Multivariate analysis of factors associated with in-hospital case fatality in ventilated TBI patients admitted to the ICU
| Variable | OR | Low | High | p Value |
|---|---|---|---|---|
| Intercept* | 0.02 | 0.01 | 0.04 | <0.0001 |
| Age (Ref. <45 years) | ||||
| 45–64 years | 1.6 | 1.1 | 2.3 | 0.02 |
| ≥65 years | 4.0 | 2.3 | 7.0 | <0.0001 |
| Comorbidities (Ref. none) | ||||
| One or more | 2.9 | 1.0 | 8.7 | 0.05 |
| Glasgow Coma Scale (Ref. GCS>12) | ||||
| GCS<8 | 9.8 | 5.5 | 17.6 | <0.0001 |
| Mean arterial pressure (MAP) (Ref. normal) | ||||
| Lowest MAP<60 mm Hg | 1.7 | 1.2 | 2.3 | 0.003 |
| Highest MAP≥120 mm Hg | 2.1 | 1.3 | 3.2 | 0.001 |
| Temperature | ||||
| Fever (highest T°C>37.5) | 0.4 | 0.3 | 0.7 | <0.0001 |
| Hypothermia (lowest T°C<36) | 1.7 | 1.2 | 2.3 | 0.003 |
| Anaemia (haematocrit <30%) | 1.7 | 1.2 | 2.5 | 0.002 |
| Organ dysfunction (Ref. none) | ||||
| Only one | 1.7 | 1.0 | 2.9 | 0.05 |
| Two or more | 2.1 | 1.6 | 2.9 | <0.0001 |
| Oxygen exposure (Ref. normoxia) | ||||
| Hypoxia (PaO2<60mmHg or PaO2/FiO2 <300) | 1.7 | 1.2 | 2.6 | 0.008 |
| Hyperoxia (PaO2 ≥300 mm Hg (39.99 kPa)) | 1.5 | 1.02 | 2.4 | 0.04 |
Model also adjusted for the following variables: female sex (OR 1.1, 95% CI 0.8 to 1.5), GCS 8–12 (OR 1.4, 95% CI 0.7 to 2.5), non-white race (OR 1.4, 95% CI 0.9 to 2.1), ED boarder status (OR 1.6, 95% CI 0.8–3.2) ICP monitor (OR 1.1, 95% CI 0.8 to 1.5), hospital type (community non-academic (OR 0.8, 95% CI 0.5 to 1.4), public (OR 1.1, 95% CI 0.8 to 1.6)), hospital location (rural (OR 0.6, 95% CI 0.4 to 1.1), suburban (OR 0.7, 95% CI 0.5 to 1.1)) and hospital size (small (OR 1.1, 95% CI 0.8 to 1.5), large (OR 0.8, 95% CI 0.4 to 1.9)), and abnormal pH (arterial pH <7.35 or >7.45 (OR 1.1, 95% CI 0.8 to 1.5)).
*We used generalised estimated equations under a robust estimation technique assuming an independence working correlation matrix. Exchangeable, unstructured and autoregressive (AR1) matrices all provided inferior fit suggesting increased risk of death in hospitals with lower patient volume for all diagnoses. Hospitals with lower patient volume had higher case fatality (see online supplementary material).
GCS, Glasgow Coma Scale; ICU, intensive care unit; TBI, traumatic brain injury.