About dextrana group of long-chain polysaccharides composed of glucose,intravenous fluids, plasma expanders (((substitutes for whole blood))) in severe shock.mechanism of action of dextrandextran is a plasma volume expander which reduces blood viscosity. it forms a coating on rbc and maintains their electronegative charge and prevents rbc sludging that occurs in shock. it improves microcirculation. they are both osmotically active, and too large to pass through the uninjured vessel wall. they possess antiplatelet and anti-fibrin activities. they bind to platelets, rbcs, and the lining of the vessel wall decreasing their ability to stick together and forming clots.