blodsubstitut

Blodsubstitut, or blood substitute, refers to a range of medical products designed to replicate selected functions of blood, especially oxygen transport or volume expansion, in situations where donor blood is unavailable or unsafe. They are intended to extend transfusion options, improve logistics, and reduce dependence on matched blood supplies.

Oxygen-carrying substitutes include hemoglobin-based oxygen carriers (HBOCs), which use chemically modified hemoglobin to transport oxygen, and perfluorocarbon-based emulsions (PFCs), which dissolve and deliver oxygen through a different mechanism. HBOCs aim to substitute red blood cells’ oxygen transport, while PFCs provide oxygen-cupping properties through emulsified liquids. Both classes have faced safety challenges, including vasoconstriction, hypertension, and adverse cardiovascular events in some trials.

Volume expanders and plasma substitutes form another major class. These products, such as synthetic colloids (for example, dextrans and hydroxyethyl starch), natural polymers like albumin, and crystalloids, are used to restore circulatory volume and improve tissue perfusion. They typically do not provide oxygen-carrying capacity but help stabilize patients during acute blood loss or shock.

History and current status: Research into blood substitutes began in the mid-20th century. Several HBOCs and PFC products were developed and tested, with some obtaining regulatory approval in certain regions in the past, but safety concerns have limited their widespread use. As of the 2020s, broad routine human use of HBOCs or PFCs has not been realized in many markets, though certain products remain under investigation or approved for niche indications or veterinary use.

Ongoing research seeks safer HBOCs, improved encapsulation methods, and alternative approaches to reduce transfusion needs while maintaining patient safety.