Plasma Volume Expansion by Rapid Infusion of a Low Molecular Weight Dextran

Large infusions of a 10% solution of dextran of molecular weight 40,000 were given to dogs during 3 min using a specially designed apparatus. The initial expansion of plasma volume was about twice the volume of solution injected. Plasma volume then fell rapidly (with a half life of about 2 hr), more rapidly than the fall in dextran concentration (half-life of about 4.5 hr). Fluctuations in plasma volume and protein concentration were repeatedly observed during the return towards normal values. At 5 to 6 hr renal excretion accounted for 40% of the infused dextran, about 20% was intravascular and the remaining 40% was presumably extravascular. No dextran was found in the cerebrospinal fluid.