Anaesthetic Considerations for Adrenalectomy
Pre-operative Endocrine Evaluation
Every patient scheduled for adrenalectomy must undergo comprehensive functional testing to identify hormone-secreting tumors, as this fundamentally determines perioperative management and risk stratification. 1, 2
Screen all patients for pheochromocytoma/paraganglioma using plasma or urinary metanephrines, as massive catecholamine release during tumor manipulation can cause life-threatening hypertensive crises, cerebrovascular events, and multi-system crisis. 1, 2
Test for cortisol excess (Cushing's syndrome or mild autonomous cortisol secretion) via 1-mg dexamethasone suppression test or 24-hour urinary free cortisol, because these patients have suppressed hypothalamic-pituitary-adrenal (HPA) axes and will develop acute adrenal insufficiency immediately post-resection. 3, 4, 1
Evaluate for primary aldosteronism with aldosterone-to-renin ratio and confirmatory testing, as chronic aldosterone excess causes hypertension, hypokalemia, and end-organ cardiovascular and renal damage that increase perioperative risk. 1, 2
Optimize all metabolic and cardiovascular comorbidities pre-operatively—including hypertension, diabetes, electrolyte disorders, and volume status—as hormone-related organ damage significantly elevates surgical morbidity. 3, 1, 2
Specific Pre-operative Preparation for Functional Tumors
For pheochromocytoma: initiate selective alpha-1 blockade (e.g., doxazosin) at least 7–14 days before surgery to prevent intraoperative hypertensive crises; add beta-blockade only after adequate alpha-blockade to avoid unopposed alpha-stimulation. 5, 2
For cortisol-secreting tumors: arrange endocrinology consultation to plan immediate postoperative glucocorticoid replacement, as the contralateral adrenal and HPA axis will be profoundly suppressed and unable to respond to surgical stress. 3, 4
Discontinue metformin 24–48 hours pre-operatively to reduce the risk of perioperative lactic acidosis, particularly when renal perfusion may be transiently compromised. 3
Intra-operative Haemodynamic Management
Administer hydrocortisone 100 mg intravenously at induction of anaesthesia for all patients with confirmed or suspected cortisol-secreting tumors or pre-existing adrenal insufficiency, followed immediately by continuous infusion of hydrocortisone 200 mg over 24 hours. 6, 7, 3
This continuous infusion regimen is superior to intermittent bolus dosing for maintaining physiologic cortisol levels during surgical stress and preventing adrenal crisis. 7
If intravenous access is unavailable or impractical, use intramuscular hydrocortisone 50 mg every 6 hours as an acceptable alternative. 6, 7
Haemodynamic Monitoring and Support
Anticipate profound haemodynamic instability during pheochromocytoma resection, with hypertensive crises occurring in approximately 15% of cases despite adequate alpha-blockade, and hypotensive crises in 5–8% of patients. 5
Prepare vasopressors (phenylephrine, norepinephrine) and short-acting antihypertensives (sodium nitroprusside, nicardipine) before tumor manipulation, as catecholamine surges can occur abruptly during handling of the adrenal gland. 5, 2
Consider invasive arterial blood pressure monitoring for all pheochromocytomas and large adrenal masses, as rapid blood pressure fluctuations require real-time monitoring and immediate pharmacologic intervention. 7, 2
Monitor for volume-resistant hypotension in patients with cortisol excess, as chronic hypercortisolism impairs alpha-adrenergic receptor responsiveness to endogenous and exogenous catecholamines. 3
Critical Anaesthetic Drug Considerations
Avoid etomidate for induction whenever possible, as it suppresses cortisol synthesis via 11-β-hydroxylase inhibition and can precipitate acute adrenal insufficiency in vulnerable patients. 7
Do not use dexamethasone as sole glucocorticoid therapy in patients with primary adrenal insufficiency or bilateral disease, because it lacks mineralocorticoid activity and its long half-life makes dose titration difficult. 6, 7, 3
Postoperative Adrenal Support
Continue hydrocortisone infusion at 200 mg per 24 hours until the patient tolerates oral intake, then switch to double the usual oral maintenance dose (typically 40–50 mg hydrocortisone daily in divided doses). 6, 7
Taper to normal maintenance doses within 48 hours for uncomplicated procedures; extend the taper up to 7 days for major or complicated surgeries, guided by clinical recovery. 6, 7, 3
For patients undergoing resection of cortisol-secreting tumors, expect prolonged tertiary adrenal insufficiency lasting weeks to months, as the contralateral adrenal gland and HPA axis have been chronically suppressed and cannot mount an adequate stress response. 4
Provide all at-risk patients with a steroid emergency card and medical-alert bracelet to ensure rapid recognition and treatment of adrenal crisis in any future acute illness or emergency. 3
Monitoring for Adrenal Crisis
Maintain high vigilance for early signs of impending adrenal crisis: non-specific malaise, somnolence, decreased consciousness, cognitive dysfunction, orthostatic hypotension, persistent fever despite antibiotics, and hyponatremia. 7, 3, 4
Volume-resistant hypotension is a late and potentially fatal sign; earlier recognition and treatment of subtle symptoms can prevent cardiovascular collapse. 7, 4
Do not reduce or withdraw steroid supplementation while the patient remains febrile or clinically unstable, as infection and sepsis are common triggers for adrenal crisis. 6
Manage patients who develop major postoperative complications in a critical care environment with intensive monitoring and continued stress-dose glucocorticoid infusion until clinical stability is achieved. 6, 3
Surgical Approach Considerations
Laparoscopic adrenalectomy is the preferred approach for most benign adrenal lesions ≤6 cm, including functional tumors, as it reduces postoperative pain, shortens hospital stay (mean 3.2 days vs. 5–7 days), and accelerates return to normal activity. 6, 8, 9
Pheochromocytoma is not a contraindication to laparoscopic adrenalectomy; laparoscopic and open approaches produce similar hemodynamic changes, and minimally invasive surgery does not increase conversion rates or complications when performed by experienced surgeons. 5, 9
Consider open adrenalectomy for lesions >6–8 cm, suspected adrenocortical carcinoma, or tumors with evidence of local invasion or venous involvement, as these features increase the risk of incomplete resection and peritoneal dissemination with laparoscopic techniques. 6, 8, 9
Conversion from laparoscopic to open surgery occurs in approximately 5% of cases, most commonly for large tumors (>6 cm) or unexpected intraoperative bleeding; this should not be considered a complication but rather appropriate surgical judgment. 5, 9
Special Populations
Pediatric Patients
Children with adrenal insufficiency are more vulnerable to perioperative hypoglycemia than adults; therefore, initiate hourly blood glucose monitoring if pre-operative fasting exceeds 4 hours, and never fast a child with adrenal insufficiency for more than 6 hours. 6
Prioritize pediatric adrenal patients as first cases on the surgical list to minimize fasting time and metabolic stress. 6, 7
Dosing for children: administer hydrocortisone 2 mg/kg IV at induction, followed by continuous infusion based on weight: up to 10 kg = 25 mg/24 h; 11–20 kg = 50 mg/24 h; >20 kg prepubertal = 100 mg/24 h; pubertal = 150 mg/24 h. 6, 7
Obstetric Patients
Women with adrenal insufficiency may require higher maintenance glucocorticoid doses after 20 weeks gestation to meet increased physiologic demand during pregnancy. 6, 7, 4
At the onset of labor or for cesarean section, administer hydrocortisone 100 mg IV, followed by continuous infusion of 200 mg/24 h or 50 mg IM every 6 hours until after delivery. 6, 4
Critical Pitfalls to Avoid
When uncertainty exists about adrenal function, always administer glucocorticoids; short-term use carries minimal long-term risk (transient hyperglycemia, fluid retention), whereas omission can be fatal. 6, 7
Never delay stress-dose steroid administration based on preoperative cortisol levels alone, as surgical stress requires supplementation even in patients with borderline-normal baseline function. 3
Do not stop stress-dose steroids abruptly; gradual tapering over 48 hours to 7 days (depending on surgical complexity and clinical recovery) prevents rebound adrenal insufficiency. 3, 4
Consider higher hydrocortisone dosing in obese patients or those receiving CYP3A4-inducing drugs (e.g., phenytoin, rifampin), as these factors increase cortisol clearance and may render standard doses inadequate. 7