The impact of high-flow nasal cannula oxygen therapy on exercise capacity in fibrotic interstitial lung disease: a proof-of-concept randomized controlled crossover trial

Table 1 Patient characteristics

	All	Group A	Group B	P value
Number	20	10	10
Age, years	70.7 ± 7.6	73.0 ± 7.6	68.5 ± 7.2	0.192
Sex, M/F	19/1	10/0	9/1	0.305
BMI, Kg/m²	22.3 ± 5.1	20.7 ± 2.7	24.0 ± 6.4	0.149
Smoking status
Ever/Never	19/1	9/1	10/0	0.305
Pack-years	53.7 ± 40.4	41.8 ± 30.7	65.6 ± 46.8	0.196
mMRC	2.7 ± 1.0	2.8 ± 0.9	2.6 ± 1.2	0.676
FVC, %pred.	60.0 ± 14.7	62.9 ± 19.2	57.0 ± 8.4	0.386
FEV₁/FVC, %	88.0 ± 8.6	88.5 ± 7.7	87.6 ± 9.8	0.821
DLco, %pred.*	32.5 ± 15.2	32.3 ± 15.0	32.8 ± 16.4	0.953
RV, %pred.**	59.7 ± 23.9	66.8 ± 27.2	52.8 ± 19.4	0.258
Oxygen therapy, Yes	8 (40%)	3 (30%)	5 (50%)	0.361
Flow at rest, L/min	2.2 ± 1.5	2.5 ± 2.3	2.0 ± 1.0
PaCO₂, torr	43.2 ± 5.4	44.2 ± 5.6	42.3 ± 5.2	0.433
FILD classification, n
IPF	12	5	7
NSIP	1	1	0
CTD-ILD	2	1	1
Unclassifiable IIP	5	3	2
Pulmonary hypertension***	12 (60%)	6 (60%)	6 (60%)	1.000
RVSP ≥35 mmHg	10/15	5/6	5/9
MPAP ≥25 mmHg	6/18	4/9	2/9
Baseline CWRET
Endurance time, min	3.9 ± 3.3	3.5 ± 1.1	4.4 ± 4.6	0.518
Min SpO₂, %	77.7 ± 6.6	76.9 ± 7.4	78.5 ± 5.9	0.601
Max HR, bpm	121.2 ± 17.9	128.0 ± 11.4	114.3 ± 21.0	0.086
Final Borg scale
Dyspnea	6.9 ± 2.1	7.2 ± 1.9	6.5 ± 2.3	0.468
Leg fatigue	6.2 ± 2.8	7.0 ± 1.9	5.4 ± 3.3	0.188

Group A: venturi mask (VM) → high-flow nasal cannula (HFNC)
Group B: HFNC → VM
Data are presented as number (%) or mean ± standard deviation (SD)
P-value from chi-squared test or Student’s t-test
* n = 17 (A: n = 9, B: n = 8), ** n = 16 (A: n = 8, B: n = 8), *** Pulmonary hypertension was assessed by echocardiography (right ventricular systolic pressure > 35 mmHg) or right heart catheterization (mean pulmonary artery pressure ≥ 25 mmHg)
BMI body mass index, CTD connective tissue disease, CWRET constant work-rate endurance test, DLco diffusion capacity for carbon monoxide, FEV₁ forced expiratory volume in 1 s, FVC forced vital capacity, IIP idiopathic interstitial pneumonia, FILD fibrotic interstitial lung disease, HR heart rate, IPF idiopathic pulmonary fibrosis, mMRC the modified Medical Research Council dyspnea scale, MPAP mean pulmonary artery pressure, NSIP non-specific interstitial pneumonia, PaO₂ partial pressure of oxygen, PaCO₂ partial pressure of carbon dioxide, RV residual volume, RVSP right ventricular systolic pressure

ISSN: 1471-2466