title: Renal protection by radical scavenging in cardiac surgery patients.
abstract: OBJECTIVE
  Renal function impairment is a common complication in cardiac surgery patients. Because cardiopulmonary bypass and cardioplegic arrest are associated with formation of free radicals, which have been shown to impair various organs including the kidneys, radical scavenging may protect renal function. Therefore, the purpose of our study was to evaluate the impact of the radical scavenger N-acetylcysteine (NAC) versus placebo on peri-operative renal function in cardiac surgery patients.
  
  
  METHODS
  We reanalyzed the data of our previous study in which 40 coronary artery surgery patients (66 +/- 9 [SD] years, 9 women and 31 men) with normal pre-operative renal function had been randomized in a double-blind fashion to receive either NAC (100 mg/kg into the cardiopulmonary bypass prime followed by infusion at 20 mg/kg/h; n = 20) or placebo (n = 20). We determined serum creatinine levels as an indicator for renal function pre- and at 1 day post-surgery as well as peri-operative urinary output and diuretic medication. Creatinine clearance was calculated according to Cockcroft and Gault.
  
  
  RESULTS
  Biometric and intra-operative patient data were similar between both groups. In the placebo group, serum creatinine increased from 93.1 +/- 35.4 micromol/L pre-operatively to 115.9 +/- 47.2 micromol/L on post-op day 1 (p < 0.001). In contrast, serum creatinine in the NAC group remained unchanged (92.3 +/- 31.3 micromol/L pre-op; 99.3 +/- 25.4 micromol/L on post-op day 1; p = 0.084). Accordingly, creatinine clearance decreased by 16.9 +/- 14.3 mL/min in the placebo group as compared to 7.5 +/- 17.7 mL/min in the NAC group (p = 0.039). Urinary output and diuretic medication were similar between NAC and placebo.
  
  
  CONCLUSIONS
  Our data suggest that free radical-scavenging using NAC protects renal function in patients subjected to cardiac surgery on cardiopulmonary bypass.
authors.affiliation: Department of Cardiothoracic Surgery, University of Cologne, Cologne, Germany. uwe.fischer@uk-koeln.de
authors.forename: Uwe M
authors.initials: UM
authors.lastname: Fischer
authors.forename: Paschalis
authors.initials: P
authors.lastname: Tossios
authors.forename: Uwe
authors.initials: U
authors.lastname: Mehlhorn
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage / Q000627:therapeutic use*; D000208:Acute Disease; D058186:Acute Kidney Injury / Q000209:etiology / Q000517:prevention & control*; D000368:Aged; D002315:Cardiopulmonary Bypass; D013504:Cardiovascular Surgical Procedures / Q000009:adverse effects*; D003331:Coronary Vessels / Q000601:surgery*; D003404:Creatinine / Q000097:blood; D005260:Female; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies
chemical_list: D016166:Free Radical Scavengers; D003404:Creatinine; D000111:Acetylcysteine