The effect of concomitant peripheral injury on traumatic brain injury pathobiology and outcome
BACKGROUND Severe head injury (HI) is known to be a major determinant of mortality in patients with multiple injuries but additional injuries also contribute to the clinical outcome. The Trauma Registry of the German Society for Trauma Surgery offers sufficient data for comparative outcome analysis in relation to the injury pattern. METHODS A total of 21,356 cases from Trauma Registry of the German Society for Trauma Surgery with complete data for pattern of injury (Abbreviated Injury Scale [AIS], Injury Severity Score), the incidence of hospital mortality, organ failure, sepsis, duration of hospital stay, and intubation-free days. Maximum AIS severity of HI, including brain, skull, face, and cervical spine, and injuries to the torso and/or extremities (TEI) were used for comparative subgroup analysis. RESULTS Overall mortality rate was 13.7% (mean age, 41.3 years; 72.6% men; mean Injury Severity Score, 24.4). Patients with relevant HI (AISHI >/=3) were found to have a higher mortality rate (22.1%) than patients with relevant TEI (12.9%). In all HI severity subgroups mortality increased consistently by about 5% with TEI of grade 4, and by 15% with TEI of grade 5, but no increase is observed for lower severity grades. The incidence of organ failure (overall 31.4%), multiple organ failure (15.0%), and sepsis (9.9%) are mainly influenced by the severity of TEI. Intubation-free days are equally influenced by both types of injuries of grade 3 or higher. CONCLUSIONS Mortality in patients with severe trauma is mainly determined by the severity of HI, while TEI contribute consistently only from AIS grade 4 or higher.