The Significance of Out-of-hospital Hypotension in Blunt Trauma Patients

Objective: To determine the significance of a low out-of-hospital systolic blood pressure (SBP) reading in blunt trauma patients who have a normal SBP upon ED arrival.
Methods: A retrospective case-control study compared admitted blunt trauma patients who were hypotensive (SBP ≤90 mm Hg) in the field and normotensive in the ED (group 1) with those who were normotensive both in the field and in the ED (group 2). The groups were compared for mortality, intensive care unit (ICU) admission, injury severity scale (ISS) score, need for transfusion in the ED, incidence of intra-abdominal injury, and incidence of pelvic or femur fracture.
Results: Each group consisted of 52 patients. The groups were similar with respect to age, gender, and initial ED SBP. The group 1 patients had a higher mortality (10 vs 1, p = 0.008), a higher number of ICU admissions (28 vs 12, p = 0.001), more pelvic or femur fractures (16 vs 7, p = 0.03), and a higher ISS score (19.0 vs 10.5, p = 0.01). Although not significant, group 1 also had higher incidences of intra-abdominal injury (10 vs 3, p = 0.07) and transfusion (8 vs 2, p = 0.09).
Conclusion: The injured patients who were hypotensive in the out-of-hospital setting but normotensive upon ED arrival were more severely injured and had more potential for blood loss than were the patients who were normotensive both in the out-of-hospital setting and in the ED. Out-of-hospital hypotension may be a clinical predictor of severe injury, even in the face of normal ED SBP. Prospective studies are indicated to validate this hypothesis.