title: Better lactate clearance associated with good neurologic outcome in survivors who treated with therapeutic hypothermia after out-of-hospital cardiac arrest.
abstract: BACKGROUND
  Several methods have been proposed to evaluate neurological outcome in out-of-hospital cardiac arrest (OHCA) patients. Blood lactate has been recognized as a reliable prognostic marker for trauma, sepsis, or cardiac arrest. The objective of this study was to examine the association between initial lactate level or lactate clearance and neurologic outcome in OHCA survivors who were treated with therapeutic hypothermia.
  
  
  METHODS
  This retrospective cohort study included patients who underwent protocol-based 24-hour therapeutic hypothermia after OHCA between January 2010 and March 2012. Serum lactate levels were measured at the start of therapy (0 hours), and after 6 hours, 12 hours, 24 hours, 48 hours and 72 hours. The 6 hour and 12 hour lactate clearance were calculated afterwards. Patients' neurologic outcome was assessed at one month after cardiac arrest; good neurological outcome was defined as Cerebral Performance Category one or two. The primary outcome was an association between initial lactate level and good neurologic outcome. The secondary outcome was an association between lactate clearance and good neurologic outcome in patients with initial lactate level >2.5 mmol/l.
  
  
  RESULTS
  Out of the 76 patients enrolled, 34 (44.7%) had a good neurologic outcome. The initial lactate level showed no significant difference between good and poor neurologic outcome groups (6.07 ±4 .09 mmol/L vs 7.13 ± 3.99 mmol/L, P = 0.42), However, lactate levels at 6 hours, 12 hours, 24 hours, and 48 hours in the good neurologic outcome group were lower than in the poor neurologic outcome group (3.81 ± 2.81 vs 6.00 ± 3.22 P <0.01, 2.95 ± 2.07 vs 5.00 ± 3.49 P <0.01, 2.17 ± 1.24 vs 3.86 ± 3.92 P <0.01, 1.57 ± 1.02 vs 2.21 ± 1.35 P = 0.03, respectively). The secondary analysis showed that the 6-hour and 12-hour lactate clearance was higher for good neurologic outcome patients (35.3 ± 34.6% vs 6.89 ± 47.4% P = 0.01, 54.5 ± 23.7% vs 25.6 ± 43.7% P <0.01, respectively). After adjusting for potential confounding variables, the 12-hour lactate clearance still showed a statistically significant difference (P = 0.02).
  
  
  CONCLUSIONS
  The lactate clearance rate, and not the initial lactate level, was associated with neurological outcome in OHCA patients after therapeutic hypothermia.
authors.forename: Tae Rim
authors.initials: TR
authors.lastname: Lee
authors.forename: Mun Ju
authors.initials: MJ
authors.lastname: Kang
authors.forename: Won Chul
authors.initials: WC
authors.lastname: Cha
authors.forename: Tae Gun
authors.initials: TG
authors.lastname: Shin
authors.forename: Min Seob
authors.initials: MS
authors.lastname: Sim
authors.forename: Ik Joon
authors.initials: IJ
authors.lastname: Jo
authors.forename: Keun Jeong
authors.initials: KJ
authors.lastname: Song
authors.forename: Yeon Kwon
authors.initials: YK
authors.lastname: Jeong
authors.forename: Jun Hwi
authors.initials: JH
authors.lastname: Cho
mesh_terms: D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced; D007773:Lactates / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000097:blood* / Q000209:etiology*; D058687:Out-of-Hospital Cardiac Arrest / Q000097:blood* / Q000628:therapy*; D012189:Retrospective Studies; D017741:Survivors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D007773:Lactates