Prognostic significance of blood lactate and lactate clearance in trauma patients

Abstract

BACKGROUND:: Lactate has been shown to be a prognostic biomarker in trauma. Although lactate clearance has already been proposed as an intermediate endpoint in randomized trials, its precise role in trauma patients remains to be determined. METHODS:: Blood lactate levels and lactate clearance (LC) were calculated at admission and 2 and 4 h later in trauma patients. The association of initial blood lactate level and lactate clearance with mortality was tested using receiver-operating characteristics curve, logistic regression using triage scores, Trauma Related Injury Severity Score as a reference standard, and reclassification method. RESULTS:: The authors evaluated 586 trauma patients (mean age 38 ± 16 yr, 84% blunt and 16% penetrating, mortality 13%). Blood lactate levels at admission were elevated in 327 (56%) patients. The lactate clearance should be calculated within the first 2 h after admission as LC0-2 h was correlated with LC0-4 h (R = 0.55, P < 0.001) but not with LC2-4 h (R = 0.04, not significant). The lactate clearance provides additional predictive information to initial blood lactate levels and triage scores and the reference score. This additional information may be summarized using a categorical approach (i.e., less than or equal to-20 %/h) in contrast to initial blood lactate. The results were comparable in patients with high (5 mM/l or more) initial blood lactate. CONCLUSIONS:: Early (0-2 h) lactate clearance is an important and independent prognostic variable that should probably be incorporated in future decision schemes for the resuscitation of trauma patients. © 2012, the American Society of Anesthesiologists, Inc.