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Table 1 MW of ventilation (cmH2O.L) with different flow waveforms (decelerating, square, and sinusoidal) with three types of lung mechanics

From: The effects of pressure- versus volume-controlled ventilation on ventilator work of breathing

Pressure setting

Inspiratory flow waveform

Normal lung R 10 cmH2O/L/s, C 0.1 L/cmH2O

Restrictive lung diseases R 10 cmH2O/L/s,

C 0.05 L/cmH2O

Obstructive lung diseases R 20 cmH2O/L/s, C 0.1 L/cmH2O

tr 0.01 s,

PS 10 cmH2O

Decelerating

Square

Sinusoidal

6.17

5.81

6.71

4.18

3.57

3.99

3.86

3.77

4.48

tr 0.1 s,

PS 10 cmH2O

Decelerating

Square

Sinusoidal

4.98

4.40

5.08

3.11

2.44

2.72

3.23

2.99

3.55

tr 0.01 s,

PS 20 cmH2O

Decelerating

Square

Sinusoidal

24.69

23.23

26.85

16.71

14.28

15.95

15.44

15.09

17.91

tr 0.1 s,

PS 20 cmH2O

Decelerating

Square

Sinusoidal

19.92

17.57

20.31

12.44

9.74

10.88

12.90

11.96

14.20

  1. Also illustrated 2 levels of pressure support and 2 rise times. The square flow waveform has the smallest MW for all lung conditions. In normal and restrictive lungs the largest MW results from decelerating flow, while in obstructive lung condition the sinusoidal flow has the largest MW