title: The lactate:pyruvate ratio following open cardiac surgery in children.
abstract: OBJECTIVE
  To explore the relationship between lactate:pyruvate ratio, hyperlactataemia, metabolic acidosis, and morbidity.
  
  
  METHODS
  Prospective observational study in the paediatric intensive care unit (PICU) of a university hospital.
  
  
  METHODS
  Ninety-seven children after open cardiac surgery. Most children (94%) fell into low-moderate operative risk categories; observed PICU mortality was 1%.
  
  
  METHODS
  Blood was sampled on admission for acid-base analysis, lactate, and pyruvate. Metabolic acidosis was defined as standard bicarbonate lower than 22 mmol/l, raised lactate as higher than 2 mmol/l, and raised lactate:pyruvate ratio as higher than 20.
  
  
  RESULTS
  Median cardiopulmonary bypass and aortic cross-clamp times were 80 and 46 min. Metabolic acidosis occurred in 74%, hyperlactataemia in 42%, and raised lactate:pyruvate ratio in 45% of children. In multivariate analysis lactate:pyruvate ratio increased by 6.4 in children receiving epinephrine infusion and by 0.4 per 10 min of aortic cross-clamp. Duration of inotropic support increased by 0.29 days, ventilatory support by 0.27 days, and PICU stay by 0.42 days, for each 1 mmol/l increase in lactate. Neither standard bicarbonate nor lactate:pyruvate ratio were independently associated with prolongation of PICU support.
  
  
  CONCLUSIONS
  Elevated lactate:pyruvate ratio was common in children with mild metabolic acidosis and low PICU mortality. Hyperlactataemia, but not elevated lactate:pyruvate ratio or metabolic acidosis, was associated with prolongation of PICU support. Routine measurement of lactate:pyruvate ratio is not warranted for children in low-moderate operative risk categories.
authors: Division of Critical Care and Children's Heart Disease, School of Child and Adolescent Health, University of Cape Town, Cape Town, South Africa. mark.hatherill@uct.ac.za.
authors: Mark
authors: M
authors: Hatherill
authors: Division of Critical Care and Children's Heart Disease, School of Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors: Shamiel
authors: S
authors: Salie
authors: Division of Critical Care and Children's Heart Disease, School of Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors: Zainab
authors: Z
authors: Waggie
authors: Division of Critical Care and Children's Heart Disease, School of Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors: John
authors: J
authors: Lawrenson
authors: Division of Critical Care and Children's Heart Disease, School of Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors: John
authors: J
authors: Hewitson
authors: Division of Critical Care and Children's Heart Disease, School of Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors: Louis
authors: L
authors: Reynolds
authors: Division of Critical Care and Children's Heart Disease, School of Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors: Andrew
authors: A
authors: Argent
mesh_terms: D000138:Acidosis / Q000097:blood*; D000293:Adolescent; D001639:Bicarbonates / Q000097:blood*; D006348:Cardiac Surgical Procedures / Q000706:statistics & numerical data*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D007773:Lactates / Q000097:blood*; D016014:Linear Models; D011184:Postoperative Period; D011446:Prospective Studies; D011773:Pyruvates / Q000097:blood*
chemical_list: D001639:Bicarbonates; D007773:Lactates; D011773:Pyruvates