Anesthesiology

Adrenal Surgery - Procedures

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What the Anesthesiologist Should Know before the Operative Procedure

Anesthetizing a patient for adrenal surgery requires an understanding of the nature of the tumor to be removed. Adrenal glands support a wide range of endocrine and homeostatic functions within the body. Tumors can arise from each cellular level within the adrenal, with each causing specific signs and symptoms and necessitating specific perioperative care.

  1. Catecholamine-secreting adenomas or malignancies (pheochromocytomas): These tumors arise from the adrenal medulla and cause classic symptoms of hypertension, palpitations, tachycardia, tremulousness, and diaphoresis. These are due to an excess production and periodic release of large amounts of catecholamines into the bloodstream. Preoperative treatment with alpha- and then beta-blockade is key to the success of intraoperative management.

  2. Mineralocorticoid-secreting adenomas (Conn's syndrome): These tumors arise from the adrenal cortex. Patients will typically present with refractory hypertension and possibly electrolyte abnormalities. An excess of circulating aldosterone is the causative agent of symptoms, and aldosterone antagonists are frequently used in treatment before surgery.

  3. Glucocorticoid-secreting adenomas (Cushing's syndrome): These tumors of the adrenal cortex result in secretion of excess glucocorticoid. Symptoms include abnormal fat deposition, diabetes, hypertension, and development of purple striae. These adenomas may be primary or secondary to an adrenocorticotropin (ACTH)-secreting tumor in the pituitary gland.

  4. Other adenomas or tumors: Adrenocortical malignancies are rare and rarely result in endocrine effects. Other adenomas may result in excess sex steroid production or other abnormalities of the steroid synthesis pathway.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

Adrenal adenomas and malignancies are almost never surgically urgent or an emergency, with the rare exception of an acute hemorrhage in a malignancy that becomes life threatening. It is essential that patients undergo appropriate preoperative evaluation and treatment to optimize physiology prior to surgery.

Particular patients with pheochromocytomas must receive alpha- and beta-blockade prior to the operation. Failure to do so may result in tremendous intraoperative swings in blood pressure.

2. Preoperative evaluation

The most common medical indications for procedures on the adrenal glands are endocrinopathies and catecholamine-secreting tumors. The preoperative evaluation must include a thorough analysis of tumor size and location as well as lab testing. Lab testing should include, depending on the suspected adenoma type, cortisol level, ACTH level, ACTH stimulation test, aldosterone level, 17-hydroxyprogesterone, complete metabolic panel, urinary metanephrine, and vanillylmandelic acid (VMA) levels. Occasionally, selective adrenal vein sampling is performed to ascertain which adrenal gland is the source of the problem.

Radiologic testing includes computed tomography (CT) scanning and magnetic resonance imaging (MRI) and is generally performed to gauge both the size and potential vascularity of the tumor.

Based on functional characteristics of the patient, preoperative cardiac evaluation may be warranted, especially in pheochromocytoma resections.

If a patient has a new-onset cardiac dysrhythmia from excess catecholamine production, surgery should be delayed until definitive rhythm management occurs.

Hypertension in the setting of pheochromocytoma and Conn's syndrome should be controlled prior to surgical resection.

3. What are the implications of co-existing disease on perioperative care?

Perioperative evaluation

The endocrine and sympathetic abnormalities that occur with adrenal adenomas and malignancies can have varied and far-reaching effects on perioperative care. Specifically, adrenergic tumors can cause abnormalities in heart function that can lead to perioperative morbidity. Changes in electrolyte regulation and glucose metabolism may also contribute to perioperative morbidity. Preoperative evaluation should include extensive directed laboratory evaluations and cardiac evaluation and treatment. If there is any sign of heart failure, preoperative echocardiogram or possibly cardiac catheterization will be indicated. Stress testing should usually be avoided because it may exacerbate the symptoms of a catecholamine-producing tumor.

The most important risk reduction strategy for adrenal procedures is the recognition and pretreatment of abnormalities caused by the adenoma itself. For pheochromocytomas, the most important perioperative risk reduction strategy is assurance of adequate alpha- and then beta-blockade. For mineralocorticoid tumors, it would be correction of electrolyte abnormalities and treatment of hypertension.

b. Cardiovascular system

The most common acute cardiac conditions encountered in patients with adrenal adenomas are acute dysrhythmias (commonly atrial fibrillation) and catecholamine-induced congestive heart failure secondary to catecholamine surges associated with pheochromocytomas. Patients may also have acute hypertensive urgency and emergency events related to aldosteronomas or cortisol-secreting tumors. Dysrhythmia management should include beta-blockers (after alpha-blockers are initiated to prevent unopposed alpha-agonism) or type III antiarrhythmic agents. Hypertension caused by hyperaldosteronism should be treated with an aldosterone antagonist along with calcium channel blockade. Heart failure may be treated with diuretics and afterload-reducing agents.

In patients with adrenal disease who have underlying coronary disease, a thorough evaluation of baseline cardiac function should take place, including an echocardiogram and possibly catheterization if there has been a recent change in symptoms or physiologic reserve.

c. Pulmonary

Patients are typically intubated for adrenal surgery, and patients with chronic obstructive pulmonary disease (COPD) may be subject to prolonged ventilation following the procedure. Optimization of lung function preoperatively is essential. If the patient is experiencing an exacerbation of COPD, the surgery should in most circumstances be postponed until adequate lung function returns. In patients with severe disability from COPD, preoperative pulmonary function tests including spirometry and arterial blood gases should be performed.

Patients with reactive airway disease should have optimized lung function prior to adrenal surgery. Chronic medications including bronchodilators and steroids should be continued up until and on the day of surgery.

d. Renal-GI:

Electrolyte abnormalities may result from aldosteronomas or cortisol-secreting adrenal tumors. These should be corrected prior to the operation. Patients may also suffer from severe dehydration as a result of high circulating catecholamines from a pheochromocytoma. Every effort to normalize intravascular circulating volume should be undertaken prior to adrenalectomy.

e. Neurologic:

Cortisol-secreting adenomas may be secondary to a pituitary adenoma secreting ACTH. Other signs of pituitary adenoma should be evaluated prior to surgery for Cushing's syndrome. These may include inappropriate levels of thyroid-stimulating hormone or antidiuretic hormone, both of which may result in severe perioperative physiologic derangements.

f. Endocrine:

N/A

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

N/A

4. What are the patient's medications and how should they be managed in the perioperative period?

Medications that should be stopped in the immediate preoperative period include antiplatelet agents and other blood thinners (Coumadin [warfarin]) in patients who will benefit from regional anesthesia.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

Depending on the specific tumor type, certain medications may be expected to be administered in the perioperative period:

  • Pheochromocytoma: alpha-blocker (phenoxybenzamine, prazosin) and beta-blocker (propanolol or metoprolol)

  • Cushing's disease: glucose control with insulin

  • Aldosteronoma: aldosterone antagonist (spironolactone), antihypertensive (calcium channel blocker or angiotensin-converting enzyme inhibitor)

i. What should be recommended with regard to continuation of medications taken chronically?

All cardiac and pulmonary medications should be continued through the day of surgery. All antiepileptic and chronic pain medications should be continued. Antiplatelet medications should be stopped if the patient is a candidate for regional anesthesia and there is no contraindication to stopping (i.e., recent coronary stenting). All psychiatric medications should be continued.

j. How To modify care for patients with known allergies -

Follow general institutional guidelines for antibiotic administration in the perioperative period while taking care to avoid allergens.

k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

If the patient has a latex allergy, be vigilant about preparing the operating room with latex-free equipment and supplies.

l. Does the patient have any antibiotic allergies? (common antibiotic allergies and alternative antibiotics)

Follow general institutional guidelines for antibiotic administration in the perioperative period while taking care to avoid allergens.

m. Does the patient have a history of allergy to anesthesia?

Malignant hyperthermia

For patients with documented malignant hyperthermia (MH), avoid all trigger agents such as succinylcholine and inhalational agents. Follow a proposed general anesthetic plan: patients with MH may be induced with propofol or etomidate along with a nondepolarizing neuromuscular blocking agent. Maintenance of anesthesia with propofol and adequate narcotic administration can be achieved. Ensure an MH cart is available.

Local anesthetics/muscle relaxants

Patients with allergies to local anesthetics should not have an epidural placed and infused during the surgical procedure. Care must be taken by the surgical team to avoid infiltration of local anesthetic into the wound. For patients who are allergic to muscle relaxants, a narcotic infusion may be used to maintain relaxation and immobility during the surgical procedure.

5. What laboratory tests should be obtained and has everything been reviewed?

The most common medical indicationsfor procedures on the adrenal glands are endocrinopathies andcatecholamine-secreting tumors. The preoperative evaluation must includea thorough analysis of tumor size and location as well as labtesting. Lab testing should include, depending on the suspected adenomatype, cortisol level, ACTH level, ACTH stimulation test, aldosteronelevel, 17-hydroxyprogesterone, complete metabolic panel, urinarymetanephrine, and VMA levels. Occasionally, selective adrenal veinsampling is performed to ascertain which adrenal gland is the source ofthe problem.

Common laboratory normal values will be same for all procedures, with a difference by age and gender.

Hemoglobin levels should in most cases be normal. Patients with aldosteronomas and cortisol-secreting tumors may exhibit hypokalemia and hypernatremia. The coagulation panel should in most cases be normal; if not, correction prior to surgery should occur. CT scanning and MRI of the involved adrenal gland should be performed. Vascularity of the tumor should be assessed. Testing for pituitary adenomas may be indicated.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

Adrenal surgery may be performed via an open, a laparoscopy-assisted, or a laparoscopic approach. Anesthetic plans will vary to some degree based on the surgical approach. Positioning will also play a key role in determination of the anesthetic plan. Surgery is typically performed in the lateral flexed position, although supine and prone approaches are also used as each individual resection is different.

General anesthesia is typically achieved with a routine induction, followed by endotracheal intubation. Care should be taken not to treat hypotensive episodes around the time of induction with indirect sympathetic agonists (i.e., ephedrine) as this will result in an exaggerated effect in patients with pheochromocytomas.

For pheochromocytoma resections, an arterial catheter is placed, typically before induction. After induction and airway control, central venous access is important, for both intraoperative and postoperative administration of vasoactive agents. If cardiac function is a concern, a pulmonary artery catheter or transesophageal echocardiographic probe should be placed before final positioning.

For adrenalectomies that are non–catecholamine secreting, arterial catheters should only be placed in patients with uncontrolled hypertension, or in cases where it is medically appropriate based on the patient's underlying physiologic status.

For lateral positioning, patients are typically placed on a bean bag with the bed flexed. Care must be taken to ensure stability and alignment of the cervical spine and protection of all nerve groups, particularly the bachial plexus as it travels through the dependent axilla.

a. Regional anesthesia

For open adrenalectomies, analgesia may be achieved with a thoracic epidural. Placement should be between T7 and T10. It is important to remember that patients undergoing pheochromocytoma resections receive long-acting alpha- and beta-blockade and may experience hypotension after tumor removal. The sympathectomy from an epidural may contribute to this and the risk of hypotension should be balanced against the benefit of improved pain control. There is no existing evidence for improved outcomes for patients with an epidural in this setting.

b. General anesthesia

Patients with Cushing's disease may have large fat deposits at the back of their neck that may make intubation more difficult. A thorough airway assessment should be performed before induction of general anesthesia in patients undergoing adrenal surgery.

c. Monitored anesthesia care

Monitored anesthesia care is inappropriate for patients undergoing adrenalectomy. These patients may have consequential physiologic changes during surgery and should be anesthetized with a protected airway. Any stressor can cause release of catecholamines from a catecholamine-secreting tumor.

6. What is the author's preferred method of anesthesia technique and why?

Cefazolin in a weight-appropriate dose should be administered. If the patient has allergies to penicillin or cephalosporins, other appropriate skin flora coverage may be given (i.e., vancomycin).

Surgery is typically performed via a lateral approach for both laparoscopic and open adrenalectomies. For large tumors or for further exploration, an abdominal approach may be taken. For non–catecholamine-secreting tumors, there are typically few significant hemodynamic changes during the procedure. After tumor removal for a cortisol-secreting tumor, the patient may exhibit signs of adrenal insufficiency including hypotension and hypoglycemia. These patients should receive stress-dose steroids in the perioperative period.

Patients may also experience hypotension following aldosterone-secreting tumor removal. This will typically resolve after antihypertensive agents are cleared from the body; until then, treatment with vasocative infusions may be necessary. For catecholamine-secreting tumors, there are often wide swings in blood pressure throughout the procedure.

The stress of incision and manipulation of the tumor are the typical periods in which severe hypertension will become apparent even in patients who are well alpha- and beta-blocked. Treatment with intravenous vasodilators is appropriate; these may include phentolamine, nitroprusside, nitroglycerin, or nicardipine. Clevidipine is an emerging option that may be beneficial for its short duration of action. After pheochromocytoma removal, the patient will likely experience profound hypotension as the source of excess catecholamines has been removed, yet the sympathetic blockers remain. Patients will often remain on vasoactive infusions (norepinephrine) for the remainder of the immediate perioperative period.

Excellent communication with the surgeon regarding hemodynamic changes is imperative for the success of the operation. For example, if a patient's blood pressure remains high even after removal of a pheochromocytoma, it is likely that there is another source of catecholamine excess that may necessitate further surgical exploration.

It is possible and even likely that there will be some catecholamine surge during resection of a pheochromocytoma. If not promptly treated this can result in hypertensive crises and end organ damage including congestive heart failure and cerebrovascular accident.

Patients may have prolonged mechanical ventilation following adrenal resection. With the location of the incision, there is a high risk for perioperative atelectasis.

a. Neurologic:

N/A

b. If the patient is intubated, are there any special criteria for extubation?

Clearly, before extubation following adrenal surgery, basic extubation criteria must be met including adequacy of oxygenation, ventilation, and ability to protect the airway. If a patient is hemodynamically unstable, requiring frequent titration of vasoactive infusions and fluid administration, he should remain intubated.

c. Postoperative management

Following surgery for adrenal resection, patients will likely require extended postoperative monitoring in the intensive care unit (ICU) or post-anesthesia care unit (PACU) setting. For patients following pheochromocytoma, there will likely be a period of profound hypotension in the postoperative period necessitating vasoactive medication infusions. These patients should be taken to the ICU for further monitoring. Following adrenalectomies for non-catecholamine secreting tumors patients still may exhibit hypotension from adrenal insufficiency or hypoaldosteronism. If they remain on vasoactive infusions or demonstrate hemodynamic instability during the intraoperative or immediate postoperative course they should also go to the ICU. If they are hemodynamically stable in the PACU they may be appropriate for ongoing care on a regular nursing unit.

Analgesia may be achieved via either an epidural or narcotic patient-controlled anesthesia. In patients with an ongoing sympathectomy following removal of a catecholamine-secreting tumor, a sympathectomy from epidural analgesia may confuse the clinical milieu.

What's the Evidence?

Tritos, NA, Biller, BMK, Swearingen, B. "Management of Cushing disease". Nat Rev Endocr. vol. 7. 2011. pp. 279-89.

(Comprehensive clinical review of Cushing’s disease.)

Harari, A, Inabnet, WB. "Malignant pheochromocytoma: A review". Am J Surg. vol. 201. 2011. pp. 693-701.

(Comprehensive clinical review of neuroendocrine tumors in the adrenal glands.)

Karagiannis, A. "Treatment of primary aldosteronism: Where are we now?". Rev Endocr Metab Disord. vol. 12. 2011. pp. 15-20.

(Describes current treatment protocols for aldosteronism.)

O’Riordan, JA. "Pheochromocytomas and anesthesia". Int Anesth Clin. vol. 35. 1997. pp. 99-127.

(Reviews anesthetic management of pheochromocytomas.)

Maddi, R, Gabel, RA. "Anesthetic considerations for adrenalectomy". Contemp Anesth Pract. vol. 3. 1980. pp. 1-9.

(Reviews anesthetic management of adrenal resections.)
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