Blood Transfusion

A transfusion replaces a specific blood-component deficit; it is not a reflex response to one laboratory value. Red blood cells improve oxygen-carrying capacity, platelets support primary hemostasis, and plasma or other components are selected for the clinical problem identified by the prescriber and transfusion service. For a hemodynamically stable hospitalized adult, the 2023 AABB guideline recommends considering red-cell transfusion when hemoglobin is below 7 g/dL. A threshold near 7.5 g/dL may be considered for cardiac surgery, and near 8 g/dL for orthopedic surgery or pre-existing cardiovascular disease. Adults with hematologic or oncologic disorders generally use the below-7-g/dL threshold, although the recommendation is conditional and supported by lower-certainty evidence. The number does not replace clinical judgment. Active hemorrhage, shock, ongoing ischemia, severe hypoxemia, or symptoms attributable to anemia change the priority; the nurse should not delay emergency resuscitation while waiting for a hemoglobin value to cross a restrictive threshold. For hemodynamically stable critically ill children without hemoglobinopathy, cyanotic heart disease, or severe hypoxemia, a restrictive threshold below 7 g/dL is recommended. Congenital heart disease requires lesion- and repair-stage-specific decisions: approximately 7...