title: Early lactate clearance in septic patients with elevated lactate levels admitted from the emergency department to intensive care: time to aim higher?
abstract: OBJECTIVE
  Septic patients with hyperlactatemia have increased mortality rates, irrespective of hemodynamic and oxygen-derived variables. The aims of the study are the following: (1) to ascertain whether lactate clearance (LC) (percentage change in lactate over unit time) predicts mortality in septic patients admitted to intensive care directly from the emergency department and (2) to calculate the optimal "cut-off" value for mortality prediction.
  
  
  METHODS
  Three-year retrospective observational study of consecutive patients with severe sepsis and septic shock admitted to intensive care from the emergency department of a tertiary UK hospital. We calculated 6-hour LC, performed receiver operating characteristic analyses to calculate optimal cut-off values for initial lactate and LC, dichotomized patients according to the LC cut-off, and calculated hazard ratios using a Cox proportional hazards model.
  
  
  RESULTS
  One hundred six patients were identified; 78, after exclusions. Lactate clearance was independently associated with 30-day mortality (P<.04); optimal cut-off, 36%. Mortality rates were 61.1% and 10.7% for patients with 6-hour LC 36% or less and greater than 36%, respectively. Hazard ratio for death with LC 36% or less was 7.33 (95% confidence interval, 2.17-24.73; P<.001).
  
  
  CONCLUSIONS
  Six-hour LC was independently associated with mortality, and the optimal cut-off value was 36%, significantly higher than previously reported. We would support further research investigating this higher LC as a distinct resuscitation end point in patients with severe sepsis and septic shock.
authors.affiliation: The Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh, Scotland, United Kingdom EH16 4SA. Electronic address: craigawalker@nhs.net.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Walker
authors.forename: David M
authors.initials: DM
authors.lastname: Griffith
authors.forename: Alasdair J
authors.initials: AJ
authors.lastname: Gray
authors.forename: Deepankar
authors.initials: D
authors.lastname: Datta
authors.forename: Alasdair W
authors.initials: AW
authors.lastname: Hay
mesh_terms: D018806:APACHE; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004636:Emergency Service, Hospital; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012606:Scotland / Q000453:epidemiology; D018805:Sepsis / Q000378:metabolism* / Q000401:mortality; D012772:Shock, Septic / Q000378:metabolism* / Q000401:mortality; D013997:Time Factors
chemical_list: D019344:Lactic Acid
keywords: Lactate clearance; Mortality; Predict; Sepsis