SN9 SHORT NOTE 5M

Write a short note on blood transfusion and its complications.

General Medicine · Final Professional

Blood Components

Whole blood is rarely used; component therapy allows several patients to benefit from one donation and delivers the specific deficient element.

Component	Contents	Indications	Storage
Packed red cells	Red cells, haematocrit ~60–70%	Symptomatic anaemia, acute blood loss	2–6 °C, up to 35–42 days
Platelet concentrate	Platelets	Thrombocytopenia with bleeding; prophylaxis at very low counts; platelet function defects	20–24 °C with agitation, 5 days (high infection risk)
Fresh frozen plasma	All coagulation factors	DIC, massive transfusion, liver disease with bleeding, warfarin reversal when PCC unavailable, TTP (plasma exchange)	−30 °C, 1 year
Cryoprecipitate	Fibrinogen, factor VIII, vWF, factor XIII, fibronectin	Hypofibrinogenaemia, DIC, massive haemorrhage	−30 °C
Factor concentrates	Specific factors	Haemophilia, specific deficiencies	Per product

Modifications: leucodepletion (reduces febrile reactions, alloimmunisation and CMV transmission), irradiation (prevents transfusion-associated graft-versus-host disease in immunocompromised recipients and directed donations from relatives), and washing (for recurrent severe allergic reactions and IgA deficiency).

Principles of Safe Transfusion

Transfuse for a clinical indication, not for a haemoglobin number. Restrictive thresholds are as safe as or safer than liberal ones in most stable patients.
Correct the cause — iron, B12 or folate where appropriate; transfusion is not a treatment for nutritional anaemia.
Positive patient identification at the bedside at sampling and at administration — clerical error is the commonest cause of fatal transfusion reaction.
Informed consent; compatibility testing (ABO and Rh grouping, antibody screening, crossmatch).
Monitor vital signs before, during the first 15 minutes (when severe reactions declare themselves), and after; complete each unit within 4 hours.
Give only normal saline through the same line — dextrose causes haemolysis and calcium-containing fluids cause clotting.

Complications

A. Immediate immunological

Reaction	Mechanism	Features	Management
Acute haemolytic reaction	ABO incompatibility — usually a clerical error; preformed IgM causes intravascular haemolysis	Fever, chills, loin and chest pain, hypotension, dark urine (haemoglobinuria), DIC, acute kidney injury; a sense of impending doom	STOP the transfusion immediately; maintain venous access with saline; aggressive fluids to maintain urine output; treat DIC and shock; return the unit and send samples for repeat crossmatch and Coombs test; report and investigate
Febrile non-haemolytic reaction	Recipient antibodies against donor leucocytes; cytokines in stored components	Fever and rigors without haemolysis; the commonest reaction	Slow or stop transfusion, paracetamol; use leucodepleted products in future
Allergic / urticarial	Antibodies to donor plasma proteins	Urticaria, itching; anaphylaxis in IgA-deficient recipients with anti-IgA antibodies	Antihistamine and continue for mild urticaria; adrenaline and full anaphylaxis management for severe reactions; washed cells subsequently
TRALI (transfusion-related acute lung injury)	Donor anti-leucocyte antibodies activating recipient neutrophils in the pulmonary vasculature	Acute dyspnoea and hypoxia with bilateral pulmonary infiltrates within 6 hours; normal jugular venous pressure and no fluid overload	Supportive — oxygen and ventilation; diuretics are unhelpful and potentially harmful; usually resolves in 48–96 hours

B. Immediate non-immunological

TACO (transfusion-associated circulatory overload) — pulmonary oedema from volume overload, especially in the elderly, in cardiac and renal disease, and with rapid transfusion. Presents with dyspnoea, raised JVP and hypertension — the key features distinguishing it from TRALI. Treat with oxygen, diuretics, upright posture and slowing or stopping the transfusion.
Bacterial contamination and septic shock — highest risk with platelets (stored at room temperature): high fever, rigors and profound hypotension soon after starting. Stop, culture the unit and the patient, and give broad-spectrum antibiotics.
Hypothermia, citrate toxicity with hypocalcaemia, hyperkalaemia, and dilutional coagulopathy — features of massive transfusion.
Air embolism, and haemolysis from mechanical or thermal damage.

C. Delayed

Delayed haemolytic transfusion reaction — 5–10 days later, from an anamnestic response to a minor red cell antigen: falling haemoglobin, jaundice, positive direct Coombs test.
Transfusion-transmitted infection — HIV, hepatitis B and C, syphilis, malaria (screened for in India), and CMV, HTLV, and emerging agents. Residual risk persists because of the window period, which is why unnecessary transfusion is never harmless.
Transfusion-associated graft-versus-host disease — rare but almost always fatal; donor lymphocytes engraft in an immunocompromised recipient. Prevented by irradiation of components; particularly important with directed donations from blood relatives, which are a specific hazard.
Iron overload — after repeated transfusion (thalassaemia, MDS, sickle cell disease); requires chelation.
Alloimmunisation — to red cell, HLA or platelet antigens, causing future crossmatch difficulty and platelet refractoriness.
Post-transfusion purpura — severe thrombocytopenia about a week after transfusion.

Massive Transfusion

Defined as replacement of the whole blood volume within 24 hours, or 10 or more units. Modern practice uses a massive transfusion protocol with early balanced replacement of red cells, plasma and platelets in a fixed ratio, plus tranexamic acid in trauma, avoidance of large-volume crystalloid, and correction of the "lethal triad" of hypothermia, acidosis and coagulopathy. Monitor calcium, potassium, fibrinogen and temperature throughout.

DANGER / REMEMBER

The first action in any suspected acute transfusion reaction is to STOP the transfusion and keep the line open with normal saline. Then assess, treat and check the identity of the patient and the unit. Fever with hypotension and loin pain within minutes of starting is an ABO-incompatible haemolytic reaction until proved otherwise — almost always caused by a bedside identification error, and preventable entirely by rigorous checking of patient identity against the unit label at the bedside, by two people, every time.

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