title: Characterization of platelet dysfunction after trauma.
abstract: BACKGROUND
  The increased morbidity and mortality associated with coagulopathy and thrombocytopenia after trauma are well described. However, few studies have assessed platelet function after injury.
  
  
  METHODS
  Blood samples were prospectively collected from 101 patients with critical injury and trauma on arrival to the emergency department and serially after admission to a Level I urban trauma intensive care unit from November 2010 to October 2011 and functionally assayed for responsiveness to adenosine diphosphate, thrombin receptor-activating peptide, arachidonic acid (AA), and collagen using multiple electrode impedance aggregometry.
  
  
  RESULTS
  Of the 101 enrolled patients, 46 (45.5%) had below-normal platelet response to at least one agonist ("platelet hypofunction") at admission, and 92 patients (91.1%) had platelet hypofunction some time during their intensive care unit stay. Admission platelet hypofunction was associated with low Glasgow Coma Scale score and a nearly 10-fold higher early mortality. Logistic regression identified admission Glasgow Coma Scale (odds ratio, 0.819; p = 0.008) and base deficit (odds ratio, 0.872; p = 0.033) as independent predictors of platelet hypofunction. Admission AA and collagen responsiveness were significantly lower for patients who died (p < 0.01), whereas admission platelet counts were similar (p = 0.278); Cox regression confirmed thrombin receptor-activating peptide, AA, and collagen responsiveness as independent predictors of in-hospital mortality (p < 0.05). Receiver operating characteristic analysis identified admission AA and collagen responsiveness as negative predictors of both 24-hour (AA area under the curve [AUC], 0.874; collagen AUC, 0.904) and in-hospital mortality (AA AUC, 0.769; collagen AUC, 0.717).
  
  
  CONCLUSIONS
  In this prognostic study, we identify clinically significant platelet dysfunction after trauma in the presence of an otherwise reassuring platelet count and standard clotting studies, with profound implications for mortality. Multiple electrode impedance aggregometry reliably identifies this dysfunction in injured patients, and admission AA and collagen responsiveness are sensitive and specific independent predictors of both early and late mortality.
authors: Department of Surgery, University of California, San Francisco, CA, USA. matthew.kutcher@ucsfmedctr.org
authors: Matthew E
authors: ME
authors: Kutcher
authors: Brittney J
authors: BJ
authors: Redick
authors: Ryan C
authors: RC
authors: McCreery
authors: Ian M
authors: IM
authors: Crane
authors: Molly D
authors: MD
authors: Greenberg
authors: Leslie M
authors: LM
authors: Cachola
authors: Mary F
authors: MF
authors: Nelson
authors: Mitchell Jay
authors: MJ
authors: Cohen
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000502:physiology*; D015600:Glasgow Coma Scale; D006801:Humans; D015539:Platelet Activation / Q000502:physiology; D010974:Platelet Aggregation / Q000502:physiology; D010976:Platelet Count; D010979:Platelet Function Tests; D011446:Prospective Studies; D013997:Time Factors; D014947:Wounds and Injuries / Q000097:blood*