What is the recommended management for hypertension in the Intensive Care Unit (ICU)?

Management of Hypertension in the ICU

For patients with hypertensive emergencies in the ICU, admission to an intensive care unit is recommended for continuous monitoring of BP and target organ damage and for parenteral administration of appropriate antihypertensive agents. 1

Classification of Hypertensive Crisis

• Hypertensive urgency: Severe BP elevation (>180/120 mmHg) without evidence of new or progressive target organ damage 2
• Hypertensive emergency: Severe BP elevation with evidence of new or worsening target organ damage (encephalopathy, stroke, acute heart failure, etc.) 2

Blood Pressure Reduction Goals

• For patients with a compelling condition (aortic dissection, severe preeclampsia/eclampsia, pheochromocytoma crisis):

  • SBP should be reduced to less than 140 mm Hg during the first hour 1
  • For aortic dissection specifically, target SBP less than 120 mm Hg 1

• For patients without a compelling condition:

  • SBP should be reduced by no more than 25% within the first hour 1, 2
  • Then, if stable, to 160/100 mm Hg within the next 2-6 hours 1
  • Finally, cautiously to normal during the following 24 to 48 hours 1

First-Line Intravenous Medications by Clinical Presentation

Malignant hypertension with/without TMA or acute renal failure

• First line: Labetalol 1
• Alternatives: Nitroprusside, Nicardipine, Urapidil 1

Hypertensive encephalopathy

• First line: Labetalol 1
• Alternatives: Nitroprusside, Nicardipine 1

Acute ischemic stroke

• First line: Labetalol 1
• Alternatives: Nitroprusside, Nicardipine 1

Acute hemorrhagic stroke

• First line: Labetalol 1
• Alternatives: Urapidil, Nicardipine 1

Acute coronary event

• First line: Nitroglycerin 1
• Alternatives: Urapidil, Labetalol 1

Acute cardiogenic pulmonary edema

• First line: Nitroprusside or Nitroglycerin (with loop diuretic) 1
• Alternatives: Urapidil (with loop diuretic) 1

Acute aortic disease

• First line: Esmolol and Nitroprusside or Nitroglycerin 1
• Alternatives: Labetalol or Metoprolol, Nicardipine 1

Eclampsia and severe pre-eclampsia

• First line: Labetalol or Nicardipine and Magnesium sulfate 1

Specific Intravenous Antihypertensive Medications

Nicardipine

• Dosing: Initial 5 mg/h, increasing every 5 min by 2.5 mg/h to maximum 15 mg/h 1, 3
• Onset of action: 5-15 minutes 1
• Duration of action: 30-40 minutes 1
• Contraindications: Advanced aortic stenosis 3
• Notes: No dose adjustment needed for elderly; headache and reflex tachycardia may occur 1, 3

Clevidipine

• Dosing: Initial 1-2 mg/h, doubling every 90 seconds until BP approaches target 1
• Onset of action: 2-3 minutes 1
• Duration of action: 5-15 minutes 1
• Contraindications: Soybean/egg allergies, defective lipid metabolism 1, 3
• Notes: Headache and reflex tachycardia may occur 1

Labetalol

• Dosing: 0.25-0.5 mg/kg IV bolus; 2-4 mg/min continuous infusion 1
• Onset of action: 5-10 minutes 1
• Duration of action: 3-6 hours 1
• Contraindications: History of 2nd or 3rd degree AV block, systolic heart failure, asthma, bradycardia 1
• Notes: May cause bronchoconstriction and fetal bradycardia 1

Nitroprusside

• Dosing: 0.3-10 μg/kg/min, increase by 0.5 μg/kg/min every 5 min 1
• Onset of action: Immediate 1
• Duration of action: 1-2 minutes 1
• Contraindications: Liver/kidney failure (relative) 1
• Notes: Risk of cyanide toxicity; should be used with caution and for short durations 1, 4

Esmolol

• Dosing: 0.5-1 mg/kg IV bolus; 50-300 μg/kg/min as continuous IV infusion 1
• Onset of action: 1-2 minutes 1
• Duration of action: 10-30 minutes 1
• Contraindications: History of 2nd or 3rd degree AV block, systolic heart failure, asthma, bradycardia 1
• Notes: May cause bradycardia 1

Special Clinical Scenarios

Acute Aortic Disease

• Immediate reduction of systolic BP to 120 mmHg or lower and heart rate to 60 bpm or less 1
• Beta-blockers (esmolol) are first-line treatment, combined with ultra-short acting vasodilators like nitroprusside or clevidipine 1

Eclampsia and Severe Pre-eclampsia

• Target BP <160/105 mmHg to prevent acute hypertensive complications 1
• Both labetalol and nicardipine are safe and effective 1
• Magnesium sulfate should be administered concurrently 1
• Monitor fetal heart rate; cumulative dose of labetalol should not exceed 800 mg/24h to prevent fetal bradycardia 1

Monitoring and Follow-up

• Patients with hypertensive emergencies should be admitted to an ICU for continuous BP monitoring 1
• Intra-arterial BP monitoring is recommended when using potent vasodilators like nitroprusside to prevent "overshoot" 1
• Change peripheral infusion site every 12 hours if administered via peripheral vein 3
• Monitor closely when titrating in patients with congestive heart failure or impaired hepatic or renal function 3

Common Pitfalls and Caveats

• Avoid rapid BP reduction as it can lead to cardiovascular complications including ischemic stroke and death 1, 2
• Sodium nitroprusside is extremely toxic and should be used with caution due to risk of cyanide toxicity 4, 5
• Nifedipine, nitroglycerin, and hydralazine should not be considered first-line therapies due to significant toxicities and side effects 4
• In patients with hypertensive encephalopathy, labetalol may be preferred as it leaves cerebral blood flow relatively intact compared to nitroprusside 1
• Poor medication adherence is a common cause of hypertensive crisis; address this issue before discharge 2