Blood transfusion:
Indications:
o Hemorrhage ≥ 20% of blood loss.
o To restore one deficient element (RBCs, WBCs, platelets, clotting factors, plasma proteins).
o For alive baby with erythroblastosis fetalis (exchange transfusion).
Precautions:
o Blood free from disease.
o Blood free from contamination.
o Compatible blood and Rh –ve donor for Rh –ve recipient.
o Cross matching (especially in massive blood transfusion, subgroup incompatibility, Rh incompatibility).
o Fresh blood (not > 2 weeks in refrigerator).
o Blood with high hemoglobin content.
Changes occurring in stored blood:
o ↓platelets.
o ↓WBCs and loss of phagocytic power.
o ↓flexibility of RBCs.
o No labile factors (nor factor V, no factor VIII).
o ↑lactic acid (glucose and anticoagulant is added).
o ↑potassium (During blood storage, there is a slow but constant leakage of potassium from cells into the surrounding plasma along a
concentration gradient as a result of Na-K ATPase pump failure. The plasma level of potassium may ↑by 0.5 – 1 mmol/L per day of
refrigerator storage).
Complications of blood transfusion:
Donor: anemia (if repeated blood donation, donation should be not before 2 months after the previous donation), and shock.
Compatible recipient:
Infection: e.g AIDS, hepatitis C and B, malaria, syphilis.
Mechanical complications: air embolism and dislodgement of thrombus from less important vessel to more important vessel.
Heart failure (due to over transfusion).
Allergy (3% of patients) →fever and rigors (due to additives) (allergy/clear urine, incompatibility/reddish urine).
Incompatibility: (if transfusion without cross matching)
RBCs agglutination (donor antibodies/agglutinins with recipient antigens/agglutinogens).
ABO incompatibility by IgM that has 10 binding sites (≥ 10 RBCs) → large agglutinations → vessels occluded →pain (back
pain, joints pain, cardiac pain).
Rh incompatibility by IgG that has 2 binding sites (for 2 RBCs).
Hemolysis by complement leading to:
o Histamine from RBCs →vasodilatation →↓blood pressure →shock.
o K⁺ from RBCs →arrhythmia.
o Hemoglobin from RBCs →↑bilirubin and ↑free hemoglobin →jaundice, ↑blood osmotic pressure and ↑blood
viscosity (↑blood volume and blood viscosity →↑work of heart →heart failure).
o Free hemoglobin in kidney tubules reacts with acidic urine →acid hematin that occludes renal tubules →renal
failure (cause of death).