Understanding the Impact of Pulmonary Rehabilitation on Airway Resistance in Patients with Severe COPD: A Single-Center Retrospective Study

Figures & data

Table 1 Patient Characteristics

Gender, n (%)
Male	23 (88.5)
Female	3 (11.5)
	Mean ± SD
Age, yr	62.6 ± 5.8
Smoking, pack/ yr	46.1 ± 26.2
BMI, kg/m^2	25.4 ± 4.0
BODE-index	5.19 ± 1.83
FVC, % (spirometric)	57.8 ± 17.0
FEV1, % (spirometric)	35.0 ± 13.1
GOLD grade n (%)
Severe	11 (42)
Very severe	15 (58)
SaO2, %	93.4 ± 2.6
Co-morbidities, n (%)
No	16 (62)
Yes	10 (38)

Abbreviations: BMI, body mass index; FEV₁, forced expiratory volume in one second; FVC, forced vital capacity; SaO₂, haemoglobin O₂ saturation.

Table 2 Changes in Lung Volumes in Plethysmography Measurements After PR

Variable	Before PR	After PR	p
	Mean ± SD	Mean ± SD
Raw tot [kPa*s/L]	1.53 ± 1.11	1.32 ± 0.79	0.209
Raw tot [% of pred]	506.7 ± 371.1	441.5 ± 262	0.234
Gaw tot [L/s/ kPa]	0.93 ± 0.56	1.09 ± 0.75	0.054
Gaw tot [% of pred]	28.3 ± 17.1	32.6 ± 22.4	0.077
sRaw tot [kPa*s]	6.76 ± 4.65	6.13 ± 3.99	0.055
sRaw tot [% of pred]	609.0 ± 392.5	536.2 ± 341.3	0.040
sGaw tot [1/(kPa*s)]	0.22 ± 0.20	0.28 ± 0.25	0.003
sGaw tot [% of pred]	25.8 ± 23.4	31.2 ± 29.1	0.010
FEV1 [L]	1.01 ± 0.41	1.06 ± 0.47	0.065
FEV1 [% of pred]	35.0 ± 13.1	36.8 ± 14.3	0.080
TLC [L]	6.05 ± 1.47	6.04 ± 1.69	0.983
TLC [% of pred]	97.6 ± 21.3	96.4 ± 22.0	0.767
FRC [L]	4.46 ± 1.38	4.41 ± 1.47	0.820
FRC [% of pred]	133.7 ± 37.2	132.0 ± 39.9	0.788
RV [L]	3.91 ± 1.23	3.81 ± 1.59	0.687
RV [% of pred]	169.9 ± 51.3	163.8 ± 67.9	0.565
RV/TLC	163.5 ± 29.4	156.0 ± 42.5	0.139
mMRC	2.27 ± 0.92	1.73 ± 1.08	< 0.001
CAT	17.6 ± 5.7	11.2 ± 5.3	< 0.001

Note: The p values of < 0.05 was shown in red colour.

Abbreviations: sR_{aw tot}, total specific resistance of airways; sG_{aw tot}, total specific conductance of airways; FEV₁, forced expiratory; volume in one second; TLC, total lung capacity; FRC, functional residual; capacity; RV, residual volume; mMRC, modified Medical Research Council; CAT, COPD assessment test.

Figure 1 A graph showing the parameters for which statistically significant differences were observed in patients who has participated in an eight-weeks PR program.

Abbreviations: PR, pulmonary rehabilitation; sR_awtot, total specific resistance of airways; sG_awtot, total specific conductance of airways; ΔSaO₂, delta of haemoglobin O₂ saturation; mMRC, modified Medical Research Council; CAT, COPD assessment test.

Figure 2 A Body plethysmography data samples of a 57-year-old male patient with a history of smoking 60 pk/year, who has attended sixteen sessions (8 weeks) of PR program; before attending (A) and after attending (B).

Table 3 Comparison of 6-MWT Data

6-MWT		Mean ± SD	p
Desaturation changes, (ΔSaO2)	Before PR	10.1 ± 6.6	0.029
	After PR	7.8 ± 6.3
Borg score	Before PR	1.52 ± 1.08	0.314
	After PR	1.33 ± 0.95
Distance, meter	Before PR	307.7 ± 98.3	< 0.001
	After PR	363.7 ± 105.7
	Change	55.9 ± 64.6

Abbreviations: 6-MWT, 6-Minute Walk Test; PR, pulmonary rehabilitation; ΔSaO_2, delta of haemoglobin O₂ saturation.