Comparison of physiological, biochemical and admission data between survivors and non-survivors in the group of patients deemed unsuitable for invasive mechanical ventilation (IMV)
| All patients considered not suitable for IMV | Not suitable for IMV survivors | Not suitable for IMV non-survivors | p-value | |
| Subjects, n | 98 | 27 | 71 | |
| Age, mean±sd | 76.1±4.6 | 72.4±4.1 | 76.3±4.8 | 0.053 |
| Male, n (%) | 58 (59) | 14 (52) | 44 (62) | 0.362 |
| Clinical Frailty Score, median (range) | 4 (1–6) | 3.5 (2–5) | 4 (1–6) | 0.022 |
| CPAP/HFNO duration days, median (range) | 4 (1–24) | 7 (1–24) | 4 (1–11) | 0.172 |
| CPAP/HFNO well tolerated, n (%) | 81 (83) | 25 (93) | 56 (79) | 0.053 |
| Comorbidities, n (%) | ||||
| HTN | 63 (64) | 18 (67) | 45 (58) | 0.593 |
| Diabetes mellitus | 29 (30) | 9 (33) | 20 (31) | 0.539 |
| COPD | 32 (33) | 5 (19) | 27 (38) | 0.081 |
| Asthma | 6 (6) | 1 (4) | 5 (6) | 0.563 |
| Home NIV/CPAP | 12 (12) | 4 (15) | 8 (11) | 0.585 |
| Previous cancer | 12 (12) | 2 (7) | 10 (19) | 0.397 |
| IHD | 32 (33) | 5 (19) | 27 (38) | 0.081 |
| Smoking history | 49 (50) | 11 (41) | 38 (54) | 0.258 |
| Obesity | 37 (38) | 13 (48) | 24 (34) | 0.033 |
| Laboratory results, mean±sd | ||||
| Admission WCC ×109·L−1 | 10.5±5.2 | 7.4±4.3 | 11.5±5.1 | 0.036 |
| Admission lymphocyte count ×109·L−1 | 0.98±0.6 | 0.81±0.46 | 1.04±0.75 | 0.425 |
| Admission C-reactive protein mg·L−1 | 160±105 | 191±78 | 150±113 | 0.160 |
| Observations pre-CPAP/HFNO, mean±sd | ||||
| Respiratory rate | 28.5±6.6 | 26.3±5.8 | 29.2±6.8 | 0.052 |
| Heart rate | 97.9±21.9 | 89.8±17.1 | 100.6±23.0 | 0.089 |
| Oxygen saturations | 88.6±7.5 | 88.4±7.6 | 88.6±5.9 | 0.899 |
| PaO2/FIO2 ratio | 75.7±40.1 | 75.1±38.8 | 75.9±40.9 | 0.932 |
| CPAP/ HFNO settings, mean±sd | ||||
| Starting CPAP PEEP | 9.4±1.6 | 8.5±2.0 | 9.7±1.4 | 0.111 |
| Starting CPAP FIO2 | 70.0±19.7 | 75.0±13.8 | 68.3±21.4 | 0.073 |
| Starting HFNO flow rate L·min−1 | 54.2±9.2 | 51.3±9.9 | 55.2±9.1 | 0.308 |
| Starting HFNO FIO2 | 68.3±14.4 | 66.6±16.7 | 69.0±13.8 | 0.702 |
CPAP: continuous positive airway pressure; HFNO: high-flow nasal oxygen; HTN: hypertension; NIV: noninvasive ventilation; IHD: ischaemic heart disease; WCC: white cell count; PaO2: arterial oxygen tension; FIO2: inspiratory oxygen fraction; PEEP: positive end-expiratory pressure.