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Difficulty: HardPharmacologic Interventions

A 42-year-old man is diagnosed with a 5-cm right adrenal pheochromocytoma after presenting with episodic palpitations, diaphoresis, and severe hypertension. He is scheduled for a laparoscopic adrenalectomy in 14 days. His current blood pressure is 185/110 mmHg, and his heart rate is 98/min. To ensure optimal surgical outcomes and minimize perioperative complications, an escalating protocol of hemodynamic management is required.

Arrange the following pharmacologic interventions in the correct chronological sequence of administration, from 14 days preoperatively through to the intraoperative period.

  1. 1Initiate oral phenoxybenzamine therapy
  2. 2Initiate oral propranolol therapy
  3. 3Administer intravenous normal saline
  4. 4Administer intravenous nitroprusside

Answer

The correct sequence is: 1) Initiate oral phenoxybenzamine therapy, 2) Initiate oral propranolol therapy, 3) Administer intravenous normal saline, 4) Administer intravenous nitroprusside.
The correct chronological sequence ensures patient safety by preventing perioperative hypertensive crises and post-resection cardiovascular collapse. Alpha-adrenergic blockade (phenoxybenzamine) must be initiated 10-14 days before surgery to lower blood pressure and allow for initial volume expansion. Beta-adrenergic blockade (propranolol) is subsequently added 2-3 days preoperatively to manage tachycardia, strictly after alpha-blockade is achieved to prevent unopposed alpha vasoconstriction. Immediately prior to anesthetic induction, intravenous normal saline is administered to fully reverse chronic volume contraction and prepare the patient for the sudden drop in catecholamines post-resection. Finally, during surgical manipulation, transient hypertensive emergencies are managed with short-acting intravenous agents like nitroprusside.

Step-by-Step Solution

1
Identify the initial preoperative intervention (10-14 days prior to surgery).
Oral phenoxybenzamine is placed first.
Patients with pheochromocytoma require alpha-blockade to normalize blood pressure and begin expanding the chronically contracted intravascular volume.
2
Determine the subsequent preoperative intervention (2-3 days prior to surgery).
Oral propranolol is placed second.
Once adequate alpha-blockade is established, beta-blockade is added to control tachycardia. Reversing this order is contraindicated.
3
Select the immediate pre-induction intervention.
Intravenous normal saline is placed third.
Despite oral hydration during the preoperative period, patients require aggressive intravenous volume expansion just prior to surgery to prevent profound hypotension once the catecholamine source is removed.
4
Identify the intraoperative intervention.
Intravenous nitroprusside is placed fourth.
Surgical manipulation of the gland causes catecholamine surges, necessitating immediate access to rapid-acting intravenous vasodilators during the procedure.

Key Concept

In the perioperative management of pheochromocytoma, irreversible alpha-adrenergic blockade must always precede beta-adrenergic blockade to prevent unopposed alpha stimulation. This is followed by volume expansion and readiness for intraoperative vasodilator therapy.
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Pharmacologic Interventions

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