When to transfuse Packed Red Blood Cells (PRBCs)?

From the Guidelines

Packed Red Blood Cells (PRBCs) should be transfused when a patient's hemoglobin concentration decreases to < 7.0 g/dL in adults in the absence of extenuating circumstances, such as myocardial ischemia, severe hypoxemia, or acute hemorrhage. This recommendation is based on the strongest and most recent evidence from the Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016 1.

Key Considerations

• The guidelines recommend a restrictive transfusion strategy, which has been shown to reduce complications and conserve resources 1.
• For patients with cardiovascular disease or those undergoing orthopedic surgery, a higher threshold of 8 g/dL may be considered, although the evidence for this is weaker 1.
• In acute bleeding situations, transfusion may be initiated at higher hemoglobin levels (9-10 g/dL) depending on the rate of blood loss and hemodynamic stability.
• Each unit of PRBCs typically raises hemoglobin by approximately 1 g/dL in an average-sized adult.

Administration and Monitoring

• PRBCs should be given through a large-bore IV (18-gauge or larger) with appropriate blood filters.
• Patients should be monitored for vital signs before, during, and after transfusion.
• The transfusion should occur within 4 hours of the blood bag being opened to prevent bacterial contamination.

Rationale

• The rationale for these thresholds is based on oxygen delivery physiology; hemoglobin levels above 7-8 g/dL generally provide adequate oxygen-carrying capacity for most patients 1.
• Restrictive transfusion strategies have been shown to reduce complications including transfusion reactions, volume overload, and immunomodulation effects while conserving a limited resource 1.

From the Research

Indications for Transfusion of Packed Red Blood Cells (PRBCs)

• The decision to transfuse PRBCs should be based on the patient's hemodynamic status, comorbidities, risks and benefits of transfusion, and clinical setting 2, 3.
• A restrictive threshold of 7 g/dL is recommended in the new American Association of Blood Banks guidelines and multiple meta-analyses, and is supported in gastrointestinal bleeding, sepsis, critical illness, and trauma 2, 4.
• For patients with acute upper gastrointestinal (GI) bleeding, transfuse for hemoglobin less than 7 g/dL 3.
• In patients with acute coronary syndromes, let symptoms/signs be your guide 3.
• In patients with ischemic heart disease, transfuse for hemoglobin levels less than 8 g/dL or if they are symptomatic 3.
• For patients with unimpaired cardiopulmonary and vascular function, transfusion is generally indicated at hemoglobin values of 6 g/dL or less 5.

Special Considerations

• Patients with chronic anemia can benefit from scheduled transfusions of PRBCs, while urgent transfusions have specific indications 4.
• In chronic anemic patients, the appropriateness of transfusions should be assessed according to the American Association of Blood Banks (AABB) 2016 criteria, using the recommended threshold of 7 g/dL for hemodynamically stable adults and 8 g/dL for patients with pre-existing cardiovascular disease 4.
• Children with severe anemia of gradual onset requiring transfusion therapy can be safely transfused with continuous infusion of PRBC at the rate of 2 cc/kg/h 6.

Risks and Benefits

• Transfusion reactions and infections are rare but can have significant morbidity and mortality 2.
• The age of transfusion products likely has no effect on products before 21 days of storage 2.
• Overtransfusion, undertransfusion, as well as other transfusion errors can be markedly reduced by means of appropriate organizational measures and training 5.