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Table 4 Loading conditions of the right ventricle in the average breath

From: Heart–lung interactions during neurally adjusted ventilatory assist

 

PSVlow

PSVal

PSVhigh

NAVAlow

NAVAal

NAVAhigh

P value

       

Level

Mode

Interaction

Transmural central venous pressures at c wave

         

 End expiratory (mmHg)

2.6 ± 4

1.3 ± 5.1

2.3 ± 4.1

4.2 ± 4.5

2.4 ± 2.5

3.1 ± 3.4

0.331

0.018

0.817

 End inspiratory (mmHg)

4.8 ± 4.5

1.5 ± 4.3

1.5 ± 3.9

6.6 ± 3.0

3.6 ± 3.3

4.2 ± 2.2

0.001

0.1

0.697

 Cyclic change (mmHg)

2.2 ± 3

0.3 ± 1.7

−0.8 ± 2.1

2.4 ± 4

1.2 ± 1.2

1.1 ± 2.4

0.015

0.015

0.303

Isovolumetric pressure generation

         

 Inspiratory transmural isovolumetric pressure (mmHg)

11 ± 4.6

12.3 ± 4.4

14 ± 4.6

11.5 ± 4.7

11.1 ± 4.6

10.8 ± 4.2

0.057

0.095

0.005

 Expiratory transmural isovolumetric pressure (mmHg)

12.7 ± 4.7

11.5 ± 4.5

12 ± 5.2

12.8 ± 4.1

12.8 ± 3.7

12.1 ± 4.7

0.266

0.257

0.318

 Cyclic change in transmural isovolumetric pressure (mmHg)

−1.8 ± 1.4

0.8 ± 2.2

2 ± 2

−1.3 ± 1

−1.8 ± 2.1

−1.3 ± 1.1

0.003

0.009

0.003

Total pressure generation

         

 Inspiratory transmural pressure generation (mmHg)

29.7 ± 10.7

27.2 ± 7.8

29.6 ± 9.4

29.8 ± 9.6

26.9 ± 8.5

26.9 ± 7

0.06

0.38

0.561

 Expiratory transmural pressure generation (mmHg)

30.4 ± 10.8

23.5 ± 8.3

26.5 ± 9.4

28.6 ± 10.4

27.9 ± 8

27 ± 6.9

0.231

0.053

0.241

 Cyclic change in transmural pressure generation (mmHg)

−0.7 ± 2.3

3.8 ± 8

3.1 ± 1.5

1.2 ± 3.7

−1 ± 4.5

0 ± 2

0.543

0.076

0.033

  1. Data presented as mean ± standard deviation. Data derived from the analysis of the single average breath with measurement of the central venous pressure (CVP) at the base of the c wave. Isovolumetric pressure generation was calculated as the difference between pulmonary artery pressure at valve opening and CVP at the c wave, and the total pressure generation as systolic pulmonary artery pressure minus CVP at the c wave. P values from repeated-measures analysis of variance (within-subject factors: ventilation mode, support level). NAVA, neurally adjusted ventilator assist; NAVAal, adequate NAVA level identified by a titration procedure; NAVAhigh, 200% of the adequate NAVA level; NAVAlow, 50% of the adequate NAVA level; PSV, pressure support ventilation; PSVal, adequate level of pressure support ventilation identified on clinical grounds; PSVhigh, 150% of adequate PSV level; PSVlow, 50% of adequate PSV level.