Effects of Vasopressors on Circulation of Porcine Abdominal Island Flap Model

Abstract

OBJECTIVES: During reconstructive surgical procedures, systemic vasopressors are frequently used to maintain normal blood pressure. However, questions have arisen regarding the pharmacologic effects of vasopressors on flap circulation. Many plastic surgeons have expressed concern about the possibility of impaired flap circulation caused by the vasoconstrictive effect of the drugs. However, the opposing argument exists that the increase of mean arterial pressure from vasoactive agents may improve flap perfusion. The purpose of this study was to evaluate the effect of commonly used vasopressors on flap circulation. MATERIALS AND METHODS: The vertical rectus abdominis myocutaneous island flap was raised in 5 female pigs (38.2~40.7 kg). Hemodynamic parameters were measured continuously by carotid arterial catheter. A bidirectional transonic vascular Doppler flow probe and laser Doppler perfusion monitor unit were applied to record the continuous change of pedicle artery flow and microvascular perfusion following intravenous administration of dopamine (3, 5, 10 μg/kg/min), dobutamine (1.25, 2.5, 5 μg/kg/min), and norepinephrine (0.05, 0.1, 0.2 μg/kg/min). RESULTS: Both microvascular perfusion and pedicle flow were generally proportional to mean arterial pressure, and all the 3 vasopressors improved flap perfusion and pedicle flow without deleterious effect. Norepinephrine showed that the highest microvascular perfusion and dobutamine showed the highest pedicle flow rate. Mean blood pressure was the only statistically significant factor that affects both microvascular perfusion and pedicle flow (P < 0.0001). CONCLUSIONS: Our results strongly suggest that the foremost 3 vasopressors can be used for flap surgery without deterioration, and maintaining adequate systemic blood pressure is crucial for good flap circulation.