title: Transfusion ratios for postpartum hemodilutional coagulopathy: an in vitro thromboelastographic model.
abstract: OBJECTIVE
  A 1:1:1 ratio of packed red blood cells (PRBC), fresh frozen plasma (FFP), and platelets (PLT) has been advocated for trauma hemorrhage, but the effectiveness of this ratio for postpartum hemorrhage is unknown. We created an in vitro hemodilutional model to investigate this strategy.
  
  
  METHODS
  Blood from 20 parturients at term was diluted 50% with 0.9% normal saline. Diluted samples were reconstituted with 1:1 PRBC:FFP or 3:1 PRBC:FFP. In 10 samples, PLT were also added. Baseline, diluted, and reconstituted sample thromboelastographic values were compared.
  
  
  RESULTS
  Maximum amplitude (MA) was lower compared to baseline values in both groups after 50% dilution with normal saline (P < .001) and remained lower than baseline despite reconstitution with 3:1:0 or 1:1:0 PRBC:FFP:PLT (P < .0001) or 3:1:1 PRBC:FFP:PLT (P < .01). MA approached baseline (P = not significant) in the samples with 1:1:1 PRBC:FFP:PLT.
  
  
  CONCLUSIONS
  The addition of PLT to 1:1 PRBC:FFP optimized MA in this in vitro hemodilutional model of postpartum hemorrhage.
authors.affiliation: Department of Anesthesiology and Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA.
authors.forename: Michaela Kristina
authors.initials: MK
authors.lastname: Farber
authors.affiliation: Department of Anesthesiology, Tufts University School of Medicine, Boston, MA.
authors.forename: Neeti
authors.initials: N
authors.lastname: Sadana
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Richard Max
authors.initials: RM
authors.lastname: Kaufman
authors.affiliation: Department of Anesthesiology and Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Anesthesiology and Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA.
authors.forename: Bhavani Shankar
authors.initials: BS
authors.lastname: Kodali
mesh_terms: D000293:Adolescent; D000328:Adult; D001803:Blood Transfusion / Q000379:methods*; D004906:Erythrocyte Count; D005260:Female; D006438:Hemodilution; D006801:Humans; D066298:In Vitro Techniques; D008954:Models, Biological; D010976:Platelet Count; D006473:Postpartum Hemorrhage / Q000097:blood* / Q000628:therapy*; D011247:Pregnancy; D013916:Thrombelastography; D055815:Young Adult
keywords: dilutional coagulopathy; postpartum hemorrhage; thromboelastography; transfusion ratios