Patients with Chronic Obstructive Pulmonary Disease Can Accurately Perform Home-Based Measurements of Inspiratory Capacity and Dynamic Hyperinflation

Figures & data

Figure 1. Spirometry protocol for one measurement. BF = Breathing Frequency; MPT = Metronome-paced Tachypnea; IC = Inspiratory Capacity.

Table 1. Patients characteristics per subject.

Subject (nr)	Age (yr)	Sex (F/M)	GOLD [12]	BMI (kg/m^2)
1	66	F	3B	20.3
2	56	F	3D	35.0
3	67	F	1A	26.2
5	67	M	4D	22.5
6	65	M	4D	26.4
7	53	F	2B	24.4
8	57	F	2B	25.0
9	57	M	3D	31.7
10	64	F	3B	40.6
11	79	F	3B	27.4
12	61	F	3D	17.6
13	65	F	3B	26.4
14	76	M	4D	34.2
15	66	F	3B	20.4
16	57	F	4D	22.5

Table 2. Mean IC_REST and IC_MPT, ΔIC and ΔIC% supervised and unsupervised. SD = Standard Deviation.

		Mean IC (SD)
Visit		Supervised	Unsupervised
2	ICREST (L)	1.844 (0.449)	1.842 (0.494)
	ICMPT (L)	1.388 (0.348)	1.411 (0.381)
	ΔIC (mL)	−456 (202)	−431 (244)
	ΔIC (%)	−24.53 (7.59)	−22.96 (9.17)
3	ICREST (L)	1.832 (0.443)	1.835 (0.441)
	ICMPT (L)	1.386 (0.342)	1.402 (0.387)
	ΔIC (mL)	−466 (233)	−433 (209)
	ΔIC (%)	−23.90 (9.16)	−23.70 (9.77)
4	ICREST (L)	1.871 (0.400)	1.864 (0.419)
	ICMPT (L)	1.400 (0.331)	1.392 (0.299)
	ΔIC (mL)	−471 (267)	−471 (253)
	ΔIC (%)	−24.68 (10.53)	−24.60 (8.98)

Table 3. Bias and limits of agreement for ICREST, ICMPT, ΔIC and ΔIC% from visits 2, 3 and 4.

Visit		Bias	Limits of agreement (1)
			Upper	Lower
2	ICREST (L)	0.003	0.264	−0.258
	ICMPT (L)	−0.023	0.210	−0.255
	ΔIC (mL)	−25	252	−303
	ΔIC (%)	−1.57	12.27	−15.41
3	ICREST (L)	−0.003	0.332	−0.338
	ICMPT (L)	−0.016	0.228	−0.260
	ΔIC (mL)	−13	320	−345
	ΔIC (%)	−0.19	16.72	−17.10
4	ICREST (L)	0.007	0.208	−0.194
	ICMPT (L)	0.007	0.270	−0.255
	ΔIC (mL)	0	205	−205
	ΔIC (%)	−0.09	10.72	−10.89

Figure 2. Bland Altman plot comparing ΔIC (mL) supervised and ΔIC (mL) unsupervised measured at visit 2 on right. Bias (solid) = –0.025 mL; Limits of agreement (solid) = upper: 0.252 mL, lower: –0.303 mL; Bland Altman plot comparing ΔIC% supervised and ΔIC% unsupervised measured at visit 2 on left. Bias (solid) = 1.57%; Limits of agreement (solid) = upper: 12.27%, lower: –15.41%; Threshold = 11.1% (dashed). Threshold = 150 mL (dashed). Regression lines (not displayed) were non-significant.

Figure 3. Bland Altman plot comparing ΔIC (mL) supervised and ΔIC (mL) unsupervised measured at visit 4 on right. Bias (solid) = 0.000 mL; Limits of agreement (solid) = upper: 0.205 mL, lower: –0.205 mL; Bland Altman plot comparing ΔIC% supervised and ΔIC% unsupervised measured at visit 4 on left. Bias (solid) = 0.09%; Limits of agreement (solid) = upper: 10.72%, lower: –10.89%; Threshold = 11.1% (dashed). Threshold = 150 mL (dashed). Regression lines (not displayed) were non-significant.