How to prepare a patient with pheochromocytoma for surgery?

Preoperative Management of Pheochromocytoma for Surgery

All patients with pheochromocytoma should receive preoperative alpha-adrenergic blockade for at least 10-14 days before surgery to prevent hypertensive crises and arrhythmias during the procedure. 1

Alpha-Adrenergic Blockade Protocol

• Begin alpha-adrenergic blockade 10-14 days before surgery with specific blood pressure targets of <130/80 mmHg in the supine position and systolic blood pressure >90 mmHg in the upright position 1, 2
• Two main options for alpha blockade:
  • Non-selective, non-competitive alpha-blocker: Phenoxybenzamine (FDA-approved for pheochromocytoma) 3
    • Starting dose: 10 mg twice daily with adjustments every 2-4 days 1
  • Selective alpha-1 blockers: Doxazosin, prazosin, or terazosin 1, 2
    • May have fewer side effects than phenoxybenzamine 1
    • Phenoxybenzamine may provide less intraoperative hemodynamic instability compared to selective blockers 1, 2

Additional Preoperative Medications

• Beta-blockers should ONLY be added after adequate alpha blockade if tachyarrhythmias develop 1, 2, 3
  • Never start beta-blockers before alpha-blockers as this can precipitate a hypertensive crisis 1, 2
• If target blood pressure is not achieved with alpha blockade alone, consider:
  • Calcium channel blockers (nifedipine slow release) 1, 2
  • Metyrosine (alpha-methyl-p-tyrosine) - inhibits catecholamine synthesis 1, 4, 5
    • Studies suggest the combination of metyrosine with alpha-blockers results in better blood pressure control, less blood loss, and reduced need for intraoperative medications 4, 5

Volume Expansion

• High-sodium diet and administration of 1-2 liters of saline 24 hours before surgery 2
• Use compressive stockings to reduce the risk of orthostatic and postoperative hypotension 2
• Adequate volume expansion is crucial to prevent postoperative hypotension 1

Intraoperative Management

• Be prepared to manage hypertensive episodes with:
  • Magnesium sulfate 1
  • Intravenous alpha-adrenergic antagonist (phentolamine) 1
  • Calcium channel blockers 1
  • Nitroprusside or nitroglycerin 1, 2
• For tachycardia, use intravenous beta-blockers such as esmolol 1, 2
• Monitor for hypotension after tumor removal, which should be treated aggressively with fluid resuscitation 1, 2

Postoperative Care

• Monitor glucose levels carefully as hypoglycemia may occur after reduction of catecholamine levels 1, 2
• Continue hemodynamic monitoring for 24-48 hours postoperatively 6
• Biochemical testing should be performed 2-8 weeks after surgery to confirm complete resection 2, 7

Common Pitfalls to Avoid

• Never starting beta-blockers before adequate alpha blockade 1, 2, 8
• Inadequate duration of preoperative alpha blockade (should be at least 10-14 days) 1
• Insufficient volume expansion, leading to postoperative hypotension 1, 2
• Failure to monitor for hypoglycemia after tumor removal 1, 2

Special Considerations

• For bilateral pheochromocytomas, functional tumors should be resected as an initial priority 2
• In patients with hereditary syndromes, consider cortical-sparing techniques versus total adrenalectomy 2
• Laparoscopic approach is preferred for most pheochromocytomas, but open surgery should be considered for tumors >6 cm or with suspicion of malignancy 2

This protocol optimizes preoperative management to minimize perioperative morbidity and mortality in patients undergoing surgery for pheochromocytoma.