Elevated plasma ammonia concentration in patients with traumatic hemorrhage

Introduction

The blood ammonia concentration has been reported to be elevated by hemorrhagic shock in animal studies, but this finding has been reported in only one clinical study in a small number of selected surgical patients. We therefore conducted a study to determine whether plasma ammonia is elevated in trauma patients at hospital admission and can be used as a predictive factor for serious hemorrhage.

Methods

The subjects were consequent trauma patients admitted to our level 1 trauma center between November 2006 and November 2007. Blood was sampled on admission from patients who met the inclusion criteria to determine plasma ammonia and arterial lactate concentrations. Patients requiring blood transfusion or intervention for bleeding within 24 hours were classified into a blood transfusion and intervention group (BTI group). Patients not requiring the transfusion or the interventions were classified into a non-BTI group. Logistic regression analysis was performed using patients requiring BTI as the dependent variable and ammonia concentration, lactate concentration, shock index on admission, systolic blood pressure on admission, and ISS as independent variables.

Results

The subjects were 148 trauma patients. The mean age was 44.8 ± 20.8 years, and the mean injury severity scale was 17.7 ± 13.2. Patients showed a significant correlation between ammonia and lactate concentrations (r = 0.46, P < 0.001). Intervention for arterial bleeding was required in 16 patients. Blood transfusion was required in 17 patients. The BTI group consisted of 21 patients. The BTI group had more hemodynamic instability and significantly higher ammonia and lactate concentrations than the non-BTI group. Logistic regression analysis shows that only plasma ammonia was a significant independent variable for BTI (P = 0.001). The odds ratio of requiring blood transfusion and/or intervention for arterial bleeding was 18.2 when ammonia was ≥ 80 μg/dl.

Conclusion

Elevated ammonia concentration on admission will be a predictive factor for traumatic hemorrhage requiring treatment.