You must check the BUN and creatinine to evaluate renal function. In hypovolemia, the BUN generally rises out of proportion to the creatinine, but significant elevations in creatinine may occur with isolated hypovolemia without underlying renal disease. Inotropic agents have a distinct mechanism of action. Dopamine is an intermediate product in the catecholamine pathway. The final product of this pathway is epinephrine and norepinephrine.
Dopamine is used in early septic shock and in distributive shock.
Dobutamine is principally used in cardiogenic shock or late septic shock. Additionally, there is vasodilatation, with a greater effect in the pulmonary vasculature. It is beneficial in patients with increased pulmonary vascular resistance.