Renal effects of dopamine during prolonged hemorrhagic hypotension in the dog

Dopamine has been reported to increase renal blood flow during hemorrhagic shock. Since this effect would be of considerable benefit in shock, the effect of dopamine on hemorrhagic hypotension to 70 mm Hg for five hours was studied. Plasma renin activity and outer cortical blood flow were significantly greater in the group of dogs receiving dopamine. Total renal blood flow, sodium excretion, and potassium excretion were similar in both groups; however, the ratio of urine sodium to potassium concentration followed closely the plasma renin activity. We conclude that dopamine infusion alone is of limited value in improving renal hemodynamics and function during hemorrhagic hypotension to 70 mm Hg. In addition, increased plasma renin activity produced by dopamine infusion during hemorrhage would tend to offset the expected increases in renal blood flow and sodium excretion.