What are the risks associated with blood transfusion?

Risks Associated with Blood Transfusion

Blood transfusion carries substantial risks that can be categorized into infectious complications (now rare with modern screening) and non-infectious complications (which account for 87-100% of fatal transfusion reactions and represent the predominant safety concern in contemporary practice). 1, 2

Non-Infectious Risks (Most Clinically Significant)

Transfusion-Associated Circulatory Overload (TACO)

• TACO is now the leading cause of transfusion-related mortality and major morbidity 1, 3
• Occurs in 1-8% of transfused patients, with rates of 2-4% in surgical patients 1
• Presents as acute respiratory compromise, pulmonary edema, tachycardia, and hypertension during or within 12 hours of transfusion 1
• High-risk patients include those >70 years old, patients with heart failure, renal failure, hypoalbuminemia, low body weight, and those receiving rapid transfusion 1, 3
• Prevention requires body weight-based dosing, slow transfusion rates, close vital sign monitoring, and consideration of prophylactic diuretics 1

Transfusion-Related Acute Lung Injury (TRALI)

• Occurs at 8.1 per 100,000 transfused blood components 1, 3
• Presents within 6 hours of transfusion with hypoxemia, respiratory distress, dyspnea, and bilateral pulmonary infiltrates without circulatory overload 4
• Fresh frozen plasma and platelet concentrates carry the highest TRALI risk 3, 4
• Critical management point: immediately stop transfusion and provide respiratory support; do NOT give diuretics as they are ineffective and potentially harmful 4

Hemolytic Transfusion Reactions

• Fatal hemolysis occurs at approximately 8 per 10 million RBC units transfused (1:1,250,000) 1, 3
• Acute hemolytic reactions result primarily from human error and ABO incompatibility 1
• Delayed hemolytic transfusion reactions can occur even with compatible crossmatch when antibodies have waned below detection but rapidly increase post-transfusion 3

Febrile and Allergic Reactions

• Febrile non-hemolytic reactions occur in 1.1% with prestorage leukoreduction and 2.15% with poststorage leukoreduction 1, 3
• Allergic reactions are increasingly reported, particularly with plasma and platelet products 1
• Management should be tailored to reaction type: paracetamol alone for febrile reactions, antihistamines for allergic reactions; avoid indiscriminate steroid use 1

Life-Threatening Transfusion Reactions

• Occur at 7.1 per million transfusions, requiring major interventions such as vasopressors, intubation, or ICU transfer 1

Infectious Risks (Now Rare but Still Present)

Viral Transmission

• HIV: 6.8 per 10 million components (1:1,467,000) 1, 3
• Hepatitis C: 8.7 per 10 million components (1:1,149,000) 1, 3
• Hepatitis B: 28-36 per 10 million components (1:282,000 to 1:357,000) 1, 3

Bacterial Contamination

• Bacterial contamination of platelet components occurs at 1:2,000, with sepsis at 1:50,000 5
• Red cell bacterial contamination and sepsis is less frequent at 1:500,000 due to refrigerated storage 5

Immunologic and Systemic Complications

Transfusion-Associated Immunomodulation (TRIM)

• Increases risk of multi-organ failure and infection in critically ill patients 1
• Associated with increased infection rates in multiple studies 1

Alloimmunization

• Occurs in 7-30% of patients with sickle cell disease 3
• Standard ABO/RhD matching alone does NOT eliminate alloimmunization risk 3
• Leads to delayed hemolytic reactions, difficulty finding compatible blood, and potentially life-threatening hyperhemolysis 3

Storage Lesion Effects

• RBC changes during storage include reduced deformability, altered adhesiveness, reduction in 2,3-DPG and ATP, and accumulation of proinflammatory compounds 1
• These changes reduce post-transfusion RBC viability and may contribute to adverse outcomes 1

Critical Monitoring Requirements

All transfusions require systematic monitoring to detect complications early: 1

• Vital signs (pulse, blood pressure, temperature, respiratory rate) before transfusion (within 60 minutes), at 15 minutes after starting each unit, and within 60 minutes of completion 1
• Respiratory rate monitoring is essential as dyspnea and tachypnea are early symptoms of serious transfusion reactions 1
• Fluid balance monitoring, particularly in high-risk patients for TACO 1

Pediatric Considerations

• Adverse outcome incidence is 18:100,000 RBC units in children <18 years and 37:100,000 in infants (compared to 13:100,000 in adults) 2
• Majority of pediatric complications relate to human error, including overtransfusion and lack of knowledge of neonatal requirements 2
• Acute allergic reactions are the second most frequent category in pediatric patients 2