What are the diagnostic blood pressure (BP) criteria for orthostatic hypotension?

Diagnostic Criteria for Orthostatic Hypotension

Orthostatic hypotension is defined as a decrease in systolic blood pressure ≥20 mmHg or diastolic blood pressure ≥10 mmHg within 3 minutes of standing from a supine or sitting position. 1, 2

Standard Diagnostic Criteria

• Classical definition:

  • Decrease in systolic BP ≥20 mmHg OR
  • Decrease in diastolic BP ≥10 mmHg
  • Within 3 minutes of standing
  • Measured after 5 minutes of rest in supine position 1

• Additional criteria for severe cases:

  • A fall in systolic blood pressure of 30 mmHg may be considered for severe orthostatic hypotension 2

Types of Orthostatic Hypotension

1. Classical orthostatic hypotension:

   • Immediate BP decrease within 15 seconds of standing
   • Shows a "concave" curve pattern
   • Meets standard criteria (≥20/10 mmHg drop)

2. Initial orthostatic hypotension:

   • BP decrease >40 mmHg systolic or >20 mmHg diastolic
   • Occurs within 15 seconds
   • Spontaneous recovery within 40 seconds

3. Delayed orthostatic hypotension:

   • BP decrease occurring beyond 3 minutes of standing 1

Proper Measurement Protocol

1. Patient preparation:

   • Rest for 5 minutes in supine or sitting position
   • Avoid testing within 2 hours after meals, caffeine, alcohol, or smoking
   • Avoid testing after strenuous exercise (within 24 hours)
   • Avoid testing during acute illness, fever, dehydration, or marked hyperglycemia 1

2. Measurement technique:

   • First measurement: After 5 minutes of rest in supine/sitting position
   • Second measurement: At 1 minute after standing
   • Third measurement: At 3 minutes after standing
   • Use validated and calibrated blood pressure device 1

3. Special considerations:

   • Measure BP in both arms at initial assessment
   • If difference >10 mmHg, use arm with higher BP for subsequent measurements
   • Supine position is more sensitive for detecting orthostatic hypotension
   • Sitting position may be more feasible in clinical practice 1

Clinical Pearls and Pitfalls

• Important considerations:

  • Both magnitude of change and absolute BP values are important
  • Rate of BP recovery after initial drop has important prognostic implications
  • Diastolic pressure is typically 5 mmHg higher when sitting compared to supine 1

• Common pitfalls:

  • Not waiting the full 3 minutes for proper assessment
  • Failing to check both arms initially
  • Testing too soon after meals or medication administration
  • Not considering the patient's age, medications, and comorbidities 1

• Documentation:

  • Record both supine/sitting and standing blood pressures
  • Document time points of measurements (baseline, 1 minute, 3 minutes)
  • Note any symptoms that occur during position change 2, 1

The European Society of Cardiology, American Autonomic Society, and American Academy of Neurology all support these diagnostic criteria, making them the standard for clinical practice 1, 3, 4. Proper adherence to these measurement protocols ensures accurate diagnosis and appropriate management of orthostatic hypotension.