The Optimal Heart Rate to Reduce Mortality after Traumatic Brain Injury

Background: Increasing data indicates treatment with beta blockers improves survival after traumatic brain injury (TBI). Although the optimal heart rate (HR) to reduce mortality for trauma patients assumes a lower heart rate is better, no study exists that demonstrates the optimal HR for mortality reduction after isolated moderate to severe TBI. Hypothesis: Mortality is reduced for a specific heart rate range in patients with isolated TBI. Patients and Methods: The Los Angeles County Trauma System Database, consisting of 5 Level I and 8 Level II trauma centers, was queried for all injured patients admitted between 1998 and 2005 (n=147,788). Moderate to severe isolated head injured patients (head AIS ≥3, all other ≤3) were then identified. Patients who were dead on arrival, with head AIS=6, or had any missing data were excluded. Demographics and outcomes were compared at various heart rate ranges (<50, 50-59, 60-69, 70-79, 80-89, 90-99, 100-109, ≥110). Logistic regression was performed to determine significant risk factors for mortality. Results: After exclusions, a total of 11,977 moderate to severe isolated TBI patients were then analyzed. Mortality for all HR was 11.5%; heart rate 80-89 was identified as having the lowest mortality (7.3%). HR 80-89 had significantly lower mortality compared to all other HR ranges except 90-99 and 100-109. The table below demonstrates the OR for death for each HR subgroup compared to HR 80-89. Conclusion: The optimal HR after isolated moderate to severe TBI is 80 to 109; a trend or significant decrease in mortality was demonstrated HR 80 to 89. The 80 to 89 HR range could serve as the target of therapeutic goals for beta blockade after TBI. Alternatively, parameters for preexisting beta blockade therapy may require hold orders for HR less than 80 as mortality almost doubled when HR reduced to the 60s.