Blood Transfusion Lecture 5

Blood Transfusion

• Blood transfusion is the intravenous administration of whole blood or a component such as plasma, packed red blood cells, or platelets to a patient.

Three Modalities to Replace Blood Loss

• Homologous transfusion: transfusion of blood taken from another human being (donor) and stored.
• Autologous transfusion: re-infusion of a patient's own blood.
• Transfusion of plasma expanders and blood components.

Purposes

• To increase circulating blood volume.
• To increase the number of red blood cells and maintain the haemoglobin level.
• To provide plasma clotting factors to help control bleeding.
• To combat infection due to decreased or defective white cells or antibodies.

Indications

• After surgery.
• Trauma or haemorrhage.
• Severe anaemia.
• Haemophilia.
• Agranulocytosis.

Selection of Donor

• Should not be suffering from diseases of the heart, kidneys, liver, lungs, cancer, jaundice, tuberculosis, hepatitis, AIDS, allergies, etc.
• Should not have donated blood within the previous 90 days.
• Should be healthy and in the age group of 18-65 years.
• Should not be pregnant.
• Should have HB level above 12gm.
• Should have normal vital signs (TPR, BP).
• Should not be empty stomach.

Complications of Blood Transfusions

• Transfusion reaction: characterized by fever, chills, headache, dyspnoea, cyanosis, and resultant drop in blood pressure.
• Oliguria followed by anuria may signal renal failure.
• Chest pain, nausea, vomiting, increased pulse rate and respiratory rate, and haemoglobinuria (red urine).
• Haemolytic transfusion reaction.
• Pyrogenic reactions.
• Allergic reactions.
• Circulatory overload.
• Transmission of infection diseases.
• Anaphylactic reactions.

Management of Complications

• Ongoing transfusion should be stopped.
• Crystalloids should be administered to maintain intravascular volume and perfusion to kidneys.
• Steroid suppresses the immune system, thereby reducing the release of inflammatory mediators.

Osmotic Fragility Test

• Osmosis = water concentration.
• Hypotonic = high water + low salt.
• Hypertonic = low water + high salt.
• The test is used to diagnose different types of anemia in which the physical properties of the RBC are altered.
• Conditions associated with increased osmotic fragility include hereditary spherocytosis, autoimmune spherocytosis, poisoning, and severe burns.
• Conditions associated with decreased fragility include thalassemias, iron deficiency anemia, and sickle cell anemia.