Haematology SC084: Is Blood Transfusion Safe And Necessary In My Treatment?

Question 1

Indications of blood transfusion

Answer 1

1. Anaemia to a degree with moderate to serious symptoms
   - Anaemia in elderly with medical illness (e.g. comorbidities, nutritional deficiencies, drug causing GI bleeding) likely require transfusion because of symptoms + less likelihood of self recovery
2. Active blood loss in trauma / during surgical operation
   - can be minimal / zero to massive / life threatening
3. Leukaemia, Thalassaemia major, other causes of BM failure (e.g. Aplastic anaemia)
   - BM haematopoiesis fail to generate sufficient + functional RBC, Plt, WBC
   - Likely permanent but can be temporary
   - Transfusion aim to alleviate anaemia symptoms + bleeding

Question 2

Blood transfusion not always needed

Answer 2

1. Elective operation
2. Alternatives to enhance patients’ haematopoiesis / correct underlying situation (enhance erythropoiesis / prevent bleeding)
3. Tools available to monitor coagulopathy + guide specific treatment (e.g. POC testing to check deficiency of particular clotting factors during OT)
4. Doctors should have skill to reduce / stop bleeding (e.g. stop anticoagulant)
5. Drug to reduce / stop bleeding (e.g. top up patients’ reserve by correcting coagulopathy / Fe reserve before joint replacement surgery)

Question 3

4 Dimensions to consider blood transfusion

Answer 3

1. Availability / Adequacy / Sufficiency
   - Apply to common blood products only (e.g. RBC, Plt, Plasma of common blood groups of local community)
   - WBC not commonly transfused
   - Also rmb shelf life of donated blood and its components
   - Special blood components with common blood groups may not be always available / need time to prepare
   - Special blood components with rare blood groups need to ask special donors to donate / from frozen inventory / from overseas
   - Even common blood products may be limited in supply in time when there are high demand / when donations affected by weather / public holiday (e.g. short life blood products e.g. Plt concentrates)
   - Sometimes difficult to maintain adequate blood supply
   —> Increasing demand from aging population + lesser young people
   —> Supply in bottleneck with extreme difficulties in mobilising young people to donate blood
   —> Only 3% of general population is enough for maintain safe blood supply
   —> Impact of COVID19
   —> Clinical control in blood usage has been behind other western countries
   - Other factors: Society changes, Low Hb (~20% of general population) + High prevalence of Fe deficiency in HK population
2. Safety
   - Donors are safe to donate
   - Blood collected is safe to transfuse
3. Quality
   - Blood quality can be affected by:
   —> Donor’s medication, dietary, health, blood processing procedure
   —> Storage + handling at hospital blood bank and wards
4. Outcome

Question 4

Balance of Supply vs Demand in Blood transfusion

Answer 4

Sometimes difficult to maintain balance

Supply:
1. No substitute
2. Collect from voluntary non-remunerated blood donors
3. Go through eligibility and stringent infectious diseases screening
4. Need proper storage with limited shelf life
5. Wastage must be avoided

Demand:
1. Patients’ / Clinical driven (blood group, component type, amount, timing)
2. Patients’ outcome oriented (restore O2 carrying capacity, control bleeding, relieve symptoms, save lives)
3. But not without adverse reaction

Maintaining balance:
1. BTS (Blood Transfusion Service) responsible for blood collection, processing, testing
2. BTS supplies blood to hospital blood banks where blood is then distributed to patients for transfusion according to clinical needs
3. Blood supply is driven by clinical demand

Question 5

Patient Blood Management (PBM)

Answer 5

• Multidisciplinary, evidence-based approach to optimising care of patients who might need a blood transfusion
• Aims to improve patient outcome
• Better outcomes can be achieved with reduction / avoidance of exposure to allogeneic blood
• HK practising ~4-5 years, western countries ~10 years

Themes: Modifying risk factors
3 pillars:
1. Anaemia, Fe deficiency —> Optimise red cell mass
2. Blood loss + bleeding —> Minimise
3. Transfusion —> Harness + optimise physiological reserve of anaemia, only transfuse in haemodynamically unstable patients, “One unit and reassess”, alternative measures e.g. IV Fe to replace transfusion

(Now prefer IV Fe > Oral Fe:
- IV Fe much higher bioavailability (Oral Fe 300mg BD / TDS —> only 90mg elemental Fe —> also not 100% absorbed in GI tract)
- Less GI SE e.g. constipation)

Benefits of PBM:
Reduction in:
1. Transfusion
2. Mortality
3. Average length of stay
4. Reoperation
5. Readmissions
6. Complications
7. Costs

Question 6

Safe blood

Answer 6

• Blood is biological substance (similar but not always same)
• Screening as comprehensive as possible but not exhaustive
• Patients relatively immunocompromised during transfusion
• Individual response to above challenges can be nothing, minimal, early acute, subacute, delay

Risk of blood transfusion:
Infectious:
1. HIV
2. Hep B, C
3. Bacteria
4. Dengue, malaria, West Nile virus (WNV), Trypanosoma
5. Zika virus, Japanese encephalitis, vCJD (these cannot be tested during donation)

Non-infectious:
1. Febrile non-haemolytic transfusion reaction (common)
2. Minor allergic reaction (common)
3. Haemolytic reaction (rare but fatal)
4. Circulatory overload
5. Transfusion related acute lung injury
6. Transfusion associated graft vs host disease
7. Post transfusion purpura

Processing:
- Whole blood into different components for maximal quality on storage + right component to the right patient

Mandatory tests:
- ABO grouping, Rh(D) typing, Ab screening
- HBsAg, Anti-HCV, Anti-HTLV 1+2, HIV Ag / Ab combo, Anti-Syphilis Ab
- NAT (Nucleic acid testing): HBV DNA, HCV RNA, HIV RNA
- Bacterial culture (all Plt concentrate units)

Supplementary tests for selected group:
- Anti-CMV, Zika by NAT

Question 7

Minimising blood transfusion

Answer 7

1. Doctor’s factor
   - Skills
   - Experience
   - Confidence level
   - Willingness to ask for support
2. Surgical factor
   - Disease
   - Type of procedure
   - Surgical site
   - Local haemostatic control
3. Patient’s factor
   - Age
   - Comorbidity
   - Blood problems e.g. coagulation, red cell Ab, rare blood groups
   - Drug (e.g. Anticoagulants)
   - Liver status
4. Others

Management:
1. Pre-surgical optimisation
- Diagnose + Manage anaemia esp. Fe deficiency
2. Pre-surgical autologous deposits (donate blood beforehand for own use)
3. Peri-operative deposits + salvage
4. Post-operative salvage

Question 8

Refusing blood transfusion

Answer 8

1. Religious
2. Cultural
3. Own reasons
   - Own perceived risk of transfusion e.g. infectious risk
   - Request for directed donation (i.e. request to donate blood only for a particular person)

Approach:
1. Balance risk vs benefits
2. Understand risk of homologous transfusion (i.e. one person to another), autologous, directed donation
3. Any alternatives for blood transfusion
4. Treatment issues

Question 9

Risks of autologous blood

Answer 9

• Theoretically safer / Patients take their own risk

However:
- Not every patient eligible / suitable for blood donation
- Risk of bacteraemia
- Risk of mixing up
- Risk of wastage

Question 10

Risks of directed donation

Answer 10

• Not every potential donor is eligible / suitable
• Potential donor may hide some important information in donor / blood safety
• Risk of positive infectious disease markers and leading to wastage
• Risk of transfusion associated GvHD (donor T lymphocyte attack recipient)

Management:
- Not advised in most countries
- Unless very special blood group