What is the proper preoperative workup for a patient with orthostatic hypotension prior to surgery?

Preoperative Workup for Patients with Orthostatic Hypotension

The proper preoperative workup for a patient with orthostatic hypotension should include a structured assessment for orthostatic hypotension, identification of underlying causes, evaluation of cardiovascular status, and optimization of medications and volume status before surgery.

Diagnosis and Assessment of Orthostatic Hypotension

• Perform a standardized orthostatic hypotension test:

  • Measure blood pressure after 10 minutes of lying down
  • Measure blood pressure at 1,2, and 3 minutes after standing
  • Confirm orthostatic hypotension if there is a decrease in systolic BP ≥20 mmHg (or ≥30 mmHg in hypertensive patients) and/or diastolic BP ≥10 mmHg 1

• Document symptoms associated with position changes:

  • Common symptoms: dizziness, lightheadedness, blurred vision, weakness, fatigue
  • Less common symptoms: syncope, dyspnea, chest pain, neck/shoulder pain 2

Identify Underlying Causes

• Review medication history for drugs that can cause or worsen orthostatic hypotension:

  • Antihypertensives (especially alpha-blockers)
  • Diuretics
  • Vasodilators
  • Antidepressants
  • Antipsychotics

• Evaluate for medical conditions associated with orthostatic hypotension:

  • Diabetic autonomic neuropathy
  • Cardiac autonomic neuropathy (CAN)
  • Parkinson's disease
  • Multiple system atrophy
  • Volume depletion
  • Adrenal insufficiency 1

Cardiovascular Assessment

• Perform a comprehensive cardiovascular evaluation:

  • ECG to assess for arrhythmias, ischemia, and QTc prolongation
  • Echocardiogram if indicated by history or physical exam
  • Assess for signs of cardiac autonomic neuropathy (CAN) in diabetic patients 1

• For diabetic patients with suspected CAN, perform specific tests:

  • Deep respiration test to assess heart rate variability
  • Orthostatic test to evaluate blood pressure response 1

Preoperative Optimization

1. Volume Status Optimization:

   • Consider administering 1-2 liters of saline 24 hours prior to surgery in patients with orthostatic hypotension 1
   • Implement high-sodium diet preoperatively when appropriate 1

2. Medication Management:

   • Continue essential antihypertensive medications up to the morning of surgery 1
   • For patients with severe orthostatic hypotension, consider starting midodrine (5-20mg three times daily) or fludrocortisone (0.1-0.3mg daily) preoperatively 3, 4
   • Adjust or temporarily discontinue medications that worsen orthostatic hypotension when possible

3. Anesthetic Planning:

   • Plan for intraoperative hemodynamic monitoring
   • Prepare for potential vasopressor support during anesthesia induction and maintenance 5
   • Consider use of compression stockings during surgery 1

Risk Stratification

• Assess for risk factors that may complicate perioperative management:

  • Severity of orthostatic hypotension (magnitude of BP drop)
  • Presence of symptoms with position changes
  • History of syncope
  • Comorbid cardiovascular disease
  • Planned surgical procedure and anticipated blood loss

• For high-risk patients (severe orthostatic hypotension or symptomatic with minimal provocation), consider:

  • More intensive perioperative monitoring
  • Potential ICU admission postoperatively
  • Arterial line placement for continuous BP monitoring 1

Postoperative Planning

• Develop a plan for postoperative BP management:

  • Early mobilization strategy
  • Volume management goals
  • Vasopressor support if needed
  • Monitoring frequency and parameters

• Prepare for potential postoperative complications:

  • Hypotension requiring vasopressor support
  • Volume management challenges
  • Delayed mobilization

Common Pitfalls to Avoid

• Assuming all hypotension is due to hypovolemia 3
• Focusing solely on BP numbers rather than symptoms and end-organ perfusion 3
• Overlooking non-pharmacological measures for orthostatic hypotension 3
• Treating hypertension too aggressively, which can lead to worsened orthostatic hypotension 1
• Failing to assess for supine hypertension in patients with orthostatic hypotension 4

By following this structured approach to preoperative evaluation and optimization, patients with orthostatic hypotension can be better prepared for surgery with reduced risk of perioperative complications related to hemodynamic instability.