title: Alterations in anion gap following cardiopulmonary bypass.
abstract: OBJECTIVE
  To evaluate the changes in the anion gap and their relation to hyperlactatemia and alterations in plasma proteins after cardiopulmonary bypass.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Cardiothoracic intensive therapy unit.
  
  
  METHODS
  One hundred eleven consecutive patients after cardiopulmonary bypass.
  
  
  RESULTS
  Data were collected before cardiopulmonary bypass and every 6 hrs for 24 hrs after cardiopulmonary bypass. Results were analyzed for the entire cohort and for hyperlactatemic subgroups. The major finding of this study was that the anion gap decreased significantly at all sampling periods relative to precardiopulmonary bypass values, despite the presence of clinically important hyperlactatemia. No correlation between the decrease in plasma protein concentrations and the decrease in anion gap could be demonstrated.
  
  
  CONCLUSIONS
  The decrease in anion gap after cardiopulmonary bypass appears to represent a balance between the influences of increased serum chloride and lactate concentrations and reduced plasma protein concentrations. This analysis demonstrates the limitations of the anion gap in the evaluation of a metabolic acidosis after cardiopulmonary bypass.
authors.affiliation: Intensive Therapy Unit, Royal North Shore Hospital, Sydney, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Ernest
authors.forename: R G
authors.initials: RG
authors.lastname: Herkes
authors.forename: R F
authors.initials: RF
authors.lastname: Raper
mesh_terms: D000136:Acid-Base Equilibrium; D000140:Acidosis, Lactic / Q000097:blood* / Q000453:epidemiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis; D001798:Blood Proteins / Q000032:analysis*; D001026:Coronary Artery Bypass; D004573:Electrolytes / Q000097:blood; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007773:Lactates / Q000097:blood*; D019344:Lactic Acid; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood* / Q000453:epidemiology; D011237:Predictive Value of Tests; D011446:Prospective Studies
chemical_list: D001798:Blood Proteins; D004573:Electrolytes; D007773:Lactates; D019344:Lactic Acid