title: Monitoring patients at risk of massive transfusion with Thrombelastography or Thromboelastometry: a systematic review.
abstract: BACKGROUND
  Thrombelastography (TEG) and Thrombelastometry (ROTEM) are viscoelastic whole-blood assays evaluating the haemostatic capacity of blood. These devices are used in algorithms to guide transfusion of haemostatic blood components.
  
  
  METHODS
  The methods used for this study were systematic reviews with meta-analyses and trial sequential analyses of randomised clinical trials (RCTs) of TEG/ROTEM-based algorithm compared with standard treatment in patients with bleeding. Primary outcome was all-cause mortality. We searched the literature in seven databases (up to 31 October 2010), reference lists, registers of ongoing trials, and contacted authors and experts. We extracted data from included studies related to study methods, interventions, outcomes, bias risk and adverse events using Cochrane methodology. All trials irrespective of blinding or language status were included.
  
  
  RESULTS
  Nine trials involving 776 participants were included. Eight trials involved cardiac surgery with an average blood loss of 390-960  ml, and one trial investigated liver transplantations. One trial was classified as low-risk-of-bias trial. We found two ongoing trials. No impact was identified on mortality, amount of blood transfused, incidence of surgical reinterventions, time to extubation, or length of stay in hospital and intensive care unit. We identified a significant reduction in blood loss favouring the use of TEG/ROTEM {85  ml [95% confidence interval (CI) 29.4-140.7]} and in the proportion of patients receiving freshly frozen plasma and platelets [relative risk 0.39 (95%CI 0.27-0.57)].
  
  
  CONCLUSIONS
  There is currently weak evidence to support the use of TEG/ROTEM as a tool to guide transfusion in patients with severe bleeding. Further studies need to address other clinical settings and with larger blood losses.
authors.affiliation: Department of Anesthesiology and Intensive Care, Herlev Hospital, University of Copenhagen, Denmark. wikkelso@gmail.com
authors.forename: A J
authors.initials: AJ
authors.lastname: Wikkelsoe
authors.forename: A
authors.initials: A
authors.lastname: Afshari
authors.forename: J
authors.initials: J
authors.lastname: Wetterslev
authors.forename: J
authors.initials: J
authors.lastname: Brok
authors.forename: A M
authors.initials: AM
authors.lastname: Moeller
mesh_terms: D000465:Algorithms; D016913:Blood Component Transfusion; D016063:Blood Loss, Surgical / Q000503:physiopathology; D001803:Blood Transfusion / Q000401:mortality; D001809:Blood Viscosity; D006348:Cardiac Surgical Procedures; D016208:Databases, Factual; D006470:Hemorrhage / Q000628:therapy; D006487:Hemostasis / Q000502:physiology; D006801:Humans; D016031:Liver Transplantation; D008991:Monitoring, Physiologic / Q000379:methods*; D010949:Plasma; D017713:Platelet Transfusion; D016032:Randomized Controlled Trials as Topic; D013916:Thrombelastography / Q000379:methods* / Q000401:mortality; D065227:Transfusion Reaction; D016896:Treatment Outcome