title: Dopamine therapy for patients at risk of renal dysfunction following cardiac surgery: science or fiction?
abstract: OBJECTIVE
  We aimed to evaluate the renoprotective role of renal-dose dopamine on cardiac surgical patients at high risk of postoperative renal dysfunction. The latter included older patients or those with pre-existing renal disease, elevated preoperative serum creatinine (Cr), poor ventricular function, hypertension, diabetes mellitus and unstable angina requiring intravenous therapy.
  
  
  METHODS
  Fifty patients undergoing cardiopulmonary bypass (CPB) who fulfilled the entry criteria were prospectively randomized into two groups: Group 1 received a 'renal-dose' (3 microg kg(-1) min(-1)) dopamine infusion starting at anaesthetic induction for 48 h whilst saline infusion acted as placebo in Group 2. The anaesthetic and CPB regimes were standardized. Urinary excretion of retinol binding protein (RBP) indexed to Cr, an accurate and sensitive marker of early renal tubular damage, was assessed daily for 6 days. Additional outcome measures included daily fluid balance, blood urea and serum Cr. Statistical comparisons were made using ANOVA and Mann-Whitney U-test.
  
  
  RESULTS
  No significant difference was found between the groups in their age, gender, preoperative NYHA class, ejection fraction, baseline serum Cr and duration of CPB and aortic cross-clamping. Renal replacement therapy was not required in any instance. Both groups demonstrated a similar and significant rise in urinary RBP throughout the study period. Dopamine-treated patients achieved more negative average fluid balance than those on placebo (5 vs. 229 ml, P<0.05).
  
  
  CONCLUSIONS
  Renal-dose dopamine therapy failed to offer additional renoprotection to patients considered at increased risk of renal dysfunction after CPB.
authors.affiliation: Department of Cardiothoracic Surgery, Wythenshawe Hospital, Southmoor Road, Manchester M23 9LT, UK.
authors.forename: Edwin B C
authors.initials: EB
authors.lastname: Woo
authors.forename: Augustine T M
authors.initials: AT
authors.lastname: Tang
authors.forename: Ahmed
authors.initials: A
authors.lastname: el-Gamel
authors.forename: Brian
authors.initials: B
authors.lastname: Keevil
authors.forename: Donna
authors.initials: D
authors.lastname: Greenhalgh
authors.forename: Mark
authors.initials: M
authors.lastname: Patrick
authors.forename: Mark T
authors.initials: MT
authors.lastname: Jones
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Hooper
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass; D002316:Cardiotonic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D003404:Creatinine / Q000097:blood; D004298:Dopamine / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007668:Kidney / Q000098:blood supply; D007674:Kidney Diseases / Q000517:prevention & control*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012177:Retinol-Binding Proteins / Q000652:urine; D014664:Vasodilation / Q000187:drug effects
chemical_list: D002316:Cardiotonic Agents; D012177:Retinol-Binding Proteins; D003404:Creatinine; D004298:Dopamine