Emergency physicians face the challenge of rapidly identifying high-risk trauma patients. Lactate (LAC) is widely used as a surrogate of tissue hypoperfusion. However, clinically important values for LAC as a predictor of mortality are not well defined. Objectives: 1. To assess the value of triage LAC in predicting mortality after trauma. 2. To compute interval likelihood ratios (LR) for LAC.Methods:
Retrospective chart review of trauma patients with a significant injury mechanism that warranted labs at an urban trauma center. Outcome: In-hospital mortality. Data are presented as median and quartiles or percentages with 95% confidence intervals. Groups (lived vs. died) were compared with Man-Whitney-U or Fisher's-exact test. Multivariate analysis was used to measure the association of the independent variables and mortality. The interval likelihood ratios were calculated for all LAC observed values.Results:
10,575 patients; median age: 38 [25–57]; 69% male; 76% blunt; 1.1% [n = 119] mortality. LAC was statistically different between groups in univariate (2.3 [1.6,3.0] vs 2.8 [1.6,4.8], p = 0.008) and multivariate analyses (odds ratio: 1.14 [1.08–1.21], p = 0.0001). Interval ratios for LR- ranged from 0.6–1.0. Increasing LAC increased LR +. However, LR + for LAC reached 5 with LAC > 9 mmol/L and passed 10 (moderate and conclusive increase in disease probability, respectively) with LAC > 18 mmol/L.Conclusions:
In a cohort of trauma patients with a wide spectrum of characteristics triage LAC was statistically able to identify patients at high risk of mortality. However, clinically meaningful contribution to decision-making occurred only at LAC > 9. LAC was not useful at excluding those with a low risk of mortality.