A colloid is a homogeneous non-crystalline substance consisting of large molecules or ultra microscopic particles of one substance dispersed through a second substance – the particles do not settle and cannot be separated out by ordinary filtering or centrifuging like those of a suspension such as blood. Colloid solutions used in clinical practice for fluid therapy are divided into the semisynthetic colloids (gelatins, dextrans and hydroxyethyl starches) and the naturally occurring human plasma derivatives (human albumin solutions, plasma protein fraction, fresh frozen plasma, and immunoglobulin solution). Most colloid solutions are presented with the colloid molecules dissolved in isotonic saline but isotonic glucose, hypertonic saline and isotonic balanced or “physiological” electrolyte solutions are also used. See Table.
Hextend also contain magnesium 0.9 mmol/L and lactate 28 mmol/L.
Volulyte also contain magnesium 1.5 mmol/L and acetate 34 mmol/L.