title: Use of serum lactate levels to predict survival for patients with out-of-hospital cardiac arrest: A cohort study.
abstract: OBJECTIVE
  We examined the association of serum lactate levels and early lactate clearance with survival to hospital discharge for patients suffering an out-of-hospital cardiac arrest (OHCA).
  
  
  METHODS
  A retrospective cohort analysis was performed of patients with OHCA transported by ambulance to two adult tertiary hospitals in Perth, Western Australia. Exclusion criteria were traumatic cardiac arrest, return of spontaneous circulation prior to the arrival of the ambulance, age less than 18 years and no serum lactate levels recorded. Serum lactate levels recorded for up to 48 h post-arrest were obtained from the hospital clinical information system, and lactate clearance over 48 h was calculated. Descriptive and logistic regression analyses were conducted.
  
  
  RESULTS
  There were 518 patients with lactate values, of whom 126 (24.3%) survived to hospital discharge. Survivors and non-survivors had different mean initial lactate levels (mean ± SD 6.9 ± 4.7 and 12.2 ± 5.5 mmol/L, respectively; P < 0.001). Lactate clearance was higher in survivors. Lactate levels for non-survivors did not decrease below 2 mmol/L until at least 30 h after the ambulance call.
  
  
  CONCLUSIONS
  In OHCA patients who had serum lactate levels measured, both lower initial serum lactate and early lactate clearance in the first 48 h following OHCA were associated with increased likelihood of survival. However, the use of lactate in isolation as a predictor of survival or neurological outcome is not recommended. Prospective studies that minimise selection bias are required to determine the clinical utility of serum lactate levels in OHCA patients.
authors.affiliation: Prehospital Resuscitation and Emergency Care Research Unit, School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Western Australia, Australia.|Discipline of Emergency Medicine, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, Western Australia, Australia.|St John Ambulance, Belmont, Western Australia, Australia.
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Williams
authors.affiliation: Discipline of Emergency Medicine, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Ry
authors.initials: R
authors.lastname: Martin
authors.affiliation: Discipline of Emergency Medicine, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, Western Australia, Australia.|Emergency Department, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
authors.forename: Antonio
authors.initials: A
authors.lastname: Celenza
authors.affiliation: School of Population Health, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Bremner
authors.affiliation: Discipline of Emergency Medicine, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, Western Australia, Australia.|Emergency Medicine, Royal Perth Hospital, Perth, Western Australia, Australia.|Centre for Clinical Research in Emergency Medicine, Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia.
authors.forename: Daniel
authors.identifier: http://orcid.org/0000-0001-9414-6905
authors.initials: D
authors.lastname: Fatovich
authors.affiliation: Discipline of Emergency Medicine, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Joel
authors.initials: J
authors.lastname: Krause
authors.affiliation: Discipline of Emergency Medicine, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Steven
authors.initials: S
authors.lastname: Arena
authors.affiliation: Prehospital Resuscitation and Emergency Care Research Unit, School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Western Australia, Australia.|Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.|St John Ambulance, Belmont, Western Australia, Australia.
authors.forename: Judith
authors.initials: J
authors.lastname: Finn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D004632:Emergency Medical Services / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood* / Q000378:metabolism; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D058687:Out-of-Hospital Cardiac Arrest / Q000097:blood* / Q000401:mortality; D010351:Patient Discharge / Q000706:statistics & numerical data; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D016019:Survival Analysis; D014904:Western Australia / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D019344:Lactic Acid
keywords: cardiac arrest; clearance; lactate; out-of-hospital; survival