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Table 1 Differences in measurements between different types of spirometers, spirometers of same type, and repeated measurements with a spirometer

From: A pilot study of hot-wire, ultrasonic and wedge-bellows spirometer inter- and intra-variability

Spirometers

FVC

FEV1

Mean diff. (L)

Mean rel. diff. (%)

Bland–Altman 95% lim. agr.

Mean diff. (L)

Mean rel. diff. (%)

Bland–Altman 95% lim. agr.

HW–US

0.33***

8.99

(0.09, 0.58)

0.11***

3.59

(− 0.03, 0.24)

WB–US

0.24***

6.56

(0.02, 0.47)

0.15***

5.13

(− 0.06, 0.36)

HW–WB

0.09*

2.28

(− 0.14, 0.31)

− 0.05 n.s.

− 1.46

(− 0.25, 0.16)

HW1–US1

0.35***

9.52

(0.01, 0.69)

0.12**

4.00

(− 0.05, 0.29)

HW1–US2

0.36***

9.64

(− 0.004, 0.72)

0.18**

5.99

(− 0.04, 0.39)

HW2–US1

0.32***

8.53

(0.03, 0.60)

0.04 n.s.

1.29

(− 0.21, 0.29)

HW2–US2

0.32***

8.65

(0.06, 0.57)

0.09 n.s.

3.22

(− 0.14, 0.33)

HW3–US1

0.40***

10.79

(− 0.02, 0.81)

0.14*

4.67

(− 0.13, 0.41)

HW3–US2

0.40***

10.91

(0.03, 0.77)

0.20**

6.67

(− 0.07, 0.46)

HW4–US1

0.25**

6.86

(− 0.06, 0.57)

0.02 n.s.

0.53

(− 0.16, 0.19)

HW4–US2

0.26***

6.98

(− 0.02, 0.54)

0.07 n.s.

2.45

(− 0.15, 0.30)

WB–US1

0.24***

6.50

(− 0.002, 0.48)

0.12*

4.14

(− 0.10, 0.34)

WB–US2

0.24***

6.62

(0.02, 0.47)

0.18**

6.13

(− 0.05, 0.40)

HW1–WB

0.11 n.s.

2.84

(− 0.19, 0.41)

− 0.004 n.s.

− 0.13

(− 0.24, 0.23)

HW2–WB

0.08 n.s

1.91

(− 0.18, 0.33)

− 0.09 n.s.

− 2.74

(− 0.37, 0.20)

HW3–WB

0.16 n.s.

4.02

(− 0.26, 0.58)

0.02 n.s.

0.51

(− 0.31, 0.33)

HW4–WB

0.01 n.s.

0.34

(− 0.21, 0.24)

− 0.11*

− 3.46

(− 0.30, 0.09)

HW1–HW2

0.04 n.s.

0.91

(− 0.31, 0.38)

0.08 n.s.

2.68

(− 0.25, 0.41)

HW1–HW3

− 0.05 n.s.

− 1.14

(− 0.43, 0.34)

− 0.02 n.s.

− 0.64

(− 0.31, 0.27)

HW1–HW4

0.10 n.s.

2.49

(− 0.21, 0.41)

0.10 n.s

3.45

(− 0.14, 0.35)

HW2–HW3

− 0.08 n.s.

− 2.04

(− 0.47, 0.30)

− 0.10 n.s.

− 3.23

(− 0.36, 0.16)

HW2–HW4

0.06 n.s.

1.56

(− 0.17, 0.29)

0.02 n.s.

0.75

(− 0.19, 0.23)

HW3–HW4

0.15 n.s.

3.67

(− 0.25, 0.54)

0.12 n.s

4.12

(− 0.14, 0.38)

US1–US2

0.004 n.s.

0.11

(− 0.1, 0.13)

0.06 n.s.

1.91

(− 0.09, 0.20)

Repeatability

FVC

FEV1

Mean diff. (L)

Mean rel. diff. (%)

ATS/ERS approved

Mean diff. (L)

Mean rel. diff. (%)

ATS/ERS approved

HW1

0.05

1.31

Yes

0.05

1.70

Yes

HW2

0.03

0.63

Yes

0.03

1.03

Yes

HW3

0.06

1.51

Yes

0.04

1.30

Yes

HW4

0.04

1.09

Yes

0.03

1.15

Yes

US1

0.04

1.07

Yes

0.03

1.07

Yes

US2

0.05

1.35

Yes

0.05

1.62

Yes

WB

0.03

0.64

Yes

0.03

0.84

Yes

  1. Repeatability: difference between best and second best test, Mean difference: e.g. HW–US, Mean relative difference: e.g. HW–US/US*100
  2. diff difference, HW hot-wire, lim. agr. limits of agreement, n.s. not significant, rel relative, US ultrasonic, WB wedge-bellows
  3. * p < 0.05, ** p < 0.01,*** p < 0.001 (Bonferroni-corrected from linear mixed models, n = 12)
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BMC Research Notes

ISSN: 1756-0500

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