Overview of blood transfusion Flashcards
name the 3 labels on a unit of red cells?
Donation No. and barcode
14 character no. finishes with a letter
component label
tells dr what is in the bag
ABO label
tall and thin down the RHS
gives blood group of donor and expiry date
How does the anticoagulant used on donor blood work?
-what does this mean in terms of donation?
Citrate based, Citrate chelates Ca, needed at various point for coagulation
-the anticoagulant needs to be present in the correct ratios and so 465ml should be taken
What tests must be done on blood from donors to ensure it is safe for recipients in terms of:
- infective risk
- Risk of disease transmission
- what specific tests are done?
- bacterial, viral, protozoal
- malignancy, neurological conditions of uncertain aetiology
-HIV 1+2 antibody/PCR HCV antibody/PCR HBV antibody/PCR Syphilis antibody HTLV I+II antibody HEV antibody
How are the following components stored:
- Red cells
- Platelets
- Fresh Frozen plasma
-stored at 4+/- 2 deg
shelf life 35 days
cannot be removed from storage for longer than 30 mins
must be transfused within 4 hours of leaving controlled storage
-stored at 22 deg with continua agitation
shelf life of 7 days
transfuse within i hr once removed
-stored at -30 deg for up to 3 years
thawed prior to transfusion, transfuse within 4 hours
give the main blood groups (2)
-name the antigens involved and the possible blood groups
-ABO
Rh (D)
-A antigen, B antigen
Group A- membranes have antigen A
Group B- membranes have antigen B
Group AB- membranes have both A and B antigens
Group O- membranes do not carry A or B antigens
ABO inheritance of blood groups
- chromosome involved?
- dominance?
-chromosome 9
-A and B are co dominant over O
so genotype AO= phenotype A
Rh(D) inheritance
- chromosome involved?
- give the 2 alleles involved in this grouping, the possible genotypes and phenotypes
-chromosome 1
-D and d DD- Rh(D) pos Dd- Rh(D) pos dd- Rh(D) neg D codes for the Rh(D) protein, d does not code for anything
Describe the process of obtaining a sample for cross matching?
- Obtain blood sample from patient (check name and DOB and confirm with wristband, write details on tube beside bed)- accurate ID is critical
- Complete request form:
patient ID, location, indication for transfusion
time required, number of units required,
previous transfusion history, your name (legible)
and contact number - Send sample and form to the transfusion lab
(if outwith normal hours, contact the MLSO) - Prepare patient for transfusion
why might a patient have irregular red cell antibodies?
develop after previous exposure to red cells
e.g. due to prev transfusion or pregnancy
commonest e.g. Anti- D
What is an indirect Coombs test?
A test that detects the presence of irregular antibody against RBCs in the patient’s plasma
Describe the role of the doctor in the transfusion process?
-role of nurses?
- Prescribe red cells, no. units and special requirements, rate of transfusion, accompanying medication
- ensure patient has established IV access
- record the indications for transfusion in the case notes
- blood should be completely transfused within 4 hours after leaving the fridge*
- They check the bag itself, to make sure there is no damage or leakage, and the contents of the bag, to ensure there are no bubbles (possible bacterial contamination), clots (insufficient anticoagulant or possible bacterial contamination) and that there does not appear to be any red cell haemolysis, also check date
-check the name and DOB of the patient against the compatibility label on the bag
record a patients pre-transfusion obs
observe for the first 5 minutes to ensure no immediate adverse reactions
what are the 2 main indications for red cell transfusion?
Anaemia & Acute blood loss
Anaemia low Hb + reduced exercise capacity coincidental medical/surgical probs heart or lung disease anaemic symptoms
Acute blood loss
if more than 50% of blood volume
degree of tachycardia
vasoconstriction
Protection of brain, heart, adrenal cortex
pulmonary hyperventilation fluid shift ECF to IV space
renal conservation of Na+ and H2O
Acute blood loss
-describe the approach the acute blood loss
- Arrest Bleeding
- Gain IV access
- samples for cross matching and other tests
- Restore and maintain blood vol (N saline, albumin gelofusine)
- ABO and Rh(D), Ab screen and cross match
- aim to maintain normal pulse rate, BP, consciousness, urine output
Indications for a platelet transfusion (overall)?
Low platelet count Patient age Symptoms of bleeding direction of change of platelet count Platelet kinetics Underlying infection/fever concomitant anaemia concomitant drugs recovery from surgery congenital platelet functional defects acquired platelet functional defects
low platelets count itself not enough, need to consider the clinical circumstances
Fresh frozen plasma
-indications?
-bleeding /surgery in liver disease with impaired coagulation
coagulopathy following massive transfusion (evidenced by abnormal lab results)
DIC- coagulation factors to try and maintain haemostasis
