Dopamine therapy for patients at risk of renal dysfunction following cardiac surgery: science or fiction?
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.
Woo
Edwin B C
EB
Department of Cardiothoracic Surgery, Wythenshawe Hospital, Southmoor Road, Manchester M23 9LT, UK.
Tang
Augustine T M
AT
el-Gamel
Ahmed
A
Keevil
Brian
B
Greenhalgh
Donna
D
Patrick
Mark
M
Jones
Mark T
MT
Hooper
Timothy L
TL
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
D002316:Cardiotonic Agents; D012177:Retinol-Binding Proteins; D003404:Creatinine; D004298:Dopamine