A 45-year-old man is evaluated for treatment-resistant hypertension, episodic severe headaches, and diaphoresis. Laboratory testing reveals markedly elevated plasma fractionated metanephrines. Magnetic resonance imaging of the abdomen demonstrates a 5-cm right adrenal mass. The patient is scheduled for a laparoscopic adrenalectomy in 14 days.
Arrange the following interventions in the correct chronological sequence for this patient's perioperative pharmacologic management.
- 1Initiate oral phenoxybenzamine
- 2Encourage a high-sodium diet and oral fluid intake
- 3Initiate oral propranolol
- 4Administer intravenous phentolamine
Cevap
The correct chronological sequence is to first initiate oral phenoxybenzamine, followed by a high-sodium diet and fluid intake, then initiate oral propranolol, and finally administer intravenous phentolamine as needed intraoperatively.
The perioperative management of pheochromocytoma requires a strict temporal sequence to prevent lethal hemodynamic instability. First, alpha-blockade (e.g., phenoxybenzamine) is initiated 10 to 14 days prior to surgery to control blood pressure and relieve chronic vasoconstriction. As the vasculature dilates, underlying volume depletion is unmasked, requiring aggressive volume expansion with a high-sodium diet and fluids a few days later. Once adequate alpha-blockade and volume expansion are achieved (typically 2 to 3 days prior to surgery), a beta-blocker (e.g., propranolol) is added to control catecholamine-induced tachycardia. Finally, during surgical resection, rapid release of catecholamines is managed with short-acting intravenous agents like phentolamine.
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Preoperative pharmacologic preparation for pheochromocytoma requires alpha-blockade prior to beta-blockade to prevent unopposed alpha-adrenergic stimulation and paradoxical hypertensive crisis.
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