What is the recommended anesthetic management for adrenal tumor resection, including pre‑operative preparation based on the tumor’s hormonal activity and intra‑operative monitoring and drug protocols?

Anesthetic Management of Adrenal Tumors

Pre-operative Preparation Based on Hormonal Activity

All patients with adrenal tumors must undergo comprehensive hormonal screening before surgery, with specific pre-operative medical optimization protocols tailored to the tumor's endocrine activity to prevent life-threatening perioperative complications. 1

Mandatory Hormonal Screening

• Screen all patients for pheochromocytoma using plasma-free metanephrines OR urinary-fractionated metanephrines, as failure to identify catecholamine-secreting tumors can result in fatal hypertensive crises and arrhythmias during surgery 1, 2
• Screen all patients for autonomous cortisol secretion using the 1 mg overnight dexamethasone suppression test (cortisol cutoff ≤50 nmol/L or ≤1.8 μg/dL) regardless of clinical symptoms 1, 2
• Screen patients with hypertension and/or hypokalemia for primary aldosteronism using the aldosterone-to-renin ratio 2

Pheochromocytoma/Paraganglioma Pre-operative Protocol

All patients with confirmed pheochromocytoma must receive alpha-blockade for at least 10-14 days before surgery to prevent intraoperative hypertensive crises 1

• Start with phenoxybenzamine 10 mg twice daily, adjusting every 2-4 days to achieve blood pressure targets of <130/80 mmHg supine and systolic >90 mmHg upright 1
• Alternative: doxazosin (selective α1-antagonist) may be equally effective with fewer side effects 1
• Add calcium channel blockers (nifedipine slow release) or metyrosine if target blood pressure is not achieved with alpha-blockade alone 1
• Beta-blockers should NEVER be started before alpha-blockade is established, but may be added for tachyarrhythmias after adequate alpha-blockade 1
• Administer intravenous saline the day before surgery to prevent postoperative hypotension 1

Cortisol-Secreting Tumors Pre-operative Protocol

All patients with glucocorticoid excess (overt Cushing's syndrome or mild autonomous cortisol secretion) must receive perioperative hydrocortisone supplementation to prevent adrenal crisis 1

• Administer hydrocortisone 150 mg/day during surgery and postoperatively 1
• Pre-operative optimization should address associated comorbidities including hypertension, diabetes mellitus, osteoporosis, increased infection risk, and thromboembolism risk 3

Aldosterone-Secreting Adenomas Pre-operative Protocol

• Pre-operative treatment with spironolactone is highly recommended to correct hypokalemia and metabolic alkalosis 3
• Optimize blood pressure control and correct electrolyte abnormalities before surgery 3

Intra-operative Monitoring and Management

For Pheochromocytoma/Paraganglioma

Intraoperative hypertensive crises require immediate aggressive treatment with short-acting agents:

• First-line agents for hypertension: magnesium sulfate, intravenous phentolamine (α-antagonist), calcium channel blockers, nitroprusside, or nitroglycerin 1
• For tachycardia: intravenous esmolol (β-blocker) only after adequate alpha-blockade 1
• Aggressive treatment of postoperative hypotension with intravenous fluids is essential 1
• Monitor glucose levels closely postoperatively as hypoglycemia may occur after catecholamine reduction 1

For All Hormone-Secreting Tumors

• Continuous invasive blood pressure monitoring is essential given the risk of rapid hemodynamic fluctuations 4, 5
• Central venous access should be considered for vasopressor/fluid administration 5
• Careful fluid management to prevent both hypovolemia and fluid overload 5

Surgical Approach Considerations

Minimally invasive surgery (laparoscopic adrenalectomy) should be performed when feasible for most adrenal tumors, as it reduces blood loss and complications 1

Key Surgical Principles

• For suspected adrenocortical carcinoma <6 cm without local invasion, laparoscopic approach may be safe in experienced centers with strict adherence to oncological principles 1
• Convert to open surgery immediately if involvement of surrounding tissues is discovered or capsular rupture risk exists during laparoscopy 1
• For tumors invading adjacent organs, en bloc resection of involved structures (vena cava, liver, spleen, colon, pancreas, stomach) may be necessary for R0 resection 1
• Concomitant nephrectomy is NOT recommended for adrenocortical carcinoma not invading the kidney, as it does not improve survival 1

Critical Perioperative Pitfalls

• Never perform surgery on pheochromocytoma without adequate alpha-blockade (minimum 10-14 days) as this can result in fatal hypertensive crisis 1
• Never start beta-blockers before alpha-blockade in pheochromocytoma patients, as unopposed alpha-stimulation can cause severe hypertension 1
• Never omit hydrocortisone supplementation in patients with any degree of cortisol excess (including "subclinical"), as adrenal crisis can be fatal 1
• Patients with cortisol excess have vulnerable skin, increased infection risk, and thromboembolism risk requiring specific precautions 3
• Biopsy of adrenal masses is rarely indicated and should only be considered in highly specific cases after multidisciplinary discussion 1