Platelet Transfusion (BSH 2016)
o 275,000 adult platelet units used per year in England
o Increasing demand, 25% over 7-8 years. Due to ageing population and increasing survival and treatment intensity of haematological malignancy
§ Haematology 70%, Cardiac surgery 10%, ITU 10%
o Number of donors down 35% compared to year 2000
o Approx 240 x109 contained in 150-300ml plasma/PAS
WHO Bleeding Score (summarized)
- 0 – No bleeding
- 1 – Petechiae in dependent sites, oropharyngeal bleeding, epistaxis <30 min
- 2 – Mild GI bleeding, epistaxis >30 min, multiple bruising, bleeding in cavity fluids
- 3 – Bleeding requiring RBC transfusion, Neuro bleed on CT without symptoms
- 4 – Debilitating bleeding, haemodynamic instability from bleeding, fatal bleed
- Identify cause of thrombocytopenia first so as to treat correctly
- Use other measures first
o Local measures (compression), use of lowest risk procedure / equipment
o Think about desmopressin, fibrinogen, TPO’s
- Thrombotic microangiopathies
- Allergic Reaction (1 in 6000)
o Patients with history of >mild allergic reaction to platelets should receive platelets suspended in PAS. If continues to react, use washed platelets.
- ABO and Rh Incompatibility (1 in 600,000)
o Acceptable to use ABO incompatible platelets to reduce wastage, but these should be high titre negative units. Use for Platelet Additive Solution (PAS) for pooled platelets reduces risk further
o Rh D- girls and women of childbearing potential should receive Rh D- platetlets. In emergency, give Anti-D 250 IU to cover Rh D+ platelets
o Rh D- boys <18 yo, those with anti-D anitbodies and transfusion-dependent adults should ideally receive Rh D- platelets, but not at the expense of Rh D+ wastage. Anti-D not required
- TRALI (<1 in 1 million)
o Reaction between donor leukocyte antibodies and recipients leukocyte antigens
o HIV 1 in 7 million, Hep B 1 in 1 million, Hep C 1 in 30 million
o Bacterial contamination, rare since bacterial screening started in 2010
- Post-transfusion Pupura
o Almost exclusively occurs in women following transfusion of platelet containing blood products (RBC, Plt, Granulocytes) leading to alloimmunisation against an antigen of the donor cells but that then causes destruction of patient’s own platelets.
o Typically 5 days post-transfusion. Lasts days to weeks. Rx with IVIg
- All clinical areas transfusing platelets should be able to deal with acute transfusion reactions and have guidelines for such events in place.
A one hour post transfusion increment of <5 on two separate occasions when using ABO-identical platelets and in the absence of non-immune factors.
Non-immune causes are more common than immune
- Consumptive coagulopathy, sepsis & splenomegaly account for 80% of cases
1. Use ABO matched platelets
2. Patients refractory to platelets for non-immune reasons, HLA matching not indicated
3. Class 1 HLA-matched platelets
4. HPA matched platelets
- Glazmann thrombasthenia
o Lack of 2b/3a receptor increases the risk of alloimmunisation
o Consider fFVIIa first line. HLA-matched if plt used.
- Other congenital platelet disorders – consider TXA + Desmopressin first line.
o Only consider if treatment has failed and urgent intervention required.
o Give in combination with IVIg
- Acquired platelet disorders (i.e. Anti-platelets)
o In vitro studies suggest aspirin more reversible than clopidogrel/ticagrelor
o However, aspirin increases bleeding risk but not severity and so platelet transfusion rarely indicated
o Odds of death or disability higher for platelet transfused patients in a RTC looking at ICH on anti-platelets. ?Due to being on aspirin for an underlying thrombotic condition. However overall was not a good quality trial
o Do not use platelets when antiplatelet agents have not been stopped
o Use general measures +/- TXA
o Consider plt transfusion if critical bleeding not responding to other measures
o Consider plt transfusion in bleeding with plt count <1 due to abciximab
Platelet transfusion thresholds