a trached and spontaneously breathing 62 y.o. male inpatient presents to OR for abdominal washout, and GA is required. milrinone is running at 20 mg/hr from the floor.

EF 25%
s/p CABG x 4
MI x 4 (last one two yrs ago)
chronic AF (on CCB)
baseline BP hanging around 100's-mid teens/50's

during the case, the blood pressure is dropping and you're just about as low on volatile as you can get. you need something to help out. what would your best choice be, and why?