The dextrans--clinical data.

The use of dextrans in clinical practice are mainly based on the following effects: 1. Plasma volume effects 2. Flow Promotion 3. Antithrombotic effects. The dextrans are the only plasma volume substitute with the antithrombotic effect but this discussion will only deal with their effects on plasma volume and flow. The effect on plasma volume--the colloid supported intravascular volume--can be calculated as ml of water held in circulation per gram circulating colloid--for dextran 70 around 20 ml/g, for albumin 18 ml/g and for plasma protein 12-13 ml/g. After infusion of a plasma volume substitute the volume effect depends on dose injected, molecular weight distribution, rate of disappearance from the intravascular department mainly via the kidneys. The clinical experience of a reliable plasma volume expansion can be demonstrated in animal experiments comparing different infusion fluids. The effect on erythrocyte aggregation depends on kind of substance and molecular weight distribution. The flow promoting effect is mainly due to restoration of plasma volume but also related to hemodilution and aggregation. The vasoconstriction seen in shock can be counteracted essentially with colloid supported plasma volume expansion. The supposed influence of the dextrans on the kidney function in some clinical cases has been investigated experimentally.