Base Excess usefulness for prediction of immediate mortality in severe trauma patients admitted to the Emergency department

Abstract

Background: Trauma is a leading cause of death in young people and hemorrhagic shock is a leading mechanism of this mortality. Hypoperfusion can be difficult to diagnose clinically, especially in younger patients. Arterial Base Excess (BE) has been used as an early indicator of hypoperfusion.
Aim: To evaluate the prognostic value of admission BE in severe trauma patients admitted to the emergency department (ED). 
Methods: In this prospective study, severe trauma patients meeting high velocity criteria admitted to the ED during the study period were included. BE was calculated from arterial blood gas samples. Multivariate analysis was performed for Day-1 and Day-7 post trauma mortality. ROC characteristics and survival curves were used. 
Results: We included 479 patients. Median age was 37 (18-90). Eighty-one per cent were male. Clinical characteristics n(%): GCS<13: 170(35); SBP<90 mmHg: 64(13) and SpO2 <90%: 82(17). Mean ISS was 22 ± 13. Mortality was at days 1 and 7: 2.2% and 27.3%, respectively. Median BE was -3.2 mmol/l (-25; 28). Forty-five per cent had a BE ≤ -3.5 mmol/l. In multivariate analysis, initial BE ≤ -6.5 mmol/l was predictive of first day mortality with an Odds Ratio; [CI95%] = 3.17; [1.4-7.1]; p=0.005. Similar results were found at Day 7: Odds Ratio; [CI95%] = 1.5; [1.14-1.96]; p=0.003. BE showed high prognostic value for both mortality rates. Survival curve was significant for BE> -6.5mmol/l.
Conclusion: in this study, a high BE above 6.5mmol/L showed a significant prognostic value in immediate and early mortality and is proposed as a marker of injury severity in trauma patients admitted to the ED. Prediction was better for the immediate mortality and thus could be proposed as a triage tool in the ED