Effects of Vasopressor on the Graft Blood Flow in TRAM

The purpose of this pilot study is to investigate whether two major vasopressors (norepinephrine vs. phenylephrine) used for treatment of hypotension during breast reconstruction with free flap transfer surgery have different effects on blood flow of the flap vessel measured by transit time flowmetry. Since there are few prior studies that compared the effects of these two vasopressors on the blood flow of the flap, this study will be conducted in the form of a pilot study in order to establish the evidence for the future randomized controlled trial.