Mortality in polytrauma patients with moderate to severe TBI on par with isolated TBI patients: TBI as last frontier in polytrauma patients

Background: Mortality caused by Traumatic Brain Injury (TBI) remains high, despite improvements in trauma and critical care. Polytrauma is naturally associated with high mortality. This study compared mortality rates between isolated TBI ( _ITBI) patients and polytrauma patients with TBI ( _PTBI) admitted to ICU to investigate if concomitant injuries lead to higher mortality amongst TBI patients. Methods: A 3-year cohort study compared polytrauma patients with TBI ( _PTBI) with AIS head ≥3 (and AIS of other body regions ≥3) from a prospective collected database to isolated TBI ( _ITBI) patients from a retrospective collected database with AIS head ≥3 (AIS of other body regions ≤2), both admitted to a single level-I trauma center ICU. Patients <16 years of age, injury caused by asphyxiation, drowning, burns and ICU transfers from and to other hospitals were excluded. Patient demographics, shock and resuscitation parameters, multiple organ dysfunction syndrome (MODS), acute respiratory distress syndrome (ARDS), and mortality data were collected and analyzed for group differences. Results: 259 patients were included; 111 _PTBI and 148 _ITBI patients. The median age was 54 [33-67] years, 177 (68%) patients were male, median ISS was 26 [20-33]. Seventy-nine (31%) patients died. Patients with _PTBI developed more ARDS (7% vs. 1%, p = 0.041) but had similar MODS rates (18% vs. 10%, p = 0.066). They also stayed longer on the ventilator (7 vs. 3 days, p=<0.001), longer in ICU (9 vs. 4 days, p=<0.001) and longer in hospital (24 vs. 11 days, p=<0.001). TBI was the most prevalent cause of death in polytrauma patients. Patients with _PTBI showed no higher in-hospital mortality rate. Moreover, mortality rates were skewed towards _ITBI patients (24% vs. 35%, p = 0.06). Discussion: There was no difference in mortality rates between _PTBI and _ITBI patients, suggesting TBI-severity as the predominant factor for ICU mortality in an era of ever improving acute trauma care.