Table 2.
Effects of increasing NHF set flow rate on target physiologic variables
| NHF-0.5 | NHF-1 | NHF-1.5 | ANOVA p value | |
|---|---|---|---|---|
| Set flow rate (L/min) | 35 (30–35) | 65 (60–70)a | 100 (92–109)a,b | < 0.001 |
| PaO2/FiO2 | 194 ± 96 | 211 ± 106 | 219 ± 118 | 0.064 |
| SpO2 (%) | 94 ± 2 | 95 ± 2 | 96 ± 2 | 0.139 |
| Arterial pH | 7.40 (7.39–7.43) | 7.40 (7.39–7.41) | 7.41 (7.40–7.45) | 0.105 |
| PaCO2 ( mmHg) | 36.3 ± 6.4 | 37.6 ± 5.3 | 36.2 ± 5.7 | 0.108 |
| RR (bpm) | 20 ± 6c | 17 ± 5 | 18 ± 6 | 0.014 |
| Corrected MV (au/min) | 46,440 ± 18,515 | 48,562 ± 17,781 | 53,870 ± 17,737 | 0.068 |
| HR (bpm) | 78 ± 16 | 76 ± 17 | 77 ± 16 | 0.391 |
| MAP (mmHg) | 76 (62–91) | 73 (65–80) | 74 (61–89) | 0.447 |
NHF, nasal high flow; 0.5-1-1.5, set flow rate in L/kg PBW/min; PaO2/FiO2, arterial partial pressure of O2/inspired fraction of O2 ratio; SpO2, peripheral oxygen saturation; PaCO2, arterial partial pressure of CO2; RR, respiratory rate; HR, heart rate; MAP, mean arterial pressure
aPost hoc Dunn’s test versus NHF-0.5 (p < 0.05)
bPost hoc Dunn’s test versus NHF-1 (p < 0.05)
cPost hoc Bonferroni test versus NHF-1 (p < 0.05)