title: Association between postoperative acute kidney injury and duration of cardiopulmonary bypass: a meta-analysis.
abstract: OBJECTIVE
  This meta-analysis examined the association between cardiopulmonary bypass (CPB) time and acute kidney injury (AKI).
  
  
  METHODS
  Meta-analysis of previously published studies.
  
  
  METHODS
  Each single-center study was conducted in a surgical intensive care unit and/or academic or university hospital.
  
  
  METHODS
  Adult patients undergoing heart surgery with CPB.
  
  
  METHODS
  A systematic literature review was conducted using PubMed, EMBASE, and Cochrane Library databases and Google Scholar from January 1980 through September 2009. Initial search results were refined to include human subjects, age >18 years, randomized controlled trials, and prospective and retrospective cohort studies, meet the Acute Kidney Injury Network definition of renal failure, and report times on CPB.
  
  
  RESULTS
  The length of time on CPB has been implicated as an independent risk factor for development of AKI after CPB (AKI-CPB). The 9 independent studies included in the final meta-analysis had 12,466 patients who underwent CPB. Out of these, 756 patients (6.06%) developed AKI-CPB. In 7 of the 9 studies, the mean CPB times were statistically longer in the AKI-CPB cohort compared with the control group (cohort without AKI). The absolute mean differences in CPB time between the 2 groups were 25.65 minutes with the fixed-effects model and 23.18 minutes with the random-effects model.
  
  
  CONCLUSIONS
  Longer CPB times are associated with a higher risk of developing AKI-CPB, which, in turn, has a significant effect on overall mortality as reported by the individual studies.
authors.affiliation: Department of Anesthesia, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA. avinash-kumar@uiowa.edu
authors.forename: Avinash B
authors.initials: AB
authors.lastname: Kumar
authors.forename: Manish
authors.initials: M
authors.lastname: Suneja
authors.forename: Emine O
authors.initials: EO
authors.lastname: Bayman
authors.forename: Garry D
authors.initials: GD
authors.lastname: Weide
authors.forename: Michele
authors.initials: M
authors.lastname: Tarasi
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology* / Q000209:etiology* / Q000503:physiopathology; D002315:Cardiopulmonary Bypass / Q000009:adverse effects* / Q000379:methods; D006801:Humans; D011446:Prospective Studies; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome