Lecture 20: Practical Aspects of Blood Transfusion

Question 1

What are the aims of pre transfusion testing?

Answer 1

The aim of pre-transfusion practice is:

• To provide red cells for transfusion that will survive normally in the recipients’ circulation
• To avoid haemolytic transfusion reactions

Question 2

What are the steps in ensuring safe transfusion

Answer 2

Steps In Ensuring Safe Transfusion

• Correct patient identification, _blood samplin_g and labelling at the bedside *
• Determination of the ABO and Rh(D) type of the recipient
• An antibody screen designed to detect c_linically significant antibodies_
• Selection of appropriate red cells for transfusion
• _A final cross matc_h or compatibility test
• _Removal of selected red cel_l units from Blood Refrigerator
• Final identity check at bedside *

Question 3

What are some sources of transfusion error?

Answer 3

Sources of errors include:

(1) wrong patient wrong sample;
(2) laboratory procedures;
(3) blood issuing and collection;
(4) wrong blood wrong patient.

Question 4

What are the Pre-transfusion ANZSBT guidelines?

Answer 4

Patient Identification

Patient identity shall be confirmed by asking the patient [if conscious and rational] to state their surname, given name(s), and date of birth and by checking the identity label securely fastened to the patient.

Sample Labelling

Should be completed by hand at the bedside. Pre-printed labels are not acceptable

Confirmation on Request Form

I have checked the information on the s_ample label_ and the request form against the patient’s ID wristband before leaving the patient, and verify this as correct.

Question 5

Describe the 3 Pre-Transfusion Testing Steps

Answer 5

It involves three separate steps: (1) determine ABO and Rh(D) type of recipient; (2) antibody screen; (3) selection of blood component.

1. Determination Of The ABO And Rh(D) Type
   * The red cells of the potential recipient are typed using commercial monoclonal reagents (known patient compared to historical record, unknown patient checked twice). These are normally lgM in nature and capable of producing results in a few minutes.
2. Antibody Screen

• Antibody screen uses specially selected red cells that show homozygous expression (identification) of clinically significant antibodies.
• Antibody screening is performed using _anti-human globulin (_AHG) test.
• The test aims to identify the presence of these on the surface of the red cells following incubation of screening cells and patient serum at 37 .

1. Selection of Red Cell Units

• Normally, red cell units of the same ABO and Rh(D) type as the patient will be selected for compatibility testing (group for group approach).
• ln the event that red cell antibodies have been detected in the screening test, then antibody will be identified and red cell units that lack the antigen against which the antibody is detected. ln this setting, it will often be necessary to select group O red cells since extended typing of red cell units is usually restricted to group O (the universal donor type).

Question 6

Which recicipient blood group (O, A, B, AB) have what antibodies present and what are the acceptable donor groups for these individuals?

Answer 6

Question 7

What are the 3 Blood Ordering Policies?

Answer 7

(Group and Screen; Compatibility Testing; Emergency Situations)

Question 8

Describe Group and Screen- Blood Ordering Policies

Answer 8

• Used in _surgical setting_s when likelihood of blood being required is low
• Antibody screen should be negative
• Serum retained in laboratory for 7 days
• _Red cells can be provided quickly when needed (_within 15 minutes of request)

Question 9

Describe the different types of Compatibility Tests

Answer 9

The final crossmatch involves some form of matching of the red cells from the donation with the patient’s serum.

Only do this when the antibody test is positive and we’ve identified a speicific antibody in the patient

Three broad approaches include:

• Full crossmatch (up to 45 minutes)
  
  • Involves anti human globulin (AHG) testing
  • Progressive decline in use
  • Used primarily when the antibody screen is positive
• Immediate spin crossmatch (5-10 minutes)
  
  • Aims to detect ABO incompatibility
• Computer crossmatching (<5 minutes)
  
  • Final ABO check performed electronically (data on blood groups of patient and donation are matched prior to issue)
  • Aims to detect ABO incompatibility

Question 10

Describe Provision of Red Cells in Emergency Situations- Blood Ordering Policies

Answer 10

Effective communication is essential. In these siuations, more patients die by lack of blood than lack of compatibility.

Three main approaches are often used sequentially:

• Emergency O Rh(D) negative units
  
  • Requirement for blood desperate, patient group not known
• Group specific blood
  
  • Requirement for blood desperate, patient group known
• Provision of fully compatible blood

Question 11

Describe process of The Final bedside Check- Administration of Red cell Transfusions

Answer 11

Final Bedside Check

The most frequent cause of severe haemolytic transfusion reactions relate to errors in patient identification.

• This can occur at the time that the initial sample is taken for pre-transfusion testing.
• It can also occur at the point at which the red cell unit is set up for transfusion at the patient bedside.
• Final bedside check should involve two people, and it checks patient identity against compatibility label (full name, DOB, NHI, blood group)

Systems for identification of the patient at all steps in the transfusion chain are essential if the risk of transfusion errors leading to haemolytic transfusion reactions are to be avoided.

Question 12

Describe the Monitoring of transfusion step of Administrationo f Red Cell Transfusions

Answer 12

Monitoring of Transfusion

Monitor patient closely during transfusion:

• Major problems likely to produce early symptoms/signs
• If problems develop: (1) stop transfusion; (2) maintain line with saline; (3) seek advice

Question 13

If symptoms/signs appears during transfusion, what should you do

Answer 13

If problems develop: (1) stop transfusion; (2) maintain line with saline; (3) seek advice

Question 14

What are some complications that can occur from transfusion?

Answer 14

Immunological Complications

• Early
• Immediate haemolytic reactions (red cells)
• Febrile non-haemolytic reactions (white cells)
• Transfusion related acute lung Injury (TRALI) (while cells)
• Reactions to plasma proteins (native proteins reaction is anaphylaxis; ingested proteins reaction is urticaria)
• Late
• Delayed haemolytic reactions (red cells)
• Post-transfusion purpura (platelets)
• Graft versus host disease

Non-Immunological Complications

• Bacterial
• Viral transmission

Question 15

Describe Acute Transfusion Reactions

If problems develop what should you do?

What are some differentil diagnoses?

Answer 15

If problems develop:

1) Stop transfusion
2) Maintain line with salinne
3) Seek advice

Differential diagnosis?

• Bacterial sepsis
• Immediate haemolytic transfusion reaction
• ANaphylaxis
• Circulatory overload
• Febrile non haemolytic transfusion reactions

Question 16

Describe Bacterial Sepsis and Transfusion- one of the causes of major reaction during transfusion

Answer 16

• A rare but serious complication of transfusion associated with contamination of the blood component with a bacteria capable of producing endotoxin

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• Classically presents as sudden onset of hypotensive shock occurring within minutes of starting a transfusion
• Unrecognised will likely lead toserious morbidity or death
• Bacterial contamination of red cell components is very rare because few bacteria can grow at 4 degrees Celsius
• Bacterial contamination of platelet components is more common since bacteria will commonly grow at 22 degrees Celsius
  
  • Platelet components now routinely cultured to reduce this risk

Question 17

Describe the Immediate Haemolytic Transfusion Reaction

Answer 17

Red cells are transfused and is immediately destroyed by antibodies present in the recipient’s serum.

The majority of immediate intravascular haemolytic reactions are due to ABO incompatibility and relate to human error.

• ln this type of reaction, the antibody is capable of activating complement cascade.
• Many complications of the reaction arise as a consequence of the effector ability of the activated compliment cascade. It includes:
• Microvascular bleeding brought about by disseminated intravascular coagulation.
• Vasoconstriction leading to renal failure and ischaemic problems

Treatment is essentially supportive in nature with fluids to maintain blood pressure and an adequate urine output.

This is one of the most severe types of transfusion reaction and is probably the most frequent cause of death following transfusion. Significant morbidity is common, 10% of cases are fatal, usually preventable.

Symptoms and signs may occur as soon as the transfusion commences.

• Symptoms include fever and rigors, restlessness, retrosternal or loin pain, (local pain at infusion site).
• Signs include increased temperature, hypotension, uncontrolled bleeding, (pallor and sweating).

Question 18

What are the symptoms of Immediate Haemolytic Reaction?

Answer 18

• Symptoms include
  
  • fever and rigors,
  • restlessness,
  • retrosternal or loin pain, (local pain at infusion site).
• Signs include
  
  • increased temperature,
  • hypotension,
  • uncontrolled bleeding, (pallor and sweating).

Question 19

Describe the Extravascular Haemolytic Reactions

Answer 19

Extravascular haemolytic reactions are due to lgG antibodies in patient plasma (Rh antibodies, Kell, Kidd Duffy, etc.) and may also occur simultaneously with transfusion.

Complement activation usually does not occur, may be activated but does not extend beyond C3 (early phase).

Clinically : Symptoms and signs of extravascular haemolysis may be indistinguishable from acute intravascular haemolysis, particularly so in the early stages. The basic principle of management is ‘if in doubt stop the transfusion, maintain the IV access and seek advice’.

Question 20

Describe the Delayed Haemolytic Transfusion Reaction

Answer 20

Delayed Haemolytic Transfusion Reactions (Late Immunological)

These reactions occur 7-10 days post transfusion. Potentially avoidable.

• Patient normally presents with a falling haemoglobin and slight jaundice.
• Transfusion of red cells results in an amanestic (memory) antibody response with r_apid production of antibody._
• Sensitisation by previous transfusion or pregnancy
• Antibody not detectable during pre-transfusion testing

Red cell destruction is extravascular in nature.

Question 21

Describe the Febrile Non Haemolytic Transfusion Reactions

Answer 21

Febrile non haemolytic transfusion reactions occur r_elatively common_ in multiply transfused patients.

• It is most commonly caused by antibodies directed against donor leukocytes and HLA antigens.*
• This is in contrast to transfusion-associated acute lung injury, in which the donor plasma has antibodies directed against the recipient HLA antigens, mediating the characteristic lung damage.
• Alternatively, FNHTR can be mediated by pre-formed cytokines in the donor plasma as a consequence of white blood cell breakdown.*

Occur most frequently in association with platelet transfusion but also with red cell components

• During or shortly following the transfusion, the patient will develop a fever (>38 ) often associated with rigors. (usually no major danger)
• Clinically, often i_ndistinguishable from immediate haemolytic reaction._
• FNHTR occur in response to cytokines and other biological response modifiers that accumulate in blood components during storage.
  
  • Occur because of presence of antibodies to HLA antigens present within the recipient’s serum.
• Frequency has reduced with the introduction of pre-storage leucodepletion (lack of white cells)
  
  • Febrile non-haemolytic reactions most frequently occur in patients with anti-HLA antibodies.
  • HLA antibodies may be produced by exposure to white cells either associated with transfusion of red cells or pregnancy.

lf a patient develops a fever during transfusion, management include:

• Stop transfusion
• Maintain line
• Investigate
• Take blood cultures
• Medication (paracetomol, antihistamine, hydrocortisone)

Question 22

lf a patient develops a fever during transfusion, management include:

Answer 22

• Stop transfusion
• Maintain line
• Investigate
• Take blood cultures
• Medication (paracetomol, antihistamine, hydrocortisone

Question 23

Describe Transfusion related Acute Lung Injury

Answer 23

TRALI is characterised by acute respiratory distress and non-cardiogenic lung oedema developing during of within 6 hours of transfusion.

The diagnosis of TRALI is a clinical and radiographic diagnosis. It is increasingly recognised as an important cause of morbidity and mortality associated with transfusion.

• It involves transfusion of donor plasma components containing white cell antibodies (HLA or neutrophil specific antibodies) (requires donor antibody to recognize HLA or neutrophil specific antigen in recipient).
• The transfused antibodies cause white cell agglutinatio_n and sequestration of recipient neutrophils in pulmonary vasculature leading to an a_cute respiratory distress syndrome.

Blood services aims to reduce the risk by:

• Manufacturing plasma components (e.g. fresh frozen plasma) only from male donors who have not been previously transfused. These donors will not have been exposed to foreign white cell associated antigens and so _will not have white cell antibodies presen_t in their blood.
• Screening platelet pheresis donors for HLA antibodies

Question 24

Describe Transfusion Associated Circulatory Overload

Who is at risk of circulatory overload?

Answer 24

• The patient’s underlying cardiovascular function is a major determinant of risk for volume overload from transfusion
• Patients at risk of circulatory overload include:
  • Those with compromised cardiovascular function
  • Those in a volume overload state
    
    • Renal failure
    • Congestive cardiac failure
  • High transfusion volumes compared to the patient’s intravascular volume (e.g. elderly patients and small children)

Question 25

Describe the Allergic Reactions to transfusion

Answer 25

Allergic Reactions to Plasma Proteins (Early Immunological)

Allergic reactions are the most frequent immunological complication of transfusion. These reactions are due to _antibodies to protein_s.

Usually involve reactions to plasma proteins

There are two types of reactions, anaphylaxis and urticarial.

• Anaphylaxis/anaphylactoid is rare.
  
  • It has early onset severe reaction
  • Present with hypotension, dyspnoea, abdominal cramps
  • Classically occurs in an IgA deficient individual who has anti-IgA antibodies
• Urticarial (rash) is common
  
  • Present with severe itching
  • Controlled by slow transfusion and administer anti-histamine