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Table 2 Comparison of forced oscillatory parameters

From: Predictors of expiratory flow limitation measured by forced oscillation technique in COPD

 

Patients with COPD n = 74

High EFL index group n = 37

Low EFL index group n = 37

Controls n = 39

R5 (cmH2O/L/s)   Whole breath

4.36 (1.58 – 8.06)

5.09 (2.45 – 8.06)†*

3.51 (1.58 – 7.99)*

2.79 (1.15 – 5.70)

          Inspiratory

3.80 (1.57 – 8.16)

4.80 (1.90 – 8.16)†*

3.11 (1.57 – 7.64)*

2.48 (1.01 – 5.03)

           Expiratory

4.78 (1.60 – 10.45)

5.55 (2.86 – 10.45)†*

4.17 (1.60 – 8.34)*

3.04 (1.29 – 6.36)

             ΔR5

-0.78 (-5.51 – 0.45)

-0.98 (-5.51 – 0.45)

-0.70 (-2.71 – 0.36)

-0.54 (-2.39 – 0.16)

R20 (cmH2O/L/s)  Whole breath

3.21 (1.45 – 6.41)

3.59 (1.77 – 6.00)†*

2.86 (1.45 – 6.41)*

2.57 (1.20 – 4.20)

          Inspiratory

3.03 (1.44 – 6.56)

3.38 (1.79 – 5.27)†*

2.56 (1.44 – 6.56)*

2.47 (1.14 – 3.76)

           Expiratory

3.41 (1.52 – 7.66)

3.72 (1.73 – 7.66)†*

3.08 (1.52 – 6.26)*

2.69 (1.26 – 4.84)

            ΔR20

-0.29 (-3.31 – 0.34)

-0.32 (-3.31 – 0.34)

-0.28 (-1.72 – 0.30)

-0.28 (-1.3 – 0.29)

R5-R20 (cmH2O/L/s) Whole breath

1.22 (-0.04 – 2.96)

1.51 (0.50 – 2.96)†*

0.64 (-0.04 – 1.83)*

0.25 (-0.76 – 1.76)

          Inspiratory

0.82 (-0.10 – 2.89)

1.32 (0.11 – 2.89)†*

0.39 (-0.10 – 1.99)*

0.11 (-0.96 – 1.27)

           Expiratory

1.42 (0.02 – 3.52)

1.99 (0.88 – 3.52)†*

0.78 (0.02 – 2.08)*

0.36 (-0.57 – 2.24)

          Δ(R5-R20)

-0.50 (-2.20 – 0.32)

-0.68 (-2.20 – 0.30)†*

-0.31 (-1.05 – 0.32)

-0.29 (-1.15 – -0.04)

X5 (cmH2O/L/s)   Whole breath

-1.23 (-6.92 – 0.17)

-2.77 (-6.92 – -0.48)†*

-0.42 (-3.50 – 0.17)*

-0.29 (-1.48 – 0.20)

          Inspiratory

-0.78 (-3.85 – 0.09)

-1.57 (-3.85 – -0.11)†*

-0.42 (-3.24 – 0.09)*

-0.33 (-1.33 – 0.18)

           Expiratory

-1.63 (-11.17 – 0.25)

-3.74 (-11.17 – -0.85)†*

-0.37 (-3.77 – 0.25)*

-0.23 (-1.64 – 0.21)

            ΔX5

0.55 (-0.47 – 8.50)

1.80 (0.59 – 8.50)†*

-0.03 (-0.47 – 0.54)

-0.06 (-0.37 – 0.48)

Fres (Hz)     Whole breath

13.74 (4.23 – 26.52)

19.61 (7.91 – 26.52)†*

7.97 (4.23 – 25.96)*

6.53 (4.03 – 14.89)

          Inspiratory

10.87 (4.46 – 27.07)

16.10 (5.76 – 24.83)†*

8.16 (4.46 – 27.07)*

6.71 (4.05 – 12.36)

           Expiratory

16.10 (4.00 – 28.20)

22.27 (10.06 – 28.20)†*

7.82 (4.00 – 24.85)*

6.30 (4.00 – 17.42)

            ΔFres

-2.33 (-15.00 – 2.98)

-6.34 (-15.00 – -0.08)†*

0.14 (-5.74 – 2.98)

0.17 (-5.37 – 1.75)

ALX (cmH2O/L/s x Hz) Whole breath

7.44 (0.04 – 62.87)

22.16 (1.96 – 62.87)†*

1.42 (0.04 – 33.88)*

0.92 (0.01 – 7.64)

          Inspiratory

3.54 (0.07 – 45.55)

10.60 (0.37 – 45.55)†*

1.48 (0.07 – 32.92)*

1.02 (0.01 – 6.47)

           Expiratory

11.34 (0.00 – 106.35)

32.20 (3.54 – 106.35)†*

1.19 (0.00 – 34.83)*

0.74 (0.00 – 8.87)

            ΔALX

-3.31 (-86.95 – 2.35)

-15.51 (-86.95 – 0.00)†*

0.05 (-5.73 – 2.35)

0.15 (-3.96 – 1.11)

  1. Values are shown as a median (range).
  2. Abbreviations: ALX integrated low-frequency reactance area, Δ difference between inspiratory and expiratory phases, EFL expiratory flow limitation, Fres resonant frequency, R5 and R20 respiratory system resistance at 5 Hz and 20 Hz, R5-R20 difference between R5 and R20, X5 respiratory system reactance at 5 Hz.
  3. *p <0.05 versus controls, †p <0.05 versus low EFL index group.
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BMC Pulmonary Medicine

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