Pheochromocytoma: preop preparation
Advanced, Clinical - Endocrine/Metabolic, Organ-Based and Clinical Sciences
Intro (Why does it Matter?)
Approximately 25% to 50% of hospital deaths in patients with pheochromocytoma occur during induction of anesthesia or during operative procedures for other causes.
Excessive sweating; headache; hypertension; orthostatic hypotension; previous hypertensive or arrhythmic response to induction of anesthesia or to abdominal examination; paroxysmal attacks of sweating, headache, tachycardia, and hypertension; glucose intolerance; polycythemia; weight loss; and psychological abnormalities.
Most specific test: Vanillylmandelic acid excretion
Most sensitive: abdominal CT
α-Adrenergic receptor blockade with prazosin or phenoxybenzamine restores plasma volume by counteracting the vasoconstrictive effects of high levels of catecholamines
β-Adrenergic receptor blockade with propranolol is suggested for patients who have persistent arrhythmias or tachycardia because these conditions can be precipitated or aggravated by α-adrenergic receptor blockade. β-Adrenergic receptor blockade should not be used without concomitant α-adrenergic receptor blockade lest the vasoconstrictive effects of the latter go unopposed and thereby increase the risk for dangerous hypertension.
Pheochromocytoma Preoperative Treatment and GoalsTreatment Regimen
- At least 10-14 days (there is no rush to remove these slow growing tumors)
- Alpha blockade (phenoxybenzamine) in all patients
- Beta blockade (propranolol) if arrhythmias/tachycardia persist
Goals on DOS
- No reading > 165/90 within 48 hours of surgery, including 1 hour of stressful readings (ex. PACU, SAS)
- Orthostatic hypotension should not be lower than 80/45
- No EKG ST or T changes
- PVCs less than one every 5 minutes