From the Guidelines
Blood transfusion is generally recommended for hemoglobin (Hgb) levels below 7 g/dL in most stable, hospitalized patients, while a threshold of 8 g/dL is appropriate for patients with cardiovascular disease or those undergoing orthopedic or cardiac surgery. This restrictive transfusion strategy has been shown to be as effective as more liberal approaches (transfusing at higher Hgb levels) while reducing unnecessary transfusions and associated risks 1. However, transfusion decisions should not be based solely on hemoglobin levels but should also consider the patient's clinical status, symptoms of anemia (such as chest pain, dyspnea, tachycardia, or hypotension), ongoing blood loss, and comorbidities.
Key Considerations
- Patients who are actively bleeding, hemodynamically unstable, or showing signs of inadequate tissue oxygenation may require transfusion at higher hemoglobin thresholds.
- The goal of transfusion is to improve oxygen delivery to tissues, and one unit of packed red blood cells typically increases hemoglobin by approximately 1 g/dL in an average-sized adult.
- Reassessment after each unit is important to determine if additional transfusions are needed.
- A restrictive transfusion strategy is safe and associated with less blood use, as shown in several trials, including the TRICC (Transfusion Requirements in Critical Care) and TRIPICU (Transfusion Strategies for Patients in Pediatric Intensive Care Units) trials 1.
Clinical Guidelines
- The AABB recommends adhering to a restrictive transfusion strategy (7 to 8 g/dL) in hospitalized, stable patients (Grade: strong recommendation; high-quality evidence) 1.
- The AABB suggests adhering to a restrictive strategy in hospitalized patients with preexisting cardiovascular disease and considering transfusion for patients with symptoms or a hemoglobin level of 8 g/dL or less (Grade: weak recommendation; moderate-quality evidence) 1.
From the Research
Transfusion Thresholds
- The decision to transfuse blood at a hemoglobin (Hb) level of 7 or 8 g/dL is a complex one, and guidelines may vary depending on the clinical setting and patient population 2, 3.
- A restrictive transfusion strategy with a threshold of 7 to 8 g/dL has been shown to be as safe as a liberal strategy with a threshold of 9 to 10 g/dL in many clinical settings 2.
- However, some studies suggest that a liberal transfusion strategy may be associated with improved outcomes in certain patient populations, such as those with stable cardiovascular disease or acute coronary syndromes 3.
Patient-Specific Factors
- Patient symptoms and preferences should be taken into account when making transfusion decisions, in conjunction with the patient's Hb concentration 2.
- The etiology of the anemia should also be evaluated and managed, as iron-restricted erythropoiesis is a common cause of anemia severe enough to require transfusion 2.
- In patients with myelodysplastic syndromes, erythropoiesis-stimulating agents may be a viable alternative to transfusion, with a favorable safety profile 4.
Clinical Evidence
- A regression discontinuity study found that transfusion at a Hb threshold of 7 g/dL was not associated with improved organ dysfunction compared to no transfusion in critically ill patients 5.
- A meta-analysis and systematic review found that a transfusion threshold of <7 g/dL was not associated with decreased short-term mortality in ICU patients, but may have a role in reducing myocardial infarction incidence 6.
- Another study suggested that a restrictive transfusion strategy may be associated with an increased risk of new-onset acute coronary syndromes in patients with cardiovascular disease 3.