Blood Products and Transfusion Flashcards
What are the implications of having Anti-D Antibodies?
RhD negative patient must ONLY receive RhD neg blood 🡪 else risks developing Anti-RhD Ab
Otherwise, causes delayed haemolytic transfusion reaction (~5-10 days post-transfusion) where anti-D antibodies latch on to the D positive blood cells transfused which are then recognised & removed in the spleen
Anaemia; high bilirubin from breakdown; jaundice; free haemoglobin released can damage kidneys – renal failure etc.
How does haemolytic disease of the newborn present?
If Severe: Fetus anaemic 🡪 heart beats faster to compensate 🡪 overwhelmed 🡪 fluid backlogs 🡪 Hydrops Fetalis and Death
If Less Severe
- After birth: Bilirubin rises (no more placenta to remove, only immature liver which cannot cope) 🡪 neonatal jaundice 🡪 brain damage (kernicterus), hyperextended arms +legs + neck, v often fatal
- Kernicterus = BR Encephalopathy (BR is neurotoxic if concentration is too high)
- Neonates are most susceptible to Kernicterus
- Neonates are v susceptible to HyperBR due to time required for hepatic enzymes to upregulate and cope with BR after birth
What is the prophylaxis against maternal sensitisation of Rh-D?
Give anti-D Ig at delivery if baby is RhD positive, or for ‘events’ during pregnancy where fetal-maternal haemorrhage is likely to occur (where there is risk of fetal blood entering into maternal circulation)
Works by coating fetal red cells and removing them in mother’s spleen before sensitization can occur.
Must give IM anti-RhD within 72 hours of ‘event’ where fetal-maternal haemorrhage occurs.
Routine Antenatal Anti-D prophylaxis can be given in the third trimester for RhD negative mothers
What are the antibodies against infections tested for in pre- transfusion testing?
Mandatory in SG:
- Hepatitis B: HbsAg
- Hepatitis C: anti-HCV, PCR
- HIV: anti-HIV 1 & 2, PCR
- Syphilis: TPPA
- Malaria
- Zika
Discretionary: examples include
- HTLV: anti-HTLV (not tested in BSG Singapore)
- CMV (can be dangerous in immunosuppressed patients) however no point testing, as most people will be CMV +ve by adulthood
- Prion disease – vCJD
What are the indications for plasma transfusion?
If bleeding + abnormal coagulation test results (PT prothrombin time, APTT activated partial thromboplastin time) e.g. liver disease with bleeding/going for invasive procedure
Reversal of warfarin (anticoagulant) e.g. for urgent surgery
- Prothrombin Complex Concentrate (PCC; contains factors 2, 7, 9, 10 which warfarin acts against) preferred: smaller volume, patients tolerate it better, acts more quickly
- As well as give VITAMIN K 10mg Infusion on top of PCC
Other conditions occasionally: massive bleeding, disseminated intravascular coagulation
FFP not just to replace volume/ fluid loss – simple non-human products can be used (eg: recombinant F7)
What are the indications for cryoprecipitate?
If massive bleeding & fibrinogen very low (there is fibrinogen in FFP, but more concentrated in cryoprecipitate)
- Eg: DIC patients
- Low fibrinogen is MAIN indicator for using cryoprecipitate
Rarely hypofibrinogenaemia
What is platelet refractoriness?
Occurs in pt with severe chronic thrombocytopenia who need many repeated transfusions. Eventually, we will see that the rise in platelet count after each
This is because platelets are given together with WBCs (as part of the buffy coat)
All nucleated cells (platelets and WCC) present HLA Ag. (RBC are anucleate and does not possess HLA).
However, WCC has much MORE HLA than platelets as platelets are merely cell fragments 🡪 will stimulate Anti-HLA Ab production more strongly, which will eventually wipe out Leucocytes and Platelets.
Hence in pt with severe thrombocytopenia that necessitates many transfusions will get leuco-reduced platelets (and leuco-depleted RBC if necessary)
What are the 3 indications for leukoreduction?
1) To reduce risk of FNHTR
- the most common cause of transfusion related fever
- eg: if patient on fever presents with fever + no other symptoms 🡪 and we have determined it is a FNHTR 🡪 we will proceed by giving leuco-depleted blood/platelets instead
2) To reduce risk of CMV infection (esp if recipient is immunosuppressed and is CMV-ve)
3) To reduce platelet refractoriness
What are the indications for albumin transfusion?
4.5%: useful in burns (loss of fluid and plasma proteins due to loss of skin coverage), plasma exchanges. Not indicated in malnutrition
20%: For certain severe liver + kidney conditions (e.g. nephrotic syndrome)
What are the indications for clotting factors concentrates?
Factor 8 and 9: for Haemophilia A and B respectively
Factor 8 for Von Willebrand’s disease
What are the immediate Adverse Reactions to Transfusions (<24 hours)?
Immune
- Acute Haemolytic Transfusn Rxn: possible DIC!
- Febrile non-haemolytic reaction (isolated fever) due to WBC in platelet transfusions
- Allergy (most commonly Urticaria)
- Anaphylaxis
- TRALI (transfusion related acute lung injury)
Non immune
- Bacterial Contamination
- Transfusion associated cardiac overload
- Air embolism
- Massive transfusion: hypothermia, hyperkalemia, hypocalcemia
What are the delayed Adverse Reactions to Transfusions (<24 hours)?
Immune
- Delayed haemolytic transfusion reaction (jaundice, renal failure, anaemia)
Non immune
- Viral infections (hep B, C, etc.)
- Iron overload (in chronic, multiple transfusions)
[ACUTE HAEMOLYTIC TRANSFUSION REACTION (WRONG BLOOD)]
What are the early signs?
- Fever, Chills, N&V, Flushing
- Chest / Loin / Back Pain
- Pain along infusion vein (occurs rapidly, hence pain upon infusion)
- Haematuria – red urine (due to Hb release 🡪 ATN)
[ACUTE HAEMOLYTIC TRANSFUSION REACTION (WRONG BLOOD)]
What are the late signs?
Hypotension – can even lead to DIC ☹
Hemoglobinuria
Jaundice MAY occur – however since occurs at the start 🡪 may not have sufficiently high BR to cause jaundice
[ACUTE HAEMOLYTIC TRANSFUSION REACTION (WRONG BLOOD)]
What are the relevant investigations?
Haemolysis panel: Br, Haptoglobin, Hemopexin, LDH
Assess organ involvement: Renal Panel, K, Ca, Pi, Mg
Confirm AHTR: Direct Coomb’s Test, Check pt identifiers, perform GXM once again
