Isolated prehospital hypotension correlates with injury severity and outcomes in patients with trauma

OBJECTIVE: Patients normotensive in the trauma bay despite documented prehospital hypotension may not be recognized as significantly injured. The purpose of this study was to determine whether isolated prehospital hypotension portends poor outcomes and correlates with injury severity. METHODS: Prospective cohort study conducted at a level 1 university trauma center. The lowest recorded prehospital systolic blood pressure (SBP) and the first recorded SBP on hospital arrival were used to divide patients into either the normotensive (NP) or hypotensive (HP) group. Patients who failed to achieve normotension on hospital arrival were excluded. Hypotension was defined as SBP≤110 mmHg. RESULTS: Compared to NP (n=206), HP (n=81) had lower Glasgow Coma Scores both prehospital (12.81±0.44 vs 14.38±0.13) and at hospital admission (12.78±0.47 vs 14.37±0.14). Injury Severity Score positively correlated with prehospital hypotension (HP 12.27±1.12 vs NP 9.22±0.49). Prehospital hypotension positively correlated with intensive care unit (ICU) admission (HP 56.79% vs NP 22.82%), ICU length of stay (LOS) (HP 3.23±0.71 vs NP 0.71±0.17), hospital LOS (HP 8.58±1.39 vs NP 4.86±0.33), ventilator days (HP 3.38±1.20 vs NP 0.27±0.08 days), and repeat hypotensive episodes during their hospital stay (HP 81.71% vs NP 38.16%). HP also required more packed red blood cells in the first 24 hours after admission (22% vs 6%). Significance was set at p<0.05. CONCLUSIONS: Isolated prehospital hypotension in patients in the trauma and emergency department correlates with increased injury severity and portends worse outcomes despite a normal blood pressure reading at admission. Prehospital hypotension must be given heavy consideration in triage, as these patients may be transiently hypotensive and appear less critical than their true status. LEVEL OF EVIDENCE: Level II, Prognostic study.