title: Effect of cardiopulmonary bypass on lactate metabolism.
abstract: OBJECTIVE
  We have investigated the role of cardiopulmonary bypass on lactate metabolism in patients undergoing uncomplicated surgery for elective coronary artery bypass grafting (CABG).
  
  
  METHODS
  Prospective non-randomized observational study.
  
  
  METHODS
  National Cardiovascular Center. PATIENTS. Three independent groups were studied: preoperative ( n=20), postoperative with bypass (CPB, n=20) and postoperative without bypass (NO-CPB, n=20).
  
  
  METHODS
  Lactate metabolism was investigated with the use of an exogenous lactate challenge test (2.5 mmol Na-lactate/kg body weight in 15 min). Blood lactate was sequentially determined after the end of infusion. Lactate clearance and endogenous production were estimated from the area under the curve, and a bi-exponential fitting permitted modeling the lactate-decay into two compartments.
  
  
  RESULTS
  Lactate metabolism parameters (basal lactate, clearance, endogenous production and half-lives [HL] I and II) were not different between the NO-CPB and preoperative groups. In the CPB group, as compared to the other two groups, basal lactate and endogenous production were not significantly affected while lactate clearance (CPB: 6.02+/-0.97 versus preoperative: 9.41+/-0.93 and NO-CPB: 9.6+/-0.8 ml/kg per min) and HL-I (CPB: 10.6+/-1.4 versus preoperative: 17.2+/-2.3 and NO-CPB: 18.8+/-2.5 min) were decreased ( p<0.001) and HL-II was increased (CPB: 171+/-41 versus preoperative: 73+/-12 and NO-CPB: 48+/-2.9 min, p<0.01).
  
  
  CONCLUSIONS
  While surgery and anesthesia per se do not seem to alter lactate metabolism, CPB significantly decreased lactate clearance, this effect being possibly related to a mild liver dysfunction even in uncomplicated elective surgery.
authors.affiliation: Intensive Care Unit, Harapan Kita National Cardiovascular Center, Jakarta, Indonesia.
authors.forename: Iqbal
authors.initials: I
authors.lastname: Mustafa
authors.forename: Hubert
authors.initials: H
authors.lastname: Roth
authors.forename: Asikin
authors.initials: A
authors.lastname: Hanafiah
authors.forename: Tarmizi
authors.initials: T
authors.lastname: Hakim
authors.forename: Maizul
authors.initials: M
authors.lastname: Anwar
authors.forename: Erwin
authors.initials: E
authors.lastname: Siregar
authors.forename: Xavier M
authors.initials: XM
authors.lastname: Leverve
mesh_terms: D000328:Adult; D000368:Aged; D002315:Cardiopulmonary Bypass; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008875:Middle Aged; D011182:Postoperative Care; D011300:Preoperative Care; D011446:Prospective Studies
chemical_list: D019344:Lactic Acid