User:Electronic Yemeni Forum

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).