What are the causes of hypertension and hypotension in the immediate postoperative period in patients undergoing bilateral (b/l) adrenalectomy?

Causes of Hypertension and Hypotension in the Immediate Post-Operative Period in Patients of Bilateral Adrenalectomy

The most common causes of blood pressure fluctuations after bilateral adrenalectomy are adrenal insufficiency leading to hypotension and sympathetic stimulation causing hypertension, both of which significantly impact patient morbidity and mortality.

Causes of Hypotension

Adrenal Insufficiency

• Removal of both adrenal glands results in acute adrenal insufficiency with inadequate cortisol and aldosterone production, leading to hypotension 1
• Postoperative adrenal insufficiency requires immediate treatment with IV hydrocortisone (100 mg followed by 100 mg every 6-8 hours) and isotonic saline (0.9%) at an initial rate of 1 L/hour until hemodynamic improvement 1
• Patients who experience intraoperative hypotension are more likely to develop recurrent hypotension in the postoperative period, suggesting an autonomic endotype that predisposes to hypotension 2

Autonomic Dysfunction

• Anesthetic agents impair baroreflex sensitivity, removing a key defense mechanism for blood pressure control 2
• Loss of arterial baroreflex manifests as both low and high extreme swings in blood pressure 2
• Reduced baroreflex sensitivity and cardiac vagal function are common in higher-risk patients and are linked mechanistically to worse outcomes 2

Volume Depletion

• Inadequate fluid replacement during surgery can lead to hypovolemia 2
• Only about 54% of patients with suspected hypovolemia (based on clinical signs) actually respond to fluid boluses, suggesting that vascular tone or inotropy issues may be responsible in the remaining cases 2
• Passive leg raise (PLR) test can help identify patients who will respond to fluid therapy (positive likelihood ratio = 11) 2

Causes of Hypertension

Sympathetic Stimulation

• Postoperative hypertension is characterized by sympathetic stimulation resulting in catecholamine release, vasoconstriction, tachycardia, and impaired baroreceptor sensitivity 2
• Hypertension often occurs with sympathetic nociceptive stimulation during induction of anesthesia, during surgery, and with acute pain in the early postoperative period 2

Pain and Inadequate Analgesia

• Excessive pain is associated with higher risk of developing postoperative hypertension 2
• Inadequate analgesia should be addressed before considering specific blood pressure therapy 2

Hypothermia and Hypoxia

• Hypothermia can trigger hypertension in the immediate postoperative period 2
• Hypoxia can lead to sympathetic stimulation and hypertension 2

Fluid Overload

• Excessive intraoperative fluid therapy can lead to hypertension, particularly in the ensuing 24-48 hours as fluid is mobilized from the extravascular space 2
• Volume overload may be particularly problematic in patients with pre-existing cardiovascular disease 2

Management Considerations

Hypotension Management

• Perform bedside assessment to define the cause of hypotension 2
• Consider PLR test to determine if inadequate preload is contributing to hypotension 2
• If PLR test is positive, administer intravenous fluid; if negative, consider vasopressor or inotropic support 2
• All patients with bilateral adrenalectomy require postoperative corticosteroid supplementation until recovery of the hypothalamus-pituitary-adrenal axis 1
• Standard replacement includes hydrocortisone 15-25 mg daily in split doses and fludrocortisone 50-200 μg as a single daily dose 1

Hypertension Management

• Determine if there is a reversible underlying cause of hypertension (pain, anxiety, hypoxemia, hypothermia, urinary retention) 2
• Common non-pharmacological interventions include supplemental oxygen for hypoxemia, forced air warmer for hypothermia, catheterization for urinary retention, and verbal reassurance/anxiolytics for anxiety 2
• Treatment goal should be based on preoperative blood pressure with a target of approximately 10% above baseline 2
• Untreated postoperative hypertension increases the risk of myocardial ischemia, myocardial injury, infarction, arrhythmia, pulmonary edema, stroke, and surgical site bleeding 2

Monitoring Recommendations

• Greater frequency of postoperative blood pressure measurement helps identify risk of harm and clinical deterioration earlier 2
• All patients with adrenal insufficiency should wear medical alert identification and carry a steroid alert card 1
• Patients should be reviewed at least annually with assessment of health and well-being, weight, blood pressure, and serum electrolytes 1
• Monitor for the development of new autoimmune disorders, particularly hypothyroidism 1

Common Pitfalls

• Assuming all hypotension is due to hypovolemia - approximately 46% of hypotensive patients do not respond to fluid boluses 2
• Failing to recognize adrenal insufficiency as a cause of refractory hypotension 1
• Delaying corticosteroid replacement in patients with bilateral adrenalectomy 1
• Not addressing pain, anxiety, and other reversible causes before treating hypertension pharmacologically 2