title: Lactate clearance time and concentration linked to morbidity and death in cardiac surgical patients.
abstract: BACKGROUND
  Early predictors of morbidity after cardiac operations are lacking. Elevated lactate concentrations in the immediate postoperative period reflect unmet metabolic demand and may be associated with outcome. This study examined the association between early plasma lactate concentrations and outcome after cardiac operations.
  
  
  METHODS
  As a retrospective cohort investigation, patient information was obtained from the Cardiovascular Information and the Anesthesiology Institute's patient registries. Inclusion criteria were all adult cardiac surgical patients undergoing isolated coronary artery bypass grafting or valve procedures, or coronary artery bypass grafting with a valve procedure, from January 1, 2008, to August 7, 2008 (arterial lactate values were added to the patient registry beginning January 1, 2008).
  
  
  RESULTS
  Lactate concentrations during the initial 12 postoperative hours of a patient's stay in the cardiovascular intensive care unit were averaged (mean lactate concentration), and linear regression concentrations over time were used to predict when the lactate concentration would reach 1.5 mmol/L in individual patients (predicted lactate clearance time). We also considered the product of the mean and clearance (product value). Predicted lactate clearance time, mean lactate concentration, and product value were associated with any type of reoperation, death, and a set of composite outcomes (p < 0.001 for each). The accuracy of these indices was moderate to good, with the highest C statistic (for product value) being 0.82.
  
  
  CONCLUSIONS
  Predicted lactate clearance time, mean lactate concentration, and product value are each associated with death, any type of reoperation, and a set of composite outcomes in patients undergoing coronary artery bypass grafting or valve operations, or both. Product value provided the best early prognostic guidance in individual patients.
authors.affiliation: Department of Outcomes Research, Cleveland Clinic, Cleveland, Ohio 44195, USA.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Lindsay
authors.forename: Meng
authors.initials: M
authors.lastname: Xu
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Sessler
authors.forename: Eugene H
authors.initials: EH
authors.lastname: Blackstone
authors.forename: C Allen
authors.initials: CA
authors.lastname: Bashour
mesh_terms: D000328:Adult; D006348:Cardiac Surgical Procedures; D002423:Cause of Death; D015331:Cohort Studies; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D011183:Postoperative Complications / Q000453:epidemiology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D019344:Lactic Acid