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blood_transfusion

blood product transfusions

Jehovah's Witnesses

  • early involvement of the hospital's Haematology team should be sought if likely to need blood products
  • most carry a Medical Directive that clearly states the person’s view on the non-use of blood products
    • BUT the existence of a medical directive does not automatically mean the patient carrying it will refuse treatment.
    • clinicians have an obligation to be satisfied that the patient is fully informed prior to the patient making a decision to refuse treatment
    • inability to consent:
      • if the patient is unconscious or not competent to make an informed decision the staff should make every effort to notify next of kin or other representatives to discuss treatment options
      • only an agent under the Medical Treatment Act or a guardian under the Guardianship and Administration Act can refuse medical treatment
      • other persons responsible can merely withhold consent to treatment, they cannot refuse treatment
    • Jehovah’s Witnesses have set up a number of Hospital Liaison Committees with representatives who are available to advise or assist in individual cases - there is a 24hr emergency contact number
    • refusal should be documented as per hospital's Refusal of Treatment procedure
    • children:
      • Section 24 of the Human Tissue Act 1982 enacts that a medical practitioner who gives a child a blood transfusion against the express wishes of the parent is not committing a criminal offence.
      • the blood transfusion must be treatment for a condition the child has and without the transfusion the child is likely to die.
    • where there is a dispute or disagreement, contact the Office of the Public Advocate
  • most will usually NOT accept:
    • whole blood transfusions
    • transfusion of major blood components - red blood cells, platelets, plasma and white blood cells
    • preoperative autologous blood collection and storage for later re-infusion
  • on an individual basis, may accept:
    • blood fractions such as albumin, clotting factors, etc
    • autotransfusion (intra/postop blood salvage & re-infusion)
    • heart bypass –when primed with non-blood products
    • haemofiltration/haemodilution
    • haemodialysis -when no blood prime is used
    • renal dialysis
  • see the following documents distributed by JW in 2019 to assist doctors in management to avoid transfusions:

indications for RBC transfusion in patients

  • consider:
    • signs and symptoms of hypoxia
    • ongoing blood loss
    • risk to the patient of the anaemia
    • risk to the patient of the transfusion
    • level of anaemia:
      • Hb < 70 g/L (although if asymptomatic and specific therapy available may consider no transfusion)
      • Hb 70-100 g/L AND EITHER:
        • likely to have blood loss in surgery, or,
        • signs or symptoms of impaired oxygen transport, or
        • anaemia-related symptoms in a patient on a chronic transfusion regime, or,
        • during marrow suppressive therapy
      • NB. Hb > 100 g/L unlikely to need blood transfusion unless significant acute blood loss

usage of RBCs

  • complete transfusion bag within 4 hours of commencement of that bag
  • 1 unit of RBCs ~240ml and will raise Hb level in an adult by ~10g/L (paediatric unit is ~50ml)
  • NB. see your hospital's policy and procedure for the administration of blood products - the following is only a guide!
  • administer through a new IV blood giving set incorporating a 170-200 micron filter (large particle filter which only removes aggregates and other large particles)
  • usually give over 2-4hrs but faster if acute bleeding
  • start transfusion within 30 minutes of removing blood from fridge, otherwise, return blood to fridge
  • use a blood warmer if massive transfusion
  • transfuse one unit at a time
  • avoid transfusing overnight unless an emergency
  • check patient vital signs (pulse rate, respiration rate, blood pressure and temperature) at the start of transfusion AND at least after 15 minutes, at the end of the transfusion
  • special requirements:
    • irradiated RBC's:
      • to reduce Transfusion Associated Graft-Versus Host Disease (TA-GVHD) thus examples of when to use irradiated RBCs are:
        • infants under 3 months age
        • patients treated with ECMO or LVAD
        • immunocompromised patients (eg. transplant recipients, malignancies, haem/onc patients)
        • intrauterine and exchange transfusions
        • directed donations
      • timing of irradiation is important for neonatal and paediatric patients.
      • irradiation reduces the storage-life of red cells and whole blood
        • Packs irradiated within 14 days of collection expire 28 days after collection.
        • Packs irradiated more than 14 days after collection expire either 5 days after irradiation OR at original expiry of pack, whichever comes first.
      • in patients where hyperkalaemia is a concern, red cells should be transfused within 24 hours of irradiation eg:
        • Examples include large volume neonatal transfusion such as exchange transfusion, ECMO or rapid large volume transfusion
    • renal patients
      • consider washed RBCs (less electrolytes)
    • CMV neg

indications for fresh frozen plasma (FFP)

usage of FFP

  • standard bag of FFP = 300ml; paediatric bag = 74ml; cryo depleted > 160ml; apheresis > 500ml
  • dose: 10-20ml/kg given as fast as tolerated and within 4 hours of commencement of infusion.

indications for platelet transfusion

  • bone marrow failure:
    • no risk factors ⇒ administer if platelet count less than or equal to 10×109/L
    • risk factors such as fever, antibiotics, etc ⇒ administer if platelet count less than or equal to 20×109/L
  • surgery in patients with thrombocytopenia:
    • aim to maintain platelets > 50×109/L
    • high risk of bleeding surgery (eg. neuro/ocular), aim to maintain platelet count > 100×109/L
    • maybe appropriate in other patients with thrombocytopenia
  • platelet function disorders:
    • administer based on clinical features as platelet count unreliable marker
  • massive blood transfusion or haemorrhage:
    • patients whose bleeding is caused by thrombocytopenia
    • may be appropriate when platelet count < 50×109/L (< 100×109/L if diffuse micro vascular bleeding)

usage of platelets

  • most platelets arrive as a single pooled unit suspended in T-sol and reduced plasma
  • DO NOT refrigerate - platelets are stored for up to five days at 20 - 24°C with gentle agitation on a platelet shaker.
  • volume: pooled > 160ml; apheresis 100-400ml; apheresis paeds 40-60ml
  • give 1 bag as fast as is tolerated (but not faster than 5mls/minute for first 15 minutes unless acute bleeding) and complete within 4 hours of start

indications for cryoprecipitate

  • fibrinogen deficiency with clinical bleeding AND EITHER:
    • invasive procedure, or
    • trauma, or,
    • DIC

usage of cryoprecipitate

  • standard bag 10-40ml; apheresis 60ml;

blood / RBC transfusion reactions

immediate:

immediate simple febrile reactions:
  • most often due to presence of WBC Abs formed by recipient as a result of previous transfusions or pregnancies, (rarely now due to Gram -ve endotoxin in blood or apparatus) usually not severe & last only few hrs;
  • occur in 3-4% of blood transfusions
  • Always Ix as fever is sign of haemolytic reactions as well!
  • Rx: panadol;
allergic reactions:
  • Urticaria usually due to sensitising Abs in recipient reacting with exogenous Ag such as milk or egg protein in donor serum - esp. if recipient atopic. Rx antihistamine;
  • Generalised anaphylaxis rare (1 in 20,000 units transfused) due to this cause;
  • Immediate HS reactions may be severe due to donor proteins such as IgA which recipient either lacks or has different IgA subclass.
  • In addition, allergic reactions may occur if donor has Hx of striking HS & thus has much Ab, therefore of recipient comes in contact with that Ag, a HS reaction may occur but only via donor Ab (ie. passive transfer of a HS state).
haemolytic reactions:
  • occur in 1 in 40,000 units transfused and result in death in 1 in 100,000 units transfused
  • intravascular haemolysis:
    • Usually due to rapid destruction of donor RBCs - usually due to incompatible ABO gps mainly result from labelling errors rather than technical error in failing to detect incompat.
    • Soon after Tx begins → heat/pain along transfused vein → facial flushing, rigors, fever, severe loin pains, constriction feeling in chest, hypotension/shock/death may follow;If severe, Hbaemia, Hburia, decr. [haptoglobin], methaemalbuminaemia appears; DIC;
    • Jaundice may take several hrs to develop;
    • Oliguria due to intense renal vasoconstriction & acute renal failure may develop;
  • extravascular haemolysis in MP system (esp. spleen):
    • Usually due to other blood gp incompatibilities (Rh, etc) & is slower & less dramatic with milder symptoms although Hbaemia may occur to same degree but renal failure/death rare.
    • May also result from faulty storage of blood (freezing or heating), over-long storage or bacterial contamination;
circulatory overload:
  • XS or too rapid administration may → CCF/APO esp. heart dis/severe anaemia;
  • Thus if susceptible then limit to 2 units packed cells/24hrs each unit <4hrs Tx time;
  • Consider exchange transfusion or intraperitoneal (irradiated) Tx if severe anaemia;
bacterial contamination:
  • Esp. Pseudomonas & coliforms (cold-growing Gram -ves);
  • After brief latent period, → profound shock, fever, abdo. pain → death in hrs!
  • Thus don't use blood kept @ room temp > 4hrs;
biochemical derangements in massive transfusions:
  • hyperkalaemia esp. old cells or irradiated cells, or if renal impairment & potentiated by citrate induced hypocalcaemia;
  • increased ammonia levels ⇒ hepatic encephalopathy;
  • increased citrate
    • ⇒ coagulopathy (may also be due to dilutional effect as blood has coag. defects)
    • ⇒metabolic alkalosis and hypokalaemia if large volume of citrated cells
  • hypothermia; XS 2,3 DPG → shifts Hb-O2 curve;
  • coagulopathy due to dilutional effect and lack of platelets and clotting factors in packed red cells
air embolism:
  • May tolerate 200ml air but 40ml can have serious results (see elsewhere);
  • may be caused by transfusing any plasma-containing blood product
  • it is caused by the interaction between the recipient's leukocytes and preexisting donor antileukocyte antibodies
  • this results in complement activation and increased pulmonary vascular permeability
  • complicates 0.1-0.2% of all transfusions

delayed reactions:

sensitisation:
  • Foreign Ags on donor cells, IgA, etc may → prod. of alloAbs which may complicate future transfusions or pregnancies;
delayed haemolytic transfusion reactions:
  • In pts. sensitised by previous preg/Tx, alloAb titre may be undetectable & thus apparent compatible blood when transfused may restimulate Ab production → sudden destruction of donor cells usually within 3-7 days → jaundice or failure of Hb to rise as expected or falls;
  • May then find the irregular Ab when re-Xmatch or if Direct Coombs test pts blood;
donor blood-borne infection:
  • EB virus
  • CMV probably the most common;
  • Hep A/B/C/D/E
    • ⇒ screen all for HBsAg as 50% will develop hepatitis if +ve;
    • risk of hep C is ~1 per 3000-4000 units transfused
    • risk of hep B is ~1 per 50,000 units transfused
  • HIV screened blood risk ~1 per 150,000 units transfused
  • Malaria
  • Syphilis now rare as survives poorly in storage & many recipients on penicillin;
  • Brucellosis
  • Toxoplasma
  • Filariasis
  • Trypanosoma
  • Kala-azar
multiple microemboli:
  • Significant pulmonary microemboli may occur in seriously ill pts due to aggregated platelets/WBCs as well as other particulate matter in Tx such as particles of:
    • rubber bungs, glass, cellulose fibres;
toxic substances in plastic leached out from plastic bag/tubing by blood:
  • Phthalate plasticisers, although toxic in minnows - unknown human effects;
transfusional haemosiderosis:
  • Repeated Tx over many yrs for chronic anaemias such as aplastic, may result in Fe overload;
thrombophlebitis:
  • esp. if: > 12hrs Tx (different units though)
  • rubber tubing not plastic;
  • adminis. autoclave glucose soln → decr. pH, esp. if post-Tx → ?lyse RBCs;
  • indwelling catheters > 8hrs;
graft-vs-host reaction (TA-GVHD):
  • now reduced to 0.15% of transfusions due to improved preventive measures
  • TA-GVHD occurs when donor lymphocytes from transfused blood engraft in the recipient and cause disease.
  • typically TA-GVHD occurs 10-14 days post transfusion with clinical features of fever, skin rash, hepatitis, diarrhoea and pancytopenia.
  • it is fatal in more than 90% of cases.
  • at risk patients:
    • immuno-compromised
    • receiving transfusion from a relative (directed donation)
    • reported rarely in patients with a 'normal' immune system.
  • prevent by giving irradiated cells to at risk patients (leukocyte depletion using current technology is inadequate for this purpose)

references and other resources

blood_transfusion.txt · Last modified: 2019/10/18 02:53 by wh