title: Changes in blood lactate levels after major elective abdominal surgery and the association with outcomes: a prospective observational study.
abstract: BACKGROUND
  Prolonged elevated blood lactate levels strongly correlate with poor outcomes in a variety of critically ill patients. We hypothesized that the dynamic postoperative changes in blood lactate levels during the first 24 h were significantly associated with postoperative morbidity and mortality in patients undergoing elective major abdominal surgery.
  
  
  METHODS
  We performed a single-center prospective observational study of 114 consecutive patients undergoing elective major abdominal surgery from September 2009 to December 2010. Blood lactate was determined postoperatively at 6 h intervals during the first 24 h. In-hospital complications and deaths occurring within 30 d of enrollment were included in the data analysis.
  
  
  RESULTS
  A total of 88 postoperative complications were recorded in 51 patients (44.7%). There was a significant difference in blood lactate levels among patients with no, minor, and major complications (ANOVA, Groups, P < 0.001; time, P < 0.001; groups × time interaction, P = 0.014). The accuracy of lactate levels to predict both overall and major complications increased postoperatively from 0 h to 24 h. Using a multivariate analysis, the time-weighted average lactate was independently predictive of both overall (OR 7.108, 95% CI 2.271-22.249, P = 0.001) and major (OR 3.277, 95% CI 1.363-7.877, P = 0.008) postoperative complications, and lactate clearance at 0-24 h (OR 0.217, CI 0.077-0.616, P = 0.004) was independently predictive of major postoperative complications. The optimal time-weighted average lactate cutoff value for complication prediction was 1.46 mmol/L; below this level, both overall and major complication rates were significantly reduced, which was true even after adjusting for potential confounding factors.
  
  
  CONCLUSIONS
  The dynamic changes in blood lactate levels during the first 24 postoperative h were significantly associated with complications after major elective abdominal surgery. This result warrants a "golden hour and silver day" perspective of early resuscitation in this patient cohort.
authors.affiliation: Department of Anesthesiology, The Affiliated Hospital of Jianghan University, Wuhan, Hubei, China.
authors.forename: Shenghua
authors.initials: S
authors.lastname: Li
authors.forename: Kaiqin
authors.initials: K
authors.lastname: Peng
authors.forename: Fen
authors.initials: F
authors.lastname: Liu
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
authors.forename: Yingtian
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000368:Aged; D015415:Biomarkers / Q000097:blood; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D007773:Lactates / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011184:Postoperative Period; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies
chemical_list: D015415:Biomarkers; D007773:Lactates
keywords: Critical care; Lactate; Surgery