haematology Flashcards
types of haematologists
benign
blood transfusion
malignant
haemostasis + thrombosis
definition of anaemia
haemoglobin conc below normal range
male <125g/l
female <115g/l
due to either low red cell mass or increased plasma volume (preg)
symptoms of anaemia
fatigue reduced exercise tolerance SOB post hypotension dizziness angina palps hf - SOB, peripheral oedema
signs of anaemia
pallor + conjunctiva tachycardic heart murmurs koilonychia - iron deficiency angular stomatitis glosssitis - B12/folate
classes of anaemia
microcytic - iron deficient, thalassaemia, anaemia of chronic disease, sideroblastic
macrocytic - vit B12 deficient, folate deficient, without anaemia = liver disease, hypothyroid,
normocytic - acute bleeding, haemolysis, chronic disease, haemolytic anaemia, primary marrow problem, pregnancy, renal failure
myelodysplasia
found in elderly
what doses of oral ferrous sulphate would you prescribe for iron deficient anaemia
200mg OD
BNF says TDS but recently been found OD works just as good but with less s/e
most common preventable error with blood transfusions
incorrect blood product
- most couldve been prevented with the final identification check
what antibodies would someone produce if they had type 0 blood
anti-A
anti-B
what antibodies would someone produce if they had type AB blood
none
what antibodies would someone produce if they had type B blood
anti-A
what antibodies would someone produce if they had type A blood
anti-B
what happens if you transfuse the wrong blood to someone
triggers massive immune response leading to shock and DIC
Individuals may die from circulatory collapse, severe bleeding or renal failure, often within minutes or hours.
which blood type can be safely given to anyone and why
blood group O
as there are no A or B antigens for the recipient’s antibodies to react with
what antigen do people who are rhesus positive create
D-antigen
talk through the steps in the decision to transfuse
- is the patient at risk of transfusion associated circulatory overload - low body weight, >70, pre-existing conditions eg cardiac/renal failure
- use of single unit recommended in non bleeding adult
- signed consent isnt a legal requirement in UK and Ireland - but patient should be informed in a timely manner for indication/risks/benefits
- record of this discussion documented in notes
- The patient should have the opportunity to raise any concerns and discuss alternative therapies, e.g. oral iron therapy (BSH 2017) have stated that a record of the administration of each blood component is essential (i.e., reason for transfusion, number of units prescribed and outcome)
what needs to be included to reach the minimum patient identification data set when requesting blood
full name dob unique identifier eg NHS number adress gender middle name
what information is required to request blood in someone who cannot be identified
the assigned unique hospital identification number e.g. ED number / Major Incident Number and gender are required as a minimum
who is responsible for checking for previous transfusion history/ specific requirements?
the person making the request
what information is needed when requesting a pre-transfusion test or blood component
minimum patient identification data set
the reason for the request, the pre-transfusion test or number and type of component required, urgency of request, location of patient, blood group antibodies (if known), previous transfusion history and/or transfusion in the past three months, any special requirements, the date and time required
what specific blood should be requested for neonates up to 28 days post expected date of delivery
cytomegalovirus negative blood
what specific blood should be requested for patients who are immunocompromised and why
irradiated blood
Is used to destroy any T lymphocytes remaining in the blood donation, which may cause graft-versus-host disease in vulnerable patients. If an immunocompromised patient receives blood components that are not irradiated, the donors T cells can cause tissue and organ damage leading to death.
worried about potassium overload - what blood should be requested
blood of specified age
For example, blood of less than 5/7/10 days is required because of concerns of the potassium content in older units.
what blood is used for transfusion in children
paedipacks
One adult unit divided between 4 - 8 aliquots. Several aliquots are allocated to one child to allow sequential transfusions from the same donor, reducing donor exposure.
what is the difference between the group and save and crossmatch tests
group and save
- is the sample processing that determines the patient blood group (ABO and RhD) and screens for any atypical antibodies.
The process takes around 40 minutes and no blood is issued
crossmatch
- is the final step of pretransfusion compatibility testing, to request blood from the laboratory.
Crossmatching involves physically mixing of patient’s blood with the donor’s blood, in order to see if any immune reaction occurs
After ensuring that donnor blood is compatible, the donor blood is issued and can be transfused to the patient.
This process takes around 40 minutes, in addition to the 40 minutes required to G&S the blood.
what blood do you prescribe in an emergency setting when not knowing the patients blood type
type O D negative
how long can a pre-transfusion testing sample be used for repeat cross-matching purposes
7 days
sampling procedure for pre-transfusion testing
1 - identify patient
2 - complete minimum indentification requiements on blood form
3- Take the blood sample and immediately after hand-write on the tube unless using a computer prepared label generated by an electronic bar-coding system. If electronic systems are used the bar-coded label must be printed at the bedside from the patients ID band. Re-check that the details on the sample tube and request form match before putting them in the transport bag
who is responsible for ensuring that the patient identification details on the sample tube and request form match when taking for blood transfusion
the person taking the sample
what must be included on the sample tube when taking blood for transfusion
date
time
signature
blood availability - timescales
OD negative - emergency immediate 5 mins
group compatible blood - 10-15 mins
fully crossmatched blood - 30-40 mins (maybe hours if antibody found)
if someone has no history of transfusions what may also be required as a pre-transfusion test?
a secondary confirmatory blood group sample - as long as it doesn’t impede on delivery of urgent blood components
red cells storage
- time
- temp
- if removed
35 days
2-6 degrees
alarmed fridge
transfused within 4 hours of removal from fridge
if removed and not transfused sent back to lab with the length of time it was out to see if it can be reused
platelets storage
- time
- temp
- if removed
20-24 degrees
not in fridge as they aggregate
5-7days
if removed and not used returned to lab
FFP + cryoprecipitate
- time
- temp
- if removed
-25 degrees
- 3 years
transfused as soon as possible
if unused return to lab
collection steps before transfusion
ensure patient has identification band in situ
check minimum patient identification data set
ensure informed consent
IV access?
pre-tranfusion obs taken within 60 mins of the transfusion
only collect one unit at a time
only pass over the blood to the person who requested it
Clinical staff are required to check the correct component is received upon delivery, and to sign and time receipt.
what do you need to do if you use group O cells in an emergency
inform the lab so they can replace it
blood transfusion bedside checklist
- blood integrity eg no clots, leaks, damage, discoloration, expirary etc
- informed consent documented
- positive patient identification
- check unit tag against unit label, prescription, patient ID band and PPID
- perform obs - temp, pulse, resp, bp
what venous access is required for transfusions
central line normally
when using this the blood should be warmed through a blood warming device
venous access for blood transfusions big no no’s or do do’s
must be a CE-marked tranfusion set with an integral mesh filter to remove microaggregates
do not prime with 0.9 saline
do not administer meds or other IV fluids through the access for the tranfusion as there is a risk of incompatibility (e.g. dextrose & calcium containing solutions can cause haemolysis or lead to clotting of the transfusion components
the administration set should be changed every 12 hours
never use the same admin set for platelets as red cells as will cause aggregation
administration of blood components steps
- full patient identification data set with patient and on the laboratory generated label attached to the blood component against the patient’s identity band
- check the laboratory generated label attached to the blood component against the label affixed to the unit to ensure all the following is the same:
- donation number
- patients blood group
- component type
methods for patient identification for transfusion best practise points
NO WRISTBAND NO TRANSFUSION
in the unconscious/compromised patient (e.g. neonates or paediatric practice or confused patients) it is imperative that greater vigilance should be taken to identify these patients,
unidentified patients in A&E should use unique identification number and gender
documenting a transfusion
sign the transfusion documentation
record the donation number
complete traceability documentation
treatment of choice for emergency reversal of warfarin
prothrombin comples concentrate
signs and symptoms of a transfusion reaction
patients should be transfused in an area where they can observed
- advise pt on signs symps to look out for
- stop transfusion immediately following any sign
- check the blood component against the wrist band
- antipyretic or antihistamine may be required
can you restart a transfusion if they have only had mild reaction to the first component?
yes after 30 mins if the patient has responded to symptomatic treatment
management of a severe transfusion reaction?
- stop transfusion
- check compatibility of unit
- assess patient - ABCDE
-Replace the administration set and preserve IV access with normal saline to maintain systolic BP
Check urine for signs of haemoglobinuria
Commence appropriate treatment
Maintain airway and give high flow Oxygen.
If appropriate administer adrenaline and/or diuretic and resuscitate if/as required.
Reassess patient and treat appropriately - Seek expert advice if patient’s condition continues to deteriorate
document it as adverse event
delayed haemolytic transfusion reaction
-what is it?
signs/symps
rare
usually seen in patients who have developed red cell antibodies in the past from transfusion or pregnancy. A combination of the features occurs days after the transfusion, suggesting that the red cells are being destroyed abnormally quickly
signs/sympts
- fever
- falling haemoglobin or a rise less than expected
- jaundice
- haemoglobinuria
what should be measured 15 mintues after starting a transfusion
temp
bp
hr
rr
alternatives to a donor blood transfusion
sometimes can have autologous transfusion - recycling your own blood
allogenic - drug therapies eg oral or IV iron, erythropoietin and tranexamic acid
when should you crossmatch blood?
only when a transfusion is likely to be required
what is the universal donor for plasma?
group AB
has no anti-A or anti-B antibodies in it
what percent of the population are rhesus positive or resus neg
85% rhesus pos
15% neg
how much blood can someone donate in blood per year
470mLs of whole blood three times a year
what is a bag of red blood cells?
red cells in additive solution - contains up to 20 mLs of plasma
leucocyte-depleted
haematocrit typically 0.55
stored for up to 5 weeks at 4 degrees +/- 2 degrees
can be irradiated +/or CMV neg
when would you prescribe transfusion of red cells?
improve oxygenation to tissues by increasing circulating red cell mass
main indications =
- bleeding
- anaemia
- haemoglobin disorders
- loss of 30-40% volume
- if hb is below 70g/L in fit pt
- if below 80-90 g/L in pt with CVS
transfusing red cells will give a rise of haemoglobin to what ratio?
for 4mL/kg of red cells = rise of 10g/L of Hb
this works for people with body weights of 70-80kg if very low then use smaller volumes
define apheresis donation
a single donor
pooled donation
whole blood derived - 4 donations
adult therapeutic dose
one pack
one adult therapeutic dose of platelets should increase the platelet count by what?
20x10(9)/L
when will platelets be tranfused?
to prevent bleeding not stop it
when platelet count drops below 10x10(9)
for example in:
- Reversible bone marrow failure including allogeneic stem cell transplant and critical illness
- Chronic bone marrow failure if patient is receiving intensive treatment or to prevent persistent bleeding
- to prevent bleeding prior to a procedure
- thrombocytopenia
dont have to cross match but preferre
do you need to match the group when tranfusing fresh frozen plasma
yes as a first choice
fine tho as long as its ‘low-titre’ and another group
when is fresh frozen plasma given?
inherited coagulation factor deficiency where no suitable factor concentrate is available, e.g. Factor V deficiency
Acute disseminated intravascular coagulation (with evidence of bleeding)
Thrombotic thrombocytopenic purpura (TTP)
Major haemorrhage*
Prophylaxis before surgery (or another invasive procedure) if abnormal coagulation test results AND one or more additional risk factors for bleeding:
i) Personal or family history of abnormal bleeding
ii) Procedure associated with major blood loss
iii) Procedure involves critical tissues such as eye, brain or spinal cord
iv) Concurrent thrombocytopenia.
dose of fresh frozen plasma for:
- prophylaxis for surgical or invasive procedure
- major haemorrhage
- proph - 15ml/kg
- major - 15-20ml/kg
when should FFP not be used
As a plasma expander to correct hypovolaemia.
For the reversal of warfarin anticoagulation, treatment of bleeding in this circumstance is vitamin K, with or without prothrombin complex concentrate.
To non-bleeding patients with liver disease*
To critically ill patients with prolonged PT or APPT in the absence of bleeding.
For patients with liver disease: there is no evidence that prophylactic FFP reduces the risk of bleeding from percutaneous liver biopsy or variceal haemorrhage.
how much cryoprecipitate should be used to increase fibrinogen levels by approx 1g/l in non-bleeding average-sized adult of 70kg
2 x 5-donor pools
which blood component is the most likely to cause an allergic or serious reaction
FFP
define major haemorrhage
- loss of one blood volume within a 24 hour period
- 50% blood volume loss within 3 hours
- rate of loss of 150mLs/min
Bleeding which leads to a heart rate of >110 bpm and/ or a systolic BP < 90 mm Hg is a useful indicator of major blood loss of 1000 mL or more in an adult.
commonest causes of major haemorrhage
GI haemorrhage]trauma
ruptured AA
obstetric haemorrhage
management of major haemorrhage in adults
Activate major haemorrhage protocol
Administer high flow oxygen
Insert 2 wide bore peripheral cannulae and provide fluid resuscitation.
Contact key personnel, including experts to treat bleeding cause.
Arrest bleeding and treat underlying cause as soon as possible.
Request laboratory investigations and perform Point of Care Tests where available, including blood gas analysis and viscoelastic tests (ROTEM/ TEG).
Transfuse red cells to maintain a haemoglobin level of 70-90 g/L
Administer tranexamic acid within 3 hours of onset of haemorrhage unless complicated by disseminated intravascular coagulation
Transfuse FFP empirically if estimated blood loss greater than 20% blood volume or if microvascular bleeding
Anticipate the need for additional blood components (including red cells, FFP, platelets and cryoprecipitate)
Use cell salvage where available and appropriate
When bleeding is under control additional doses of FFP should be based on results
