Determining the utility of metabolic acidosis for trauma patients in the emergency department.

BACKGROUND

Metabolic acidosis has been proposed as the gold standard to define shock in trauma patients. Other studies determine the presence of shock by use of serum lactate. However, not all medical centers have the ability to utilize point-of-care lactate at bedside.

OBJECTIVE

This study seeks to determine the relationship between serum lactate and metabolic acidemia in trauma patients, and if metabolic acidemia can be used to guide therapy. We hypothesized that acidemia would be strongly correlated with lactate levels and would be associated with activation of massive transfusion (MT) in the presence of shock in trauma.

METHODS

This was a prospective observational cohort study, level II evidence; this study aids in decision-making. Setting was a Level I academic, urban trauma center. The study took place from July 1, 2012 to March 1, 2013 and included patients who were ≥18 years old and required trauma team activation. Observations included baseline demographics (age, gender, type of injury), vital signs, point-of-care arterial blood gas, lactate, and need for MT.

RESULTS

One hundred patients were enrolled over the study period. The average age was 34 years, and 82% were male. Forty patients were acidemic (pH < 7.35), and there was a significant difference in lactate levels between the acidemic and non-acidemic groups (p < 0.002). We found a strong correlation between pH and lactate: rs = -0.38, t = -4.03, p < 0.001. In addition, using a logistic regression, we show that pH was associated with activation of MT (p = 0.002).

CONCLUSION

This is a prospective observational cohort study with level II evidence. This study demonstrates that acidemia was strongly correlated to serum lactate, lactate levels were higher in the acidemic group, and metabolic acidemia was associated with the activation of MT for trauma patients at our institution.