Secondary outcomes | FreeO2 | Manual O2 | Adjusted difference (95% CI) | p-value |
Overall oxygen administration days | ||||
Total | 5.6±5.4 | 7.1±6.3 | 1.4 (2.3; 0.5) | 0.002 |
Hypoxaemic respiratory failure | 5.0±5.0 | 6.6±6.5 | 1.6 (2.7; 0.6) | 0.003 |
Hypercapnic respiratory failure | 7.4±6.2 | 8.2±5.8 | 0.8 (2.0; 0.4) | 0.173 |
ICU LOS days | ||||
Total | 4.2±3.2 | 4.7±3.5 | 0.6 (2.9; 1.7) | 0.630 |
Hypoxaemic respiratory failure | 4.9±3.3 | 4.7±3.9 | 0.2 (1.8–2.2) | 0.831 |
Hypercapnic respiratory failure | 2.5±2.4 | 4.7±3.0 | 2.2 (5.2–0.8) | 0.147 |
Hospital LOS days | ||||
Total | 9.2±6.9 | 11.1±7.0 | 2.0 (3.1–0.85) | 0.001 |
Total: censored data | 9.0 (7.0–10.0) | 10 (8.0–11.0) | 1.1 (1.5–0.8) | 0.452 |
Hypoxaemic respiratory failure | 9.0 (6.0–10.0) | 9 (8.0–10.0) | 1.0 (1.4–0.7) | 0.995 |
Hypercapnic respiratory failure | 9.0 (7.0–11.0) | 13 (8.0–16.0) | 1.6 (2.9–0.9) | 0.122 |
Data are presented as mean±sd; for hospital length-of-stay (LOS), values are provided as median (95% CI) when taking into account censored data. p-values equal to or below 0.05 were considered as statistically significant. FreeO2 indicates patients assigned to the automated oxygen administration group, and Manual O2 patients assigned to the standard oxygen administration control group. Hypoxaemic indicates the stratification group of patients with carbon dioxide tension (PCO2) ≤45 mmHg that were assigned to an arterial oxygen saturation measured by pulse oximetry (SpO2) range of 92–96%. Hypercapnic indicates the stratification group of patients with PCO2 >45 mmHg that were assigned to a SpO2 range of 90–94%. ICU LOS indicates the overall length-of-stay within the intensive care unit in the different groups. Hospital LOS indicates the overall length-of-stay within the hospital, until discharge or death in the different groups; subgroup analysis was performed on censored data for death.