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Table 1 Measured and theoretical mean airway pressure during inspiration (i meas and i Th) in different respiratory mechanics

From: Accuracy of delivered airway pressure and work of breathing estimation during proportional assist ventilation: a bench study

Gain (%)

Mechanics

i meas (cmH2O)

i Th (cmH2O)

Δi (cmH2O)

i (%)

30

Normal

6.6

9.4

−2.8

−29.8

 

Obstructive

8.4

10.8

−2.4

−22.2

 

Restrictive

7.0

8.5

−1.5

−17.6

 

Mixed

6.7

8.8

−2.1

−23.9

60

Normal

9.6

13.7

−4.2

−29.9

 

Obstructive

9.5

13.6

−4.1

−30.1

 

Restrictive

10.2

13.0

−2.8

−21.5

 

Mixed

10.3

13.5

−3.2

−23.7

All conditions

 

8.5 ± 1.6

11.4 ± 2.3

−2.9 ± 0.9

−25.4 ± 4.6

  1. Difference and percentage of difference between i meas and i Th were calculated as follows: Δi = i meas − i Th and %Δi = (i meas − i Th)/i Th × 100. Inspiratory trigger = 5 L/min; muscular pressure = 10 cmH2O; PEEP = 5 cmH2O; respiratory rate = 20/min. Respiratory system mechanics, normal: resistance (R) = 10 cmH2O/L/s and compliance (C) = 60 mL/cmH2O; obstructive: R = 20 cmH2O/L/s and C = 60 mL/cmH2O; restrictive: R = 10 cmH2O/L/s and C = 30 mL/cmH2O; and mixed: R = 20 cmH2O/L/s and C = 30 mL/cmH2O