Blood groups and transfusions Flashcards
What can neutrophil levels be affected by that are not pathological
ethnicity variation
What colour is AntiA (type B) blood in lab
Blue
What colour is AntiB (type A) in lab
yellow
What blood type has anti-A and anti-B antibodies
O
What blood type has neither Anti-A or AntiB anitbodies
AB 2
Anaemia investigations
HB, MCV
Ferritin, B12, folae leves
U+Es, LFTs, TFTs,
Blood film
Reticulocyte count + haemolysis screen
Trend - new or old, fall quick or slow
Why does speed of losing Hb matter
Patients may tolerate low Hb extremely well if slow over time and compensated
Rapid fall, sick quickly even if still mdertae levles
Transfusion dependent patients how differ in managing anaemia
Transfuse based on individual Hb thershold established over time
Why is transfusion carefully considered especially in women
Can make rhesus positive/some other antibodies
Triggers for RBC transfusion - stable without acute blood loss
Hb<70g/L in otherwise fit
Hb<80g/L - elderly/cardiac/resp disease
Target Hb for cirtical care patients
70-90g/L
Btter long term outcomes
Higher threshold ina cute spesis, neuro injury and ACS but dont excceed 90
Chronic anaemia Hb target eg thalassemia
Just above lowest concentration ass with no symptoms
Hb 95g/L max
Post chemo target Hb
80-90
Radiotherapy target Hb
maintain >100 g/L
What is recommended amount to transfuse adults in absence of blood loss
ONE unit of RBC at a time and reassess response Hb and clinica symtpoms
What consider in low weight adults transufsion esp <50kg
Weight based volume transfusions eg 4ml/kg
Risks of transfusion categories
Immunological
Circulatory - TACO
Infection
Immunological transfusions
Febrile - common to be mildy
Allergic
Alloimmunisation eg rhesus
Less frequent - TRALI, others
Infection risks transfusion
Bacterial
Viral - HEV
vCJD
unknown
Reactions to trasnfusion
AHTR - acute transfusion reaction
DHTR - delayed
FNHTR -febrile non haemolytic trasnfusion reactions
TACO risk factors
Already fluid overloaded
Known HF/other cardiac abnormalities
Chronic lung disease
Renal failure
Significant hypoalbuminaemia
Low body mass
Elederly
Components of blood transfusion
FFP
Cryoprecipitate
Platelets
RBC
When are platelets used
Low platelet levels
<30 for non severe bleeding
<50 if severe/life threatening
What is FFP
Plasma from single donor, replaces clotting factors and fibrinogen
Frozen - 15 mins to thaw
When use FFP
Bleeding patients lacking clotting factors
PT:APTT>1.5
Prophylactic major surgery risk of major bleed
How much FFP needs to be given
4 units - 1L (15-25ml/kg)
What is cryoprecipitate
Replace fibrinogen - more concentrated than FFP
When cryoprecipitate used
In bleeding actively
Early in major haemorrhage
Usual adult dose of Cryoprecipitate
2 pools - each of 5U
What is prothrombin complex concnetrate
Vit K dpenedent clotting factors - II, VII, IX, X, protein C+S
What is main indication for PCC use
Rapid reversal of warfarin therapy
What is patient blood management
Alternative and conservation of blood supply - optimise circulation before need haemorrhage
Patient blood amnagemnet pillars
Diagnose and manage anaemia (eg correct before surgery so blood loss doesnt affect as much)
Minimise blood loss - control bleeding eg take off anticaogs, tranexamic acid add
Avoid unnecessary transfusion
When do you test for anaemia before operation
ASA 3 or 4 before intermediate surgery
Major surgery
Intra operative strategies PBM
Intra operative cell salvage
Wash RBC -> return to patient
What is a drug to treat haemorrhage especially major/obstetric
Tranexamic acid
General PBM recommendations
Education
Restrcitive transfusion thresholds
1U then reassess
Active manage anaemia
Minimise vol of blood smaples taken
Active management of abnormal haemostasis
Empowerment of lab staff to challenge innapropriate requests
What causes an acute haemolytic transfusion reaction
ABO incompatibulity eg human error
RBC destruction by IgM
Features of AHTR
Reaction within minutes of starting transfusion
Fever, abdominal pain, hypotension
Can-> DIC, renal failure
Treatment AHTR
Stop transfusion
Confirm diagnosis
check the identity of patient/name on blood product
send blood for direct Coombs test, repeat typing and cross-matching
Supportive care
fluid resuscitation
TACO features
Excessive transfusion rate or HF -> pulm oedema, HTPTN
TACO treatment
Slow or stop transfusion
Consider IV loop diuretic eg furosemide and ozygen
TRALI features
Neutrophil activation ->
Hypoxia, pulmonary infiltrates on CXR, fever, hypotension
Within 6 hours of transfusion
TRALI treat
Stop transfusion and oxygen and supportive care
Febrile recation to transfusion what d0
Paracetamol
WBC HLA antibodies cause
