Normal Orthostatic Vital Signs
Normal orthostatic vital signs in a 25-year-old patient are defined as LESS than a 20 mmHg drop in systolic blood pressure or LESS than a 10 mmHg drop in diastolic blood pressure within 3 minutes of standing from a supine position. 1
Measurement Technique
- Measure blood pressure and heart rate after 5 minutes lying supine, then at 1 minute and 3 minutes after standing 2
- The patient should transition from lying flat to standing upright without prolonged sitting in between 3
- Blood pressure drops meeting or exceeding the thresholds (≥20 mmHg systolic or ≥10 mmHg diastolic) indicate abnormal orthostatic hypotension 1
Normal Heart Rate Response
- A heart rate increase of 10-25 bpm upon standing is considered a normal physiologic compensatory response 4, 2
- In a 25-year-old specifically, a heart rate increase of less than 30 bpm is normal (the threshold for abnormal orthostatic tachycardia is ≥30 bpm in adults, or ≥40 bpm in those aged 12-19 years) 1
- A heart rate increase ≥15 bpm suggests adequate autonomic compensation and rules out neurogenic causes if orthostatic hypotension is present 2
Key Clinical Pitfalls
- A blunted heart rate response (<10 bpm increase) with blood pressure drop indicates neurogenic orthostatic hypotension and autonomic dysfunction, not simple volume depletion 4, 2
- Initial orthostatic hypotension can occur within 15 seconds of standing with rapid recovery and may be missed if measurements are only taken at 3 minutes 1
- Delayed orthostatic hypotension occurs beyond 3 minutes of standing and requires prolonged standing measurements if clinical suspicion is high despite normal 3-minute readings 1, 4
- If the patient cannot stand safely or bedside testing is normal despite high clinical suspicion, head-up tilt table testing at 60 degrees or more is recommended 3, 5