Table 2. Arterial blood gas and laboratory findings.
Data are mean ± SD, median (min-max) or n (%). PaCO2, PaO2: arterial carbon dioxide and oxygen tensions. P/F: arterial oxygen partial pressure/fractional inspired oxygen ratio. AaDO2: alveolar-to-arterial oxygen gradient. HCO3-: bicarbonate. FiO2: fractional inspired oxygen. WBC: white blood cells. N/L ratio: neutrophils/lymphocytes ratio. LDH: lactate dehydrogenase. CPK: creatine phosphokinase. CRP: C-reactive protein. PCT: procalcitonin. NS: not significant. ROX index: the ratio of oxygen saturation as measured by pulse oximetry/FiO2 to respiratory rate. FEU: fibrinogen equivalent units
| All patients (n=667) | Discharged (n=202) | Hospitalized (n=465) | p-value | Survivors (n=559) | Non-survivors (n=108) | p-value | |
| Arterial Blood Gas Analysis | |||||||
| pH | 7.4 ± 0.6 | 7.4 ± 0.0 | 7.4 ± 0.7 | < .001 | 7.4 ± 0.6 | 7.4 ± 0.1 | NS |
| pO2, mmHg | 75.9 ± 22.1 | 90.1 ± 13.6 | 69.7 ± 22.3 | < .001 | 77.8 ± 19.9 | 65.9 ± 29.5 | < .001 |
| pCO2, mmHg | 33.7 ± 6.7 | 35.5 ± 4.6 | 32.9 ± 7.3 | < .001 | 33.6 ± 6.1 | 34.1 ± 9.3 | NS |
| HCO3- mmol/L | 23.8 ± 3.4 | 24.1 ± 2.3 | 23.6 ± 3.8 | .016 | 23.9 ± 2.8 | 23.1 ± 5.4 | .007 |
| Lactate, mmol/L | 1.2 ± 1.1 | 1 ± 0.6 | 1.4 ± 1.3 | < .001 | 1.1 ± 0.7 | 2.1 ± 2.2 | < .001 |
| FiO2 | 23.1 ± 9.9 | 21 ± 0.0 | 24.0 ± 11.8 | < .001 | 21.8 ± 6.0 | 30.0 ± 19.4 | < .001 |
| P/F | 347.0 ± 99.1 | 426.8 ± 63.5 | 312.4 ± 91.5 | < .001 | 362.8 ± 90.5 | 261.7 ± 100.4 | < .001 |
| AaDO2 | 34.8 ± 17.7 | 18 ± 9.9 | 42.4 ± 14.9 | < .001 | 32.8 ± 17.1 | 47.8 ± 15.6 | < .001 |
| AaDO2 expected for age | 19.4 ± 4.7 | 15.6 ± 3.6 | 21 ± 4.2 | < .001 | 18.5 ± 4.4 | 24.2 ± 2.8 | < .001 |
| Rox Index | 24.3 ± 6.5 | 27.7 ± 4.2 | 22.8 ± 6.7 | < .001 | 25.3 ± 5.9 | 18.6 ± 7.1 | < .001 |
| Laboratory tests | |||||||
| WBC, 109/L | 7.9 ± 5.5 | 6.8 ± 2.9 | 8.3 ± 6.2 | .028 | 7.4 ± 5.2 | 10.0 ± 6.5 | < .001 |
| Neutrophils, 109/L | 6.1 ± 6.4 | 4.4 ± 2.2 | 6.8 ± 7.3 | < .001 | 5.7 ± 6.4 | 8.2 ± 6.0 | < .001 |
| Lymphocytes, 109/L | 1.6 ± 2.7 | 1.8 ± 1.1 | 1.6 ± 3.1 | < .001 | 1.7 ± 2.9 | 1.3 ± 1.3 | < .001 |
| Eosinophils, 109/L | 0.1 ± 0.1 | 0.1 ± 0.2 | 0.0 ± 0.1 | < .001 | 0.1 ± 0.1 | 0.0 ± 0.1 | < .001 |
| N/L ratio | 5.8 ± 6.9 | 2.9 ± 1.9 | 6.9 ± 7.8 | < .001 | 5.0 ± 5.9 | 9.8 ± 9.9 | < .001 |
| Platelets, 109/L | 220.4 ± 21.3 | 230.6 ± 71.5 | 216.4 ± 97.7 | .001 | 221.2 ± 83.5 | 215.9 ± 123.5 | .047 |
| D-dimer, mg/L FEU | 1.6 ± 4.0 | 0.4 ± 0.4 | 2.0 ± 4.6 | < .001 | 1.1 ± 2.8 | 3.9 ± 7.3 | < .001 |
| Creatinine, mg/dL | 1.1 ± 1.0 | 0.8 ± 0.6 | 1.2 ± 1.0 | < .001 | 1.0 ± 0.8 | 1.6 ± 1.2 | < .001 |
| LDH, U/L | 289.6 ± 183.2 | 206.1 ± 70.5 | 322.6 ± 202.5 | < .001 | 262.4 ± 104.0 | 437.4 ± 363.5 | < .001 |
| CPK, U/L | 83.0 (11-26758) | 68.0 (30-276) | 83.0 (11-26758) | NS | 77.5(11-26758) | 148.0 (16-953) | .012 |
| Bilirubin, mg/dL | 0.8 ± 1.9 | 0.6 ± 0.5 | 0.8 ± 2.0 | < .001 | 0.6 ± 0.3 | 1.5 ± 4.2 | < .001 |
| CRP, mg/dL | 6.2 ± 7.4 | 1.3 ± 2.3 | 8.1 ± 7.8 | < .001 | 4.9 ± 6.0 | 13.1 ± 10.0 | < .001 |
| PCT, ng/mL | 1.7 ± 11.3 | 0.1 ± 0.0 | 1.8 ± 11.6 | .017 | 0.7 ± 3.5 | 5.8 ± 23.8 | < .001 |
| Lymphopenia, | 269 (40.3) | 35 (17.3) | 234 (50.3) | < .001 | 203 (36.3) | 66 (61.1) | < .001 |