How to measure orthostatic blood pressure?

How to Measure Orthostatic Blood Pressure

The proper technique for orthostatic blood pressure measurement requires measuring blood pressure after 5 minutes of rest in the sitting or lying position, followed by measurements at 1 minute and 3 minutes after standing. 1

Equipment and Patient Preparation

• Use a validated blood pressure device with an appropriate cuff size based on arm circumference 1
• Ensure the patient is in a quiet, comfortable environment 1
• The patient should be fasted for 3 hours before the test and avoid nicotine and caffeine for accurate diagnosis 2
• Testing should be performed in a temperature-controlled environment (21-23°C) 2

Step-by-Step Measurement Technique

Initial Assessment

• Measure blood pressure in both arms at the first visit to detect inter-arm differences 1
• If systolic BP differs by >10 mmHg between arms, use the arm with the higher BP value for subsequent measurements 1, 2
• Record heart rate and check for arrhythmias during the assessment 1

Baseline Measurement

• Have the patient sit or lie down for 5 minutes before taking the baseline measurement 1, 3
• The lying position is preferred for greater sensitivity, though sitting is more practical in clinical settings 1
• Ensure the BP cuff is at the level of the heart with the patient's back and arm supported 1

Standing Measurements

• Ask the patient to stand up 1
• Measure blood pressure at 1 minute after standing 1, 3
• Measure blood pressure again at 3 minutes after standing 1, 3
• Maintain the arm at heart level during all measurements 1
• Consider extending standing time beyond 3 minutes if symptoms suggest orthostatic hypotension but initial testing is negative 2

Diagnostic Criteria

• Orthostatic hypotension is defined as:
  • A decrease in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg within 3 minutes of standing 1, 2, 3
  • In patients with supine hypertension, a systolic BP drop ≥30 mmHg should be considered diagnostic 2
  • A decrease in systolic BP to <90 mmHg within 3 minutes of standing 2

Clinical Pearls and Caveats

• The simplified Schellong test (measurements after five minutes supine and three minutes standing) is a common bedside method for diagnosis 3
• If the patient is unable to stand safely or clinical suspicion remains high despite normal findings, head-up tilt table testing is recommended 3
• Home blood pressure measurements that include standing positions can significantly improve detection of orthostatic hypotension compared to clinic measurements (37% vs. 15% prevalence) 4
• Orthostatic hypotension assessment is particularly important before starting or intensifying BP-lowering medication, especially in older patients and those with suggestive symptoms 1
• Observe the pattern of BP decrease: classical orthostatic hypotension shows a "concave" curve immediately after standing, while delayed orthostatic hypotension shows a decrease occurring after 3 minutes 2

Common Pitfalls to Avoid

• Failing to allow adequate rest time before baseline measurement 1
• Not maintaining the arm at heart level during all measurements 1
• Missing delayed orthostatic hypotension by not extending measurement time in symptomatic patients with initially negative results 2
• Overlooking the need to test both arms at initial assessment 1, 2
• Underdiagnosing orthostatic hypotension by relying solely on clinic measurements rather than incorporating home measurements 4