title: Lactate clearance metrics are not superior to initial lactate in predicting mortality in trauma.
abstract: OBJECTIVE
  Despite the availability of different lactate clearance (LC) metrics for clinical use, it remains unknown which metric is superior as a clinical predictor for outcome, particularly in trauma patients. This retrospective study compared four previously described metrics of LC and examined the association between LC and outcome in trauma patients.
  
  
  METHODS
  Lactate values of trauma patients admitted to a level I trauma center between 2010 and 2013 were retrieved from patient records. LC was calculated according to Huckabee, Regnier et al., Billeter et al. and Zhang et al. Patients were categorized as isolated traumatic brain injury (TBI), trauma with TBI, and trauma without TBI. The primary study outcome was in-hospital mortality.
  
  
  RESULTS
  367 trauma patients were eligible for LC calculation. Only LC by Zhang et al. [area under the curve (AUC) > 0.622, p < 0.01], and Billeter et al. (AUC > 0.616, p < 0.05) were predictive for mortality in trauma patients with and without TBI. However, both were equally prognostic as the initial lactate value for in-hospital mortality. The prognostic value of initial lactate and lactate clearance for in-hospital mortality were not found to differ between isolated TBI, polytrauma with TBI, and trauma without TBI.
  
  
  CONCLUSIONS
  LC metrics based on the methods of Zhang et al. and Billeter et al. predicted mortality in trauma patients, and their prognostic value did not differ between patients with and without TBI. However, initial lactate value was equally prognostic as these LC metrics. Our findings suggest that a single initial lactate measurement may be a more clinically useful tool to predict mortality than the calculation of lactate clearance.
authors.affiliation: Department of Anesthesiology, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands. sxd503@case.edu.
authors.forename: S E
authors.identifier: http://orcid.org/0000-0002-0634-3034
authors.initials: SE
authors.lastname: Dekker
authors.affiliation: Department of Anesthesiology, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
authors.forename: H-M
authors.initials: HM
authors.lastname: de Vries
authors.affiliation: Department of Anesthesiology, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
authors.forename: W D
authors.initials: WD
authors.lastname: Lubbers
authors.affiliation: Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: P M
authors.initials: PM
authors.lastname: van de Ven
authors.affiliation: Center For Acute Care, VU Medical Center Region, Amsterdam, The Netherlands.
authors.forename: E J
authors.initials: EJ
authors.lastname: Toor
authors.affiliation: Department of Trauma Surgery, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: F W
authors.initials: FW
authors.lastname: Bloemers
authors.affiliation: Department of Trauma Surgery, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: L M G
authors.initials: LMG
authors.lastname: Geeraedts
authors.affiliation: Department of Anesthesiology, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Schober
authors.affiliation: Department of Anesthesiology, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
authors.forename: C
authors.initials: C
authors.lastname: Boer
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D000070642:Brain Injuries, Traumatic / Q000097:blood / Q000401:mortality*; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D019344:Lactic Acid / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D008875:Middle Aged; D009104:Multiple Trauma; D009426:Netherlands; D011237:Predictive Value of Tests; D012189:Retrospective Studies
chemical_list: D015415:Biomarkers; D019344:Lactic Acid
keywords: Lactate; Mortality; Neurotrauma; Polytrauma; Prognosis