Pardon the poor quality images.
Newborn, s/p Norwood procedure.
Upper panel shows arterial pressure traces from 2 different lines - Right radial arterial (Red) and Umbilical arterial lines (White). There is a "standing wave" or "fling" in the red trace. This is secondary to being a small/distal vessel, smaller catheter, and state of peripheral vascular tone (vasoconstricted state).
Lower panel shows the same patient, approx. 30 min after the loading dose of Milrinone. Presumably, there is adequate vasodilation of the peripheral artery that the "standing wave" or "fling" is no longer evident or not as prominent as before!
(Click on the images to enlarge)