Discussion: Selective Intraoperative Vasopressor Use Is Not Associated with Increased Risk of DIEP Flap Complications

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Excerpt

Most plastic surgeons who have performed free flaps may have had conflicting experience when patients undergo hypotension during general anesthesia regarding whether or not to use vasopressors to maintain the stability of the patient. Even after deciding to use vasopressors, we tend to avoid epinephrine because of the fear of inducing vasospasm, which may lead to flap complications. This tendency comes a bit from anecdotal teachings and from experience. Reading the article from Orgill and colleagues, it may now give microsurgeons peace of mind when faced with a hypotensive patient during free flap surgery.
The authors present a retrospective analysis of using vasopressors in 475 consecutive deep inferior epigastric perforator (DIEP) flap cases in 333 patients. They report that ephedrine administration was significantly associated with a decreased risk of intraoperative flap complications (OR, 0.88), including vasospasm, thrombosis, and congestion requiring revision compared with controls, after controlling for the severity and duration of hypotension. This does make a strong argument, as the elevated cardiac output will increase both pedicle artery blood flow and microvascular flap perfusion They also report that phenylephrine had no significant association with complication rates. They conclude that ephedrine treatment for hypotension during DIEP flap cases is associated with decreased intraoperative flap complication rates compared with controls who did not receive vasopressors, whereas phenylephrine has no significant association.
Based on our experience, we generally agree with the authors that use of vasopressors will not bring harm to the flap in healthy patients. However, to see that it may even decrease the risk of complications comes as a pleasant surprise and something worth noting to minimize the fear of using vasopressors during a hypotensive event during surgery. This may be more evident for reconstructive procedures close to the heart such as breast, upper extremity, and head and neck reconstruction, as the perfusion pressure may remain relatively high compared with the distal flow. It would be interesting to see whether this finding will be the same for extremity reconstruction or patients with systemic risks such as peripheral vascular disease. Although the use of vasopressors will not affect flap flow after denervation, there is the theoretical likelihood that distal flow to the extremity itself can be reduced, leading to decreased perfusion to the flap as a consequence.1,2 In this sense, one should be aware of using vasopressors when recipient arteries are far from the heart. Another interesting question in the future will be how to address the hypotensive events after the patient has woken from anesthesia. The same principle may apply, and application of vasopressors during postoperative hypotensive events needs to be evaluated further. Finally, if guidelines regarding dosage or how to apply vasopressors can be established from the flap perfusion perspective, it could provide further confidence with regard to its use. In this view, finding the optimal vasopressor and the dosage regarding flap perfusion will be the task for the future.
We want to congratulate the authors for reporting new insight and evidence with regard to flap outcome when using selective vasopressors during surgery in hypotensive situations. We hope not only to see additional studies from the authors but also to challenge readers to further clarify the dosage, use with regard to recipient artery location, and possible application in hypotensive events during the initial recovery phase.
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