title: Acute kidney injury in severe trauma assessed by RIFLE criteria: a common feature without implications on mortality?
abstract: BACKGROUND
  Acute kidney injury (AKI) has been hard to assess due to the lack of standard definitions. Recently, the Risk, Injury, Failure, Loss and End-Stage Kidney (RIFLE) classification has been proposed to classify AKI in a number of clinical settings. This study aims to estimate the frequency and levels of severity of AKI and to study its association with patient mortality and length of stay (LOS) in a cohort of trauma patients needing intensive care.
  
  
  METHODS
  Between August 2001 and September 2007, 436 trauma patients consecutively admitted to a general intensive care unit (ICU), were assessed using the RIFLE criteria. Demographic data, characteristics of injury, and severity of trauma variables were also collected.
  
  
  RESULTS
  Half of all ICU trauma admissions had AKI, which corresponded to the group of patients with a significantly higher severity of trauma. Among patients with AKI, RIFLE class R (Risk) comprised 47%, while I (Injury) and F (Failure) were, 36% and 17%, respectively. None of these patients required renal replacement therapy. No significant differences were found among these three AKI classes in relation to patient's age, gender, type and mechanism of injury, severity of trauma or mortality. Nevertheless, increasing severity of acute renal injury was associated with a longer ICU stay.
  
  
  CONCLUSIONS
  AKI is a common feature among trauma patients requiring intensive care. Although the development of AKI is associated with an increased LOS it does not appear to influence patient mortality.
authors.affiliation: Unidade de Cuidados Intensivos Polivalente, Hospital de Santo António, Centro Hospitalar do Porto, 4099 - 001 Porto, Portugal. gomes.ernestina@gmail.com
authors.forename: Ernestina
authors.initials: E
authors.lastname: Gomes
authors.forename: Rui
authors.initials: R
authors.lastname: Antunes
authors.forename: Cláudia
authors.initials: C
authors.lastname: Dias
authors.forename: Rui
authors.initials: R
authors.lastname: Araújo
authors.forename: Altamiro
authors.initials: A
authors.lastname: Costa-Pereira
mesh_terms: D058186:Acute Kidney Injury / Q000145:classification / Q000175:diagnosis* / Q000401:mortality; D000328:Adult; D016638:Critical Illness; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007668:Kidney / Q000293:injuries*; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015996:Survival Rate; D015599:Trauma Severity Indices; D055815:Young Adult