IT IS A BRANCHED POLYSACCHARIDE USED INTRAVENOUSLY AS PLASMA VOLUME EXPANDER. IT IS FORMED BY A BACTERIUM, LEUCONOSTOC MESENTEROIDES, WHICH CONTRIBUTES TO ITS ANTIGENICITY, HOWEVER DUE TO IMPROVED PREPARATION TECHNIQUES THE INCIDENCE OF HYPERSENSITIVITY REACTIONS IS REDUCED. THE COLLOIDAL OSMOTIC EFFECT EXERTED BY DEXTRAN DRAWS FLUID INTO THE VASCULAR SYSTEM FROM THE INTERSTITIAL SPACES, RESULTING IN INCREASED CIRCULATING BLOOD VOLUME. DEXTRAN-40 NOT ONLY CORRECTS HYPOVOLEMIA BUT ALSO IMPROVES MICROCIRCULATION INDEPENDENTLY OF ITS VOLUME EXPANDING EFFECT.