0.5 5.71±0.4 5.83±0.5 5.83±0.5 5.81±0.5     
7 abdomen 5.8±0.5 5.71±0.4 5.78±0.4 5.89±0.4 5.83±0.4 0.109 0.694   0.723
thorax 5.78±0.4 5.58±0.4 5.72±0.3 5.67±0.4 5.82±0.5     
15 abdomen 5.78±0.4 5.67±0.3 5.72±0.4 5.72±0.4 5.8±0.4 0.713 0.689   0.922
thorax 5.73±0.4 5.65±0.5 5.77±0.4 5.74±0.5 5.72±0.5     
Respiratory rate
RR (min-1)
        0.540 0.088 0.005 0.403
0 abdomen 21±7.6 21.4±8.5 21.2±7.6 20.9±7.6 21±7.8 0.064 0.933   0.978
thorax 20.6±7.7 21±9.1 20.5±8.4 20.5±8 20.1±7.9     
7 abdomen 17.3±4 20.8±9.2 20.3±7.4 20.1±7.1 20.9±8.2 0.639 0.166 0 0.536
thorax 19.6±7.2 22.2±8.9 19.8±7.4 19.9±7.3 19.6±7.7     
15 abdomen 19.8±7 20.1±7.4 19.9±7.2 19.9±7 19.8±7.5 0.110 0.956 0,7 0.983
thorax 19.5±7.1 19.9±7.8 19.5±7.5 19.4±7.1 19.6±7.7     
Minute volume ventilation
MV (L)
        0.030 0.735 <0.001 0.517
0 abdomen 6.8±2.1 6.8±2.1 6.7±2.0 6.8±2100 6.7±1.9 0.045 0.968   0.997
thorax 6.6±2.1 6.6±2.1 6.6±2.1 6.6±2100 6.4±2.0     
7 abdomen 5.6±1.2 6.6±2.2 6.6±2.0 6.6±2.0 6.6±2.1 0.565 0.051 0 0.315
thorax 6.3±1.7 6.2±1.7 6.3±1.7 6.2±1.7 6.4±1.7     
15 abdomen 6.4±2.2 6.4±2.2 6.4±2.1 6.4±2.1 6.4±2.1 0.001 0.997 0,7 0.996
thorax 6.2±1.8 6.2±1.7 6.2±1.8 6.1±1.7 6.2±1.7     
Mean airway pressure
mean PAW (cmH2O)
        0.817 0.025 <0.001 0.009
0 abdomen 11.9±2 11.3±2.1 10.7±2 10.7±1.7 9.84±2.1 0.534 <0.001   0.780
  thorax 11.6±1.7 11.4±1.8 11±1.9 10.7±1.9 10.2±1.8     
     0 0 0,10,20     
7 abdomen 15.2±1 15.3±1.7 14.9±1.6 14.8±1.6 14.8±1.5 0.471 0.550 0 0.552
  thorax 15.5±1.4 14.8±1.2 14.8±1.3 14.6±1.3 14.6±1.4     
15 abdomen 21.4±1.4 21.5±1.5 21.7±1.5 22±1.5 22±1.4 0.696 0.792 0,7 0.983
  thorax 21.8±1.6 21.7±1.4 21.8±1.4 21.9±1.4 21.9±1.4     
Peak airway pressure
peak
PAW [cmH2O]
        0.821 <0.001 <0.001 <0.001
0 abdomen 29.5±3.6 28.4±3.7 26.8±3.7 26.8±2.7 24.7±3.9 0.214 <0.001   0.766
  thorax 29.3±3.5 28.7±3.5 27.7±3.7 26.9±3.9 25.8±3.9     
     0 0,10 0,10,20     
7 abdomen 28.5±2.1 28±2.5 27.3±2.5 27.1±2.4 26.9±2 0.572 0.023   0.797
  thorax 28.9±2.8 27.5±2.2 27.3±2.5 26.9±2.5 26.6±2.9     
     0 0 0     
15 abdomen 31.8±2 31.9±2.1 32.7±2.1 33.3±2.1 33.3±1.9 0.636 0.098 0,7 0.873
  thorax 32.2±2.1 32±2.1 32.4±2.1 32.8±2.3 32.7±2.3     
Airway driving pressure
∆PAW (cmH2O)
        0.045 <0.001 <0.001 <0.001
0 abdomen 24.5±3.2 23.8±3.3 22.3±3.4 22.5±2.8 20.4±3.6 0.088 <0.001   0.635
  thorax 24.3±3.5 24.4±3.4 23.3±3.9 22.7±4 21.7±4     
     0 0 0,10,20     
7 abdomen 17.8±2.4 17±2.5 16.2±2.2 16±1.9 15.5±1.9 0.227 <0.001 0 0.761
  thorax 18.2±2.8 16.8±2.1 16.7±2.5 16.2±2.7 16.2±3.2     
    0 0 0 0,10     
15 abdomen 12.7±1.4 13±1.3 13.6±1.4 14.4±1.1 14.2±1.1 0.288 0.001 0,7 0.425
  thorax 13.6±2.4 13.5±2.5 13.7±2.3 14.1±2.8 14.1±2.7     
      0      
Positive end-expiratory pressure
PEEP (cmH2O)
        0.411 0.894 <0.001 0.936
0 abdomen 0.313±1.2 0.209±1.2 0.172±1.2 0.341±1.4 0.208±1.2 0.177 0.885   0.947
  thorax 0.146±0.67 0.129±0.68 0.11±0.67 0.104±0.69 0.17±0.66     
7 abdomen 6.62±0.66 7.05±1.5 7.18±1.4 7.23±1.3 7.3±1.2 0.343 0.015 0 0.399
  thorax 6.86±1 7.03±0.85 6.88±0.99 6.96±1 7.19±0.93     
       0     
15 abdomen 15.3±1.3 15.4±1.3 15.4±1.3 15.3±1.3 15.4±1.3 0.908 1.000 0,7 1.000
  thorax 15.4±1.7 15.3±1.5 15.3±1.4 15.3±1.4 15.3±1.3     
Mechanical power
MP (J/min)
        0.687 0.009 <0.001 0.010
0 abdomen 12.7±4.8 12±4.4 11±3.9 10.5±3.5 9.9±3.4 0.329 <0.001   0.805
  thorax 12.4±4.8 12±4.2 11.6±4.2 11.2±3.9 10.3±3.2     
      0 0,10     
7 abdomen 7.4±1.5 8.08±2.9 7.36±1.8 7.27±1.7 7.36±2 0.957 0.448 0 0.587
  thorax 8.1±2.2 7.81±1.9 7.34±1.9 7.04±1.8 7.12±2     
15 abdomen 5.97±2.4 6.02±2.5 6.17±2.5 6.38±2.7 6.41±2.6 0.004 0.663 0,7 0.947
  thorax 5.69±1.4 5.6±1.3 5.77±1.4 5.75±1.2 5.76±1.3     
Index of over-distension
%E2 (%)
        0.787 0.262 <0.001 0.535
0 abdomen -28.5±5.3 -27.9±5.1 -27.5±3.1 -25.4±2.4 -24.1±2.9 <0.001 0.025   0.565
  thorax -30.7±7.8 -30.4±6.9 -30.7±5.5 -30.3±4.5 -29.2±4.7     
       *     
7 abdomen 0.00224±7 1.69±7.8 2.49±8.7 7.24±10 5.78±8.3 0.011 0.404 0 0.745
  thorax -8.1±12 -5.78±12 -1.84±13 4.29±13 4.58±19     
    *        
15 abdomen 49.8±16 42.4±17 44.3±14 42.8±13 43.5±14 0.002 0.632 0,7 0.505
  thorax 48.6±23 52±23 53.2±22 53.8±27 51.5±26     
Resistance R (cmH2O·s/l)         0.674 <0.001 <0.001 0.015
0 abdomen 0.244±0.043 0.235±0.043 0.218±0.034 0.209±0.027 0.191±0.033 0.014 <0.001   0.759
  thorax 0.247±0.043 0.242±0.037 0.234±0.034 0.224±0.028 0.215±0.027     
      0 0,10     
7 abdomen 0.177±0.028 0.171±0.027 0.158±0.027 0.157±0.03 0.154±0.026 0.546 0.005 0 0.948
  thorax 0.172±0.015 0.167±0.014 0.161±0.018 0.154±0.019 0.153±0.02     
      0 0,10     
15 abdomen 0.138±0.037 0.136±0.032 0.135±0.032 0.133±0.024 0.138±0.021 <0.001 0.956 0,7 0.996
  thorax 0.121±0.019 0.121±0.023 0.122±0.02 0.12±0.023 0.122±0.026     
  1. Values are mean ± standard deviation. Linear-mixed effects, repeated-measures ANOVA with factors position (abdomen or thorax), PEEP and CENP were performed for each parameter (1st line) over all values and for each PEEP-step (1st line of each PEEP step). Post hoc comparison was done according to Sidak after significant effects for CENP (0, 10, 20 and 30 indicate if the value at respective CENP was different compared to CENP 0, 10, 20 and 30 cmH2O, respectively) or PEEP (0 or 7 in PEEP effects column indicate the significant difference between the respective PEEP row with PEEP level indicated in the number, e.g. 0 or 7) or Position (* position effects at the respective CENP). Significance was accepted for P < 0.05
  2. CENP continuous external negative pressure, PEEP positive end-expiratory pressure