What are the guidelines for managing a hypertensive emergency?

Management of Hypertensive Emergency

Admit all patients with hypertensive emergency (BP >180/120 mmHg with acute target organ damage) to the ICU for continuous monitoring and immediate parenteral antihypertensive therapy, reducing BP by no more than 25% in the first hour to prevent ischemic complications. 1

Definition and Risk Stratification

Hypertensive emergency is defined as severe BP elevation (>180/120 mmHg) with evidence of new or worsening target organ damage, carrying a 1-year mortality >79% if untreated. 1

Critical distinction: The absolute BP level matters less than the rate of rise—patients with chronic hypertension tolerate higher pressures than previously normotensive individuals. 1

Target organ damage includes:

• Neurologic: hypertensive encephalopathy, intracranial hemorrhage, acute ischemic stroke 1
• Cardiac: acute MI, acute LV failure with pulmonary edema, unstable angina 1
• Vascular: aortic dissection 1
• Renal: acute renal failure 1
• Obstetric: eclampsia 1

Blood Pressure Reduction Targets

For Patients WITHOUT Compelling Conditions

Reduce SBP by no more than 25% within the first hour, then if stable, to 160/100 mmHg within the next 2-6 hours, then cautiously to normal during the following 24-48 hours. 1

This staged approach prevents cerebral, renal, or coronary hypoperfusion—a critical pitfall of overly aggressive BP reduction. 2

For Patients WITH Compelling Conditions

Aortic dissection: Reduce SBP to <120 mmHg during the first hour (most aggressive target). 1

Severe preeclampsia/eclampsia or pheochromocytoma crisis: Reduce SBP to <140 mmHg during the first hour. 1

Acute pulmonary edema: Reduce SBP to <140 mmHg. 2

First-Line Intravenous Medications

Nicardipine (Preferred First-Line Agent)

Initial dose: 5 mg/h, increasing every 5 minutes by 2.5 mg/h to maximum 15 mg/h. 1, 2

• Contraindicated in advanced aortic stenosis 1
• No dose adjustment needed for elderly 1
• Must be diluted to 0.1 mg/mL concentration (25 mg vial in 240 mL compatible IV fluid) 3
• Compatible with D5W, D5W/0.45% NaCl, D5W/0.9% NaCl, 0.9% NaCl 3
• NOT compatible with sodium bicarbonate or lactated Ringer's 3
• Change peripheral IV site every 12 hours to prevent phlebitis 3

Clevidipine (Alternative First-Line Agent)

Initial dose: 1-2 mg/h, doubling every 90 seconds until BP approaches target, then increase by less than double every 5-10 minutes; maximum 32 mg/h; maximum duration 72 hours. 1

• Contraindicated in soy/egg allergy and defective lipid metabolism (pathological hyperlipidemia, lipoid nephrosis, acute pancreatitis) 1
• Supplied at 0.5 mg/mL, no dilution required 4
• Photosensitive—store in carton but protection during administration not required 4
• Single-use product; discard unused portion within 12 hours of puncture 4

Labetalol (Alternative First-Line Agent)

Initial dose: 0.3-1.0 mg/kg (maximum 20 mg) slow IV bolus every 10 minutes OR 0.4-1.0 mg/kg/h IV infusion up to 3 mg/kg/h, maximum cumulative dose 300 mg. 1, 2

• Particularly useful when both BP and heart rate control needed 5
• Contraindicated in bronchospasm, bradycardia, heart blocks 6

Additional Parenteral Options

Sodium nitroprusside: Initial 0.3-0.5 mcg/kg/min, increase by 0.5 mcg/kg/min increments to maximum 10 mcg/kg/min. 1

• Historically most popular agent but metabolized to toxic thiocyanate and cyanide 5
• For infusion rates ≥4-10 mcg/kg/min or duration >30 min, coadminister thiosulfate to prevent cyanide toxicity 1
• Keep duration as short as possible 1

Nitroglycerin: Initial 5 mcg/min, increase by 5 mcg/min every 3-5 minutes to maximum 20 mcg/min. 1

• Preferred when acute coronary insufficiency present 6

Esmolol: Loading dose 500-1000 mcg/kg/min over 1 minute, then 50 mcg/kg/min infusion, increase by 50 mcg/kg/min increments to maximum 200 mcg/kg/min. 1

• Preferred for aortic dissection (combined with vasodilator) 5

Hydralazine: Initial 10 mg slow IV (maximum 20 mg), repeat every 4-6 hours. 1

• Drug of choice for eclampsia 6

Phentolamine: IV bolus 5 mg. 1

• For catecholamine-induced crises (pheochromocytoma) 6

Critical Management Pitfalls to Avoid

Never use oral therapy for true hypertensive emergencies—parenteral agents are required for controlled, titratable BP reduction. 1

Avoid excessive rapid BP reduction—this causes cerebral, renal, or coronary ischemia and can worsen outcomes. 2, 7

Do not use short-acting nifedipine—no longer considered acceptable for initial treatment of hypertensive emergencies. 2

Avoid immediate-release nifedipine, hydralazine (except eclampsia), and nitroglycerin as first-line agents for most hypertensive emergencies. 8

Monitoring Requirements

ICU admission is mandatory for continuous BP monitoring, assessment of target organ damage, and parenteral drug administration. 1, 2

Adjust infusion rate if hypotension or tachycardia develops—discontinue infusion, allow stabilization, then restart at lower doses (3-5 mg/h for nicardipine). 3

Transition to Oral Therapy

Initiate oral antihypertensive therapy after 6-12 hours of parenteral therapy once BP stabilized. 7, 5

When switching to oral nicardipine: Administer first oral dose 1 hour prior to discontinuing IV infusion. 3

Hypertensive Urgency (Key Contrast)

Do NOT admit to ICU or use parenteral agents—these patients have severe BP elevation (>180/120 mmHg) without acute target organ damage. 1, 2

Management: Reinstitute or intensify oral antihypertensive therapy, arrange outpatient follow-up, treat anxiety if applicable. 1

No indication for emergency department referral or hospitalization in true urgencies. 1