Isolated brain injury as a cause of hypotension in the blunt trauma patient

Background. Emerging evidence suggests that, contrary to standard teaching, isolated brain injury may be associated with hypotension. This study sought to determine the frequency of isolated brain injury-induced hypotension in blunt trauma victims. Methods. Hypotensive adult trauma patients were categorized according to the cause of hypotension: hemorrhagic (hemoglobin < 11.0), neurogenic, isolated brain, or other. Their clinical data and outcomes were compared. Results. The cause of hypotension was hemorrhagic in 113 (49%), isolated brain injury in 30 (13%), neurogenic in 14 (6%), and other causes in 24 (10%). Fifty (22%) were indeterminate. Hemorrhagic, isolated brain, and neurogenic groups were similar in age, Injury Severity Score, and systolic blood pressure. The Glasgow Coma Scale score of the isolated brain group was lower than in the hemorrhagic group (4.4 vs. 8.4,p < 0.05). Mortality was higher in the isolated brain group compared with the hemorrhagic group (80% vs. 50%, p < 0.05) and in the subgroup of hemorrhagic patients with versus without associated brain injury (57% vs. 39%, p < 0.05). Conclusion. Isolated brain injuries account for 13% of hypotensive events after blunt trauma and are associated with an increased mortality compared with hemorrhage-induced hypotension. In hypotensive brain-injured patients, hemorrhagic sources should be excluded rapidly, and the focus should be on resuscitation.