What is the management for an adverse drug reaction post blood transfusion in an adult patient with no pre-existing allergies or sensitivities?

Management of Adverse Reactions Post Blood Transfusion

Stop the transfusion immediately at the first sign of any suspected reaction—this is the single most critical intervention that can prevent progression to severe morbidity or mortality. 1, 2

Immediate Actions (First 5 Minutes)

• Halt the transfusion but maintain IV access with normal saline for medication administration and fluid resuscitation 1, 2
• Call for medical assistance and note the exact time of reaction onset 2
• Assess ABCs (Airway, Breathing, Circulation) and level of consciousness using a team-based approach 3, 2
• Administer 100% high-flow oxygen to address potential hypoxemia 1, 2
• Monitor vital signs every 5-15 minutes: heart rate, blood pressure, temperature, respiratory rate, and oxygen saturation 3, 1
• Double-check all documentation for clerical errors—verify patient identification against blood component label, as administration errors are a leading cause of fatal hemolytic reactions 1, 2, 4

Risk Stratification by Clinical Presentation

Anaphylaxis (Life-Threatening Emergency)

Clinical features: Hypotension with bronchospasm, urticaria, cardiovascular collapse, or respiratory distress 3

Immediate treatment:

• Epinephrine 0.2-0.5 mg (1 mg/mL) IM into lateral thigh muscle—repeat every 5-15 minutes as needed 3, 1
• Aggressive fluid resuscitation: Normal saline 1-2 L IV at 5-10 mL/kg in first 5 minutes, then crystalloids or colloids in 20 mL/kg boluses 3, 2
• H1/H2 antagonists: Diphenhydramine 50 mg IV plus ranitidine 50 mg IV 3, 5
• Corticosteroids: 1-2 mg/kg IV methylprednisolone every 6 hours 3
• If bradycardia: Atropine 600 μg IV 3
• If refractory hypotension: Dopamine 400 mg in 500 mL at 2-20 μg/kg/min, or vasopressin 25 U in 250 mL (0.01-0.04 U/min) 3, 2
• If patient on beta-blockers: Glucagon 1-5 mg IV over 5 minutes 3

Mild-to-Moderate Hypersensitivity Reaction (Grade 1-2)

Clinical features: Flushing, rash, urticaria, chills without hemodynamic instability 3

Treatment:

• Slow or temporarily stop infusion 3
• H1/H2 antagonists: Diphenhydramine 50 mg IV plus ranitidine 50 mg IV 3
• Corticosteroids: 1-2 mg/kg IV methylprednisolone every 6 hours 3
• Restart infusion at 50% rate and titrate to tolerance if symptoms resolve 3

Severe Hypersensitivity Reaction (Grade 3-4)

Clinical features: Severe symptoms persisting after stopping infusion, significant hemodynamic or respiratory compromise 3

Treatment:

• Stop infusion permanently 3
• H1/H2 antagonists and corticosteroids as above 3
• Rechallenge is discouraged in severe reactions 3
• 24-hour observation required 3

Essential Laboratory Workup

Send immediately (do not wait for results to initiate treatment): 1, 2, 4

• Complete blood count
• Direct antiglobulin test (Coombs test) and repeat crossmatch
• PT, aPTT, Clauss fibrinogen
• Visual inspection of plasma for hemolysis
• Blood cultures if bacterial contamination suspected (fever with hypotension within 6 hours, especially with platelets)
• Urine analysis for hemoglobinuria
• Mast cell tryptase levels at three time points if anaphylaxis suspected

Notification and Documentation

• Contact transfusion laboratory/blood bank immediately to report the reaction and initiate investigation 1, 4
• Return the blood component bag with administration set to the laboratory—do not discard 4
• Document all transfusions in patient record with 100% traceability (legal requirement) 1, 4
• Notify patient's general practitioner as this removes them from the donor pool 1
• Report to blood bank as transfusion reactions are underdiagnosed and underreported despite being a leading cause of mortality 1, 4

Critical Pitfalls to Avoid

• Never restart the transfusion even if symptoms improve—reactions may worsen with continued exposure 2, 4
• Do not give diuretics empirically—they are contraindicated in anaphylaxis, hypovolemic states, and TRALI 2
• Do not dismiss isolated symptoms (e.g., "just a headache")—serious reactions including TRALI, acute hemolytic reactions, and bacterial contamination can present subtly before progressing to life-threatening complications 4
• Do not assume general anesthesia or critical illness masks benign reactions—these conditions can hide early signs of serious reactions 2

Patient Positioning

• Hypotension: Trendelenburg position 3
• Respiratory distress: Sitting upright 3
• Unconscious: Recovery position 3

Future Transfusions After Reaction

• Severe life-threatening reactions: The implicated agent should not be used again unless under care of an allergist or expert in managing drug reactions 3
• Mild allergic reactions: Desensitization regimen should be used even if symptoms resolved; patients must be desensitized with each infusion (~90% success rate) 3
• Desensitization location: Prudent to perform in intensive care unit to maximize safety 3