title: In vitro thromboelastometric evaluation of the efficacy of frozen platelet transfusion.
abstract: BACKGROUND
  Although frozen platelets are extensively used in remote locations and military environments, scientific evidence of their efficacy is scarce. The objective of this study was to evaluate the in vitro hemostatic efficacy of frozen versus fresh platelet transfusions by rotational thromboelastometry (ROTEM) to ascertain whether the freezing and thawing process impaired platelet contribution to clot strength.
  
  
  METHODS
  An experimental study was performed using platelet in vitro transfusions. Blood samples were collected from 12 patients with non-autoimmune thrombocytopenia. The samples were each transfused with one of 6 pairs of fresh platelet concentrates and platelet concentrates frozen with dimethylsulfoxyde. Optical platelet counts, coagulation studies and ROTEM (EXTEM and FIBTEM) were performed for the baseline and the post-transfusion samples.
  
  
  RESULTS
  Only fresh platelet transfusions significantly increased the EXTEM maximum clot firmness (MCF) and maximum clot elasticity (MCE) over baseline (p<0.001), achieving values within the normal range. The frozen platelet contribution to MCE was negligible. However, the EXTEM clotting time (CT) was significantly (p<0.001) shorter after the frozen platelet transfusion compared with the fresh platelet transfusion. The EXTEM clot formation time (CFT) was significantly shortened after the transfusion of fresh platelets (p=0.002).
  
  
  CONCLUSIONS
  The ROTEM analysis assessment indicates a dual effect in frozen platelet transfusion: it produces a hypercoagulable state (shortening of CT), and a second, more predominant effect of frozen platelets' functionality impairment compared with fresh platelets (shorter MCF/MCE and longer CFT).
authors.affiliation: Department of Anaesthesia and Intensive Care, La Paz University Hospital, Madrid, Spain. Electronic address: antonioperezferrer@gmail.com.
authors.forename: Antonio
authors.initials: A
authors.lastname: Pérez-Ferrer
authors.affiliation: CMS, Department of Anaesthesia and Intensive Care, Central Hospital of Defence Gómez Ulla, IMIDEF, Madrid, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Navarro-Suay
authors.affiliation: Haematology Department, La Paz University Hospital, Madrid, Spain.
authors.forename: Aurora
authors.initials: A
authors.lastname: Viejo-Llorente
authors.affiliation: Clinical Laboratory Department, La Paz University Hospital, Madrid, Spain.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Alcaide-Martín
authors.affiliation: Department of Anaesthesia and Intensive Care, La Paz University Hospital, Madrid, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: de Vicente-Sánchez
authors.affiliation: Haematology Department, La Paz University Hospital, IdiPaz, Madrid, Spain.
authors.forename: Nora
authors.initials: N
authors.lastname: Butta
authors.affiliation: CMS, Armed Forces Transfusion Centre, Madrid, Spain.
authors.forename: Jose M
authors.initials: JM
authors.lastname: de Prádena Y Lobón
authors.affiliation: CMS, Armed Forces Transfusion Centre, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Povo-Castilla
mesh_terms: D015925:Cryopreservation; D006801:Humans; D066298:In Vitro Techniques; D008991:Monitoring, Physiologic / Q000379:methods; D010949:Plasma; D017713:Platelet Transfusion / Q000379:methods*; D013916:Thrombelastography / Q000379:methods*; D013921:Thrombocytopenia / Q000097:blood* / Q000175:diagnosis / Q000628:therapy*; D016896:Treatment Outcome
keywords: Blood transfusion/methods; Cryopreservation; Platelet function test; Platelet transfusion; Thromboelastometry