title: A risk, injury, failure, loss, and end-stage renal failure score-based trigger for renal replacement therapy and survival after cardiac surgery.
abstract: OBJECTIVE
  It is controversial whether all critically ill patients with risk, injury, failure, loss, and end-stage renal failure (RIFLE) F class acute kidney injury (AKI) should receive renal replacement therapy (RRT). We reviewed the outcome of open heart surgery patients with severe RIFLE-F AKI who did not receive RRT.
  
  
  METHODS
  We identified all patients with AKI after cardiac surgery over 4 years and obtained baseline characteristics, intraoperative details, and in-hospital outcomes. We analyzed physiologic and biochemical features at RRT initiation or at peak creatinine if no RRT was provided.
  
  
  RESULTS
  We reviewed 1504 patients. Of these, 137 (9.1%) developed postoperative AKI with 71 meeting RIFLE-F criteria and 23 (32.4% of RIFLE-F cases) not receiving RRT. Compared with RRT-treated RIFLE-F patients, "no-RRT" patients had lower Acute Physiology and Chronic Health Evaluation III scores, less intra-aortic balloon pump requirements, shorter intensive care stay, and a trend toward lower mortality. At peak RIFLE score, their urinary output, arterial pH, and Pao(2)/fraction of inspired oxygen ratio were all significantly higher. Their serum creatinine was also higher (304 vs 262 μmol/L; P = .02). Only 3 RIFLE-F no-RRT patients died in-hospital. Detailed review of cause and mode of death was consistent with non-RRT-preventable deaths. In contrast, 27 patients with RIFLE-R or RIFLE-I class received RRT. Compared with RRT-treated RIFLE-F patients, such RIFLE-R or RIFLE-I treated patients had a more severe presentation and higher mortality (51.8% vs 29.2%; P = .02).
  
  
  CONCLUSIONS
  After cardiac surgery, RRT was typically applied to patients with the most severe clinical presentation irrespective of creatinine levels. A RIFLE score-based trigger for RRT is unlikely to improve patient survival.
authors.affiliation: Intensive Care Unit, Department of Intensive Care, Austin Health, Heidelberg, Victoria, Australia.
authors.forename: Antoine G
authors.initials: AG
authors.lastname: Schneider
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Eastwood
authors.forename: Siven
authors.initials: S
authors.lastname: Seevanayagam
authors.forename: Georges
authors.initials: G
authors.lastname: Matalanis
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Bellomo
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D000368:Aged; D000369:Aged, 80 and over; D001774:Blood Chemical Analysis; D006348:Cardiac Surgical Procedures; D003404:Creatinine / Q000097:blood; D016638:Critical Illness; D058625:End Stage Liver Disease / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D062072:Patient Acuity; D017582:Renal Replacement Therapy / Q000379:methods*
chemical_list: D003404:Creatinine