Islam Mohammad Shehata 2010 Department of I.C.U.and Anesthesia

Platelets and hemostasis

Preparation it is a long journey Single donor donor random pheresiscentrifugationPreparation 300x10 9 /l in ml plasma to keep PH > 6.2 Increase by 30-50x10 9 /l 55x10 9 /l in ml plasma Increase count by 5x10 9/l In 70 kg person How much plt. Each unit donates: -Only one donor -Less incidence of refractoriness, HLA typing -Less costy -Available advantage

General consideration S : minimal 1.Each unit contain(minimal) RBCs..what about -ABO incompatibility. - pediatric with small blood volume ( dose is…..) -RH negative receipient ( women of childbearing period ) 2. stored at (room temperature=20-24c) so a common complication is…. 3.Warming > 43c : impairs plt function. 4. Shelf life = 3-5 days, so there is finite supply..

5.Continous gentle agitation : prevent plt. Aggregates 6.Infusion through filter: not through the ordinary fluid infusion set :. - Must be ( micron filter) - not microaggregate filter (20-40m) : remove most of plt. 7.You should minimize the need for transfusion: the cause of thrombocytopenia..investigate the cause of thrombocytopenia..use adjunctive therapy(dialysis for renal failure… … IVIG for I.T.P….)..Discontinue anticoagulant and antiplatelet therapy before surgery

Def : platelet count < causes Decreased production: due to: B.M.suppression Congenital Aquired : Viruses, sepsis, malignancy… Increased destruction Non immune: D.I.C. Immune mediated: I.T.P. Post transfusion, drugs.. Other causes : Dilutional : massive transfusion(1-1.5 bl.volume) Ratio of RBC: plt :FFP transfusion is 1:1:1 Distributional ; Congestive splenomegaly Heparin ( H.I.T.) Valporic acid,,carbamazepine penicillin / Beta lactam interferon Amiodarone,,digoxin

Antiplatelet therapy a daily challenge When to stop : risk /benefit risk /benefit Thienopyridine ( clopidogrel) Pt at low risk:7-10 days Pt at high risk : 5 days (platelet function test should be done) - Aspirin As long as the platelet life span(why..) Gp IIb/IIIa inhibitor: 1) Abciximab 2) aggrestat Mechanism of action

Evidence based indications 2.Perioperative 1. prophylactic <100 x 10 9 /l (why) Ophthalmic surgery Neurosurgery The trigger to avoid spontanous bleeding is < < not < Chronic patient : + active bleeding When to redose ; Shorter life span =?? <50-80 x 10 9 /l < 50 x 10 9 /l Epidural insertion or removal… Lumbar puncture… < 50 x10 9 / l < 30 x10 9 / l Invasive (surgery as laparotomy …) vaginal delivery.. Minimal invasive(..central line) the need to prevent or treat bleeding ( always keep in mind) Decision to tranfuse should not be based only on Plt. Count but should be supported by the need to prevent or treat bleeding ( always keep in mind)

1.Heparin induced thrombocytopenia. 2.Hemolytic uremic syndrome. No prophylactic transfusion because they are thrombotic Only treat clinical bleeding 3.Idiopathic thrombocytopenic purpura No benefit = quickly removed..( immunely destructed ) transfuse only before procedure or treat clinical bleeding

-calculate the corrected count increment Corrected count increment (CCI)Corrected count increment (CCI) = (post-transfusion plt count – pre-transfusion plt count) x (B.S.A.) / number of platelets transfused. accepted result : »,,. -C.C.I. > 7.5 after 1 hour,,,or -C.C.I > 4.5 after 24 hours. if not it is called…..

DefDef : failure to obtain satisfactiory response after two consecutive transfusion episodes. Causes : -random donor platelet is more risky -directly related to number of transfusion 2) Non immune1) Immune -sepsis -splenomegaly - D.I.C. : Platelet alloantibodies -HLA -HPA

Dr.Colin Brown

RISKS OF TRANSFUSION 1.T.R.A.L.I. ( 1.T.R.A.L.I. ( a phresis platelets is more risky) My own experience…it is a serious complication It is immune mediated non cardiogenic pulmonary edema. Management : stop the infusion supportive therapy. 2.transfusion associated sepsis 2.transfusion associated sepsis ( stored at …..) It is the largest overall infectious risk in blood transfusion Platelets should be screened for bacterial contamination (specific concern) 3.Non hemolytic febrile reaction 3.Non hemolytic febrile reaction (incidence is 1:20) 4.Transmitted infections 4.Transmitted infections (H.I.V,, H.C.V.)

-My dear professors who teach me-My dear professors who teach me -My dear colleagues who I really love-My dear colleagues who I really love -My lovely parents and my darling wife-My lovely parents and my darling wife References 1-Update on platelets : ASA guidelines proposed guidelines for platelet transfusion ( Bc medical journal )