Blood and Blood Products

Transfusion of blood and blood products is often required in pediatric practice where common illnesses are related to blood destruction and blood loss. This is even more important in neonatal intensive care units.

Definitions

• BLOOD: The fluid and suspended elements that are circulated through blood vessels by which oxygen, nutritive materials, and metabolic waste products are transported within the body.
• BLOOD PRODUCTS: Any therapeutic substance prepared from human blood through physical and/or chemical means.
• TRANSFUSION: Transfer of blood or blood components from one individual to another.
• Blood Component:
• The fractions of blood separable by physical measures.
• Plasma Derivative:
• Fractions of blood separable by chemical measures.

• Transfusion of a specific component needed by the patient.
• Advantages include:
• Several patients use a single donor's blood.
• Reduces blood shortage in the hospital.
• Reduces antigen load.
• Reduces volume load.

Blood Components:

1. Red cell concentrates
2. Platelet concentrates
3. Granulocyte concentrates
4. Fresh frozen plasma
5. Cryoprecipitate

Plasma Derivatives:

Plasma proteins prepared from large pools of human plasma under pharmaceutical manufacturing conditions.

• Albumin
• Coagulation factors
• Immunoglobulins

Red Cell Concentrate

• Contains separated sedimented RBCs
• Essential in correction of anemia due specifically to red-cell loss when blood volume is maintained.

Platelet Concentrate

• Contains platelets separated from platelet-rich plasma.
• Used to correct coagulation problems due to thrombocytopenia.

Fresh Frozen Plasma

• Fresh frozen plasma contains I, II, V, VII, IX and X, albumin and globulin.
• Used in deficiency states of specific coagulation factors.

Cryoprecipitate

• Cyoprecipitate contains F I, F VIII, F XIII, VWF.

Albumin

• Derived from large pools of human plasma.
• A globular protein synthesized in the liver that contributes majorly to colloid-oncotic pressure, binds endogenous and exogenous molecules and mediates coagulation.
• It is 40% extravascular and 60% intravascular with a half-life of approximately 8 days.
• Administered via transfusion of plasma products or infusion of human serum albumin (HSA).

1. Blood transfusion should be instituted only when it is absolutely indicated because there is no zero risk transfusion.
2. Only the blood component that is needed should be given.

1. Autologous
2. Allogeneic

• Autologous Transfusion:
• Donated by the intended recipient
• The principal methods of autologous transfusion are:
• Preoperative blood donation (PREDEPOSIT)
• Acute pre-operative normovolaemic haemodilution
• Intraoperative blood salvage
• Allogeneic (Homologous) Transfusion:
• Transfer of blood from a donor to a recipient

Whole Blood Transfusion

• Loss of Red Cell and Plasma in large volume:
• Rapidly bleeding patients
• RTA
• DIC

Absolute Contraindication to Whole Blood Transfusion:

• Severe Chronic Anaemia:
• Reduced red cell volume
• Compensatory increase in plasma volume
• Whole blood adds unneeded plasma to blood
• Volume overload
• Hypoxic myocardium
• Pulmonary edema and death.

Criteria for Donors Selection:

1. On voluntary basis.
2. Informed Consent.
3. Age: healthy persons 16-65 years. Donors < 18 years require parental consent to donate blood.
4. Weight: whole blood donors ≥ 50kg
5. Donation interval: not less than 3 months
6. General Health: establish and document that the prospective donor is in good health, using standard questionnaire.
7. Haemoglobin concentration: ≥ 13.5g/dl for males and 12.5g/dl for females.

Preparation of Blood Components

The preparation of blood components involves specific centrifugation processes:

• During the first centrifugation at 1500rpm for 10 mins:
• Red cell concentrate settles as a sediment.
• Platelet-rich plasma (PRP) forms as the supernatant.
• A plasma extractor is employed to carefully transfer the PRP into the second bag.
• Subsequently, a second centrifugation is conducted at 5000rpm for 20 mins:
• Platelet concentrate collects as sediment.
• Platelet-poor plasma is left as the supernatant.
• Fresh plasma is then transferred into the third bag for use.

Preparation of Platelet Concentrate

Solutions for Storage Of Whole Blood:

• ACD: Acid, Citrate, and Dextrose
  Shelf life: 21 days
• CPD: Citrate, Phosphate, and Dextrose
  Shelf life: 28 days
• CPD-A: Citrate, Phosphate, Dextrose, and Adenine
  Shelf life: 35 days

CPD-A is the solution in current use for storage of blood (63mls, Ratio 1:7, meaning for every 1 part of CPD-A, 7 parts of blood are mixed):

• Citrate: An anticoagulant
• Phosphate: An ATP metabolite
• Dextrose: Supplies energy
• Adenine: An ATP metabolite

Red Cell Preservation:

Optimal additive plasma replacement solution e.g. Saline-adenine-glucose-mannitol (SAGM), Storage life is 35 – 42 days

Frozen Red Cells:

Glycerol is added before freezing. Used for storing red cells of rare blood groups.

Platelets:

• Storage Temperature: 20 – 24°C for 5 days (constant agitation)

Platelet transfusion is indicated under the following conditions:

• Thrombocytopaenia accompanied by:
• Petechiae
• Ecchymoses
• Mucosal bleeding
• Spontaneous haemorrhage
• Severe Thrombocytopaenia < 10*10⁹/L with or without symptoms
• Moderate thrombocytopaenia 10-50*10⁹/L with associated conditions like:
• Infection
• Anaemia

Conditions Associated with Platelet Transfusion:

• Severe aplastic anaemia
• Chemotherapy Induced marrow suppression
• Disseminated Intravascular Coagulopathy
• Massive blood transfusion

FFP refers to plasma that is frozen within 6 hours of donation:

• It's kept at a chilly 18°C or colder for up to 1 year

Before being transfused:

• It's gently thawed using a warm water bath at 30-37°C for about 30-45 minutes
• Stored between 1-6°C to maintain its freshness
• Transfused within 24 hours to ensure its effectiveness
• Needs to match the recipient's ABO blood type for compatibility

Cryoprecipitate is a vital blood product derived from plasma. It plays a crucial role in addressing bleeding disorders and coagulation deficiencies. This condensed product is rich in essential clotting factors, including fibrinogen, factor VIII, von Willebrand factor, and factor XIII.

Cryoprecipitate is obtained through a controlled cryoprecipitation process, which involves the freezing and thawing of plasma. This process induces the precipitation of coagulation factors, resulting in the formation of cryoprecipitate.

Cryoprecipitate Production Procedure:

• Thawing FFP: Gently thaw Fresh Frozen Plasma (FFP) overnight at 4°C.
• Initial Cryoprecipitation: Freeze thawed FFP below -20°C to induce cryoprecipitation of coagulation factors.
• Refreezing with Plasma: Mix cryoprecipitate with 15ml thawed plasma for reconstitution.
• Quick Thawing: Rapidly thaw cryoprecipitate-plasma mixture at 37°C when needed.
• Storage and Usage: Use thawed cryoprecipitate within 4 hours if stored at room temperature.

Cryosupernatant: The leftover plasma is called cryoprecipitate reduced or cryosupernatant.

Measures to Protect the Recipient

1. Microbiological Safety of Blood:
   • Donor selection
   • Donor deferral and exclusion
   • Stringent arm cleaning
   • Donor blood screening to exclude transmissible diseases.
   • Leucodepletion of cellular products (Prevents transmission of some viruses e.g. CMV, EBV, HTLV-1 & some bacteria like yersinia.)
2. Immunological Safety of Blood:
   • Pretransfusion serological tests
   • Quality control measures

Pretransfusion Serological Tests

1. ABO and Rhesus Grouping: Both donor and recipient
2. Antibody Screening: Recipient’s serum tested with Indirect Coombs' test to assist in compatible donor selection
3. Crossmatching (Compatibility Testing):
   • Serves as a double check for blood grouping
   • Takes care of antigen/antibody not tested in blood grouping
   • Uses donor blood of the same ABO and Rhesus group as the patient

Quality Control Measures

• Confirming the identity of patients
• Proper labeling of sample bottles
• Adequate documentation and elimination of clerical errors
• Reliability of reagents and techniques
• Proper checks before transfusing blood

Indications for Whole Blood

• Haemorrhage:
• Patients actively bleeding and lost >25% of blood volume (trauma, snake bite, surgery, epistaxis)
• Exchange blood transfusion

Indications for Red Blood Cells

• Haemolysis:
• Sickle cell disease, autoimmune haemolytic anaemia, infections.
• Marrow failure:
• Aplastic anaemia
• Malignancies:
• Acute leukemia, lymphoma
• Hb < 5g/dL with or without symptoms
• Hb < 7g/dL with symptoms of decompensation.
• Transfusion may be indicated at higher thresholds for specific situations:
• Hb < 8g/dL: patients on chronic transfusion regimen or during marrow suppressive therapy (for symptom control and appropriate growth)
• Hb < 10g/dL: only for very select populations (Neonates)

Indications for Granulocyte Transfusion

• Criteria for Transfusion of Granulocytes:
• Fever with neutrophil count < 500/ml
• Septicemia unresponsive to antibiotics
• Reversible bone marrow hypoplasia
• Newborn with overwhelming sepsis
• Intensive chemotherapy for leukemia and transplant

Indications for Fresh Frozen Plasma

FFP is appropriate for the following:

• Warfarin effect, in the presence of life-threatening bleeding in addition to the use of vitamin K and vitamin-k dependent clotting factor concentrates for bleeding with abnormal coagulation.
• Liver disease, if bleeding with abnormal coagulation.
• Acute DIC when there is bleeding and abnormal coagulation.
• Antithrombin III deficiency.
• Following massive transfusion or cardiac bypass for bleeding in the presence of abnormal coagulation.

Indications for Cryoprecipitate

Cryoprecipitate is indicated for:

• Fibrinogen deficiency, in the setting of clinical bleeding, an invasive procedure, trauma or DIC.
• Haemophilia A.
• Von Willebrand’s disease.
• F XIII deficiency.