PERI - Blood Transfusion Flashcards
5 features of haemolytic disease of the newborn (HDN)
Rhesus Blood Groups
Sensitization Phase
Effector Phase
Treatment
Clinical Features x2
1.) Rhesus Blood Groups - D antigen is most important
- Rh+ = D antigens present, Rh- = D antigens absent
- D antibodies are produced when Rh- mothers are exposed to D antigens during pregnancy
2.) Sensitization Phase - pregnancy w/ 1st Rh+ fetus
- occurs if Rh antigens from the fetus enters the mother’s circulation during delivery/miscarriage etc.
- mother produces anti-Rh+ antibodies (IgG)
3.) Effector Phase - pregnancy w/ 2nd Rh+ fetus
- anti-Rh+ antibodies cross the placenta in T3, damaging the fetal RBCs causing haemolytic anaemia in newborn
4.) Treatment - RhoGAM (antibodies for Rh antigens)
- binds to Rh antigens in the newborn, so the mother doesn’t become sensitized (not exposed to Rh antigens)
- it is given to unsensitized Rh- women within 3 days after miscarriage or delivery of an Rh+ fetus
5.) Clinical Features
- ↑bilirubin leads to jaundice
- bilirubin can enter the the brain to cause kernicterus which can cause permanent neurological damage
4 features of the ABO system and haemolytic transfusion reactions
ABO Blood Groups
Type of Antibody
Donors and Receipients
Haemolytic Transfusion Reaction
1.) ABO Blood Groups - antigens on RBCs
- A has B antibodies whilst B has A antibodies
- AB has no antibodies, O has A and B antibodies
2.) Type of Antibody - usually all IgM
- IgM cannot cross the placenta so mixture of antigens does not cause haemolytic disease in the newborn
- IgG can be produced during a blood transfusion
3.) Donors and Recipients
- A receives A, B receives B, preventing RBC damage
- Rh- women only receive Rh- blood to prevent sensitisation
- AB+ is a universal acceptor as it can receive A, B or rhesus -ve since it has no antibodies in its circulation
- O- is a universal donor since it has no A, B or rhesus antigens so no immune reaction would occur
4.) Haemolytic Transfusion Reaction - life-threatening
- cardiovascular shock/collapse, kidney failure
Blood Tests
Group and Save
Crossmatch
1.) Group and Save
- determines the patient’s blood group (ABO and RhD)
- screens the blood for any atypical antibodies
- takes roughly 40mins and no blood is issued
- recommended if blood loss is not anticipated
2.) Crossmatch - mixes patient’s blood with donor blood to check compatibility for transfusion
- also takes 40mins in addition to G/S
- done if blood loss is anticipated and emergency situation where blood is needed straight away
Blood Products
Requesting Blood Products
Administering Blood Products
Irradiated Blood Products
Cytomegalovirus (CMV)
1.) Requesting Blood Products - procedures in place to prevent patient being given incorrect blood
- 3 points of identification e.g. name, DOB, patient no.
- label bottle and complete request form at bedside
- consent patient appropriately
2.) Administering Blood Products
- Hb <70g/L w/out bleeding or ACS need transfusion
- each unit must be prescribed individually, must reassess the patient after each unit
- rate of infusion should be 3-4 hours (from the blood leaves storage)
- observations taken before and after transfusion (15-20mins, 1hr, completion)
- only given in green or grey cannulas
3.) Irradiated Blood Products - required to reduce graft-versus-host disease in at risk populations (Immunocompromised):
- receiving blood from 1st/2nd degree family members
- intra-uterine transfusions, Hodgkin’s lymphoma
- haematopoetic stem cell (HSC) transplants, after
anti-thymocyte globulin or alemtuzumab therapy
- those receiving purine analogues as chemotherapy
4.) Cytomegalovirus (CMV) - common congenital infection causing deafness and cerebral palsy
- CMV negative blood should be given to pregnant women, intra-uterine transfusions, and neonates (up to 28days)
Types of Blood Products
Packed Red Cells
Platelets
Fresh Frozen Plasma (FFP)
Cryoprecipitate
1.) Packed Red Cells - contains RBCs
- indications: acute blood loss, chronic anaemia (<70 or <80 ACS) or symptomatic anaemia
- 1 unit increases Hb by 10g/L
- given over 2-4hrs, must be completed within 4 hrs
- new G/S is needed before future transfusions
2.) Platelets - contains platelets
- indications: thrombocytopenia (<20), bleeding w/ thrombocytopenia, haemorrhagic shock in trauma, pre-operative platelet level <50
- 1 dose ↑plt levels by 20-40, given over 30mins
3.) Fresh Frozen Plasma (FFP) - contains clotting factors
- indications: DIC, massive haemorrhage, haemorrhage secondary to liver disease
- given over 30mins
- universal donor for FFP is AB (O for RBCs)
4.) Cryoprecipitate - contains fibrinogen, vWF, factor VIII, fibronectin
- indications: DIC w/ low fibrinogen (<1), vWF disease, massive haemorrhage
- given stat (all at once)
General Complications of Blood Transfusions
Clotting Abnormalities
Electrolyte Abnormalities x2
Hypothermia
1.) Clotting Abnormalities - due to dilution effect
- packed red cells have no platelets or clotting factors
- FFP and platelets should be given to patients receiving more than 4 units of RBCs
2.) Electrolyte Abnormalities
- hypocalcaemia: chelation of Ca by calcium-binding agent in preservative –> ↓Ca2+
- hyperkalaemia: inevitable partial haemolysis of RBCs causing the release of intracellular potassium
3.) Hypothermia - drop in core body temperature
- blood products thawed from frozen and kept at cool temperatures so still cold by time of transfusion
Acute Transfusion Specific Complications
Acute Haemolytic Reaction
Transfusion Associated Circulatory Overload (TACO)
Transfusion Related Acute Lung Injury (TRALI)
Non-Haemolytic Febrile and Allergic Reactions
Others
1.) Acute Haemolytic Reaction - ABO incompatibility causing RBC destruction by IgM antibodies
- sx starts mins after transfusion: fever, urticaria, abdo and chest pain, hypotension, haematuria
- Ix: DAT/Coombs (definitive), repeat crossmatch, FBC (↓Hb), ↓haptoglobin, ↑bilirubin, ↑LDH
- Mx: stop transfusion, IV fluid resus, inform blood bank, and O2, seek specialist advice
- complications: DIC, renal failure
2.) Transfusion Associated Circulatory Overload
- sx: SOB, hypertension, afebrile, ↑JVP, S3 present
- urgent CXR, treat w/ O2 and IV furosemide
- common in those already overloaded e.g. HF, can be prescribed 20mg furosemide prophylactically
3.) Transfusion-Related Acute Lung Injury - a form of ARDS, a non-cardiogenic cause of pulmonary oedema
- antibodies against alveolar macrophages
- sx: SOB, fever, hypotension, normal JVP
- Mx: stop transfusion, urgent CXR (diffuse bilateral infiltrates), high flow O2, specialist input
- need to differentiate from TACO
4.) Non-Haemolytic Febrile and Allergic Reactions
- febrile reaction: fever or chills, slow/stop the transfusion and give paracetamol
- mild allergic reaction: itching/urticaria, temporarily stop the transfusion and treat w/ anti-histamines
5.) Others - anaphylaxis and sepsis
- anaphylaxis: stop transfusion and treat accordingly, more likely in IgA deficiency w/ anti-IgA antibodies
- septic shock: stop transfusion and treat accordingly
Delayed Transfusion Complications
Infection
Graft vs Host Disease (GvHD)
Iron Overload
1.) Infection - theoretical risk with any transfusion
- HepB/C, HIV, syphilis, malaria, vCJD
- uncommon due to screening of blood donors
2.) Graft vs Host Disease - rare but often fatal
- T lymphocytes in transfused blood attacks the host due to HLA mismatch between donor and recipient
- common in transfusion of non-irradiated blood products to an immunocompromised recipient
- can occur weeks after a transfusion
- symptoms: culture-negative fever, painful maculopapular rash, persistent N+V, watery/bloody diarrhoea, jaundice
3.) Iron Overload - repeated transfusions, affects
- multiple organs: liver (cirrhosis), pancreas (diabetes), heart (cardiomegaly), joint pain, skin(hyperpigmentation)
