Blood Products and Transfusion Flashcards
Indications for Blood Transfusion - Example Question
A 68-year-old patient is referred to the on-call medical team by their General Practitioner (GP) when they are found to have low Haemoglobin (Hb) on a routine set of blood tests taken for fatigue. The results, repeated in hospital, are as follows:
Hb 72 g/l
MCV 69 fl
Platelets 351 * 109/l
Film comment Microcytic hypochromic red cells with pencil cells and target cells
You assess the patient and they give no history suggestive of bleeding. On examination, they are haemodynamically stable with no melaena. Which of the following would be the strongest indication for transfusion in this patient?
> A history of exertional angina A history of myocardial infarction treated with angioplasty A history of exertional dyspnoea A history of worsening fatigue A history of myelodysplastic syndrome
Symptomatic anaemia should be treated unless there is a contraindication.
Fatigue and exertional dyspnoea are ‘soft’ symptoms that should not cause the clinician to rush into transfusion.
The data regarding blood transfusion in ischaemic heart disease are mixed. The current Cochrane consensus is that there is no good evidence to support a liberal (<10g/L) versus restrictive (<7-8g/L) transfusion strategy in any patient cohort, including those with pre-existing ischaemic heart disease. Therefore a history of MI with no current symptoms would not be an indication for transfusion in this patient.
Patients with myelodysplastic syndrome may tolerate low haemoglobin levels well, and moreover are at risk of iron overload from repeated transfusions, and therefore generally would not be transfused at this level in the absence of symptoms.
Exertional chest pain implies cardiac ischaemia, i.e. inadequate oxygen delivery to cardiac tissue, and therefore the patient would benefit from transfusion in this case.
Blood Products: Packed Red Cells
Used for transfusion in chronic anaemia and cases where infusion of large volumes of fluid may result in cardiovascular compromise. Product obtained by centrifugation of whole blood.
Blood Products: Platelet Rich Plasma
Usually administered to patients who are thrombocytopaenic and are bleeding or require surgery. It is obtained by low speed centrifugation.
Blood Products: Platelet Concentrate
Prepared by high speed centrifugation and administered to patients with thrombocytopaenia.
Blood Products: Fresh Frozen Plasma
Fresh frozen plasma
Prepared from single units of blood.
Contains clotting factors, albumin and immunoglobulin.
Unit is usually 200 to 250ml.
Usually used in correcting clotting deficiencies in patients with hepatic synthetic failure who are due to undergo surgery.
Usual dose is 12-15ml/Kg-1.
It should not be used as first line therapy for hypovolaemia.
Blood Products: Cryoprecipitate
Formed from supernatant of FFP.
Rich source of Factor VIII and fibrinogen.
Allows large concentration of factor VIII to be administered in small volume.
Blood Products: SAG-Mannitol Blood
Removal of all plasma from a blood unit and substitution with:
Sodium chloride
Adenine
Anhydrous glucose
Mannitol
Up to 4 units of SAG M Blood may be administered. Thereafter whole blood is preferred. After 8 units, clotting factors and platelets should be considered.
Cell Saver Devices
Cell saver devices
These collect patients own blood lost during surgery and then re-infuse it. There are two main types:
Those which wash the blood cells prior to re-infusion. These are more expensive to purchase and more complicated to operate. However, they reduce the risk of re-infusing contaminated blood back into the patient.
Those which do not wash the blood prior to re-infusion.
Their main advantage is that they avoid the use of infusion of blood from donors into patients and this may reduce risk of blood borne infection. It may be acceptable to Jehovah’s witnesses. It is contraindicated in malignant disease for risk of facilitating disease dissemination.
Blood products used in Warfarin Reversal
Blood products used in warfarin reversal
In some surgical patients the use of warfarin can pose specific problems and may require the use of specialised blood products
Immediate or urgent surgery in patients taking warfarin(1) (2):
- Stop warfarin
- Vitamin K (reversal within 4-24 hours)
- IV takes 4-6h to work (at least 5mg)
- Oral can take 24 hours to be clinically effective - Fresh frozen plasma
Used less commonly now as 1st line warfarin reversal
-30ml/kg-1
-Need to give at least 1L fluid in 70kg person (therefore not appropriate in fluid overload)
-Need blood group
-Only use if human prothrombin complex is not available - Human Prothrombin Complex (reversal within 1 hour)
- Bereplex 50 u/kg
- Rapid action but factor 6 short half life, therefore give with vitamin K
‘Reversal’ of NOAC: Example Question
A 64-year-old man referred by the emergency department has fluctuating confusion and a severe headache of 4-hour duration. His only past history is a deep vein thrombosis 3 months ago for which he takes rivaroxaban 20mg OD.
On examination, he is orientated to person but cannot recall the time or where he is. There is no evidence of head injury. Temperature is 36.5 degrees, pulse 90 bpm, blood pressure 149/80 mmHg. A brief examination of the peripheral nervous system elicits no abnormal signs and his pupils are size 3 and equal.
An urgent CT head shows blood in the ventricular system.
What is the best immediate management to limit the bleeding?
Vitamin K 10mg IV Pooled platelets > Prothrombin complex concentrate (PCC) Haemofiltration Fresh frozen plasma (FFP) 15mls/kg
The new oral anticoagulants (NOACs) unlike warfarin have as yet no single reversal agent or readily available method of monitoring the clinical effect. Recommendations from the company summary of product characteristics can aid the management of severe bleeding associated with the use of NOACs.
The likely diagnosis here is an intracerebral haemorrhage resulting in depression of GCS, which is a severe or life-threatening bleeding complication of the rivaroxaban.
In addition to haemodynamic support and blood transfusion when necessary, it is recommended to stop the rivaroxaban, consider tranexamic acid, consider prothrombin complex concentrate in conjunction with a consultant haematologist Haemodialysis may be used in the presence of renal failure. Activated charcoal may be useful if a history of recent ingestion is given. Haemodialysis, however, is minimally effective due to the high proportion of rivaroxaban bound to plasma proteins.
Blood Product Transfusion Complications
Blood product transfusion complications
Complications haemolytic: immediate or delayed febrile reactions transmission of viruses, bacteria, parasites, vCJD hyperkalaemia iron overload ARDS clotting abnormalities
Blood Transfusion Cx:
Immediate Haemolytic Reaction
Immediate haemolytic reaction
e.g. ABO mismatch
massive intravascular haemolysis
Blood Transfusion Cx:
Febrile Reactions
Febrile reactions
due to white blood cell HLA antibodies
often the result of sensitization by previous pregnancies or transfusions
Blood Transfusion Cx:
Immunosuppression
Causes a degree of immunosuppression
e.g. patients with colorectal cancer who have blood transfusions have a worse outcome than those who do not
Blood Transfusion Cx:
Transmission of vCJD
Transmission of vCJD
although the absolute risk is very small, vCJD may be transmitted via blood transfusion
a number of steps have been taken to minimise this risk, including:
→ from late 1999 onward, all donations have undergone removal of white cells (leucodepletion) in order to reduce any vCJD infectivity present
→from 1999, plasma derivatives have been fractionated from imported plasma rather than being sourced from UK donors. Fresh Frozen Plasma (FFP) used for children and certain groups of adults needing frequent transfusions is also imported
→ from 2004 onward, recipients of blood components have been excluded from donating blood
