• Ordering Platelets
• Platelet Product Description and Storage
• Platelet Product Selection
  • Product and Dose?
  • Blood Group?
• Special Platelet Products and How to Access Them
  • Platelets for Fetomaternal Alloimmunisation
  • Platelets for HLA immunised refractory patients
• Platelet Administration
• Adverse Effects of Platelet Transfusion
• Clinical Information and Indications
  • Guidelines for platelet transfusion in children
    • Platelet transfusion in children with malignant disease
    • Platelet transfusion in Stem Cell Transplantation
    • Platelet transfusion in children with congenital platelet disorders
    • Platelet transfusion in defects of platelet production
    • Platelet transfusion in immune thrombocytopenia
    • Platelet transfusion in cardiopulmonary bypass and ECMO
  • Guidelines for platelet transfusion in neonates
    • Fetomaternal Alloimmune Thrombocytopenia (FMAIT)
    • Congenital infections
    • Neonates of mothers with immune thombocytopenia (ITP)
    • Intrauterine platelet transfusion
  • Platelet transfusion in pregnancy

Ordering Platelets

RCH

Order platelets by phoning the RCH blood bank (x55829). 

When ordering platelets for multiple patients the RCH Oncology Unit may order by fax (RCH blood bank Fax 9345 5817).  Fax order template

Platelets will be supplied from the RCH Blood Bank Inventory if available or will be ordered from ARCBS.

Information required at time of platelet order:

RWH

Order platelets by phoning the RWH blood bank (x2036)

Platelets will be ordered from ARCBS and the clinical area will be notified when the product is available.

Information required at time of platelet order;

Platelet Product Description and Storage

A variety of platelet products are produced by ARCBS in Victoria.

PLATELETS Apheresis Paediatric Leucocyte Depleted  (split into 4 or 8 parts)
These platelets are collected from a single donor via apheresis and are suspended in plasma.
Volume: 40-60mL (actual volume is specified on the label)
Platelet Count: >60 x 10⁹/unit
White Cell Count: < 1.0 x 10⁶/unit
These platelets are suitable for neonatal and paediatric use (see table for appropriate dose)

PLATELETS POOLED in T-Sol Leucocyte Depleted
Platelets are prepared from a number of whole blood donations (4-5) and then pooled, leucocyte depleted and suspended in platelet additive solution (PAS: T-Sol, Baxter) with approximately 30% residual plasma.
Volume: >160mL (actual volume is specified on the label)
Platelet Count: >240 x 10⁹/pool
White Cell Count: < 1.0 x 10⁶/pool
These platelets are suitable for adults and paediatric patients > 40kg.

PLATELETS Apheresis Leucocyte Depleted
PLATELETS Apheresis Leucocyte Depleted (Split into 2 parts)
These platelets are collected from a single donor via apheresis and are suspended in plasma.
Volume: >100 (actual volume is specified on the label)
Platelet Count: >240 x 10⁹/unit
White Cell Count: < 1.0 x 10⁶/unit
These platelets are suitable for adults and paediatric patients > 40kg.

All platelets produced in Victoria are;

• Irradiated to prevent Ta-GVHD
• Leucocyte depleted 

Important Note:

In times of product shortage, platelets may be sourced from interstate and may not be leucocyte depleted. It is therefore imperative to read the label on every product.  
 

Storage and Shelf Life

Platelets are stored at 20-24⁰C on a platelet agitator for a period of 5 days from collection. (Do not refrigerate).

Platelet expiry is at midnight on the date specified on the platelet pack.

Platelet Product Selection

Product and Dose?

¹ For neonates give as a dose of 5-10ml/kg
For infants 5-10 kg, transfuse the contents of the pack

• If a platelet pack suitable for an infant or small child is not available, and platelet transfusion is required, transfuse using PLATELETS APHERESIS or PLATELETS POOLED at a dose of 5-10 ml/kg given over 2-3 hours.

• In some patients, limiting donor exposure to prevent alloimmunisation is vitally important eg severe aplastic anaemia. In these patients, an apheresis product should be selected when it is available, rather than a pooled product or multiple individual products

Blood Group?

Principles

• ABO and Rh(D) identical platelet transfusion is ideal, but not always available.
• Platelets collected from Rh(D) positive donors should be avoided for Rh(D) negative, non-immunosuppressed recipients. The small number of contaminating red cells may be sufficient to cause Rhesus immunisation. If transfusion of RhD positive product to RhD negative recipient is unavoidable, consider giving Rhesus immunoglobulin (Discuss with haematologist-on-call)
• Avoid incompatible plasma. Transfusing platelets from group O donors to group A, B or AB recipients may result in haemolysis (from anti-A and anti-B in group O plasma). Children and infants are more at risk than adults due to their small blood volume. If ABO incompatible transfusion is unavoidable, the use of pooled platelets in additive solution (T-Sol) may reduce the risk of haemolysis.

Special Platelet Products and How to Access Them

Platelets for Fetomaternal Alloimmunisation 

The infant or fetus with confirmed or suspected alloimmune thrombocytopenia should be transfused platelets which are negative for the implicated alloantigen. Platelets negative for the HPA-1a antigen (implicated in 85% of cases of FMAIT in Caucasian populations) are often available from ARCBS but may be sourced from interstate. Contact the haematologist-on-call for advice regarding platelet support in this clinical situation.

Platelets for HLA immunised refractory patients

When patients fail to achieve a significant and sustained rise in the platelet count following platelet transfusion (platelet increment) they are said to be 'refractory'. There are clinical and immunological causes of platelet refractoriness. Clinical causes include fever, sepsis, bleeding, DIC and some drugs. In these situations, patients may respond to more frequent platelet transfusions or higher doses of platelets. Patients undergoing stem cell transplantation, who are multiply transfused, or who have had prior pregnancy may become refractory to platelet transfusion due to the development of multispecific HLA or platelet-specific antibodies. These patients may require platelet support from HLA (Human Leucocyte Antigen) or HPA (Human Platelet Antigen) matched donors. 

Tests Required to diagnose immunological platelet refractoriness

HLA Typing

HLA/HPA Antibodies

Ordering Matched Platelets for Refractory Patients

If HLA or HPA matched apheresis platelets are required, please contact the RCH Blood Bank, ph 55829.

Platelet Administration

The patient should be ready for transfusion prior to picking up platelets from the blood bank. eg appropriate IV access, written order for transfusion. A Blood Bank Release Order is required for all products to be picked up from the blood bank, refer to issue of blood products from the blood bank.

Administer via Standard 170-260 micron filter either in-line or on transfer to syringe.

Suitable products include:

• RCH McGaw in-line blood filter IV set
• RCH Tuta Blood/Solution Administration Pump Set
• RWH Braun Sangofix
• RWH Gemini Blood Set REF 2477-0000 
• RCH and RWH Baxter Neonatal Set 

Use a fresh administration set for platelets. Do not transfuse though a standard filter straight after red cells as platelets will get caught up in fibrin strands /debris etc.

All platelet products issued from Red Cross Victoria are leucocyte depleted as indicated on the product label.

As for all blood products adhere to pre-transfusion check and care and monitoring of transfused patients, refer to Blood Administration.

Rate: Platelet transfusion must be completed within 4 hours of spiking pack. Occasionally platelets are given over 30 minutes, but this may contribute to an increased risk of some reactions (fever/chill) and fluid overload.

In patients receiving multiple other fluids etc give at a rate of 3ml/kg/hr over 2-3 hours.

Adverse Effects of Platelet Transfusion

See section on adverse effects of transfusion.

Platelet products are collected from volunteer donors screened with standard screening tests and have the same risks of infectious disease transmission as red cell products.

Some adverse reactions may occur more commonly with platelet transfusion.
These include:

Clinical Information and Indications for Platelet Transfusion

Guidelines for Platelet Transfusion in children 
(see text for details)

Platelet transfusion in children with malignant disease

Children with leukaemia are the largest single group of patients receiving platelet transfusions. Platelet transfusion is used therapeutically in patients with bleeding and significant thrombocytopenia.

Prophylactic platelet transfusion is not routinely used during induction therapy for Acute Lymphoblastic Leukaemia or for solid tumours (with the exception of brain tumours) unless patients are symptomatic, there is active bleeding, an invasive procedure or additional risks such as fever.

Prophylactic platelet transfusion during induction chemotherapy for Acute Myeloid Leukaemia using a threshold of 10 x 10⁹/L and during the pre engraftment phase of stem cell transplantation using a threshold of 20 x 10⁹/L is widely practised.

A number of studies show that bleeding is more likely to arise in disease-induced than therapy-induced thrombocytopenia, and the presence of additional risk factors such as sepsis, drugs that impair platelet function, abnormal haemostasis or invasive procedures increase the risk of bleeding and a higher threshold is recommended. A platelet count above 30-50 x 10⁹/L is generally acceptable for lumbar puncture, above 50 x 10⁹/Lfor minor surgery and above 80-100 x 10⁹/L for major surgery such as neurosurgery.

Platelet Transfusion in Stem Cell Transplantation

In the absence of evidence-based guidelines for children, the following clinical circumstances represent acceptable indications for platelet transfusion in stem cell recipients.

Prophylactic platelet transfusion during the pre engraftment phase of stem cell transplantation using a threshold of 20 x 10⁹/L.

A higher threshold may be used in the presence of bleeding, severe mucositis, coagulopathy or concurrent anticoagulation.

ABO incompatibility between the patient and stem cell donor may be major, minor or both. In major incompatibility, the recipient has antibodies to the stem cell donor's red cells (eg group A donor and group O recipient); in minor incompatibility the stem cell preparation from the donor has antibodies to recipient red cells (eg anti-A in group O donor and group A recipient); in both major and minor incompatibility, the recipients plasma contains antibodies to the donor's cells and the donor plasma contains antibodies to the recipient's cells (eg group B recipient and group A donor).

Platelets for Stem Cell Recipients

Where possible, a platelet product compatible with both donor and recipient should be used. At RCH the platelet product choice for each transplant recipient will be specified by their transplant physician and will be listed the Transplant Protocol. 

Platelet transfusion in children with congenital platelet disorders

There are several inherited platelet disorders that occasionally require platelet transfusions. Platelet transfusion has been shown to be of benefit in Bernard-Soulier syndrome and Glanzmann's thrombasthenia to cover surgery or a bleeding episode. Platelet transfusion can provoke the development of multi-specific HLA or platelet specific antibodies and they should be used sparingly. Donor exposure should be limited through the use of apheresis platelets and the risk of alloimmunisation reduced through the use of leukocyte reduced products.

Platelet transfusion in defects of platelet production

There are many rare causes of defects in platelet production such as thrombocytopenia with absent radii (TAR), Wiskott-Aldrich syndrome, Fanconi anaemia, amegakaryocytic thrombocytopenia. Platelet transfusion should be used sparingly and reserved for clinical bleeding or invasive procedures since many patients with these conditions will require stem cell transplantation.

Platelet transfusion in immune thrombocytopenia

Transfused platelets are rapidly destroyed and should be reserved for cases of life-threatening bleeding.

Platelet transfusion in cardiopulmonary bypass and ECMO

Platelet transfusion may be warranted in the patient with unexplained excessive bleeding undergoing cardiopulmonary bypass. Patients undergoing ECMO are usually transfused to maintain a platelet count > 100 x 10⁹/L.

Guidelines for Platelet Transfusion in Neonates

Thrombocytopenia is the most common haemostatic abnormality in sick newborn infants. The immature coagulation system in neonates contributes to an increased bleeding risk. Platelet transfusions are indicated for the support of selected neonates with clinically significant quantitative or qualitative platelet disorders. Consideration should be given to the cause and natural history of the thrombocytopenia, as this may alter the type of platelet product given.

In the only reported randomised controlled study of platelet transfusion in preterm infants, Andrew et. al. found no benefit (defined as the reduction of significant haemorrhage) in babies where moderate thrombocytopenia (50-150 x 10⁹/L) was prevented by platelet transfusion compared to control babies.

Guidelines for platelet transfusion in the neonate acknowledge the lack of evidence on which to make recommendations and aim for a safe approach. Experience from allo-immune thrombocytopenia indicates that in a well term neonate, the risk of significant haemorrhage as a result of thrombocytopenia is unlikely at counts above 30 x 10⁹/L, however for preterm infants, despite the lack of evidence, a higher threshold of 50 x 10⁹/L is recommended.

Fetomaternal Alloimmune Thrombocytopenia (FMAIT)

FMAIT is a serious disease capable of causing significant morbidity or mortality from haemorrhage in-utero or during the perinatal period. Intracerebral haemorrhage (ICH) secondary to severe thrombocytopenia has been reported as early as 18 weeks gestation. The level of thrombocytopenia which places the fetus at risk is not known, but ICH has rarely been reported in neonates with platelet counts greater than 30 x 10⁹/L. Weekly or fortnightly platelet transfusion given in-utero have been used to reduce the risk of ICH, however others recommend maternal IVIG to raise the fetal platelet count. Appropriate antigen-negative platelets should be available to be given to a fetus undergoing any invasive procedure such as cordocentesis.

For the neonate with FMAIT, platelet transfusion is the treatment of choice and should be given to normalise the platelet count in an infant with ICH or to treat severe throbmobocytopaenia in infants without ICH. Platelets used for neonates with FMAIT should be negative for the implicated platelet-specific antigen. Maternal platelets which have been plasma-reduced and irradiated are sometimes used.

Congenital infections

Neonates born with CMV infection, rubella, toxoplasmosis, syphilis or herpes simplex may have suppression of thrombopoiesis and/or splenomegaly with shortened platelet survival. Mild to moderate thrombocytopenia may be present. This usually does not require platelet support.

Neonates of mothers with immune thrombocytopenia (ITP)

Neonatal thrombocytopenia may be associated with past or current maternal ITP. The majority of infants are only mildly affected and the thrombocytopenia resolves spontaneously Severe thrombocytopenia is reported to occur in a approximately 4% of neonates and the incidence of ICH is extremely low. Intravenous immunoglobulin and steroids are the treatments of choice where the thrombocytopenia is severe or bleeding is present.

Intrauterine platelet transfusion

Intrauterine transfusion (IUT) of platelets is used to correct fetal thrombocytopenia caused by platelet alloimmunisation. IUT of platelets is used to correct fetal thrombocytopenia and reduce the risk of cord haemorrhage during fetal blood sampling procedures and is used as therapy to prevent intracerebral or other major haemorrhage in some cases of alloimmune thrombocytopenia. IUT is used to maintain an acceptable fetal platelet count while enabling the pregnancy to advance to a gestational age where the risks of prematurity are less than the risks of ongoing pregnancy, and with as few invasive procedures as possible. IUT is associated with a risk of fetal loss estimated at approximately 1%.

Platelet Transfusion in pregnancy

Thrombocytopenia is not uncommon during pregnancy, and the majority of women with mild to moderate thrombocytopenia do not require platelet transfusion. Platelet transfusion is virtually never required for gestational thrombocytopenia, and rarely required in ITP. The most common clinical situations requiring platelet support in pregnancy include; thrombocytopenia occurring in the setting of major post partum haemorrhage, DIC or placental abruption, or in the setting of severe pre-eclampsia or HELLP (Haemolysis, Elevated liver enzymes and Low Platelets) Syndrome.

Pregnant women who are CMV negative or CMV status unknown should receive CMV seronegative platelets (if not available check the platelet pack label to ensure it has been leucocyte depleted).