Indications for blood transfusion

1. Acute blood loss / hemorrhagic shock
   To restore oxygen-carrying capacity and help maintain circulating volume during major bleeding, such as trauma, gastrointestinal hemorrhage, ruptured ectopic pregnancy, or postpartum hemorrhage.
2. Perioperative anemia
   When anemia is significant before, during, or after surgery and compromises oxygen delivery.
3. Symptomatic chronic anemia
   For example, anemia causing dyspnea, angina, syncope, fatigue limiting function, or signs of cardiac failure, when correction by iron, vitamin therapy, or treatment of the cause is insufficient or too slow.
4. Specific component deficiencies
   • Platelets: severe thrombocytopenia with bleeding, or prophylaxis before invasive procedures.
   • Fresh frozen plasma (FFP): bleeding or urgent procedure with multiple coagulation-factor deficiency, such as DIC, liver failure, or massive transfusion.
   • Cryoprecipitate/fibrinogen concentrate: hypofibrinogenemia with bleeding, especially obstetric hemorrhage or DIC.
   • Specific factor concentrates: hemophilia or other factor deficiencies, when indicated.

Immediate complications of blood transfusion

1. Acute hemolytic transfusion reaction
   Usually from ABO incompatibility or an identification error. May cause fever, chills, back/chest pain, hypotension, hemoglobinuria, DIC, acute kidney injury, and shock.
2. Febrile nonhemolytic transfusion reaction
   Fever, chills, and rigors without hemolysis.
3. Allergic reaction
   Urticaria, itching, flushing, or rash.
4. Anaphylactic reaction
   Bronchospasm, wheeze, hypotension, shock, or angioedema. It can occur in patients with anti-IgA antibodies receiving plasma-containing products.
5. Bacterial contamination / septic transfusion reaction
   High fever, rigors, hypotension, shock, nausea/vomiting. More common with contaminated platelet products.
6. Transfusion-associated circulatory overload (TACO)
   Acute pulmonary edema due to volume overload, causing dyspnea, hypertension, raised JVP, and hypoxia. Risk is higher in elderly patients and those with cardiac or renal failure.
7. Transfusion-related acute lung injury (TRALI)
   Acute noncardiogenic pulmonary edema and hypoxemia, typically within 6 hours of transfusion. It is often associated with plasma-containing components.
8. Hypotensive reaction
   Sudden hypotension, sometimes associated with bradykinin-mediated mechanisms or ACE-inhibitor use.
9. Nonimmune hemolysis
   Hemolysis from overheating, freezing, mechanical damage, hypotonic fluids, or improper administration of blood.
10. Air embolism and thrombophlebitis
    Uncommon complications related to intravenous administration.
11. Complications of massive transfusion

• Hypothermia
• Dilutional coagulopathy and thrombocytopenia
• Hypocalcemia due to citrate toxicity
• Hyperkalemia
• Acid-base disturbances

Transfusion-transmitted diseases and screening methods

Mandatory screening for all blood donations

Other important transfusion-transmitted diseases

Screening methods used in blood banks

1. Donor history and physical assessment
   • Ask about fever, jaundice, high-risk sexual exposure, injection drug use, recent tattooing/piercing, previous transfusion, malaria, travel, and previous infections.
   • Defer ineligible or high-risk donors.
   • This helps reduce infections during the window period, before laboratory tests become positive.
2. Serological testing
   • Detects antigens or antibodies in donor blood.
   • Examples: HBsAg for HBV, anti-HCV, anti-HIV, anti-T. pallidum, anti-T. cruzi.
3. Antigen-antibody combination assays
   • Example: HIV p24 antigen plus HIV antibody testing.
   • Detect infection earlier than antibody-only tests.
4. Nucleic acid testing (NAT)
   • Detects viral DNA or RNA directly.
   • Used for HIV RNA, HCV RNA, and HBV DNA in many blood services.
   • Shortens the infectious window period substantially. Miller’s Anesthesia, 10e notes that NAT has reduced the interval between infection and test positivity.
5. Bacterial culture / rapid bacterial detection
   • Especially important for platelet concentrates.
6. Pathogen-reduction technologies
   • Used mainly for platelets and plasma in some settings.
   • Reduce the risk from certain viruses, bacteria, parasites, and donor lymphocytes, but do not replace appropriate donor screening.

Key point