Characteristics of patients admitted to RICU
| Hypoxaemic-hypercapnic acute respiratory failure | Hypoxaemic-normo/hypocapnic acute respiratory failure | Weaning | Total | |
| No (%) | 518 (68) | 179 (24) | 59 (8) | 756 (100) |
| Age (years) | 69 (10) | 63 (17) | 67 (10) | 68 (12) |
| APACHE II score | 19 (6) | 15 (7) | 14 (4) | 18 (6) |
| Glasgow coma score | 13 (2) | 14 (1) | 14 (1) | 13 (2) |
| Pao 2 at admission1-150 (kPa) | 5.5 (1.1) | 6.4 (1.3) | 10.5 (3.1) | 5.9 (1.7) |
| Paco 2 at admission (kPa) | 10.2 (2.6) | 4.8 (0.8) | 7.2 (1.9) | 8.9 (3.1) |
| pH at admission | 7.30 (0.08) | 7.41 (0.07) | 7.39 (0.07) | 7.34 (0.09) |
| Respiratory rate at admission (breath/min) | 27 (7) | 27 (8) | 23 (6) | 26 (7) |
↵1-150 Fio 2 = 0.21 but Fio 2 >0.21 if weaning.