Table 1.
Characteristics of the patients at baseline*
| Characteristic | Conservative oxygen (n = 130) | Usual oxygen (n = 121) |
|---|---|---|
| Age, years | 58.3 ± 15 | 57.2 ± 14.3 |
| Male sex, n (%) | 75 (57.7%) | 59 (48.8%) |
| Co-morbid conditions, n (%) | ||
| Respiratory | 5 (3.8%) | 1 (0.8%) |
| Cardiovascular | 2 (1.5%) | 0 (0%) |
| Hepatic | 4 (3.1%) | 1 (0.8%) |
| Renal | 5 (3.8%) | 1 (0.8%) |
| Immunosuppression by disease | 7 (5.4%) | 9 (7.4%) |
| Immunosuppression by therapy | 19 (14.6%) | 22 (18.2%) |
| Metastatic cancer | 2 (1.5%) | 5 (4.1%) |
| Source of admission to ICU, n (%) | ||
| Emergency department | 43 (33.1%) | 50 (41.3%) |
| Hospital ward | 44 (33.8%) | 34 (28.1%) |
| Transfer from another ICU | 2 (1.5%) | 1 (0.8%) |
| Transfer from another hospital (except from another ICU) | 9 (6.9%) | 12 (9.9%) |
| From OR following elective surgery | 1 (0.8%) | 2 (1.7%) |
| From OR following emergency surgery | 31 (23.8%) | 22 (18.2%) |
| Hours from initiation of invasive ventilation to randomization; median [IQR]a | 1.7 [0.9–3.5] | 1.7 [0.9–3.1] |
| Hours from ICU admission to randomization; median [IQR] | 1.9 [1.1–7.3] | 1.9 [1.2–5.9] |
| APACHE II scoreb | 22.7 ± 7.5 | 22.8 ± 8.2 |
| Physiologyc | ||
| Temperature, °C | 36.8 ± 1 | 36.9 ± 1.1 |
| Heart rate, beats per minute | 103 ± 21.5 | 104 ± 21.3 |
| Mean arterial pressure, mmHg | 78.7 ± 13.6 | 79.2 ± 13.9 |
| Mean airway pressure, cmH2O | 14.2 ± 3.9 | 12.6 ± 3.5 |
| Respiratory rate, breaths per minute | 18.5 ± 7.5 | 17.6 ± 5.2 |
| SpO2, % | 96.2 ± 3 | 95.9 ± 3.7 |
| PaO2, mmHg; median [IQR] | 97 [77.5-161] | 99 [78.8-147] |
| PaO2/FiO2 ratio, mmHg | 213 ± 118 | 200 ± 102 |
| PaCO2, mmHg | 44.5 ± 13.7 | 44.3 ± 11.1 |
| Physiological supportd | ||
| FiO2 | 0.65 ± 0.24 | 0.67 ± 0.23 |
| PEEP, cmH2O; median [IQR] | 8.3 ± 3.1 | 8.9 ± 3.7 |
| Inotropic/vasopressor support, n (%) | 87 (66.9%) | 85 (70.2%) |
| Renal replacement therapy, n (%) | 8 (6.2%) | 4 (3.3%) |
| Fulfilled Sepsis 3.0 criteria within 24 h of ICU admission, n (%) | 125 (96.2%) | 115 (95%) |
* Plus–minus values are expressed as mean ± SD
APACHE Acute Physiology And Chronic Health Evaluation, ICU intensive care unit, OR operating room, SpO2 arterial oxygen saturation on pulse oximetry, PaO2 arterial partial pressure of oxygen, FiO2 fraction of inspired oxygen, PaCO2 arterial partial pressure of carbon dioxide, PEEP positive end expiratory pressure
aIncludes hours of ventilation prior to ICU admission
bScores on the APACHE II range from 0 to 71, with higher scores indicating more severe disease and a higher risk of death
cTemperature data were available for 129 conservative oxygen patients and 120 usual oxygen patients; mean airway pressure data were available for 42 conservative oxygen patients and 36 usual oxygen patients; respiratory rate data were available for 130 conservative oxygen patients and 119 usual oxygen patients; SpO2 data were available for 129 conservative oxygen patients and 121 usual oxygen patients; PaO2/FiO2 ratio data were available for 125 conservative oxygen patients and 113 usual oxygen patients; and PaCO2 data were available for 125 conservative oxygen patients and 113 usual oxygen patients
dPEEP data were available for 128 conservative oxygen patients and 119 usual oxygen patients