What is the best approach to assess for orthostatic hypotension in a patient?

Orthostatic Vital Signs Assessment

Measurement Technique

To accurately assess for orthostatic hypotension, have the patient rest supine for 5 minutes, measure baseline blood pressure and heart rate, then remeasure at 1 minute and 3 minutes after standing, maintaining the arm at heart level throughout all measurements. 1, 2

Patient Preparation

• The patient should rest in the supine position (preferred over sitting) for 5 minutes before the initial measurement, as the supine position provides greater sensitivity for detecting orthostatic hypotension 2
• Patients should fast for 3 hours before testing and avoid nicotine, caffeine, theine, or taurine-containing drinks on the day of examination 1
• Testing should occur in a quiet, temperature-controlled environment (21-23°C) 1, 2
• The patient should empty their bladder before testing, and neither the patient nor observer should talk during measurements 2

Equipment and Positioning

• Use a validated and calibrated blood pressure device with appropriate cuff size based on arm circumference (bladder should encircle 80% of the arm) 1, 2
• Position the middle of the cuff on the upper arm at the level of the right atrium 2
• Support the patient's back and arm during supine measurements, with the BP cuff maintained at heart level 1, 3
• At the first visit, measure BP in both arms; if systolic BP differs by >10 mmHg between arms, use the arm with higher BP for all subsequent measurements 1, 2

Measurement Protocol

• Baseline: After 5 minutes of supine rest, measure and record both systolic and diastolic blood pressure plus heart rate 1, 2, 3
• 1 minute: Measure BP and heart rate at 1 minute after standing, maintaining the arm at heart level 1, 2, 3
• 3 minutes: Measure BP and heart rate at 3 minutes after standing, maintaining the arm at heart level 1, 2, 3
• If using auscultatory technique, use a deflation rate of 2 mm Hg per second 2

Diagnostic Criteria

Orthostatic hypotension is diagnosed when there is a sustained decrease in systolic BP ≥20 mmHg OR diastolic BP ≥10 mmHg OR systolic BP falls to <90 mmHg within 3 minutes of standing. 1, 2, 3

Special Diagnostic Thresholds

• In patients with supine hypertension, use a threshold of ≥30 mmHg systolic drop 1, 3
• Initial orthostatic hypotension: BP decrease >40 mmHg systolic and/or >20 mmHg diastolic within 15 seconds of standing 1, 3
• Delayed orthostatic hypotension: BP drop meeting criteria but occurring beyond 3 minutes of standing 1, 3

Heart Rate Response

• Record heart rate at each measurement point and check for arrhythmias 2
• In neurogenic orthostatic hypotension, the orthostatic heart rate increase is blunted (usually <10 beats per minute) because autonomic HR control is impaired 1
• The normal response to standing is a slight reduction in BP (by 4 mmHg systolic and 5 mmHg diastolic) and an increase in heart rate 2

Important Clinical Considerations

When to Extend Testing

• If symptoms suggest orthostatic hypotension but initial 3-minute testing is negative, extend standing time beyond 3 minutes to assess for delayed orthostatic hypotension 1, 3
• Consider head-up tilt table testing if the patient cannot stand safely or if clinical suspicion remains high despite normal bedside testing 4, 5

Common Pitfalls to Avoid

• Do not use sit-stand testing as a substitute for supine-to-standing measurements, as sit-stand testing has very low diagnostic accuracy (sensitivity only 15.5%, specificity 89.9%) 6
• Continuous BP measurement devices are more accurate than interval devices for diagnosis, as interval devices have low concordance with continuous measurements 1
• BP cannot be measured reliably in patients with atrial fibrillation using standard instruments 2, 3

High-Risk Populations Requiring Assessment

• All patients over 50 years old should have periodic orthostatic BP screening 2
• Elderly patients (≥65 years) and diabetic patients before starting or intensifying BP-lowering medications 1, 2
• Patients with symptoms of dizziness, lightheadedness, postural unsteadiness, or fainting 2
• Patients taking medications that may cause orthostatic hypotension (diuretics, vasodilators, alpha-blockers, beta-blockers, nitrates) 2, 3
• Patients with Parkinson's disease or other autonomic disorders 2, 3

Clinical Significance

• Orthostatic hypotension is present in approximately 10% of all hypertensive adults and up to 50% of older institutionalized adults 1, 3
• It is associated with a 64% increase in age-adjusted mortality, increased falls and fractures, and significant cardiovascular risk 2
• Symptoms depend more on the absolute BP level than the magnitude of the fall 1, 3