Two-way (paired) comparisons between the long-term oxygen therapy (LTOT) and nasal high flow (NHF) groups
| Variable | LTOT | NHF | p Value |
|---|---|---|---|
| Oxygen saturation (%)* | 95.8 (94.6 to 96.9) | 95.7 (93.1 to 97.1) | 0.06 |
| Transcutaneous O2 (mm Hg) | 101.2 (22.5) | 97.1 (24.2) | 0.01 |
| Transcutaneous CO2 (mm Hg) | 46.7 (9.4) | 43.3 (9.5) | <0.001 |
| Respiratory rate (breaths/min) | 19.2 (6.3) | 15.4 (4.8) | 0.001 |
| Inspiratory:expiratory ratio | 0.86 (0.20) | 0.75 (0.25) | 0.02 |
| Tidal volume (L)* | 0.40 (0.34, 0.46) | 0.50 (0.41, 0.54) | 0.003 |
| Minute volume (L/min)* | 6.20 (4.84, 8.18) | 6.18 (4.75, 7.69) | 0.88 |
| Heart rate (beats/min) | 70.1 (59.1, 79.3) | 69.8 (61.3, 79.8) | 0.21 |
| End-expiratory lung impedance (%Δ)* | 113 (98, 128) | 174 (161, 187) | <0.001 |
A p value <0.05 was considered significant. Normally distributed data are presented as mean (SD) while non-normal data are presented as median (IQR). End-expiratory lung impedance data are presented as percentage change from baseline (%Δ). All variables returned to baseline values during the washout periods and subsequently during the recovery period.
*A paired t test was used for the normally distributed data while a Wilcoxon signed rank test was used for the non-normal data.