Platelet Usage in Clinical Practice

1
Platelet Usage inClinical Practice
Dr Mahes de Silva Clinical Director
Diagnostics National Blood Service England
2
BCSH Guidelines - Indications

• Platelet transfusion is NOT indicated for all
  thrombocytopenic patients.
• Indications prophylactic, therapeutic
• Contraindications
• Side effects

3
Prophylactic

• Prophylactic platelet transfusions reduce
  morbidity and improves patients quality of life
  but there is no evidence that it reduces
  mortality
• Bone Marrow failure (disease, chemo,
  irradiation)- stable patient lt5x109/l- fever,
  sepsis, antibiotics lt10x109/l- pre-op generally
  50x109/l, CNS/eye 100x109/l

4
Therapeutic

• Therapeutic platelet transfusions used to
  arrest bleeding and reduces both morbidity and
  mortality
• Bone Marrow failure- Plt lt 20x109/l
• Massive transfusion- Plt lt50x109/l (usually gt2
  vol blood loss)
• lt100x109/l if multiple trauma /CNS pathology

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Therapeutic contd.

• Acute DIC with bleeding if platelet count
  lt50x109/l
• Platelet disorders prior to surgical procedures
  or if bleeding continues in spite of-
  withdrawing anti platelet drugs, e.g. aspirin,
  NSAIDS- correction of cause e.g. DIC-
  correction of hct to gt 0.30 (transfuse rbc or
  EPO)- correction of storage pool disease with
  DDAVP- treating uraemia with DDAVP/cryo

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Therapeutic contd.

• Cardiopulmonary by pass- stop aspirin/NSAIDs
  prior to elective procedure - consider using
  aprotinin for emergency procedures- give
  platelets if there is microvascular bleeding
  (due to platelet dysfunction or
  thrombocytopenia) or for continuing overt
  bleeding and surgical causes excluded
• Liver transplantation- thromboelastogram useful
  to guide decision to give platelets

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Therapeutic contd.

• Autoimmune thrombocytopenia (ITP)- only for life
  threatening/CNS haemorrhages
• Post Transfusion Purpura (PTP)- only for life
  threatening bleeds
• NAIT- HPA 1a/5b neg. plts- immediate response,
  95 success
• - IVIG - response takes 24-48 hrs, 75
  success - random plts immediate response, 70
  success
• In all cases post-tx plt counts must be
  monitored
• If typed platelets unavailable, give random
  platelets and if response poor, give IVIG

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Contraindications for Platelet Transfusions

• Heparin induced thrombocytopenia (HIT)
• Thrombotic thrombocytopenic purpura (TTP)

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Side-effects/hazards of Platelet tx

• PLASMA 200ml in each adult dose- ABO and other
  antibodies HTR- plasma proteins
  allergic reactions, anaphylaxis- passive tx of
  HLA/granulocyte antibodies TRALI
• LEUCOCYTESHLA antibody formation - non
  haemolytic febrile reactions -
  refractoriness to platelet transfusions

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Side-effects/hazards of Platelet tx contd.

• PLATELETS (HLA HPA antigens)- HLA antibody
  stimulation- NHFTR- Refractoriness to tx- HPA
  immunisation, antibody stimulation rarely
  refractoriness and even more rarely, in
  females, NAIT

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Leucodepletion

• UK specification
• a minimum of 99 components should have lt5x106
  leucocytes with 95 confidence and more than 90
  of components, should contain 1x106 leucocytes.
• leucocyte depleted components can re-stimulate
  pre-existing HLA antibodies in previously
  immunised pregnant or transfused patients leading
  to refractoriness
• primary sensitisation can occur but rare

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2005 NBS Audit of Platelet Usage

• 21 Hospitals
• Period of study - 4 weeks, adult patients only
• Data collected Age of patient Specialty
  Whether prophylactic or therapeutic
  Pre-transfusion platelet count No. of adult
  doses requested and given

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Usage by 21 Hospitals
Regional Use of Platelets
300
250
200
Number of Platelets
units requested
150
units used
100
50
0
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
Hospital
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Usage by Age
Platelet Use by Age
600
500
400
Number of Platelets
units requested
300
units used
200
100
0
by age lt
16-lt40
40-lt65
65
age n/a
16,
Age
15
Prophylactic vs Therapeutic
Prophylactic vs Therapeutic Use
1000
800
600
units requested
Number of Platelets
units used
400
200
0
Prophylaxis
Bleeding
Unknown
Use
16
Prophylactic Use vs Platelet Count
Prophylactic Use vs Platelet Count
700
600
500
units requested
400
Number of Platelets
300
units used
200
100
0
Platelets lt 10
Platelets gt 10
Platelet count
UK
Platelet Count
17
Prophylactic Use When Platelet Count gt 10
Prophylactic Use When Platelet Count gt10
180
160
140
120
Number of Platelets
units requested
100
80
units used
60
40
20
0
PCX
BMF
BMS
BMT
MDS
OTHER
MDS/SUR
PCX/BMT
BMF/MDS
SURGERY
MDS/PCS
NOT KNOWN
Clinical Summary
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Therapeutic use
Therapeutic Use by Platelet Count
160
140
120
100
units requested
Number of Platelets
80
units used
60
40
20
0
Platelets lt 50
Platelets gt 50
Unknown
Platelet Count
19
Units Used
20
Audit Conclusion

• patients 65 years over use most platelets
• 60 platelets prescribed by haematologists
• 75 platelets used for prophylaxis 73 had
  gt10x109 /L
• near patient testing will provide more accurate
  platelet count in bleeding patients
• hospital HTCs should monitor platelet usage
  regularly

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Blood donation and processing by the NBS is
highly regulated Blood usage by hospitals
still unregulated !