1. Miscellaneous Topics in Transfusion
Michael Wong
Department of Pathology
PMH

2. Outline Transfusion threshold Haemolytic transfusion reaction
Fever during transfusion
Leukocyte depletion
Transfusion in autoimmune haemolytic anaemia
Platelet refractoriness
Delay in availability of blood products
Product recall and look back

3. Red cell transfusion threshold
Quoted from HA transfusion guideline
There is no single haemoglobin value that must be taken as the transfusion trigger. However, a trend towards cautious blood transfusion trigger has been observed but patients’ condition may affect clinical decision. The initiation of transfusion is a clinical decision by the attending clinician. In general, the following principles are considered:
Haemoglobin concentration <7g/dL and assessment on the rate of ongoing red cell loss.
For haemoglobin concentration between 7 and 10 g/dL, transfusion strategy is less clear but general view is that transfusion is often not justified purely based on haemoglobin concentration.
A higher haemoglobin concentration may be required in patients who may tolerate anaemia poorly, e.g. patients over the age of 65 years and patients with cardiovascular or respiratory disease.

4. Transfusion threshold

6. Mortality

7. An audit of PMH
One case from ICU_HDU has transfusion give while Hb is 10.1, the patient is suffering from acute coronary syndrome and the attending clinician considered it is desirable to have a higher Hb level for the patient.

8. Mortality

10. Myocardial Ischemia and Transfusion (MINT)

11. Myocardial Ischemia and Transfusion (MINT)
Liberal Transfusion Strategy
Restrictive transfusion strategy
Patients randomly allocated to the liberal transfusion strategy will receive one unit of packed red cells following randomization and receive enough blood to raise the hemoglobin concentration above 10 g/dL any time the hemoglobin concentration is detected to be below 10g/dL during the hospitalization for up to 30 days. Any transfusion following the initial unit of packed red cells must be preceded by blood test documenting a hemoglobin concentration below 10 g/dL.
Receive a transfusion if they develop symptoms related to anemia. Transfusion is also permitted, but not required, in the absence of symptoms only if the hemoglobin concentration falls below 8 g/dL. Blood is administered one unit at a time and the presence of symptoms is reassessed. Only enough blood is given to relieve symptoms. If the transfusion is given because the hemoglobin concentration falls below 8 g/dL, then only enough blood is given to increase the hemoglobin concentration above 8 g/dL.
Symptoms of anemia that will be indications for transfusion are: 1) Definite angina requiring treatment with sublingual nitroglycerin or equivalent therapy. 2) Unexplained tachycardia or hypotension.

12. Platelet transfusion threshold
Quoted from HA transfusion guideline
Platelet <10 x109/L in stable patients (usually NOT indicated in ITP, SLE, TTP and HUS).
Platelet <20 x109/L in patients with fever or sepsis.
Platelet <50 x109/L with diffuse microvascular/mucosal bleeding, major bleeding or before invasive procedures.
Platelet <100 x109/L with retinal or CNS bleeding/ surgery, or with active bleeding in postcardiopulmonary bypass.
Platelet <50 x109/L in stable premature neonates or platelet <100 x109/L in sick premature neonates
Suspected platelet dysfunction with active bleeding or before invasive procedures.
Suspected platelet deficiency with severe active bleeding or following massive transfusion.

13. Prophylaxis vs. therapeutic

15. Threshold 10 vs. 20

16. Haemolytic transfusion reaction
Acute / delayed
Usually due to antibody in recipient binding to red cells of donor resulting in acute hemolysis
ABO mismatch – anti-A, anti-B (type)
Antibodies to minor blood group e.g. anti-Jka (screen)
Occasionally due to antibody in donor binding to red cells of recipient
Transfusion of excessive group O FFP or platelet concentrate to a group A or B individual

17. ABO mismatch transfusion
Could result in immediate shock to totally asymptomatic
Group A individual has less anti-B than group O individual
Elderly have might have lower antibody level
Particularly difficult to detect in unconscious or sedated patients
Need a high index of suspicion for ICU physicians

18. Fever during transfusion
Acute haemolytic transfusion reaction
Septic reaction
Platelets are more the common cause. However
Platelets are all cultured
Stored less than 5 days
Red cells if contaminated will be very severe due to the prolonged storage time
Febrile non-haemolytic transfusion reaction
Most common
The reason of stopping transfusion and reassess is due to the above 2 differential diagnosis

19. Leukocyte depletion WBC in packed cell could
Cause FNHTR
Transmit CMV
cause transfusion graft versus host disease
Now 50% of the red cells supply are leukocyte depleted
There is no need to use bed side filter

20. Transfusion in AIHA

21. Transfusion in AIHA
In patient with AIHA, the autoantibody is pan reacting (i.e. it will bind to all sorts of red cells with no specificity)
So cross matching will always give incompatible result
What we worry is whether the patient has alloantibody (antibody against a blood group that the patient does not have e.g. anti-Jka)
So instead of matching ABO and RhD only, we match every clinically significant minor blood group C, c, E, e, K, k, Jka, Jkb, Fya, Fyb ………….

22. How safe
A total of 7052 units was issued for 1685 patients; no haemolytic reactions were reported.
Sokol RJ, Hewitt S, Booker DJ, Morris BM. Patients with red cell autoantibodies: selection of blood for transfusion. Clin Lab Haematol. 1988;10(3):
But it is not wise to over transfuse AIHA patients as rate of haemolysis is directly related to red cell concentration

23. Platelet refractoriness
Corrected count increment = (post – pre transfusion platelet count) / number of platelet transfused x body surface area
CCI = (15000 – 10000)/(4 x 0.7) x 1.7 = 3035
CCI (60 minutes) < 5000 or CCI (24h) < 2500 are considered platelet refractory
Usually due to HLA antibodies
We could use HLA matched platelets
Platelets only have HLA-A and HLA-B antigen, they do not have HLA-DR antigen

24. Delay in availability of blood products
Require phenotype matched blood e.g. AIHA
Require blood with rare phenotype
e.g. anti-Jka + anti-Jkb (need Jka –ve and Jkb –ve blood)
These rare red cells are stored in frozen state
Rare blood group e.g. Bombay

25. Common product recall / look back
Platelet culture positive
All platelets are cultured and release on day 3 if culture negative, but culture will continue until day 5
Even if culture positive the dose is fairly low
Platelets culture are pooled in 5
There is 80% chance that the platelet transfused by your patient is not culture positive
Usually just need to observe and treat accordingly if fever

26. Common product recall / look back
Donor develop illness (usually URTI) after donation
Usually just observe
Donor report high risk behavior after donation
Check baseline and 6 month post exposure HBV, HCV, HIV, HTLV-1, VDRL
Donor seroconverted during subsequent donation
Check baseline and 6 month post exposure of the concerned infection

27. Questions?