Table 1.
Key differences between the three trials on helmet noninvasive ventilation
| Patel et al. [5] | HENIVOT [6] | Helmet-COVID [7] | |
|---|---|---|---|
| Population | Non-COVID-19 | COVID-19 | COVID-19 |
| N | 83 patients, terminated early for efficacy | 109 patients | 320 patients |
| Control | Mask noninvasive ventilation | HFNO | Usual respiratory support (82% mask noninvasive ventilation in the first 96 h) |
| Pre-enrollment respiratory support | Mask noninvasive ventilation for at least 8 h | Oxygen through a Venturi mask, with FiO2 ranging between 24 and 60% | Conventional oxygen therapy, HFNO, or mask noninvasive ventilation |
| Chest X-ray findings | Bilateral infiltrates 100% in both groups | All patients had bilateral opacities, given they had to meet Berlin criteria for enrollment | Median number of quadrants involved 4 (IQR 3–4) in both groups |
| Primary outcome | Endotracheal intubation | Respiratory support-free days | 28-day mortality |
| Devices for noninvasive ventilation | Double-limb ICU ventilator vs. single-limb noninvasive ventilator | Double-limb ICU ventilator | Double-limb ICU ventilator in both groups |
| Duration before enrollment, (median, IQR) | Duration of noninvasive ventilation before enrollment, 10.3 h (8.3–13.4) versus 13 h (8–19.7) h | ICU stay before enrollment 1 h (0–3) versus 1 h (0–2) | ICU stay before enrollment 2 days (1–2) in both groups |
| PaO2/FiO2 ratio (median, IQR) | 144 (90–223) vs. 118 (93–170) | 105 (83–125) vs. 102 (80–124) | 73 (60–93) vs. 76 (61–111) |
| PEEP, cmH2O (median, IQR) | 8 (5–10) vs. 5 (5–8) | 12 (10–12) vs. HFNO | 10 (10–10) vs. 10 (8–10) |
| Duration of helmet NIV, (median, IQR) | 19.8 h (8.4–45.6) | Continuous helmet in the first 48 h or until intubation in 91% of patients | 43 h (19.5–70.5) |
| Awake prone positioning | Not reported | 0 patients (0%) versus 32 patients (60%) | 42 patients (26.4%) versus 49 patients (30.4%) |
| Sedation/ analgesic infusions | Not reported | 20 patients (37%) versus 10 patients (18%) | 69 patients (43.4%) versus 41patients (25.5%) |
| Main results | Reduced intubation (61.5% vs. 18.2%), lower 90-day mortality (34.1% vs. 56.4%) | Similar number of days free of respiratory support within 28 days (20 days, IQR,0–25 vs.18, IQR, 0–22), reduced intubation (30% vs. 51%), similar in-hospital mortality (24%vs. 25%) | Similar 28-day mortality (27% vs. 26.1%), similar intubation (47.2% vs. 50.3%) |
Values are reported for the helmet noninvasive ventilation versus control group, respectively
HFNO high-flow nasal oxygen, PaO2/FiO2 the ratio of arterial oxygen partial pressure to fraction of inspired oxygen; IQR interquartile range