Table 2. Outcomes of the two group patients after HFNC treatment.
| All patients (n = 110) | Early HFNC group (n = 38) | Late HFNC group (n = 72) | P value a | |
| SpO2 on HFNC onset, % | 93 (92-94) | 94 (93-95) | 92 (91-93) | 0.015 |
| PaO2 /FiO2 on HFNC onset, mmHg | 183(169-218) | 230 (218-254) | 172 (165-183) | <0.001 |
| The time from hospital admission to HFNC onset, hours | 30.0 (1.0-72.0) | 1.0 (1.0-6.0) | 48.0 (36.0-90.0) | <0.001 |
| Treatment | ||||
| Antiviral therapy | 100 (100%) | 38 (100%) | 72 (100%) | NA |
| Antibiotic therapy | 66 (60%) | 20 (52.6) | 46 (63.9) | 0.027 |
| Prone ventilation | 38 (34.5%) | 3 (7.9%) | 34 (47.2%) | <0.001 |
| Non-invasive mechanical ventilation | 24 (21.8%) | 6 (15.7%) | 18 (25%) | 0.266 |
| Invasive mechanical ventilation | 42 (38.2%) | 4 (10.5%) | 38 (52.7%) | <0.001 |
| ECMO | 7 (6.4%) | 1 (2.6%) | 6 (8.3%) | 0.450 |
| Complications | ||||
| Secondary infection | 51 (46.3%) | 10 (26.3%) | 41 (56.9%) | 0.002 |
| Severe ARDS | 42 (38.2%) | 4 (10.5%) | 38 (38.9%) | 0.037 |
| Septic shock | 18 (16.4%) | 3 (7.8%) | 15 (20.8%) | 0.081 |
| Cardiovascular event | 13 (11.8%) | 2 (5.3%) | 11(15.3%) | 0.216 |
| Acute kidney injury | 6 (5.4%) | 1 (2.6%) | 5 (6.9%) | 0.613 |
| Cardiac arrest | 3 (2.7%) | 0 | 3 (4.2%) | 0.518 |
| Chest CT foci increasing ≥ 50% | 43 (39.1%) | 8 (21.1%) | 35 (48.6%) | 0.004 |
| The time from illness onset to severe ARDS, days |
12 (11-15) | 15 (13-17) | 11 (9-13) | <0.001 |
| The time from illness onset to ICU admission, days |
11 (8-14) | 14 (10-16) | 11 (8-13) | <0.001 |
| ICU admission | 62 (56.4%) | 10 (26.3%) | 52 (72.2%) | <0.001 |
| ICU stay ≥ 7 days | 57 (51.8%) | 14 (36.8%) | 43 (59.7%) | 0.022 |
| Length of ICU stay, days | 17 (12-22) | 12 (10-15) | 18 (13-22) | <0.001 |
| Length of stay, days | 27 (16-32) | 16 (15-22) | 30 (27-33) | <0.001 |
| Duration of viral shedding after illness onset, days | 16 (13-21) | 12 (9-15) | 18 (15-25) | <0.001 |
| FiO2 during hospitalization | ||||
| 100% more than 72 hours continuously | 4 (3.6%) | 0 | 4 (5.5%) | 0.345 |
| ≥80% more than 72 hours continuously | 23 (22.7%) | 3 (7.9%) | 20 (27.8%) | 0.015 |
| ≥60% more than 72 hours continuously | 40 (36.4%) | 4 (10.5%) | 36 (50%) | <0.001 |
| Prognosis | 0.002 | |||
| Discharge | 86 (78.2%) | 36 (94.7%) | 50 (69.4%) | .. |
| Death | 24 (21.8%) | 2 (5.3%) | 22 (30.6%) | .. |
Data are median (IQR), n (%), or n/N (%). ECMO=extracorporeal membrane oxygenation. FiO2=fraction of inspired oxygen. HFNC=high flow nasal cannula. ICU=intensive care unit. PaO2=partial pressure of oxygen. SpO2= pulse oxygen saturation. NA=not applicable.
aP values indicate differences between early HFNC and late HFNC group.
P < 0.05 was considered statistically significant.