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 at least 10-14 days before surgery with gradual dose escalation until blood pressure targets are achieved 1, 2
• Blood pressure targets: <130/80 mmHg in supine position and systolic blood pressure >90 mmHg in upright position 1, 2
• Alpha-blocker options:
  • Phenoxybenzamine (non-selective, non-competitive α1 and α2 blocker): Start with 10 mg twice daily and adjust every 2-4 days 1, 3
  • Doxazosin, prazosin, or terazosin (selective α1 blockers): May be as effective with fewer side effects 1, 2
  • Phenoxybenzamine may provide less intraoperative hemodynamic instability compared to selective blockers 1, 2

Additional Preoperative Measures

• Add beta-blockers ONLY after adequate alpha blockade is established to control tachyarrhythmias 1, 2
  • Never start beta-blockers before alpha-blockers as this can precipitate hypertensive crisis 1, 2, 4
• Consider calcium channel blockers (nifedipine slow release) or metyrosine if target blood pressure is not reached with alpha blockade 1, 2
  • Metyrosine inhibits catecholamine synthesis and may improve intraoperative blood pressure control and reduce blood loss when combined with alpha-blockers 5, 6
• Implement high-sodium diet and administer 1-2 liters of saline 24 hours before surgery to prevent postoperative hypotension 2
• Use compressive stockings to reduce orthostatic hypotension risk 2

Intraoperative Management

• Be prepared to manage hypertension during surgery with:
  • Magnesium sulfate
  • Intravenous phentolamine (α-adrenoreceptor antagonist)
  • Calcium channel blockers
  • Nitroprusside or nitroglycerin 1, 2
• Have esmolol (short-acting beta-blocker) available to treat tachycardia 2
• Ensure adequate volume replacement to prevent hypotension 5, 7

Postoperative Care

• Monitor for hypotension and treat aggressively if it occurs 1, 2
• Monitor glucose levels carefully as hypoglycemia may occur after reduction of catecholamine levels 1, 2
• Perform biochemical testing 2-8 weeks after surgery to confirm complete tumor resection 2, 8

Special Considerations

• For patients with multifocal disease, prioritize resection of functional pheochromocytomas first 2
• In patients with bilateral pheochromocytomas, consider cortical-sparing techniques versus total adrenalectomy based on hereditary risk factors 2
• Laparoscopic approach is preferred for most pheochromocytomas, but open surgery should be considered for tumors >6 cm or with suspicion of malignancy 2

Common Pitfalls to Avoid

• Starting beta-blockers before adequate alpha blockade (can precipitate hypertensive crisis) 1, 2, 4
• Inadequate duration of preoperative alpha blockade (minimum 10-14 days needed) 1
• Insufficient volume expansion before surgery (increases risk of postoperative hypotension) 2, 5
• Failure to monitor for hypoglycemia postoperatively 1
• Inadequate intraoperative monitoring of hemodynamic parameters 5, 6

The evidence strongly supports that proper preoperative alpha-adrenergic blockade significantly reduces perioperative morbidity and mortality in patients with pheochromocytoma undergoing surgical resection 1, 2.