Prehospital hypotension redefined

The American College of Surgeons Committee on Trauma suggests prehospital systolic blood pressure (PSBP) < 90 mm Hg as a criterion for triage of injured patients to trauma centers. However, Advanced Trauma Life Support recognizes this threshold as a late sign of shock. We undertook the current study to determine whether a higher PSBP threshold may identify patients at significant risk of death.

A retrospective analysis of an urban, Level I trauma center registry data was undertaken in patients with complete information on PSBP (n = 16,365; 1994-2003). Several thresholds of PSBP were chosen: < or = 60, < or = 70, < or = 80, < or = 90, < or = 100, and < or = 110 mm Hg, and the relationship between each threshold of PSBP and patient outcomes was explored. A p value < 0.05 was considered statistically significant.

Mean age of patients was 36 +/- 16 years, and 81% sustained a blunt injury. PSBP strongly correlated with systolic blood pressure obtained in the emergency department (Pearson r 0.65, p < 0.001). The risk of death increased sharply when PSBP dropped < 110 mm Hg, with nearly 1 in 10 (8%) dying in the emergency department and one in six (15%) dying eventually.

The definition of prehospital hypotension used for triage of injured patients to trauma centers should be redefined as PSBP < 110 mm Hg. The impact of this redefinition on trauma center resource utilization should be studied further.