Comparison between physiological effects of face mask (FM) and high-flow nasal cannula (HFNC)
| FM | HFNC | HFNC–FM | ||
| Median (IQR) | Median (IQR) | Median (95% CI) | p-value# | |
| VT global (units) | 2240 (1421–2752) | 2323 (1497–2891) | −3.0 (−138.5–153.5) | 0.9 |
| VT ROI1 (units) | 618 (440–692) | 590 (464–774) | −30.0 (−96.0–35.0) | 0.3 |
| VT ROI2 (units) | 408 (295–703) | 445 (262–656) | −18.5 (−63.5–37.0) | 0.4 |
| VT ROI3 (units) | 597 (287–816) | 589 (271–909) | 14.5 (−27.5–113.0) | 0.5 |
| VT ROI4 (units) | 290 (200–708) | 450 (286–664) | 15.0 (−21.0–77.0) | 0.4 |
| VT consolidation (units) | 290 (233–760) | 489 (198–783) | 2.5 (−57.0–40.5) | 0.9 |
| EELI global (units) | 1444 (992–3468) | 2921 (1706–4850) | 826.0 (399.5–2361.0) | <0.0001 |
| EELI ROI1 (units) | 278 (91–634) | 562 (215–1000) | 161.5 (−19.5–322.5) | 0.05 |
| EELI ROI2 (units) | 325 (181–531) | 408 (355–1152) | 187.5 (−31.5–464.0) | 0.1 |
| EELI ROI3 (units) | 378 (125–446) | 618 (370–1251) | 220.0 (57.0–719.0) | 0.01 |
| EELI ROI4 (units) | 309 (130–499) | 447 (373–738) | 169.5 (31.0–1104.0) | 0.01 |
| EELI consolidation (units) | 283 (125–477) | 486 (381–946) | 138.0 (24.5–613.0) | 0.01 |
| Respiratory rate (breaths·min−1) | 25 (23–28) | 23 (21–26) | −3 (−6–1) | 0.2 |
| SpO2/FiO2 ratio | 152 (147–152) | 163 (140–200) | 16.0 (−6.0–48.0) | 0.1 |
| SpO2 (%) | 100 (97–100) | 97 (96–100) | 0 (−2–1) | 0.5 |
| Heart rate (beats·min−1) | 82 (72–102) | 90 (78–104) | 1 (−2–4) | 0.4 |
| SBP (mmHg) | 118 (107–133) | 125 (113–137) | 6 (0–9) | 0.1 |
| MAP (mmHg) | 81 (74–92) | 85 (77–94) | 2 (1–7) | 0.01 |
| Dyspnoea score (0–10) | 0 (0–5) | 5 (2–5) | 0 (0–3) | 0.3 |
| Patient comfort score (0–10) | 8 (4–9) | 5 (4–7) | −2 (−4–0) | 0.1 |
Bold type reprensents statistical significance. IQR: interquartile range; VT: tidal volume variation; ROI: region of interest; EELI: end-expiratory lung impedance; SpO2: pulse oxygen saturation; FiO2: inspiratory oxygen fraction; SBP: systolic blood pressure; MAP: mean arterial pressure. #: Wilcoxon signed rank test.