title: Risks associated with red blood cell transfusion in the trauma population, a meta-analysis.
abstract: BACKGROUND
  A previous meta-analysis has found an association between red blood cell (RBC) transfusions and mortality in critically ill patients, but no review has focused on the trauma population only.
  
  
  OBJECTIVE
  To determine the association between RBC transfusion and mortality in the trauma population, with secondary outcomes of multiorgan failure (MOF) and acute respiratory distress syndrome (ARDS) or acute lung injury (ALI).
  
  
  METHODS
  EMBASE (1947-2012) and MEDLINE (1946-2012).
  
  
  METHODS
  Randomized controlled trials and observational studies were to be included if they assessed the association between RBC transfusion and either the primary (mortality) or secondary outcomes (MOF, ARDS/ALI).
  
  
  METHODS
  Trauma patients.
  
  
  METHODS
  Red blood cell transfusion.
  
  
  METHODS
  A literature search was completed and reviewed in duplicate to identify eligible studies. Studies were included in the pooled analyses if an attempt was made to determine the association between RBC and the outcomes, after adjusting for important confounders. A random effects model was used for and heterogeneity was quantified using the I(2) statistic. Study quality was assessed using the Newcastle-Ottawa Scale.
  
  
  RESULTS
  40 observational studies were included in the qualitative review. Including studies which adjusted for important confounders found the odds of mortality increased with each additional unit of RBC transfused (9 Studies, OR 1.07, 95%CI 1.04-1.10, I(2) 82.9%). The odds of MOF (3 studies, OR 1.08, 95%CI 1.02-1.14, I(2) 95.9%) and ARDS/ALI (2 studies, OR 1.06, 95%CI 1.03-1.10, I(2) 0%) also increased with each additional RBC unit transfused.
  
  
  CONCLUSIONS
  We have found an association between RBC transfusion and the primary and secondary outcomes, based on observational studies only. This represents the extent of the published literature. Further interventional studies are needed to clarify how limiting transfusion can affect mortality and other outcomes.
authors: London Health Sciences Centre, London, Ontario, Canada. Electronic address: spatel2009@meds.uwo.ca.
authors: Sunil V
authors: SV
authors: Patel
authors: London Health Sciences Centre, London, Ontario, Canada. Electronic address: biniam.kidane@londonhospitals.ca.
authors: Biniam
authors: B
authors: Kidane
authors: London Health Sciences Centre, London, Ontario, Canada. Electronic address: michelle.klingel@lhsc.on.ca.
authors: Michelle
authors: M
authors: Klingel
authors: London Health Sciences Centre, London, Ontario, Canada. Electronic address: neil.parry@lhsc.on.ca.
authors: Neil
authors: N
authors: Parry
mesh_terms: D055371:Acute Lung Injury / Q000209:etiology* / Q000401:mortality; D016638:Critical Illness / Q000401:mortality / Q000628:therapy*; D017707:Erythrocyte Transfusion / Q000009:adverse effects* / Q000401:mortality; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data; D009102:Multiple Organ Failure / Q000209:etiology* / Q000401:mortality; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic; D012128:Respiratory Distress Syndrome / Q000209:etiology* / Q000401:mortality; D012307:Risk Factors
keywords: Acute lung injury; Acute respiratory distress syndrome; Mortality; Multiorgan failure; Red blood cells; Transfusion; Trauma