Table 2.
Simplified esophageal pressure–time product, respiratory variables, and hemodynamic variables during non-invasive ventilation and high-flow nasal cannula at different flow rates
| Variables | NIV | HFNC-10 | HFNC-20 | HFNC-30 | HFNC-40 | HFNC-50 | p |
|---|---|---|---|---|---|---|---|
| sPTPes per breath (cmH2O × s) | 9 ± 4 | 11 ± 5 | 11 ± 6 | 10 ± 6 | 10 ± 5 | 10 ± 4 | 0.090 |
| sPTPes per minute (cmH2O × s × min−1) | 183 ± 84 | 220 ± 100 | 211 ± 90 | 187 ± 84*,** | 189 ± 87 | 201 ± 86 | < 0.001 |
| RR (breaths/min) | 25 [20–28] | 24 [20–29] | 23 [18–28] | 21 [18–27]* | 21 [18–27]* | 21 [18–26]* | 0.003 |
| SpO2 (%) | 96 ± 2 | 95 ± 3 | 96 ± 3* | 97 ± 3*,** | 97 ± 2*,** | 98 ± 2*,**, γ | 0.028 |
| PtcCO2 (mmHg) | 42 ± 7 | 41 ± 7 | 41 ± 8 | 41 ± 7 | 41 ± 7 | 41 ± 7 | 0.335 |
| MAP (mmHg) | 99 ± 22 | 94 ± 15 | 92 ± 9 | 91 ± 12 | 89 ± 12 | 91 ± 14 | 0.179 |
| HR (beats/min) | 96 ± 16 | 97 ± 15 | 94 ± 13 | 93 ± 14 | 94 ± 16 | 95 ± 17 | 0.174 |
| Oxygen flow (L/min) or Set FiO2 | 4 [3–5] | 0.35 [0.30–0.40] | 0.35 [0.30–0.40] | 0.35 [0.30–0.40] | 0.35 [0.30–0.40] | 0.35 [0.30–0.40] | – |
Continuous variables were presented as mean ± SD or median [interquartile range] and categorical variables were presented as absolute value (%)
HFNC high-flow nasal cannula, HR heart rate, MAP mean arterial pressure, NIV non-invasive ventilation, sPTPes, simplified esophageal pressure–time product, PtcCO2, transcutaneous carbon dioxide pressure, RR respiratory rate, SpO2, oxygen saturation
* Indicates p < 0.05 compared with HNFC-10, ** Indicates p < 0.05 compared with HFNC-20, γIndicates p < 0.05 compared with NIV