title: Lactate clearance as a predictor of mortality in trauma patients.
abstract: BACKGROUND
  Initial serum lactate has been associated with mortality in trauma patients. It is not known if lactate clearance is predictive of death in a broad cohort of trauma patients.
  
  
  METHODS
  We enrolled 4,742 trauma patients who had an initial lactate measured during a 10-year period. Patients were identified via the trauma registry. Lactate clearance was calculated at 6 hours. Multivariable logistic regression was used to identify the independent contribution of both initial lactate and lactate clearance with mortality, after adjustment for severity of injury.
  
  
  RESULTS
  Initial lactate level was strongly correlated with mortality: when lactate was less than 2.5 mg/dL, 5.4% (95% confidence interval [CI], 4.5-6.2%) of patients died; with lactate 2.5 mg/dL to 4.0 mg/dL, mortality was 6.4% (95% CI, 5.1-7.8%); with lactate 4.0 mg/dL or greater, mortality was 18.8% (95% CI, 15.7-21.9%). After adjustment for age, Injury Severity Score (ISS), Glasgow Coma Scale (GCS) score, heart rate, and blood pressure, initial lactate remained independently associated with increased mortality, with adjusted odds ratios of 1.0, 1.5 (95% CI, 1.1-2.0) and 3.8 (95% CI, 2.8-5.3), for lactate less than 2.5 mg/dL, 2.5 mg/dL to 4.0 mg/dL, and 4.0 mg/dL or greater, respectively. Among patients with an initially elevated lactate (≥4.0 mg/dL), lower lactate clearance at 6 hours strongly and independently predicted an increased risk of death. For lactate clearances of 60% or greater, 30% to 59%, and less than 30%, the adjusted odds ratio for death were 1.0, 3.5 (95% CI 1.2-10.4), and 4.3 (95% CI, 1.5-12.6), respectively.
  
  
  CONCLUSIONS
  Both initial lactate and lactate clearance at 6 hours independently predict death in trauma patients.
  
  
  METHODS
  Prognostic study, level III.
authors.affiliation: Division of Acute Care Surgery, Trauma and Surgical Critical Care, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA. sodom@bidmc.harvard.edu
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Odom
authors.forename: Michael D
authors.initials: MD
authors.lastname: Howell
authors.forename: George S
authors.initials: GS
authors.lastname: Silva
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Nielsen
authors.forename: Alok
authors.initials: A
authors.lastname: Gupta
authors.forename: Nathan I
authors.initials: NI
authors.lastname: Shapiro
authors.forename: Daniel
authors.initials: D
authors.lastname: Talmor
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D015600:Glasgow Coma Scale; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D016017:Odds Ratio; D011379:Prognosis; D012042:Registries; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D014193:Trauma Centers; D014947:Wounds and Injuries / Q000097:blood / Q000401:mortality*
chemical_list: D015415:Biomarkers; D019344:Lactic Acid