Blood transfusions Flashcards
Taking blood samples: order
- Blood cultures (aerobic, then anaerobic; due to any residual air in the needle/collection set)
- Clotting
- U+E/ biochemistry
- FBC
- Group + Save
Bleeding/anaemia history - important points
Sites.
- Traumatic bleeding/ bruising
- GI bleeding - PR bleed, melaena, haematemesis
- Gynae - menorrhagia
- Resp / ENT - haemoptysis, epistaxis
- Other bleeding
Effects.
- Syncope/ presyncope
- SOB, chest pain, palpitations
Cancer
- Weight loss, loss of appetite, fevers, night sweats, fatigue, weakness
- Site-related symptoms - diarrhoea, abdo pain, etc.
Group + save vs. cross-match
A group and save:
- Determines the patient’s ABO and Rh D group.
- Performs an antibody screen, and identifying
any atypical antibodies which may be present.
- Checks the results against any historical data
that might be available for the patient.
- Can be useful pre-surgery (in case blood may be needed)
- Requires 2 samples (1 can be historic)
A crossmatch:
- involves a serological test to ensure compatibility between a unit of blood and the patient
Prescribing blood (red cell) transfusions.
a) How should they be prescribed? (units and duration)
b) How many units required to raise Hb by 10g/L in a typical 70 kg patient? (factors affecting this)
c) What may also be prescribed?
d) Observations
e) Thresholds for prescription and treatment targets
a) - 1 unit at a time
- Given over 3 hours (no quicker)
- Subsequent units should not be prescribed until the first unit has been started (but sometimes are in practice)
b) 1 unit = approx. 10 g/L rise
- smaller patients will have a larger rise
- larger patients will have a smaller rise
c) - Definitive treatment - e.g. ferritin, IV iron
d) - Before
- During
- After
e) Restrictive (most patients, asymptomatic)
- Treat when < 70
- Target 70 - 90 g/L
For symptomatic patients, or those with major haemorrhage, or acute coronary syndrome, or needing regular transfusions for chronic anaemia:
- Treat when < 80
- Target 80 - 100 g/L
Types of transfusion reaction
- signs/symptoms of each
Anaphylaxis
- Acute onset of life-threatening airway, and/or breathing, and/or circulatory dysfunction
- Stridor, hypoxaemia
- Wheeze, SOB
- Hypotension, tachycardia
- Angio-oedema
- Pruritis, rash
Infection/ sepsis
- Fever, tachycardia, rigors, etc.
Haemolytic reaction (ABO incompatibility, Rhesus reactions)
- Back/loin/chest pain
- Feeling of impending doom
- Signs of intravascular haemolysis (dark urine, pain at cannula site) TRALI is now rare. In TRALI the JVP is not raised and hypotension is more suggestive than hypertension (which is more often seen with TACO)
Transfusion-associated lung injury (TRALI)
- Acute SOB, hypoxaemia, etc.
Transfusion-associated circulatory overload (TACO)
- Acute SOB, hypoxaemia, etc.
- Fluid overload - peripheral oedema, raised JVP, etc.
- HYPERtension, tachycardia
TACO.
a) Diagnostic criteria
b) Risk factors
c) vs. TRALI
d) Management
a) At least 3 or 4 of the following occurring within 6h of transfusion:
- acute respiratory distress
- tachycardia
- increased blood pressure (BP)
- acute or worsening pulmonary oedema
- evidence of a positive fluid balance
b) - Old age
- Causes of fluid overload: cardiac failure, renal failure, hypoalbuminaemia, etc.
- Low body weight
- Too rapid transfusion
c) - TACO - cardiogenic fluid overload and pulmonary oedema
- TRALI - non-cardiogenic pulmonary oedema (JVP not raised and usually HYPOtensive)
d) - Stop transfusion immediately
- ABCDE assessment and senior review
- Oxygen therapy
- Diuretics
- Critical care support - may require NIV/ invasive ventilation
Classification of anaemia.
1) MCV:
Microcytic
- IDA
- Thalassaemia
Normocytic
- Chronic disease
- Acute haemorrhage
Macrocytic
- B12 / folate deficiency
- Alcoholism / liver disease
- Hypothyroid
2) Reactive or aplastic:
- Reticulocytes low - aplastic (reduced production)
- Reticulocytes high - reactive (compensatory increase in production)
During the second unit being transfused, your patient becomes increasingly agitated, tachycardic, hypertensive and breathless.
Her respiratory rate increases from 22 breaths per min to 35. Her oxygen saturations are 90% on air.
a) Likely diagnosis
b) Management
c) What signs and symptoms are permissible (do not necessitate stopping the transfusion)?
a) Acute transfusion reaction (e.g. TACO, TRALI)
(Note: acute reactions like this can occur during transfusion but also up to 24h following a transfusion.)
b) - Stop the transfusion
- Request an urgent medical review
- Oxygen
- Critical care support - may require invasive mechanical ventilation or NIV
- Diuretics (if TACO, not if TRALI)
c) - Isolated temperature of 38–39°C or rise 1–2°C
- Pruritis or rash (without other signs of anaphylaxis)
Reporting transfusion reactions
Clinical team report to:
- Transfusion team
- Patient (duty of candour)
Transfusion team report to:
- SHOT (Serious Hazards of Transfusion), and
- SABRE (Serious Adverse Blood Reactions and Events)
Investigating anaemia.
a) Bedside
b) Bloods
c) Imaging
d) Special tests
a) - A-E and vital signs
- Postural hypotension / POTS
- Fluid balance
b) - FBC
- Haematinics - ferritin, etc.
- U+Es - uraemia in UGIB, AKI, etc.
- Clotting
- B12/ folate
- ?G+S and cross-match
- ?coeliacscreen
- ?myeloma screen
- ?other cancers - e.g. CA-125
c) - May not require routine imaging
- ?CXR - if SOB, chest pain etc.
- ?CT - ?malignancy
d) - Urgent colonoscopy (if fit criteria)
- Urgent OGD (if fit criteria)
- ?stool tests - FIT (if no frank blood), calprotectin, etc.
- ?Haematological tests
Major haemorrhage protocol.
a) Definition of major haemorrhage
b) Pragmatic definition based on BP and HR
c) Management
a) Major haemorrhage is variously defined as:
- Loss of more than one blood volume within 24 hours (around 70 mL/kg, >5 litres in a 70 kg adult)
- 50% of total blood volume lost in less than 3 hours
- Bleeding in excess of 150 mL/minute
b) A pragmatic clinically based definition is bleeding which leads to:
- Systolic BP < 90 mmHg, or
- HR > 110 beats per minute
