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Platelet Refractoriness

Platelet Refractoriness. Laura Cooling MD, MS Associate Medical Director Transfusion Medicine. Platelet Kinetics circulating life span 8-10 days. Circulation 60%. Spleen 30-40%. 10-12% loss/day 20% endothelial integrity 80% senescence. Definitions of Refractoriness.

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Platelet Refractoriness

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  1. Platelet Refractoriness Laura Cooling MD, MS Associate Medical Director Transfusion Medicine

  2. Platelet Kineticscirculating life span 8-10 days Circulation 60% Spleen 30-40% 10-12% loss/day 20% endothelial integrity 80% senescence

  3. Definitions of Refractoriness 2-3 consecutive platelet transfusions by CCI or PPR REFRACTORINESS ALLOIMMUNIZATION

  4. Immune (25-50%) Alloimmunization Autoantibodies Passive Immunity Drug-related Nonimmune (50-75%) Fever Infection Splenomegaly Drugs/Antibiotics Consumption Bleeding Platelet Dose Platelet Refractoriness Poor response to platelet by immune or nonimmune factors

  5. Effect of Platelet Count, Splenomegaly and “Refractoriness” on Platelet Survival Normal Plt>200K 75% 65% 50% Asplenia Refractory Normal Plt<50K Splenomegaly Plt<50K 1 hr 20-24 hr 2 days 8-10 days

  6. Platelet Response and Kinetics in Normal and Refractory Patients PPR = 60-66% Normal PPR>30% 20-24 hrs % Platelet Recovery (PPR) Immune Hypersplenism Nonimmune 24 hrs

  7. Evaluating Platelet Transfusion Response Corrected Count Increment (CCI): • In vivo Measurement Platelet Survival • Number of Platelets Transfused • Size of Patient • Requires a 1-4 hour post-platelet count • Positive Predictor platelet survival at 20 hrs

  8. Corrected Count Increment Whole Blood Derived Platelet Concentrates CCI= (post-platelet count - pre-platelet count)(BSA) (3.5 [approximate # platelets transfused x 1011]) CCI > 7.5 Good Response * Platelet count at 1 hour post transfusion, BSA=body surface area in M 2 Example: Patient (1.7 M 2) transfused with 5 units pooled platelets for platelet count=2. At 1 hr, plts=30K. CCI=(30-2)(1.7)/3.5=13.6

  9. Specialty Products Documented Refractory Patients Pathology consultation and approval • Crossmatched Platelets (First Choice) • Single donor apheresis platelets “crossmatched” solid-phase technique with patient’s serum • HLA Platelets • require HLA antibody screen + HLA type • Antigen negative: lack specific HLA antigens • HLA-matched: A or B matches only, require 8-10 days from Los Angeles Red Cross

  10. Influence of Patient Factors and Storage Time on Platelet Transfusion Response**Slichter 1997, adapted from Norol 1994 NS p<0.05 p<0.05 p<0.05 89% 65% 51% 21% 13%

  11. Comparison of Mean PPR with Random, HLA (Antigen Negative and Matched), or Crossmatched PlateletsPetz et al. Transfusion 2000;40:1446-1456 Mean PPR

  12. Percent of HLA-Matched (A+BU) vs HLA-Antigen Negative Compatible Platelet Donors per Patient Petz et al. Transfusion 2000;40:1446-1456 33.8 28.8 18.6 % HLA Typed Donors (n=7247) 9.5 2.1 0.7 0.6 0.6 0.1 0.3

  13. Corrected Count Increment CCI: Apheresis Platelet Concentrates =(Post-platelet count - Pre-platelet count)(BSA)* # platelets transfused (x1011) CCI >7500 (1 hr) or >5000 (20 hr) * Body surface area (M2) Ex. A woman transfused with SDP (4 x 1011). Platelet count pre=8, post=42. BSA=1.5 M2 CCI=(42-8)(1.5)/4=12.7

  14. Percentage Platelet Recovery (PPR) Percent Predicted Count (PPC) =No. platelets transfused x 0.67 x .001 blood volume (mL) Percent Platelet Recovery (PPR) = (post-platelet - pre-platelet count)x 100% percent predicted count Normal = PPR 60% (1 hr) or > 30% (20 hr) Refractoriness = PPR < 30% (1 hr) or < 20% (20 hr)

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