What are the management strategies for a patient with untreated pheochromocytoma undergoing emergency aortic rupture surgery?

From the Guidelines

Management of a patient with untreated pheochromocytoma undergoing emergency aortic rupture surgery requires immediate alpha-adrenergic blockade followed by beta-blockade to control catecholamine-induced hypertensive crisis, as recommended by the most recent guidelines 1. The initial step should be to establish alpha-adrenergic blockade using intravenous phentolamine (2-5 mg boluses) or phenoxybenzamine (10-20 mg orally if time permits) to counteract the effects of excessive catecholamines released by the pheochromocytoma 1. Once alpha blockade is established, beta-blockers such as esmolol (50-300 μg/kg/min) or metoprolol (5 mg IV increments) can be added to prevent reflex tachycardia, but it is crucial to avoid using beta-blockers alone as this can worsen hypertension due to unopposed alpha-adrenergic stimulation 1. Key considerations in the management include:

• Volume expansion with crystalloids before and during surgery to counteract catecholamine-induced vasoconstriction
• Use of anesthesia induction agents that minimize catecholamine release, such as etomidate or propofol, while avoiding histamine-releasing medications like morphine
• Maintenance of hemodynamic stability with continuous arterial pressure monitoring
• Preparation for post-tumor manipulation hypotension with vasopressors like norepinephrine
• Use of magnesium sulfate (2-4 g IV) to help control blood pressure and arrhythmias
• Close coordination between the anesthesia team and surgeons to anticipate blood pressure fluctuations during aortic cross-clamping and tumor manipulation, with calcium channel blockers like nicardipine available for breakthrough hypertension 1.

From the FDA Drug Label

INDICATION AND USAGE Phenoxybenzamine hydrochloride capsules are indicated in the treatment of pheochromocytoma, to control episodes of hypertension and sweating. If tachycardia is excessive, it may be necessary to use a beta-blocking agent concomitantly. The FDA drug label does not answer the question.

From the Research

Management Strategies for Aortic Rupture Surgery with Untreated Pheochromocytoma

• In cases where a patient with untreated pheochromocytoma requires emergency aortic rupture surgery, management strategies are crucial to prevent severe hemodynamic instability 2.
• Preoperative pharmacological treatment is essential to control blood pressure and reduce the risk of hypertensive crisis during surgery 2, 3.
• The use of alpha-blockers such as phenoxybenzamine or prazosin, and beta-blockers like carvedilol, can help control blood pressure and heart rate 2, 3, 4.
• Metyrosine, a catecholamine synthesis inhibitor, can be used in combination with alpha-blockers to reduce the risk of hypertensive crisis during surgery 2.
• In cases where beta-blockers are used, it is essential to ensure adequate alpha-blockade to prevent unopposed beta-blockade, which can trigger a pheochromocytoma crisis 3.

Diagnostic and Therapeutic Procedures

• Diagnostic procedures such as 24-hour blood pressure monitoring, biochemical tests, and imaging studies can help diagnose pheochromocytoma 5.
• Genetic analysis should be performed in all confirmed cases of pheochromocytoma, especially in young patients under 50 years of age 5.
• Pharmacological treatment using alpha or beta receptor blockers, followed by laparoscopic excision of the tumor, is usually successful in benign forms of pheochromocytoma 5.
• Perioperative management of severe hypertension during laparoscopic surgery for pheochromocytoma requires careful monitoring and the use of medications such as sodium nitroprusside and remifentanil 6.

Considerations for Emergency Surgery

• In emergency situations where a patient with untreated pheochromocytoma requires aortic rupture surgery, the anesthesiologist and surgical team must be prepared to manage potential hypertensive crises 2, 6, 4.
• Close monitoring of blood pressure and heart rate, as well as the use of medications to control blood pressure, are crucial during emergency surgery 6.
• The use of alpha-blockers and beta-blockers, as well as other medications, should be carefully considered and titrated to prevent hypertensive crises and ensure a stable perioperative course 2, 3, 4.