HYDROXYETHYL STARCH IN A COLLOIDAL SOLUTION EXPANDS PLASMA VOLUME WHEN ADMINISTERED INTRAVENOUSLY. THIS EFFECT DEPENDS ON THE MEAN MOLECULAR WEIGHT (130,000 DALTONS; RANGE 110,000 - 150,000 DALTONS), THE MOLAR SUBSTITUTION BY HYDROXYETHYL GROUPS (0.4; RANGE 0.38 - 0.45) ON GLUCOSE UNITS OF THE STARCH, THE PATTERN OF HYDROXYETHYL SUBSTITUTION (C2/C6 RATIO) OF APPROXIMATELY 9:1, AND THE CONCENTRATION (6%), AS WELL AS THE DOSAGE AND INFUSION RATE.