Table 2.
Physiological variables of healthy volunteers according to each device
| O2-mask | HFNC | CPAP | Helmet-NIV | Mask-NIV | p | |
|---|---|---|---|---|---|---|
| VT, mL | 644 [571–764] | 819* [609–918] | 648 [586–770] | 1110* [661–1305] | 1086* [833–1243] | < 0.0001 |
|
VT, mL/kg PBW |
8.8 [7.8–10.2] | 10.7* [9.6–12.4] | 9.0 [8.3–10.8] | 14.3* [10.3–18.0] | 14.0* [11.4–17.4] | < 0.0001 |
| RR, breaths/min | 11 [9–15] | 8 [6–11] | 14 [11–16] | 18* [15–20] | 14* [11–20] | < 0.0001 |
| MV, L/min | 6.6 [5.7–10.8] | 5.9 [5.0–9.2] | 9.8 [7.3–11.1] | 14.3* [11.2–23.1] | 13.0* [11.4–15.2] | < 0.0001 |
| Delta EELV vs O2-mask, mL | – | + 214 [374–711] | + 705 [951–1286] | + 939 [1115–1417] | + 226 [364–635] | < 0.0001 |
| Anterior ventilation, % | 47 [43–51] | 46 [44–52] | 43 [40–53] | 51* [45–55] | 51* [47–58] | 0.0001 |
| Discomfort scale | 2 [1–3] | 4* [3–6] | 3* [2–6] | 7* [6–8] | 4* [4, 5] | < 0.0001 |
O2-mask: non-rebreather oxygen mask; HFNC: high-flow oxygen through nasal cannula; CPAP: continuous positive airway pressure; Helmet-NIV: noninvasive ventilation with a Helmet; Mask-NIV: noninvasive ventilation with an oronasal mask; VT: tidal volume; PBW: predicted body weight; RR: respiratory rate; EELV; end-expiratory lung volume
Data are presented as median [25th–75th interquartile range]. P value presented is overall comparison on one-way ANOVA
*p < 0.05 vs. O2-mask