title: Severity scoring in the ICU: a review.
abstract: BACKGROUND
  Patients in the intensive care unit (ICU) require huge resources because of the dysfunction of several of their vital organs. The heterogeneity and complexity of the ICU patient have generated interest in systems able to measure severity of illness as a method of predicting outcome, comparing quality-of-care and stratification for clinical trials.
  
  
  METHODS
  By searching Medline and EMBASE for publications describing scoring systems in the ICU, the most frequently used systems, defined as resulting in more than 50 references, are included in this review. Scoring systems belong to one of four classes prognostic, single-organ failure, trauma scores and organ dysfunction (OD). The different systems are described and discussed.
  
  
  RESULTS
  Three different prognostic scoring systems, including several versions, four single OD scores and three OD scores, were included in this review.
  
  
  CONCLUSIONS
  Different forms of scoring systems are frequently used in the ICU. They have become a necessary tool to describe ICU populations and to explain differences in mortality. As there are several pitfalls related to the interpretation of the numbers supplied by the systems, they should not be used without knowledge on the science of severity scoring.
authors.affiliation: Department of Anaesthesia and Intensive Care, Haukeland University Hospital, Bergen, Norway. stkr@sus.no
authors.forename: K
authors.initials: K
authors.lastname: Strand
authors.forename: H
authors.initials: H
authors.lastname: Flaatten
mesh_terms: D018806:APACHE; D003422:Critical Care / Q000592:standards; D006305:Health Status Indicators; D006801:Humans; D007362:Intensive Care Units; D007676:Kidney Failure, Chronic / Q000175:diagnosis; D009102:Multiple Organ Failure / Q000175:diagnosis; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011379:Prognosis; D012720:Severity of Illness Index; D015599:Trauma Severity Indices