L.9 Products & Factors for Bleeding Flashcards
(57 cards)
What are Random Donor Platelets (RDP)?
Pooled platelets derived from whole blood donations
Each unit contains 45–85 × 10⁹ platelets, typically pooled from 4–6 units into a single therapeutic dose.
What is the typical volume of plasma or platelet additive solution (PAS) for Random Donor Platelets?
250–300 mL
This volume is used for suspension of the pooled platelets.
What are Apheresis Platelets (Single Donor Platelets – SDP)?
Platelets collected from a single donor using an apheresis machine
Each unit contains at least 240 × 10⁹ platelets.
What is the typical volume of plasma used in Apheresis Platelets?
~300 mL of male donor plasma
This is to minimize the risk of TRALI.
Who are Apheresis Platelets often used for?
- Immunocompromised patients (e.g., transplant, oncology)
- Patients requiring HLA-matched platelets
These patients may have specific needs for platelet compatibility.
Do platelets express ABO antigens?
Yes, but not RhD
This means compatibility is primarily focused on ABO blood type.
What are the risks of using non-ABO compatible platelets?
- Risk of haemolysis due to plasma antibodies
- Reduced post-transfusion platelet increment
Ensuring ABO compatibility helps mitigate these risks.
Is RhD status critical for platelet transfusions?
Less critical, but RhD-negative females of childbearing age may require RhD-negative platelets
This is to avoid alloimmunization; RhIG may be considered if RhD+ platelets must be used.
What is the required storage temperature for platelets?
22 ± 2°C (room temperature)
This temperature is necessary to maintain platelet function and prevent aggregation.
What is the shelf-life of platelets?
Up to 7 days, subject to bacterial screening
This shelf-life is crucial for ensuring safety and efficacy.
Can platelets be refrigerated?
No
Cold temperatures cause irreversible activation and clearance of platelets.
What is the purpose of leucodepletion in platelet components in Ireland?
To reduce risk of febrile non-haemolytic transfusion reactions (FNHTR), reduce HLA alloimmunization, and minimize transmission risk of vCJD.
FNHTR is a common reaction to transfusions that can cause fever and chills.
Who are the donors tested for CMV antibodies intended for?
Neonates, bone marrow transplant recipients, and other severely immunosuppressed patients.
CMV (Cytomegalovirus) can cause serious infections in immunocompromised individuals.
What is the purpose of irradiating all platelet units in Ireland since 2006?
To prevent transfusion-associated graft-versus-host disease (TA-GvHD) in at-risk patients.
TA-GvHD is a rare but serious condition where transfused immune cells attack the recipient’s tissues.
What are the clinical indications for platelet transfusion?
- Bone Marrow Failure
- Chemotherapy-Induced Thrombocytopenia
- Disseminated Intravascular Coagulation (DIC)
- Massive Transfusion
- Congenital Platelet Function Disorders
- Neonatal Alloimmune Thrombocytopenia (NAIT)
These conditions necessitate platelet transfusions to manage low platelet counts and prevent bleeding.
What conditions are associated with Bone Marrow Failure?
Aplastic anaemia, leukaemia, and myelodysplasia.
These conditions lead to decreased production of platelets in the bone marrow.
What effect do cytotoxic agents have in chemotherapy-induced thrombocytopenia?
They impair megakaryocyte function, leading to reduced platelet production.
Megakaryocytes are the bone marrow cells responsible for producing platelets.
What is Disseminated Intravascular Coagulation (DIC)?
A condition characterized by the consumption of platelets in widespread microthrombi, necessitating platelet transfusion if bleeding and low count occur.
DIC can be triggered by various conditions, including sepsis and trauma.
What is Massive Transfusion and its effect on platelet levels?
Dilutional thrombocytopenia due to large volumes of red cells/fluids, requiring platelet administration as part of a massive transfusion protocol (MTP).
MTP is often initiated in trauma or surgical cases where significant blood loss occurs.
What are some examples of Congenital Platelet Function Disorders?
Bernard–Soulier Syndrome (adhesion defect) and Glanzmann’s Thrombasthenia (aggregation defect).
These disorders affect the ability of platelets to function normally during clot formation.
What causes Neonatal Alloimmune Thrombocytopenia (NAIT)?
Maternal antibodies targeting fetal platelet antigens.
NAIT can lead to severe thrombocytopenia in the newborn, increasing the risk of bleeding.
What type of platelet transfusions are required for NAIT?
Antigen-negative platelet transfusions or maternal washed platelets.
Using antigen-negative platelets avoids further immune reactions in the fetus.
What is the expected platelet response from 1 unit of pooled random donor platelets?
Typically raises platelet count by 5–10 × 10⁹/L
How much might apheresis platelet unit (single donor) achieve in platelet increment?
May achieve a higher increment
