Journal of Applied Physiology, Vol 54, Issue 6 1630-1634, Copyright © 1983 by American Physiological Society
Intercompartmental fluid shifts after dextran infusion in rabbits
V. Mohsenin and A. B. DuBois
Intercompartmental fluid shifts were studied in New Zealand White rabbits
after infusion of hyperoncotic dextran solution with a mean molecular
weight of 64,200 and osmolality of 220 mosmol/kg H2O. In comparison with
the control period, it was found that 1) plasma volume increased by a net
volume of 83 +/- 12 ml; 2) systemic blood pressure increased slightly but
significantly and central venous pressure increased markedly (this was
accompanied by a reduction of interstitial fluid pressure from a control of
-1 to -8 cmH2O after dextran); 3) plasma volume expansion was not
accompanied by plasma sodium and chloride dilution when they were expressed
in meq/kg of plasma water; and 4) plasma osmolality did not change after
dextran infusions. The increase in plasma volume unaccompanied by any
change in plasma sodium, chloride, or osmolality may be explained by a
transcapillary fluid shift from the interstitial space to the bloodstream
caused by an increase in plasma oncotic pressure. Because the more negative
interstitial fluid pressure did not seem to attract any appreciable amount
of fluid from the cells, we concluded that the interstitial space did not
hydrodynamically couple the intravascular space to the cellular
compartment.
