Outline the anesthetic choices for pheochromocytoma.
Because this disease is rare, few data are available from controlled studies as to the benefit of one anesthetic over another. From numerous case reports and retrospective reviews one can reach several conclusions. One is that there is little difference in the choice of anesthesia for this condition with respect to outcome or incidence of intraoperative complications. What matters far more is the previously discussed preoperative vasodilation and intravascular volume expansion. Epidural anesthesia has not been shown to be more effective than general anesthesia in reducing hemodynamic complications or the requirements for vasoactive medications.
All the potent inhalation agents available today have been used safely with this condition. Halothane appears to be the least acceptable, mostly because of its negative inotropic properties and potentiation of catecholamine-induced ventricular dysrhythmias. Both enflurane and isoflurane have been used extensively with little documented advantage of one agent over the other. The use of the newer inhalation agents, sevoflurane and desflurane, has been described in case reports.
Narcotic anesthesia may have some specific theoretical advantages over inhalation anesthesia, including few or no negative inotropic effects and reduced dysrhythmogenic potential. Droperidol releases catecholamines from the adrenal medulla and should be avoided. It is probably more important for the anesthesiologist to choose a technique that he or she is most comfortable with and that is suitable for resection of an intra-abdominal tumor than to try to achieve minor theoretical advantages from unfamiliar drugs.
The choice of neuromuscular blocking agent varies widely. Succinylcholine has been used safely with this condition, but fasciculations may cause a release of cate-cholamines from the tumor. Some nondepolarizing muscle relaxants, especially curare and atracurium, may cause the release of histamine, which in turn may cause a release of catecholamines and subsequent hypertension. These drugs should be avoided when possible. Pancuronium, with its vagolytic side-effects, may cause tachycardia, which may be confusing. Vecuronium, rocuronium, and cisatracurium are logical choices for muscle relaxation.