The utility of base deficit and arterial lactate in differentiating major from minor injury in trauma patients with normal vital signs.

OBJECTIVES

Early recognition and treatment of hemorrhagic shock after trauma limits multi-organ failure and mortality. Traditional vital signs (VS) although specific are not highly sensitive for hemorrhage detection. Metabolic parameters such as lactate and base deficit (BD) are highly sensitive indicators of blood loss by measuring tissue perfusion. Does adding information from BD and lactate to traditional VS improve the identification of trauma patients with major injuries?

METHODS

We conducted a retrospective study of a prospectively collected database at a Level I trauma center from January 2003 to September 2005. Patients >13 years, suspected of having significant injury by mechanism, were included. Abnormal VS were defined by heart rate >100 beats/min or systolic blood pressure <90 mmHg. Metabolic parameters from initial arterial blood gas were measured in all patients, abnormal defined by BD >-2.0 mMol/L or lactate >2.2 mMol/L. Our outcome variable, major injury, was defined as any trauma patient who received a blood transfusion, or dropped their hematocrit >10 points in the first 24 h, or had an Injury Severity Score (ISS) >15.

RESULTS

1435 patients were enrolled, 242 (17%) had major injuries. Abnormal VS alone had a sensitivity of 40.9% (95% CI, 34.7-47.1%) for identifying major injury patients. When abnormal metabolic parameters were added, major injury detection increased significantly to a sensitivity of 76.4% (95% CI, 71.1-81.8%).

CONCLUSIONS

The addition of BD and lactate to triage vital signs increases the ability to distinguish major from minor injury.