What is the proper procedure for assessing orthostatic vital signs and managing orthostatic hypotension?

Orthostatic Vital Signs Assessment and Management

Proper Measurement Technique

Measure blood pressure after 5 minutes of supine rest, then at 1 minute and 3 minutes after standing, maintaining the arm at heart level throughout all measurements. 1

Patient Preparation

• Fast for 3 hours before testing 2, 3
• Avoid nicotine, caffeine, theine, or taurine-containing drinks on the day of examination 2, 3
• Perform testing in a temperature-controlled environment (21-23°C) 2, 3
• Use a validated blood pressure device with appropriate cuff size based on arm circumference 1, 2

Measurement Protocol

• Baseline: Measure BP and heart rate after 5 minutes in supine position (preferred for sensitivity, though sitting is more practical in clinical settings) 1
• Standing measurements: Measure BP and HR at 1 minute and 3 minutes after standing 1, 2
• Keep the patient's back and arm supported during supine/sitting measurements, with BP cuff at heart level 1
• Maintain arm at heart level during all standing measurements 1, 2
• At first visit, measure BP in both arms; if systolic BP differs by >10 mmHg, use the arm with higher BP for all subsequent measurements 1, 2
• Record heart rate and check for arrhythmias during assessment 1

Diagnostic Criteria for Orthostatic Hypotension

Classical orthostatic hypotension is diagnosed when systolic BP drops ≥20 mmHg OR diastolic BP drops ≥10 mmHg OR systolic BP falls to <90 mmHg within 3 minutes of standing. 2, 3

Special Diagnostic Thresholds

• In patients with supine hypertension, use a threshold of ≥30 mmHg systolic drop 2, 3
• Initial orthostatic hypotension: BP decrease >40 mmHg systolic and/or >20 mmHg diastolic within 15 seconds of standing 2, 3
• Delayed orthostatic hypotension: BP drop meeting criteria but occurring beyond 3 minutes of standing 2, 3

Pattern Recognition

• Classical OH shows a "concave" BP curve immediately after standing 4, 3
• Delayed OH has a more variable pattern of BP and HR decrease 4, 2
• In neurogenic OH, heart rate increase is blunted (usually <10 beats per minute) due to impaired autonomic HR control 2
• Supine BP is commonly elevated in neurogenic OH 4

Clinical Assessment

Key Symptoms to Assess

• Dizziness, lightheadedness, visual disturbances, weakness, and fatigue 3
• Syncope, presyncope, palpitations, dyspnea, and chest pain 3
• Shoulder and neck pain ("coat hanger syndrome") 5

Medication Review

Review for causative medications including: 3

• Diuretics, vasodilators, alpha-blockers, antihypertensives
• Tricyclic antidepressants, phenothiazines
• Alcohol

Initial Laboratory Testing

• Complete blood count (rule out anemia) 3
• Serum electrolytes (assess for disturbances) 3
• Serum creatinine with eGFR (evaluate renal function) 3
• Fasting blood glucose (screen for diabetes) 3
• Thyroid-stimulating hormone (rule out thyroid dysfunction) 3
• 12-lead ECG (rule out arrhythmias, conduction abnormalities, structural heart disease) 3

Advanced Testing

• Consider 24-hour ambulatory BP monitoring to detect patterns of BP variability 2
• Head-up tilt-table testing if standard orthostatic vital signs are nondiagnostic or to assess treatment response in autonomic disorders 6, 5
• Echocardiography only if cardiac cause is suspected with clinical evidence of cardiac disease (diagnostic yield is low otherwise) 2

Etiologic Classification

Neurogenic Causes

• Primary autonomic failure: Parkinson's disease, multiple system atrophy, pure autonomic failure 2, 3
• Secondary autonomic neuropathies: Diabetes mellitus, amyloidosis, autoimmune disorders 2, 3

Non-Neurogenic Causes

• Hypovolemia (dehydration, blood loss) 3, 6
• Medications (most common reversible cause) 3
• Cardiac causes 3
• Endocrine causes 3

Management Approach

Initial Steps

• Correct reversible causes and discontinue responsible medications when possible 6
• Assess orthostatic hypotension before starting or intensifying BP-lowering medication, particularly in older patients 1

Nonpharmacologic Treatment (Offer to All Patients)

• Dietary modifications (increase salt and fluid intake) 5
• Compression garments (support stockings) 7, 6
• Physical countermaneuvers 5
• Avoid triggering environments 5
• Fluid expansion and lifestyle alterations 7

Pharmacologic Treatment

For patients who do not respond adequately to nonpharmacologic treatment, midodrine is FDA-approved and proven beneficial for symptomatic orthostatic hypotension. 7

Midodrine (First-Line)

• FDA-approved indication: Treatment of symptomatic orthostatic hypotension in patients whose lives are considerably impaired despite standard clinical care 7
• Mechanism: Alpha1-agonist that increases vascular tone and elevates BP 7
• Effect: Elevates standing systolic BP by approximately 15-30 mmHg at 1 hour after a 10 mg dose, with effect persisting 2-3 hours 7
• Dosing: Typically 10 mg three times daily, with last dose not later than 6 PM 7
• Critical warning: Can cause marked elevation of supine BP (>200 mmHg systolic); patients with pre-existing sustained supine hypertension above 180/110 mmHg were excluded from trials 7
• Continuation criteria: Should only be continued for patients who report significant symptomatic improvement 7

Alternative Pharmacologic Options

• Fludrocortisone (improves symptoms but has concerning long-term effects) 5
• Droxidopa (first-line alternative) 5
• Pyridostigmine (proven beneficial) 6

Treatment Goals

• Improve hypotension without excessive supine hypertension 6
• Relieve orthostatic symptoms 6
• Improve standing time and quality of life 6, 5
• Reduce fall risk 5

Important Clinical Pearls

• Symptoms depend more on the absolute BP level than the magnitude of the fall 2
• If symptoms suggest OH but initial testing is negative, extend standing time beyond 3 minutes to assess for delayed OH 2
• Continuous BP measurement devices are more accurate than interval devices for diagnosis 2
• BP cannot be measured reliably in atrial fibrillation using standard instruments 1
• Midodrine is removed by dialysis in patients undergoing hemodialysis 7
• OH prevalence is approximately 10% in all hypertensive adults and up to 50% in older institutionalized adults 2
• OH is associated with up to 50% increase in relative risk of all-cause mortality 5