Current perioperative management of pheochromocytomas

Neuroendocrine tumors which have the potential to secrete catecholamines are either associated with sympathetic adrenal (pheochromocytoma) or nonadrenal (paraganglioma) tissue. Surgical removal of these tumors is always indicated to cure and prevent cardiovascular and other organ system complications associated with catecholamine excess. Some of these tumors have malignant potential as well. The diagnosis, localization and anatomical delineation of these tumors involve measurement of catecholamines and their metabolic end products in plasma and urine, ¹²³I-metaiodobenzylguanidine scintigraphy, computed tomography, and/or magnetic resonance imaging. Before surgical removal of the tumors, the optimization of blood pressure, as well as intravascular volume, is an important measure to avoid and suppress perioperative adverse hemodynamic events. Preoperative preparation includes the use of alpha-adrenergic antagonists, beta-adrenergic antagonists with or without other antihypertensive agents, fluid therapy as well as insulin therapy for hyperglycemia if required. Due attention should be given to type and dose of alpha-receptor antagonists to be used and the duration of this therapy to achieve an optimal level of preoperative "alpha-blockade." Despite this preoperative preparation, many patients will have hypertensive crises intraoperatively which need to be promptly and carefully managed by the anesthesia team which requires intensive and advanced monitoring techniques. The most common complication after tumor removal is hypotension which may require fluid therapy and vasopressor support for a few hours. With advancement in surgical and anesthetic techniques, the incidence of severe morbidity and mortality associated with the surgery is low in high volume centers.