Pheochromocytoma and the Role of Remifentanyl during Adrenalectomy

In the past few years, I have had a few encounters with pheochromocytoma cases. It gave me an opportunity to compare different anesthetic techniques in managing the laparoscopic adrenal mass resection case. The traditional anesthetic management includes vasodilators and vasopressors to control hemodynamic changes in response to adrenaline resection. The first 2 cases of pheochromocytoma cases I did were managed with vasodilators such as phentolamine, nitroglycerin or SNP and vasopressors. However, this anesthetic regimen has its drawbacks. First of all, it plays a catch-up game when the BP drastically changes in response to the tumor manipulation or surgical stimulation. It may take up to 2-5 minutes to normalize the BP. For example, I remember in both cases, BP increased to above 200 systolic in response to stimulation. In addition,  often times, vasopressors will be needed following removal of tumor.

The 3rd case of pheochromcytoma I did was managed with remifentanyl. As we know, remifentanil exerts both depressor and bradycardic actions. It is short-acting and can be easily titrated based on the BP.  With the remifantanil based anesthetic management, There was less extreme BP fluctuation intraoperatively, less use of vasopressor support post tumor resection.

There are several case reports on using remifantanil infusion for successfully managing the hemodynamics intraoperatively. Shimoyama et al. reported using high dose of remifentanil infusing up to 5mcg/kg/min successfully avoided the swing of BP upon surgical stimulation, tracheal intubation as well as tumor manipulation. The other case by Baraka et al. reported the use of reifentanil up to 1.5mcg/kg/min but was not able to abolish the stimulation caused by manipulation of tumor. Vasodilators were used with remifentanil during pneumoperitoneum as well as tumor manipulation. It appears that the liberal use of remifentanil for the anesthetic management of pheochromocytoma resection appears effective in managing hemodynamics during resection. Small dose of vasodilators could be used to facilitate the normalization of BP during manipulation of tumor. In the case reports, arterial systolic was successfully maintained no higher than 150mmHg with liberal use of remifentanil infusion. Minimal pressors were used post tumor resection in the high dose remifentanil cases.

In conclusion, it appears that remifentanil could be used as a depressor to successfully abolish reflex stimulation such as surgical incision and tracheal intubation. High dose of remifentanil could be used in conjunction of vasodilators to suppress response to tumor manipulation. Compared to traditional anesthetic management with the vasodilators and vasopressors, patient treated with remifentanil appeared to be more hemodynamically stable.

References:

Shimoyama Y1Masuda RSuzuki TSerada K.Successful anesthetic management of three patients receiving pheochromocytoma resection using extremely high-dose remifentanil infusion. Shimoyama Y1Masuda RSuzuki TSerada K.

Baraka A1Siddik SAlameddine M. Remifentanil for modulation of hemodynamics in a patient undergoing laparoscopic resection of pheochromocytoma. Middle East J Anaesthesiol. 2004 Feb;17(4):585-92.

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