title: N-acetylcysteine to reduce renal failure after cardiac surgery: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To assess the effect of N-acetylcysteine (NAC) on acute renal failure and important clinical outcomes after cardiac surgery.
  
  
  METHODS
  Two reviewers performed literature searches, using EMBASE and PubMed, of randomized controlled trials investigating the renoprotective effect of N-acetylcysteine in cardiac surgery. Treatment effects were calculated as relative risks (RR) with 95% confidence intervals (CI). Heterogeneity and publication bias were assessed using the I(2) test and funnel plots, respectively. Meta regression was performed to assess the effect of baseline renal function and the use of aprotinin on renal function.
  
  
  RESULTS
  Seven randomized controlled trials (RCTs) (n = 1000) were identified. No study could demonstrate, either independently or meta-analytically, an improvement in the postoperative increase in creatinine, mortality (RR 0.93, 95% CI 0.4 to 2.07), renal failure requiring renal replacement therapy (RR 1.01, 95% CI 0.49 to 2.12), myocardial infarction (RR 0.88, 95% CI 0.36 to 1.88), atrial fibrillation (RR 0.88, 95% CI 0.70 to 1.10), or stroke (RR 0.69, 95% CI 0.27 to 1.69). There was a small, though significant increase in postoperative blood loss among patients treated with NAC (weighted mean difference 119 mL 95% CI 51, 187). After meta regression neither increase in postoperative creatinine (r(2) = 0.33) nor renal replacement therapy (r(2) = 0.04) was associated with the baseline creatinine or with NAC dose (r(2) =0.04).
  
  
  CONCLUSIONS
  This analysis did not find that treatment with NAC was associated with clinical renal protection during cardiac surgery, or improvement in other clinical outcomes.
authors.affiliation: Department of Anesthesia and Pain Management, University Health Network, Toronto General Hospital, University of Toronto, Ontario, Canada. finola.naughton@uhn.on.ca
authors.forename: Finola
authors.initials: F
authors.lastname: Naughton
authors.forename: Duminda
authors.initials: D
authors.lastname: Wijeysundera
authors.forename: Keyvan
authors.initials: K
authors.lastname: Karkouti
authors.forename: Gordon
authors.initials: G
authors.lastname: Tait
authors.forename: W Scott
authors.initials: WS
authors.lastname: Beattie
mesh_terms: D000111:Acetylcysteine / Q000627:therapeutic use*; D000208:Acute Disease; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D016166:Free Radical Scavengers / Q000627:therapeutic use*; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D051437:Renal Insufficiency / Q000209:etiology* / Q000517:prevention & control*; D012306:Risk; D016896:Treatment Outcome
chemical_list: D016166:Free Radical Scavengers; D000111:Acetylcysteine