Contents

Search

platelet unit

Each unit contains approximately 5.5 x 10E10 platelets, & a small amount of plasma, leukocytes & red blood cells. Indications: - thrombocytopenia a) platelet count < 10,000/uL with or without active bleeding [7]* b) platelet count < 20,000/uL with active bleeding [1]; < 40,000/uL with pulmonary hemorrhage[2]; < 50,000/uL with clinically significant bleeding [2] c) *platelet count < 20,000/uL with central venous catheter placement [7] d) platelet count < 20,000/uL with promyelocytic leukemia e) *platelet count < 50,000/uL in patients undergoing lumbar puncture or major surgery f) platelet count < 100,000/uL for neurosurgery or intracranial bleeding [2] f) *platelet count < 100,000/uL &/or prolonged bleeding time in post-cardiopulmonary bypass patients with active bleeding. * only recommendation strongly endorsed by AABB [7] - threshold for platelet transfusion in patients needing invasive procedure may be 20,000/uL rather than 50,000/uL [2] * clinically stable patients with chemotherapy-induced thrombocytopenia without active bleeding do not benefit from platelet transfusions if the platelet count is >= 10,000/uL [2] * decreased bleeding with prophylactic transfusion of patients with platelet count < 10,000/uL who are undergoing chemotherapy or hematopoietic stem cell transplantation [2] Storage: 1) room temperature# on rotator 2) shelf life 5 days # 1) cooling of platelets causes von Willebrand factor (vWF) receptor on the surface of platelets to form complexes 2) alphaMbeta2 integrins on the surface of macrophages bind to beta N-acetylglucosamine residues of the N-linked glycans on GPIbalpha of vWF receptor complexes 3) macrophages clear the bound platelets 4) coating of the carbohydrate moiety recognized by the integrins on the surface of macrophages results in the platelets being invisible to the macrophages when cooled 5) a new platelet coating procedure (i.e. enzymatic galactosylation) will likely soon lead to routine refrigeration of platelets with greatly extended shelf-life Monitor: 1) platelet count within 24 hours before each platelet transfusion 2) post-transfusion platelet count within 1 hour post transfusion to see if expected rise in platelet count is achieved* 3) expect 5000-10,000/uL increase in platelet count for each unit of platelets transfused - an increase < 5000/uL is associated with alloimmunization - an increase of 20,000-30,000/uL for each platelet unit transfused [2] Procedure: Transfusion: 1) in emergencies, group AB plasma & platelets can be transfused to anyone 2) Rh-negative patients must receive D-negative platelets 3) 1 unit of platelets for each 10 kg of body weight Complications: Refractory response:* 1) alloimmunization (generally HLA antigens, rarely platelet-specific antigens) - HLA-matched platelets (screen for HLA antibodies) [2] 2) clinical factors: - sepsis*, DIC, amphotericin, high fever, splenomegaly, bone marrow transplantation * Risk of bacterial infection & sepsis is higher for platelet units than other blood products [2] - Staphylococcus aureus, 1 in 2500 platelet transfusions [2] * anaphylaxis: 62/100,000 platelet pools - response occurs immediately after start of transfusion * transfusion-associated lung injury reaction - hypoxemia, hypotension - delayed onset, usually 2-6 hours post-transfusion Notes: Special preparations: 1) single-donor platelets a) alloimmunized patients refractory to random donor platelets b) HLA-matched platelets 1] matched to all four HLA-A & B loci 2] donors homozygous at one or 2 loci with no mismatched antigens 3] donors with certain cross-reactive HLA antigens 4] crossmatched platelets c) autologous cryopreserved platelets [3] 1] for use with chemotherapy patients 2] 2 doses of recombinant thrombopoietin administered 3] platelets collected by apheresis on day 12 4] cryopreserved for future platelet transfusion 2) platelet apheresis a) one platelet apheresis unit is equivalent to ~ 7 units of platelets b) leukocyte-reduced platelets women/pregnancy - alloimmunization from previous pregnancies [2] - if RhD-positive platelets must be given to an RhD-negative woman with potential for becoming pregnant, rhogam should be co-administered with the platelet units [2] Expected response 1) 1 unit of platelets/10 kg can be expected to produce an increase of 50,000/uL 2) an adequate response is defined as at least 30% of the expected response 3) three platelet transfusions with a inadequate response is considered refractory 4) an increase in platelet count < 10,000/uL when measured 10-60 minutes after transfusion on 2 separate occasions is considered refractory [2] Desmopressin (DDAVP) may be alternative to platelet transfusion when platelet dysfunction contributes to bleeding, for example uremia, cardiopulmonary bypass.

Related

platelet

General

transfusion component

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 613-614
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 16, 17, 18. American College of Physicians, Philadelphia 1998, 2006, 2012, 2015, 2018. - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  3. Journal Watch 22(17):133, 2002 Vadhan-Raj et al Safety and efficacy of transfusions of autologous cryopreserved platelets derived from recombinant human thrombopoietin to support chemotherapy-associated severe thrombocytopenia: a randomised cross-over study. Lancet 359:2145, 2002 PMID: 12090979
  4. Journal Watch 23(21):170, 2003 Hoffmeister KM et al Glycosylation restores survival of chilled blood platelets. Science 301:1531, 2003 PMID: 12970565 - Couzin J Medicine. Sugary cloak protects platelets from the cold. Science 301:1457, 2003 PMID: 12970531
  5. Slichter SJ. Evidence-based platelet transfusion guidelines. Hematology Am Soc Hematol Educ Program. 2007:172-8. PMID: 18024626
  6. Hod E, Schwartz J. Platelet transfusion refractoriness. Br J Haematol. 2008 Jul;142(3):348-60 PMID: 18510692
  7. Kaufman RM et al Platelet Transfusion: A Clinical Practice Guideline From the AABB. Ann Intern Med. Published online 11 November 2014 PMID: 25383671 http://annals.org/article.aspx?articleid=1930861
  8. Pavenski K, Rebulla P, Duquesnoy R et al Efficacy of HLA-matched platelet transfusions for patients with hypoproliferative thrombocytopenia: a systematic review. Transfusion. 2013 Oct;53(10):2230-42. PMID: 23550773
  9. Estcourt L, Stanworth S, Doree C et al Prophylactic platelet transfusion for prevention of bleeding in patients with haematological disorders after chemotherapy and stem cell transplantation. Cochrane Database Syst Rev. 2012 May 16;5:CD004269 PMID: 22592695
  10. Eder AF, Kennedy JM, Dy BA et al Bacterial screening of apheresis platelets and the residual risk of septic transfusion reactions: the American Red Cross experience (2004-2006). Transfusion. 2007 Jul;47(7):1134-42. PMID: 17581147
  11. NEJM Knowledge+. Question of the Week. Dec 13, 2016 http://knowledgeplus.nejm.org/question-of-week/1132/
  12. Platelet Transfusion Therapy: NIH Consensus Statement http://consensus.nih.gov/cons/059/059_intro.htm