Anaemias- management Flashcards
Learning outcomes
• Practical aspects of transfusion including sourcing safe blood,
screening tests, group and cross match and safe infusion
• Risks of transfusion
• Understand the use of regional and national guidelines to inform
transfusion decision making
• Understand the role of blood transfusion in the management of
anaemia
• Recognise that identification of cause is key to effective management
• Specific religious considerations for blood transfusion
Blood groups- ABO and Rhesus system
-An individuals blood group is determined by the antigens present on the surface of their RBCs- all normal individuals have antibodies to the A or B
antigens that are not presenton their own red cells.
- There are 5 main Rh antigens on red cells, for which an individual can be positive or negative : C c D E e
- RhD is the most important in clinical practice
- “O positive” = patient blood group O, positive for RhD
- “A negative” = patient blood group A, negative for RhD
- Antibodies to RhD (anti-D) are only present if:
- RhD negative patient transfused with RhD positive red cells
- RhD negative woman who has been pregnant with an RhD positive baby
Who are universal donors and who are universal recipients?
Universal Donor = Group O negative
As they have no antigens on the surface of their
red cells, their red blood cells can be given to
patients from any blood group
Universal Recipient = Group AB
As they have no antibodies to A, B or RhD in
their blood, they can receive blood cells from a
donor of any blood group
Providing safe blood- quality and regulations
Key establishments for blood establishments and hospital blood banks :
• defined in the Blood Safety and Quality Regulations (BSQR)
• enforced by the Medicines and Healthcare products Regulatory Agency (MHRA).
• Designed to ensure that appropriate standards of performance are achieved
and maintained
• Blood Establishments are required to be licensed and subject to regular inspection for compliance
• The MHRA has powers to remove licences from Blood Establishments and can issue cease and
desist orders to prevent blood banks from continuing in operation
Providing safe blood- donors
• All blood donors MUST satisfy criteria outlined in the UK Donor Selection Guidelines
(DSGs)
• These DSGs are documented in the
‘Guidelines for the Blood Transfusion Services in the United Kingdom’
• The Joint Professional Advisory committee (JPAC) of the UK Blood Transfusion
Services (BTS) is responsible for this document, and receives professional advice from
the Standing Advisory Committees that form part of its structure.
• The criteria are reviewed regularly to ensure that the blood collected is of the highest
quality
Providing safe blood- testing and screening
Blood groups and blood group antibodies
• Every donation is screened to determine the ABO and RhD group of the red cells
• Plasma is screened to detect blood group antibodies
Screening for infectious agents Mandatory tests on all donations • Hepatitis B (HBsAg) • HIV (anti-HIV 1 and anti-HIV2, HIV NAT) • Hepatitis C (anti-HCV and HCV NAT) • Human T-cell lymphotropic virus (anti-HTLV I and II) • Syphilis (syphilis antibodies) Additional tests, where indicated • Malarial antibodies • West Nile Virus antibodies • Trypanosoma cruzi antibodies
Compatibility procedures in the hospital transfusion laboratory
Group and screen • Pre transfusion blood sample from the patient • To determine the ABO and RhD group • Plasma is screened for the presence of alloantibodies capable of causing transfusion reactions • Almost all laboratories use automated analysers for this screening, with computer control of specimen identification and result allocation • reduces human error • safer than traditional manual techniques Blood units of a compatible ABO and Rh group (negative for any blood group alloantibodies detected) can then be selected
Crossmatch (traditionally)
• Serological crossmatch between patient’s
plasma and a sample of red cells from the
unit of blood selected for transfusion
Electronic issue (now used by most blood banks
for the majority of blood issues)
• AKA ‘computer crossmatching’
• Can be used if the patients antibody screen
is negative
Safe transfusion- right blood, right patient, right time, right place
1. Positive patient identification (at all stages; first name, last name, DOB, unique identification number) 2. Patient information and consent for transfusion 3. Pre-transfusion documentation 4. Prescription 5. Requesting a transfusion 6. Blood samples for pre-transfusion testing 7. Collection and delivery of blood component to the clinical area 8. Administration to the patient 9. Monitoring the patient 10. Completion of the transfusion episode
Risks of transfusion
Delayed- Delayed haemolytic reaction Transfusion associated graft versus host disease Post transfusion purpura Hyperhaemolysis
Acute- severe: Acute haemolytic reaction TRALI TACO Bacterial contamination Severe allergy/anaphylaxis Allergy associated to IgG Hypotensive reactions
Less severe-
Febrile non-haemolytic reactions
Mild allergic reactions
Acute haemolytic reaction
• Due to transfusion of ABO-incompatible red cells, which react with the patient’s antiA or anti-B antibodies
• rapid destruction of the transfused red blood cells in the circulation (intravascular haemolysis)
- release of inflammatory cytokines
patient develops
• shock
• +/- acute renal failure
• +/- disseminated intravascular coagulation (DIC)
• Transfusion of <30ml of group A red cells to a group O patient can be fatal
• ABO-incompatible transfusion occurs in around 1 in 180000 red cell units transfused,
usually as a result of human error. This should be a ‘Never Event’
TACO- transfusion associated circulatory overload
acute or worsening pulmonary oedema within 6 hours of transfusion • Features • acute respiratory distress • tachycardia • hypertension • positive fluid balance • chest x ray : pulmonary oedema, enlarged heart
- Management
- stop the transfusion
- diuretics
- oxygen
- Predisposing factors
- heart or renal failure
- low albumin
- pre-existing fluid overload
• Increased risk
• elderly patients
• small or low weight patients
(including children)
TRALI- transfusion associated lung injury
(acute pulmonary odema within 6 hours of transfusion, usually 2 hrs) • Features • Acute respiratory distress • Cough productive of pink sputum • Hypotension • Often associated with fevers and rigors • Chest x ray : bilateral nodular shadowing, normal heart size
- Management
- Supportive care
- High flow oxygen +/- ventilation
• Cause
• Antibodies in the donor blood react with
the patient’s white blood cells
(neutrophils and monocytes) or
pulmonary endothelium
• -> Inflammatory cells are sequestered in
the lungs
• -> Results in leakage of plasma into the
alveolar spaces
• -> Acute respiratory distress
Bacterial contamination and transmission of viral infections
• Rare; occurs more often with platelet components(stored at 22-24℃) than red cells (stored at2-4℃)
• Visual inspection of the component pack PRIOR to
transfusion : checking for abnormal discolouration,
aggregates, offensive smell
- Features
- In severe case : fevers, rigors, hypotension, shock
- Management
- Blood cultures, followed by broad spectrum antibiotics
Transfusion transmitted Viral infections
• Very rare in the UK
• modern donor selection criteria
• screening tests
• Small remaining risk is due to the ‘window period’
• Exists early in the course of an infection, before a detectable antibody response is present
• Reduced following the introduction of nucleic acid
testing (NAT)
Reporting incidents related to blood transfusion
• Serious adverse reactions and events must be reported to the MHRA
• In addition, blood banks and Blood Establishments are encouraged to report serious
adverse reactions and near misses to the Serious Hazards of Transfusion (SHOT)
scheme.
• Participation in the scheme is voluntary, and covers both NHS and private hospitals in the UK
and Ireland.
• Reports are made via SABRE
• SHOT collects data on serious sequelae of transfusion of blood components
• The information obtained contributes to improving the safety of the transfusion process
• Informs policy within the transfusion services
• Improves standards of hospital transfusion practice
• Aids in the production of clinical guidelines for the use of blood components
NICE blood transfusion guidelines 2015
Thresholds and targets
• Use restrictive red blood cell transfusion thresholds for patients who need red blood cell
transfusions and who do not:
• have major haemorrhage or
• have acute coronary syndrome or
• need regular blood transfusions for chronic anaemia.
• When using a restrictive red blood cell transfusion threshold, consider a threshold of
70 g/litre and a haemoglobin concentration target of 70–90 g/litre after transfusion.
• Consider a red blood cell transfusion threshold of 80 g/litre and a haemoglobin
concentration target of 80–100 g/litre after transfusion for patients with acute coronary
syndrome.
• Consider setting individual thresholds and haemoglobin concentration targets for each
patient who needs regular blood transfusions for chronic anaemia.
NICE Guideline [NG24], Blood transfusion, 2015
NICE Blood Transfusion Guidelines (2015)
• Consider single-unit red blood cell transfusions for adults (or equivalent volumes
calculated based on body weight for children or adults with low body weight)
who do not have active bleeding.
• After each single-unit red blood cell transfusion (or equivalent volumes calculated based on body weight for children or adults with low body weight), clinically
reassess and check haemoglobin levels, and give further transfusions if needed.
