Prehospital lactate improves prediction of the need for immediate interventions for hemorrhage after trauma

Abstract

The blood lactate level is used to guide the management of trauma patients with circulatory disturbance. We hypothesized that blood lactate levels at the scene (Lac scene) could improve the prediction for immediate interventions for hemorrhage. We prospectively measured blood lactate levels and assessed retrospectively in 435 trauma patients both at the scene and on arrival at the emergency room (ER) of a level I trauma center. Primary outcome was immediate intervention for hemorrhage defined as surgical/radiological intervention and/or blood transfusion within 24 h. Physiological variables plus Lac scene significantly increased the predictive value for immediate intervention (area under the curve [AUC] 0.882, 95% confidence interval [CI] 0.839-0.925) compared to that using physiological variables only (AUC 0.837, 95% CI 0.787-0.887, P = 0.0073), replicated in the validation cohort (n = 85). There was no significant improvement in predicting value of physiological variables plus Lac scene for massive transfusion compared to physiological variables (AUC 0.903 vs 0.895, P = 0.32). The increased blood lactate level per minute from scene to ER was associated with increased probability for immediate intervention (P < 0.0001). Both adding Lac scene to physiological variables and the temporal elevation of blood lactate levels from scene to ER could improve the prediction of the immediate intervention.

Figure 1

Receiver operating characteristic curve for prediction of immediate need for intervention for hemorrhage. The value of a model using potential predictors of the need for immediate intervention for hemorrhage was determined. Each physiologic parameter (sBP, HR, RR, GCS, and SI) and Lac scene was used for prediction in univariate analysis (A). Lac scene had the greatest predictive value (AUC = 0.764), followed by GCS (AUC = 0.744). The predictive ability of a model using a combination of physiological parameters and a penetrating mechanism of injury, with or without Lac scene, was estimated using multivariate analysis (B). Compared with use of parameters without Lac scene (AUC = 0.837), a combination of physiological parameters, a penetrating mechanism of injury, and Lac scene enabled more accurate prediction (AUC = 0.882).

Figure 2

Case probability of patients with early therapeutic intervention in Lac delta per min groups. There was a significant difference in case probability between the negative Lac delta per min group (n = 249) and the positive Lac delta per min group (n = 186) (A *P = 0.019 with the chi-square test). In quintile subgroups of the positive Lac delta per min group, the case probability was significantly increased with increasing Lac delta per min (B **P < 0.0001 with the Cochran-Armitage test).