Dextrans are branched polysaccharides.

There are two available dextrans: Dextran 40 and Dextran 70. The number refers to the average molecular weight, which is 40 000 for Dextran 40 and 70 000 for Dextran 70.

Dextran 40 is not used as a plasma expander. It improves blood flow and is used in the treatment of peripheral ischaemic vascular disease.

Dextran 70 can be used as a plasma expander. It is available as a 5% isotonic solution either in 5% glucose or in 0.9% NaCl. A hypertonic 6% solution in 7.5% NaCl is also available. It is used less frequently than either of the modified gelatins.

Problems with use: Dextran can interfere with blood cross-matching and laboratory tests of coagulation, although not with more modern techniques. The incidence of hypersensitivity reactions is about 1 in 3000.