Transfusionssubstitute

Transfusionssubstitute is a term used for products or therapies designed to replace all or part of a red blood cell transfusion by supporting oxygen delivery or circulating blood volume without using donor blood. These substitutes aim to reduce exposure to allogeneic transfusions, address shortages, and provide options in settings where transfusion is risky or unavailable. They are not universally interchangeable for all transfusion indications, and their effectiveness and safety vary by product and clinical scenario.

Types and mechanisms include oxygen-carrying substitutes such as hemoglobin-based oxygen carriers (HBOCs) that use modified hemoglobin to transport oxygen, and perfluorocarbon emulsions that dissolve and transport gases independently of hemoglobin. HBOCs have faced safety concerns, including nitric oxide scavenging, vasoconstriction, hypertension, and organ injury, which have limited their clinical use. Perfluorocarbon oxygen carriers provide oxygen delivery under certain conditions but require special administration and have shown limited uptake in practice. Volume expanders, including crystalloids and colloids, maintain intravascular volume to treat hypovolemia but do not restore the oxygen-carrying capacity of blood and are used as bridging therapies or adjuncts in hemorrhagic situations when blood products are not immediately available.

Status and regulation vary by region. Over the past decades, no RBC substitute has achieved broad, routine approval due to safety and efficacy concerns, and several products have been withdrawn or restricted. In contemporary medicine, transfusion substitutes play a limited role and are typically reserved for niche indications or investigated in clinical trials, with modern blood management emphasizing strategies to minimize transfusion needs and optimize patient outcomes.