Aclient returns to an intensive care unit after coronary artery bypass graft surgery, which was complicated by prolonged cardiopulmonary bypass and hypotension. after 3 hours in the unit, the client's condition stabilizes. however, the urine output has decreased despite adequate filling pressures. the nurse expects the physician to add which drug, at which flow rate, to the client's regimen? a. dopamine (intropin), 3 mcg/kg/minuteb. dobutamine (dobutrex), 10 mcg/kg/minutec. epinephrine, 4 mcg/kg/minuted. norepinephrine (levophed), 8 mcg/minute