Hydroxyethyl starch (HES), gelatin, and albumin are several types of:A. Crystalloids
Several types of colloids are available, but three are most commonly used-hydroxyethyl starch (HES), gelatin, and albumin. The HES preparations differ from one another according to their concentration, molecular weight, and extent of hydroxy- ethylation or substitution, with resultant varying physiochemical properties. HES solutions most often are described according to their weight -averaged mean molecular weight in kilodaltons (kDa): high molecular weight (450 kDa), middle molecular weight (200 kDa, 270 kDa), and low molecular weight (130 kDa, 70 kDa). HES 450 kDa solutions are available in a normal saline solution (HES 450/NS) and in a lactated, balanced salt solution (HES 450/BS). Although all of these colloids are used in Europe, gelatins are not available in the United States, and the only HES preparations approved by the U.S. Food and Drug Administration are the 6% high molecular weight ( 450 kDa) formulations.