Table 3.
Overview of all studies regarding NHFT during exercise therapy
| Ref. | Study design | Type of exercise | NHFT settings | Population | Patients, n | Main results |
|---|---|---|---|---|---|---|
| NHFT compared to oxygen therapy | ||||||
| [54] | Prospective nonrandomized trial: HF vs. low-flow oxygen | CWRT unloaded T | Flow 20 L/min, temp 36° C, FiO2 39±11% | Stable severe COPD (FEV1 23% of pred.) | 10 | Increase in exercise endurance with less dyspnea and better oxygenation during HFT |
| NHFT compared to standard care | ||||||
| [55] | Cross-over RCT: NHFT vs. standard care (ambient air or oxygen therapy) | CWRT at 80% of estimated peak work rate | Flow 60 L/min, temp 31° C, FiO2 0.23±0.03 (n = 9) | Recently discharged with AECOPD (FEV1 29% of pred.) | 19 | No difference in endurance time. Reduced heart rate and nocturnal PtCO2 during NHFT |
| NHFT compared to Venturi mask | ||||||
| [56] | Cross-over RCT: NHFT vs. VM | CWRT at 75% of peak work rate | Flow 58.7 L/min, FiO2 44±11% (n = 8) | Stable severe COPD (FEV1 35% of pred.) with exercise limitation | 12 | Increased endurance time, less dyspnea and leg fatigue, and better oxygenation during NHFT |
| [51] | Cross-over RCT: NHFT vs. VM | IET and CWRT at 90% of maximal speed achieved during the IET | Flow 50 L/min, FiO2 40% | Stable COPD (FEV1 44% of. pred.) | 28 | Increased exercise tolerance during both IET and CWRT with less dyspnea, and better oxygenation during NHFT |
NHFT, nasal high-flow therapy; CWRT, constant work rate test, FiO2, fraction of inspired oxygen; FEV1, forced expiratory volume in 1 s; RCT, randomized controlled trial; AECOPD, acute exacerbation of COPD; PtCO2, transcutaneous carbon dioxide pressure; VM, Venturi mask; IET, incremental exercise test.