Anaesthesia for Adrenalectomy — non-phaeochromocytoma

Scope

This guideline does not cover phaeochromocytoma or paraganglioma. Where there is any doubt whether the tumour secretes catecholamines, use the phaeochromocytoma guideline and the local document Adrenalectomy for phaeochromocytoma (The Sheffield Approach), Dr M J Feast, 2024.

An overview of the process

The same operation as phaeochromocytoma adrenalectomy without the catecholamines, and haemodynamically far more stable. The difficulty is not the tumour but the position and the insufflation.

Carbon dioxide is insufflated at higher than normal pressure into the retroperitoneal space, and absorption rises sharply after approximately 45 minutes. Ventilation that is adequate at the start may not remain so. Position & ventilation.

Pre-op assessment

• Confirm the tumour is biochemically non-functioning before treating it as such. Plasma or urinary metanephrines should have been sent and reported as normal.

Conn's syndrome

• Check potassium and correct it before the day of surgery. Hypokalaemia causes arrhythmia and potentiates neuromuscular blockade.
• Spironolactone or eplerenone is usually running preoperatively and potassium should have normalised.
• A metabolic alkalosis may accompany the hypokalaemia.
• Assess the end-organ effects of long-standing hypertension.

Cushing's syndrome

• Anticipate a difficult airway and difficult positioning — central obesity, moon face, interscapular fat pad and a short neck.
• Diabetes or impaired glucose tolerance is common.
• Hypertension, fluid retention and hypokalaemic alkalosis.
• Osteoporosis and fragile skin. Positioning requires particular care and the check should be documented.
• Proximal myopathy affects respiratory reserve and recovery of strength.
• Poor wound healing and immunosuppression.
• Glucocorticoid replacement must be prescribed before the case. After removal of a cortisol-secreting adenoma the contralateral gland is suppressed and the patient becomes acutely adrenally insufficient.

Induction and intra-operative management

• Volatile or TIVA. Standard induction.
• Standard monitoring is appropriate for a well-controlled non-secreting tumour. An arterial line is indicated where blood pressure is poorly controlled, where there is significant cardiac disease, where a large tumour or blood loss is anticipated, or where ventilation is expected to be marginal in the prone position.
• Urinary catheter, core temperature monitoring and neuromuscular monitoring.
• Keep the patient fully paralysed for laparoscopic retroperitoneal work.
• Single-dose antibiotic prophylaxis within 60 minutes of incision.
• Mechanical thromboprophylaxis should be used if not contraindicated.

Positioning and ventilation

• For the prone retroperitoneoscopic approach, position affects ventilation pressures, particularly after the knees are dropped into position. Test ventilation before insufflation begins. If ventilation is difficult before insufflation, there is no scope to increase it afterwards, and abandoning the prone approach in favour of the lateral approach should be considered.
• Absorption of insufflated carbon dioxide rises rapidly after approximately 45 minutes, and pressure-controlled ventilation at 35/5–7 cmH₂O, rate 18, I:E 1:1 might be required.
• Surgical emphysema may develop. It persists into recovery, requires no treatment, and keeps the end-tidal carbon dioxide raised after insufflation has ceased. Note its presence on any chest radiograph request.
• Prone positioning care covers the eyes, face, breasts, genitalia, a free abdomen, pressure areas and the arms. In Cushing's syndrome, skin and bone require particular attention.
• For the lateral transperitoneal approach, raise the head of the bed as the table is broken to keep the neck straight. Once the bean bag is deflated and solid, do not move the table again. Over-breaking the table may kink the inferior vena cava and obstruct venous return; consider unbreaking the table if hypotension occurs.

Haemodynamic management

• Expect stability, with minimal pharmacological intervention.
• Where the patient is unexpectedly labile — hypertensive surges on tumour handling, or unexplained tachyarrhythmia — consider an unrecognised catecholamine-secreting tumour and manage according to the phaeochromocytoma guideline: phentolamine 1 mg boluses for hypertension, labetalol 1 mg for rate only, metaraminol for hypotension, and no ephedrine.

Perioperative analgesia

• Multimodal: paracetamol, a short-acting opioid, and local anaesthetic infiltration to the port sites.
• NSAIDs. The default is cautious use rather than avoidance. They may be used where renal function is adequate, the patient is euvolaemic and there is no specific contraindication. Use particular caution in Cushing's syndrome, given the gastric and renal effects of chronic steroid excess.
• Prone adrenalectomies are less painful postoperatively. Lateral cases may require patient-controlled analgesia.
• PONV prophylaxis with at least two agents.

Post-operative care

• Confirm full reversal of neuromuscular blockade with a nerve stimulator, particularly where hypokalaemia has been present.
• Conn's syndrome: check potassium postoperatively. Aldosterone falls abruptly after removal of an aldosterone-producing adenoma and the contralateral gland may be suppressed, producing hyperkalaemia and hypotension. Stop the spironolactone.
• Cushing's syndrome: anticipate acute adrenal insufficiency — hypotension, hypoglycaemia, hyponatraemia and vomiting. Steroid replacement must already be prescribed.
• Maintain glucose as close to normal as is safe. Hyperglycaemia is expected in Cushing's syndrome.
• Other complications to anticipate are bleeding from the adrenal bed, pain, surgical emphysema and residual hypercapnia.
• Escalate unexplained hypotension not responding to fluid, unexplained hypertension or arrhythmia, and persistent hypercapnia or respiratory distress.

References

1. Feast MJ. Adrenalectomy for phaeochromocytoma (The Sheffield Approach). Sheffield Teaching Hospitals, 2024. Cited here for the positioning and ventilation content, which describes the same operation.
2. Lenders JWM, Duh QY, Eisenhofer G, et al. Pheochromocytoma and Paraganglioma: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology and Metabolism, 2014.
3. Centre for Perioperative Care. Guideline for Perioperative Care for People with Diabetes Mellitus Undergoing Elective and Emergency Surgery, 2021, updated 2023.