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.
** Some centres advise this threshold only in the hands of an experienced operator under US guidance. For less experienced operators, a higher threshold may be according to local practice.
Quick tip; If a patient who usually needs irradiated/CMV negative blood products needs blood in an emergency, don't delay transfusion to get them the blood with these characteristics. Give them non-irradiated/non-CMV-negative as delaying transfusion is more likely to kill them than receiving a non-irradiated blood product for example
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.
Blood products which need irradiating are; red blood cell products, platelet products and granulocytes.
Those who need irradiated products are;
Patients with HIV/AIDS 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.
TaGvHD is incredibly rare. Leukodepletion of all routine blood products (except granulocytes) has reduced the risk of TaGvHD hugely. It can still occur however, therefore whenever there is time to give irradiated products to patients with the indications above, you should. However, if a patient needs transfusion as an emergency and there isn't time to wait for an irradiated unit of blood, then don't. The chance of TaGvHD is relatively small compared to the risk of death from delayed transfusion-consistently the 2nd commonest cause of death associated with transfusion.
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;