Saturday March 7, 2009


Q: Which pressor is preferable to counter-act vasodilatation (hypotension) induced by milrinone during or immediate post-op Coronary bypass surgery? (choose one)

A) Norepinephrine
B) Dopamine
C) Vasopressin
D) Phenylepherine


Answer: Vasopressin

Phosphodiesterase inhibitor is used during coronary bypass surgery in management of decompensated heart failure because it increases contractility and decreases afterload of right ventricle. It also improves hemodynamics and increases blood flow of the grafted internal mammary arteries and middle cerebral arteries during coronary artery bypass surgery. However, it induces vasodilation and necessitates the use of vasoconstrictors.

In the patients undergoing CABG surgery, both norepinephrine and low dose vasopressin were effective in restoring milrinone-induced decrease of SVR. However, only low-dose vasopressin decreased the PVR/SVR ratio that was increased by milrinone. Considering the importance of maintaining systemic perfusion pressure as well as reducing right heart afterload, milrinone–vasopressin may provide better hemodynamics than milrinone–norephinephrine during the management of right heart failure.

SVR = systemic vascular resistance
PVR = pulmonary vascular resistance


Reference: Click to get abstract

Comparative hemodynamic effects of vasopressin and norepinephrine after milrinone-induced hypotension in off-pump coronary artery bypass surgical patients - European Journal of Cardio-Thoracic Surgery, Volume 29, Issue 6, Pages 952-956 (June 2006)