title: Lactate Clearance Predicts Survival Among Patients in the Emergency Department with Severe Sepsis.
abstract: BACKGROUND
  Lactate clearance has been implicated as a predictor of mortality among emergency department (ED) patients with severe sepsis or septic shock. We aimed to validate prior studies showing that lactate clearance during the ED stay is associated with decreased mortality.
  
  
  METHODS
  Retrospective dual-centered cross-sectional study using patients identified in the Yale-New Haven Hospital Emergency Medicine sepsis registry with severe sepsis or septic shock who had initial lactate levels measured in the ED and upon arrival (<24 hours) to the hospital floor. Lactate clearance was calculated as percent of serum lactate change from ED to floor measurement. We compared mortality and hospital interventions between patients who cleared lactate and those who did not.
  
  
  RESULTS
  207 patients (110 male; 63.17±17.9 years) were included. Two reviewers extracted data with 95% agreement. One hundred thirty-six patients (65.7%) had severe sepsis and 71 patients (34.3%) had septic shock. There were 171 patients in the clearance group and 36 patients in the non-clearance group. The 28-day mortality rates were 15.2% in the lactate clearance group and 36.1% in the non-clearance group (p<0.01). Vasopressor support was initiated more often in the non-clearance group (61.1%) than in the clearance group (36.8%, p<0.01) and mechanical ventilation was used in 66.7% of the non-clearance group and 36.3% of the clearance group (p=0.001).
  
  
  CONCLUSIONS
  Patients who do not clear their lactate in the ED have significantly higher mortality than those with decreasing lactate levels. Our results are confirmatory of other literature supporting that lactate clearance may be used to stratify mortality-risk among patients with severe sepsis or septic shock.
authors.affiliation: Kaiser Permanente Santa Clara Medical Center, Department of Emergency Medicine, Santa Clara, California.
authors.forename: Sundeep R
authors.initials: SR
authors.lastname: Bhat
authors.affiliation: Yale School of Medicine, Department of Emergency Medicine, New Haven, Connecticut.
authors.forename: Kai E
authors.initials: KE
authors.lastname: Swenson
authors.affiliation: Uniformed Services Residency in Obstetrics and Gynecology, National Naval Medical Center, Bethesda, Maryland.
authors.forename: Melissa W
authors.initials: MW
authors.lastname: Francis
authors.affiliation: Yale School of Medicine, Department of Emergency Medicine, New Haven, Connecticut.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Wira
mesh_terms: D018806:APACHE; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004636:Emergency Service, Hospital; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012772:Shock, Septic / Q000097:blood / Q000401:mortality*; D016019:Survival Analysis
chemical_list: D019344:Lactic Acid