/ 17 – Blood Products & Blood Transfusion
Resources: Essential Surgery, 5th
ed., ‘Blood Transfusion.’
Blood products available for transfusion incl.: RBCs, platelets and coagulation factors (frozen plasma [FP],
cryoprecipitate, factor concentrates.)
• Specialised blood products incl.:
o Irradiated blood products
▪ Prevent proliferation of donor T-cells in potential or actual bone marrow transplant
recipients.
▪ Used for immunocompromised Pz. Or for Pz. On purine analogue chemotherapy, intrauterine
transfusions, Hodgkin lymphoma
o CMV-negative blood products
▪ For transplant recipients, neonates, AIDS patients and seronegative pregnant women.
• Laboratory aspects of blood transfusion:
o Donated blood (1 U = 500 mL) is fractionated into the aforementioned blood components
▪ Centrifugation separates whole blood into RBCs and platelet-rich plasma. Platelet-rich
plasma can be further fractioned into platelets and plasma.
• Multiple units must be pooled together to obtain therapeutic amounts
• Fresh plasma (FP) is plasma frozen within 24h of collection
• Cryoprecipitate is the high molecular weight precipitate generated when FP is
thawed at low temperatures.
o Blood grouping and compatibility testing:
▪ Transfusion practice aims to minimise the risk of transfusing ABO incompatible blood and
involves two steps: (1) determining the patient’s ABO and Rhesus groups, and (2) screening
the patient’s blood for antibodies.
• This is simply tested by Cross-Matching (Donor Blood x Patient’s serum). This
procedure is also used in determining the organ compatibility in transplantation
medicine.
Potentially lethal side effects of blood transfusion mean that a decision to transfuse blood or blood products must be
based on clear indications and after considering alternatives.
Indications include:
o Initial restoration of circulating volume in haemorrhage & maintenance of BP – Plasma substitutes
o Substantial haemorrhage or Severe anaemia – Packed or concentrated red cells
o Resuscitating patients w. traumatic or septic shock – Human albumin solution
o Deficiency of clotting factors – Fresh frozen plasma (FFP)
o Thrombocytopaenia – Platelet concentrates
o Specific coagulation deficiencies – Cryoprecipitate
• In an emergency (e.g. obstetric haemorrhage) where group-compatible blood is
unavailable, group O, Rh -ve blood can be given.
• Storage and useful life of blood products:
o Packed red cells (RBCs)
▪ Stored btw. 2O
to 6O
C and have a shelf life of 35 days. As they age pH changes & K+
leaks out
of the cells, making the packages more dangerous than useful.
▪ Empty blood packs should be retained for 48 h for examining and testing in the event of a
transfusion reaction.
▪ 1 U of packed RBCs increases the Hb level by 10g/L
o Platelets
▪ Stored at 20 to 24o
C
▪ If an increase in the platelet count is not seen post-transfusion, then autoantibodies (i.e. ITP),
alloantibodies, consumption (bleeding, sepsis), or hypersplenism may be present.
Red Blood Cells (RBCs)
Indication for RBC
transfusions
• Hb < 70 g/L (maintain Hb between 70 to 100 g/L during active bleeds.)
• Consider maintaining a higher Hb for Pz. w.:
1. CAD/Unstable coronary syndromes
2. Uncontrolled, unpredictable bleeding
3. Impaired pulmonary fct.
4. Increased O2 consumption.
Blood transfusion
& elective surgery
• Blood is expensive and its use carries risks. Blood samples must be always labelled in
the presence of the patient!
• In elective surgery, patients fall into one of three categories:
1. Transfusion not anticipated (e.g. hernia repair),
2. Transfusion possible but unlikely (e.g. cholecystectomy), or
▪ Group & Save: Send blood for ABO and Rhesus grouping and Atbs.
screening, and retain serum for compatibility testing if required later
3. Transfusion probable (e.g. major arterial reconstruction).
▪ Patients in this category req. multiple units for the operation. The blood
is prepared a day or so before the OP.
Blood transfusion
necessity
• The volume of blood req. and the rate of transfusion depend on age, and the indications
for transfusion and the patient’s general and cardiovascular condition.
I. Volume & rate in haemorrhage
▪ Class I & Class II haemorrhage: normally req. only crystalloids/colloids
except in pre-existing anaemia.
▪ Class III haemorrhage: req. Red cell transfusion
▪ Class IV haemorrhage: req. rapid volume replacement w.
crystalloids/colloids, followed by Red cell transfusion (4 units via a blood
warmer). If bleeding continues, further red cells should be accompanied
by fresh-frozen plasma (FFP) to prevent coagulopathy.
Repeat coagulation screens are needed after every 4 units.
If bleeding persists, recombinant activated factor VII is occasionally
recommended.
II. Volume & rate in anaemia
▪ If transfusion proves necessary in anaemic patients, it should be given at
least 2 days before surgery to maximise its beneficial effects and to
allow fluid balance to stabilise.
▪ It’s older patients that are less tolerant of anaemia unless it is chronic
and little operative blood loss is expected.
Platelets
Indications • Thrombocytopaenia w./w.out bleeding (use pooled platelets)
• Procedures assoc. w. blood loss and major surgeries
• Platelet dysfunction and marked bleeding
• Potential bone marrow transplant recipients (use single donor platelets)
• Pz. w. HLA antibodies (use HLA matched platelets)
Relative
contraindications
• TTP, HIT
• Post-transfusion purpura
• HELLP
Coagulation factors
Product Indication
Frozen plasma (FP) Depletion of multiple coagulation factors (e.g. sepsis, TTP/HUS, liver disease),
Emergency reversal of life-threatening bleeding secondary to warfarin OD
Cryoprecipitate Emergencies (Haemophilia A, von Willebrand disease, Hypofibrinogenemia)
vWF Von Willebrand disease
Factor VIII concentrate Haemophilia A
Factor IX concentrate Haemophilia B
Recombinant factor VIIa Factor VII deficiency w. bleeding/surgery
Haemophilia A or B w. inhibitors
Glanzmann thrombasthenia
Prothrombin complex
concentrate
Reversal of warfarin therapy or vit. K deficiency in bleeding patient
Activated prothrombin
complex concentrate
Urgent reversal of direct thrombin inhibitors.
Hazards and complications of blood transfusion
Febrile non-haemolytic
transfusion reaction
(FNHTR)
• A leucocyte incompatibility usually results in a febrile reaction, but this is a rare
reaction since universal leucodepletion of blood products.
• A temp.O
C rise > 1 and shivering during or after transfusion indicates FNHTR.
• Symptoms usually subside after stopping the transfusion for 15-30 min and
administering antipyretics and antihistamines.
Haemolytic reactions • A major ABO incompatibility causes massive haemolysis, which can be lethal.
• Almost all haemolytic reactions are caused by human error and incompatible
transfusion.
• Clinical features:
o Rapidly developing pyrexia at the onset of infusion
o Dyspnoea, constrictive feeling in the chest, intense headache
o Severe loin pain
o Hypotension
o Acute oliguric renal failure w. haemoglobinuria (due to obstruction of
tubules w. haemoglobin).
o Jaundice
o DIC w. spontaneous bruising & haemorrhage
• Dx.:
o Blood tests – Hyperbilirubinemia
o +ve Coomb’s
• Tx.:
o Halt transfusion
o Resuscitated
o Induce osmotic diuresis w. mannitol (to treat oliguria)
Allergic reactions • Clinical features:
o Fever
o Skin rashes & Pruritus
o Wheals or angio-oedema
o Anaphylaxis (rare)
• Tx.:
o Halt transfusion
o Antihistamines
Infection • Infections may arise from three source:
I. The donor
II. Contamination during blood preparation & storage
III. Giving set/Cannula site
• Donated blood can be screened for most significant transmissible infectious agents, however
diseases acquired too recently for the Atbs. response to develop cannot be detected.
• Generally, the most common/dangerous diseases transmitted via transfusion are:
I. Viral infections
▪ Hepatitis (HBV, HCV and HDV)
• Patients needing multiple transfusions need to be vaccinated against HBV
prior to a surgery.
▪ HIV
▪ HTLV
▪ Herpes viruses (CMV, EBV)
• With CMV, there is a high risk only among premature neonates.
Leucodepletion is an efficient way of reducing the risk.
II. Bacterial infections
▪ Syphilis
▪ Brucellosis
▪ Contaminants
III. Protozoal infections
▪ Malaria
▪ Chagas disease
▪ Babesiosis
IV. Prions (esp. vCJD)
Transfusion-Related
Acute lung injury
(TRALI)
• Transfusion of particularly plasma-containing products may be followed by an acute
and rapid onset of shortness of breath and cough.
• There is typically a ‘white-out’ on CXR.
• Treated like ARDS – see ‘Post-OP Complications – Respiratory Complications’
• The injury is caused by donor antibodies reacting with the patient’s leucocytes
Other complications
of blood transfusion
• Immunosuppression
• Fluid overload
• Delayed transfusion reactions
o PTP (Post-transfusion purpura) – This is a rare life-threatening complication
caused by platelet-specific alloantibodies. Symptoms usually occur after a
week w. the patient dev. thrombocytopaenia and bleeding
o Transfusion-associated graft vs host disease – When the donor’s lymphocytes
recognise the recipient’s cells as foreign, a graft vs host disease may be
initiated. Irradiation of blood products is needed to inactivate T-cells likely to
cause GvHD in susceptible patients (i.e. patients w. defective cell-mediated
immunity.)
Reducing the need for blood bank transfusion
Considering the risks & the financial implications of blood transfusion, we should try to reduce the need for
transfusion.
• Non-transfusion methods
o Preoperative
▪ Tolerating lower [Hb]
▪ Iron therapy for iron deficiency anaemia
▪ Tx. w. EPO before or after the OP
o Intraoperative
▪ Using gelatin or crystalloid solutions for hypovolaemia
• Autologous transfusion (Preoperative autologous donation, Acute normovolaemic haemodilution,
Intraoperative cell salvage & post-OP cell salvage)