Red cell transfusion
Guidance has been produced around transfusion thresholds as unnecessary transfusion is associated with morbidity and mortality
Critically ill patients
70-90g/L (up to 100g/L if acute sepsis with hypoxia))
Traumatic brain injury
70-90g/L (over 90g/L if evidence of cerebral ischaemia)
Acute ischaemic stroke in neuro ICU
Acute coronary syndrome
(Adapted from Retter et al- see Guideline (Red cell transfusion))
Platelet transfusion in bleeding
These are general thresholds and each case should be assessed individually
|Central venous line insertion with US guidance||>20x109/L|
|Epidural catheter insertion/removal||>80x109/L|
|Neurosurgery or ophthalmic surgery||>100x109/L|
|Percutaneous liver biopsy||>50x109/L|
* Some centres advocate the use of a threshold of over 70x109/L due to the potentially significant consequences of a bleed into the dural space
Quick tip; Irradiated products are needed for patients who have low T cells due to certain cancers/ immunodeficiencies, after certain chemotherapy and if receiving blood from 1st/2nd degree relatives
Irradiated products are used when there is a risk that due to weak recipient T cell immunity a normal transfusion, which contains some donor T cells, could lead to engraftment of those donor T cells into the recipients marrow causing transfusion-associated graft versus host disease (TaGvHD). This is very rare but almost uniformly fatal.
Those who need irradiated products are;
Patients with HIV/AIDS at present are not thought to need irradiated products
TaGvHD is yet to be fully understood and not all cases occur in immunodeficient recipients, but that risk is higher if the recipient lacks T cell immunity or cannot identify donor T cells as foreign.
HEV negative products
Hepatitis E virus is transmitted via uncooked meat, usually pork and shellfish, but can be transmitted by transfusion. Infection is asymptomatic in most but in patients receiving solid organ or stem cell transplants there is a risk of liver injury (albeit small) and therefore HEV negative products are recommended. These products are red cells, platelets for intrauterine transfusion and granulocytes. The patients affected are;
Ensure any patient meeting these criteria is identified to the transfusion laboratory.
There has now been a universal screening programme introduced for all blood products and therefore future blood products will no longer need Hep E designation. There will still be some frozen products however which remain in theory Hep E positive therefore for now continue to identify patients requiring Hep E products in case of the need for frozen products.
CMV negative products
Over 50% of the adult population have been exposed to Cytomegalovirus (CMV) and will have immunity (CMV IgG). In certain immunocompromised patients CMV can be reactivated. Rarely CMV can be transmitted in blood products if a donor is acutely infected. However, current literature shows that leucodepletion (performed on all blood products except granuloctyes) is as effective as making products 'CMV negative'. Therefore only when there is risk of a foetal/neonatal CMV infection should CMV negative products be used;