Orthostatic Blood Pressure Measurement Protocol for Dizziness
Measure orthostatic blood pressures twice: once at 1 minute and once at 3 minutes after standing, following 5 minutes of rest in the sitting or lying position. 1
Measurement Technique
The 2024 European Society of Cardiology guidelines provide the definitive protocol for orthostatic hypotension assessment in patients with dizziness 1:
- Have the patient rest for 5 minutes in either the sitting or lying position before beginning measurements 1
- Measure blood pressure at baseline while the patient is still seated or lying 1
- Measure blood pressure at 1 minute after standing to capture early orthostatic changes 1
- Measure blood pressure at 3 minutes after standing to detect delayed orthostatic hypotension 1
Diagnostic Threshold
Orthostatic hypotension is defined as a drop of ≥20 mmHg systolic or ≥10 mmHg diastolic blood pressure at either the 1-minute or 3-minute measurement 1, 2, 3.
Why Two Time Points Matter
The dual measurement approach captures different pathophysiologic patterns 1:
- 1-minute measurement detects initial orthostatic hypotension (occurring 0-30 seconds after standing) and classical orthostatic hypotension (occurring within 3 minutes) 1
- 3-minute measurement identifies delayed orthostatic hypotension, which develops after 3 minutes of standing and may be followed by reflex syncope 1
Practical Considerations
Lying versus sitting position for baseline: Measurement after lying may be more sensitive for detecting orthostatic hypotension and may better predict falls, but measurement after sitting is more feasible in clinical practice 1.
When to perform orthostatic measurements: The European Society of Cardiology recommends assessing for orthostatic hypotension at the initial visit and thereafter whenever concerning symptoms arise 1. In patients with established hypertension, orthostatic measurements should be performed at the first visit and subsequently if symptoms develop 1.
Common Pitfall to Avoid
Do not rely on a single measurement time point. A 2022 American Family Physician review confirms that the standard diagnostic test requires measurements "after five minutes in the supine position and three minutes after moving to a standing position" 2. Missing the 1-minute measurement may cause you to overlook initial orthostatic hypotension, while skipping the 3-minute measurement may miss delayed orthostatic hypotension 1.
If Bedside Testing is Negative but Suspicion Remains High
If the patient cannot stand safely or if clinical suspicion for orthostatic hypotension remains high despite normal bedside measurements, head-up tilt table testing is recommended 2. Home blood pressure monitoring with standing measurements may also detect orthostatic hypotension missed in the office setting, with one study showing 37% prevalence at home versus 15% in clinic 4.