How to Perform Orthostatic Blood Pressure Measurements
Measure blood pressure after 5 minutes of supine or seated rest, then at 1 minute and 3 minutes after standing, maintaining the arm at heart level throughout all measurements. 1
Patient Preparation
Have the patient rest for 5 minutes in the supine (lying) or sitting position before the initial measurement. The supine position is preferred for greater sensitivity in detecting orthostatic hypotension, though sitting is more practical in outpatient settings. 1
Ensure the patient avoids caffeine, exercise, and smoking for at least 30 minutes before measurement. 2
The patient should empty their bladder before testing. 2
Neither the patient nor the observer should talk during rest or measurement periods. 2
Remove all clothing covering the cuff placement site. 2
The environment should be quiet, comfortable, and temperature-controlled between 21-23°C. 2
Equipment Setup
Use a validated blood pressure device that has been calibrated periodically. 2
Select the correct cuff size so the bladder encircles 80% of the arm circumference. 2
Position the middle of the cuff on the upper arm at the level of the right atrium (midpoint of the sternum). 2
Support the patient's arm (e.g., resting on a desk) with the cuff maintained at heart level during all measurements. 2, 1
Measurement Protocol
Baseline Measurement
Measure blood pressure and heart rate after 5 minutes of rest in the supine or sitting position. 1, 3
At the first visit, measure blood pressure in both arms to detect inter-arm differences; if systolic BP differs by >10 mmHg, use the arm with the higher reading for all subsequent measurements. 1
Record heart rate and check for arrhythmias. 1
Standing Measurements
Have the patient stand and measure blood pressure at 1 minute and 3 minutes after standing. 1, 3
The arm must remain at heart level during standing measurements—this is critical for accuracy. 1
If using auscultatory technique, deflate the cuff at 2 mm Hg per second. 2
Record both systolic and diastolic blood pressure at each time point. 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. 2, 1, 3
The normal response to standing is a slight reduction in blood pressure (approximately 4 mmHg systolic and 5 mmHg diastolic) with an increase in heart rate. 1
Classical orthostatic hypotension typically occurs within the first 3 minutes of standing. 2, 1
Delayed orthostatic hypotension occurs beyond 3 minutes and may require longer monitoring periods. 2
Alternative Method: Sit-to-Stand Test
If the patient cannot safely perform supine-to-standing measurements, a sit-to-stand test can be used with modified diagnostic thresholds. 4
A seated-to-standing SBP drop ≥15 mmHg or DBP drop ≥7 mmHg provides optimal sensitivity (80-87%) and specificity (87-89%) for detecting orthostatic hypotension. 4
This is a practical screening alternative when supine positioning is not feasible. 4
Alternative Method: Tilt Table Testing
- If the patient cannot stand safely or clinical suspicion remains high despite normal bedside findings, head-up tilt table testing at 60 degrees is recommended. 2, 3
Clinical Considerations
Assess for orthostatic hypotension before starting or intensifying BP-lowering medications, particularly in older patients and those with symptoms suggestive of orthostatic changes. 1
Factors that can affect orthostatic response include food ingestion, time of day, medications, ambient temperature, hydration status, deconditioning, and recent vigorous exercise. 2
Blood pressure cannot be measured reliably in patients with atrial fibrillation using standard automated instruments. 1
Document the time of the most recent BP medication taken before measurements. 2
Provide patients with their BP readings both verbally and in writing. 2