Effects of hemodilution on skeletal muscle blood flow and blood viscosity in vivo after splanchnic stasis.

Pressure-flow relationships and apparent viscosity in vivo were determined in the skeletal muscle of the dog in experimental shock induced by splanchnic venous stasis and after subsequent hemodilution with low molecular weight dextran. The calf muscles of one hind limb were surgically isolated and pressure-flow curves constructed for blood and a cell-free reference solution during vasodilation. The apparent viscosity in vivo was determined by comparing the flow values for blood and the reference solution at identical perfusion pressures. A shock state with hypotension and hemoconcentration was induced by laparotomy and splanchnic venous stasis. Hemodilution was subsequently produced by low molecular weight dextran. After splanchnic stasis, skeletal muscle blood flow decreased and viscosity in vivo increased disproportionately in relation to the increase in hematocrit. Hemodilution could reverse the flow and viscosity changes induced during the shock period. It is concluded that a shock state associated with hemoconcentration results in flow stagnation in the skeletal muscle with increased in vivo viscosity and that the changes can be reversed by hemodilution.