Transfusion Flashcards
What are the various blood products?
- Packed red cells
- Platelet rich plasma
- Platelet concentrate
- Fresh frozen plasma
- Cryoprecipitate
- SAG-Mannitol Blood
What do we use packed red cells for?
Concentrated red cells (packed cells) in a suspension of SAGM, obtained by centrifugation of whole blood, used for:
- Symptomatic anaemia
- Exchange transfusion
- Radiotherapy
- If significant bleeding anticipated, activate major haemorrhage protocol
1 unit increases Hb by 10-15g/L
What are the Hb transfusion thresholds for red blood cells (before and after)?
- Transfusion threshold → 70g/L (or 80g/L in pts w/ ACS)
- Target after transfusion → 70-90g/L (80-100g/L in pts w/ ACS)
Please note that these thresholds should not be used in patients with ongoing major haemorrhage or patients who require regular blood transfusions for chronic anaemia. Also, in a non urgent scenario, a unit of RBC is usually transfused over 90-120 mins.
What do we use Fresh Frozen Plasma for?
- FFP contains all coag factors, albumin and immunoglobulin
- Prepared from single units of blood
- Given for clotting defects (eg. DIC / Warfarin OD / Liver disease)
- Unit = 200-250ml; usual dose = 12-15 ml/kg-1
- Should not be used as first line therapy for hypovolaemia
- Expensive and carries all risks of blood transfusion
What do we use platelets for?
- Platelet rich plasma → administered to pts who are thrombocytopaenic and are bleeding or require surgery, it is obtained by low speed centrifugation
- Platelet concentrate → prepped by high speed centrifugation and administered to patients w/ thrombocytopaenia
Usually only needed if bleeding or blood count is <20x109L or if surgery is planned, get advice if count is <100x109L
What do we use cryoprecipitate for?
- Formed from supernatant of FFP
- Rich source of factor VIII and fibrinogen
- Allows large concentration of factor VIII to be administered in small volume
- Typically 15-20ml
- Most suited for pts ‘clinically significant’ but without ‘major haemorrhage’ who have a fibrinogen conc <1.5g/L
What questions need to be thought about before prescribing a transfusion?
- Is the lab result recent? (Hb)
- Have you reviewed the clinical condition of your patient?
- Is there an appropriate alternative to transfusion?
- Does pt have mental capacity to make informed decision regarding transfusion?
- Obtained verbal consent?
- Documented decision on rationale for transfusion?
Consent constitutes: informed, risks/benefits, verbal, documented, discharge summary
What is the dosing for patient body weight?
- Assume increment of 10g/L per unit in a 70kg patient
- Always consider the size of the patient
What is the two sample rule at SGH?
- 1 sample → patient known to SGH with historical blood group
- 2 samples → from discrete phlebotomy episodes for new patients
We will not delay blood in an emergency
What is ‘Wrong blood in tube’ (WBIT)?
- Blood taken from wrong patient OR blood taken from right patient but labelled incorrectly
- Never event
What obs need to be recorded for transfusion?
-
Temp, BP, pulse, resp rate
- <1hr pre-transfusion
- at 15 mins
- at end (usually 2-3hrs)
What is a massive blood transfusion?
- Defined as replacement of an individual’s entire blood volume (>10U) within 24hrs
- Complications → ↓ platelets / ↓ Ca / ↓ Clotting factors / ↑K / hypothermia
- In acute haemorrhage, use crossmatched blood if possible, but if not then use ‘universal donor’ group O Rh -ve blood
How do you transfuse patients with heart failure?
- If Hb <50g/L with HF → transfuse w/ packed red cells
- Aim to restore Hb to safe levels eg. 60-80g/L - do with care!
- Give each unit over 4h + furosemide (40mg slow IV) with alternative units
- Check for increased JVP and basal lung crackles
What are the acute (<24hr) complications of transfusion?
- Acute haemolytic reactions → ABO-incompatible blood
- Anaphylaxis → pts w/ IgA deficiency + have anti-IgA antibodies
- Bacterial contamination
- Febrile reactions → Abs react w/ white cell fragments in blood product
- Fluid overload
- Transfusion-related acute lung injury (TRALI) → non-cardiogenic pulm oedema 2o to ↑vasc permability caused by host neutrophils, activated by substances in donated blood
- Transfusion-associated circulatory overload (TACO) → excessive rate of transfusion, pre-existing heart failure
What are the delayed (>24hr) complications of transfusion?
- Infections (eg. Hep B/C)
- Iron overload
- Graft versus host disease (GVHD)
- Post-transfusion purpura: potentially lethal fall in platelet count 5-7d post-transfusion