What is the management of a hypertensive emergency?

From the Guidelines

The management of a hypertensive emergency involves administering IV antihypertensives in a monitored setting, aiming to reduce blood pressure by no more than 25% within the first hour, then to 160/100-110 mmHg within the next 2-6 hours, with first-line medications including labetalol, nicardipine, or clevidipine, as recommended by the 2020 International Society of Hypertension global hypertension practice guidelines 1. The goal of treatment is to prevent or limit further hypertensive damage by a controlled blood pressure reduction, with the swiftness and magnitude of the blood pressure reduction, as well as the type of blood pressure-lowering medication, being strongly dependent on the clinical context, such as the type of hypertensive organ damage, as outlined in the ESC Council on Hypertension position document on the management of hypertensive emergencies 2. Some key considerations in the management of hypertensive emergencies include:

• The specific organ damage determines medication choice, such as nitroglycerin for cardiac ischemia or enalaprilat for heart failure, as noted in the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 3.
• Patients require admission to an ICU with continuous blood pressure monitoring, neurological assessments, and evaluation for secondary causes of hypertension, as recommended by the 2020 International Society of Hypertension global hypertension practice guidelines 1.
• Rapid blood pressure reduction is necessary to prevent further organ damage but must be controlled to avoid hypoperfusion, particularly in patients with chronic hypertension who have altered autoregulation, as noted in the ESC Council on Hypertension position document on the management of hypertensive emergencies 2. Some specific clinical presentations of hypertensive emergencies and their recommended treatments include:
• Malignant hypertension with or without thrombotic microangiopathy or acute renal failure: labetalol or nitroprusside, with a goal of reducing mean arterial pressure by 20-25% over several hours, as outlined in the 2020 International Society of Hypertension global hypertension practice guidelines 1.
• Hypertensive encephalopathy: labetalol or nicardipine, with a goal of reducing mean arterial pressure by 20-25% immediately, as noted in the ESC Council on Hypertension position document on the management of hypertensive emergencies 2.
• Acute ischemic stroke: labetalol or nicardipine, with a goal of reducing mean arterial pressure by 15% over 1 hour, as recommended by the 2020 International Society of Hypertension global hypertension practice guidelines 1.

From the FDA Drug Label

The time course of blood pressure decrease is dependent on the initial rate of infusion and the frequency of dosage adjustment. Nicardipine hydrochloride injection is administered by slow continuous infusion at a concentration of 0. 1 mg/mL. With constant infusion, blood pressure begins to fall within minutes. It reaches about 50% of its ultimate decrease in about 45 minutes Titration For a gradual reduction in blood pressure, initiate therapy at a rate of 5 mg/hr. If desired blood pressure reduction is not achieved at this dose, increase the infusion rate by 2. 5 mg/hr every 15 minutes up to a maximum of 15 mg/hr, until desired blood pressure reduction is achieved. For more rapid blood pressure reduction, titrate every 5 minutes. In patients with severe or postoperative hypertension), nicardipine hydrochloride injection (5 to 15 mg/hr) produced dose-dependent decreases in blood pressure. In a clinical pharmacologic study in severe hypertensives, an initial 0. 25 mg/kg injection of labetalol HCl, administered to patients in the supine position, decreased blood pressure by an average of 11/7 mmHg. Labetalol HCl administered as a continuous intravenous infusion, with a mean dose of 136 mg (27 to 300 mg) over a period of 2 to 3 hours (mean of 2 hours and 39 minutes) lowered the blood pressure by an average of 60/35 mmHg

The management of a hypertensive emergency involves the use of intravenous medications such as nicardipine or labetalol.

• Nicardipine is administered by slow continuous infusion at a concentration of 0.1 mg/mL, with a starting dose of 5 mg/hr and titrated every 15 minutes as needed, up to a maximum of 15 mg/hr.
• Labetalol can be administered as an initial injection of 0.25 mg/kg, followed by additional doses or as a continuous infusion with a mean dose of 136 mg over 2-3 hours. It is essential to closely monitor the patient's blood pressure and adjust the infusion rate accordingly to achieve the desired response while minimizing the risk of hypotension or other adverse effects 4, 5, 6.

From the Research

Management of Hypertensive Emergency

The management of a hypertensive emergency involves rapid controlled reduction of blood pressure to prevent or minimize end-organ damage. The following are key points in the management of hypertensive emergency:

• Rapid recognition and initiation of therapy are key to minimizing end-organ damage in patients with hypertensive emergency 7.
• Intravenous antihypertensive agents are recommended for the treatment of hypertensive emergencies, including nicardipine, nitroprusside, fenoldopam, nitroglycerin, enalaprilat, hydralazine, labetalol, esmolol, and phentolamine 7.
• The selection of a specific agent should be based on the agent's pharmacology and patient-specific factors, such as comorbidity and the presence of end-organ damage 7.
• Patients with hypertensive emergencies are best treated in an intensive care unit with titratable, intravenous, hypotensive agents 8.

Treatment Approach

The primary goal of intervention in a hypertensive crisis is to safely reduce blood pressure. The appropriate therapeutic approach for each patient will depend on their clinical presentation.

• For hypertensive emergencies, immediate reduction in blood pressure is required, and treatment with a titratable, short-acting, intravenous antihypertensive agent is necessary 8.
• Rapid-acting intravenous antihypertensive agents are available, including labetalol, esmolol, fenoldopam, nicardipine, and sodium nitroprusside 8.
• The goal is to reduce blood pressure by about 10% during the first hour and another 15% gradually over 2-3 more hours, with the exception of aortic dissection, for which the target is systolic blood pressure <120 mm Hg after 20 minutes 9.
• A maximum BP reduction of 20-25% within the first hour and then to 160/110-100 over the next 2-6 hours is considered appropriate, with a further gradual decrease over the next 24-48 hours to reach normal BP levels 10.

Choice of Antihypertensive Agents

The choice of antihypertensive agent depends on the underlying causes of the crisis, patient's demographics, cardiovascular risk, and comorbidities.

• Sodium nitroprusside is an extremely toxic drug and its use in the treatment of hypertensive emergencies should be avoided 8.
• Newer agents, such as clevidipine and fenoldopam, may hold considerable advantages over other available agents in the management of hypertensive crises 8.
• Esmolol is effective in controlling both supraventricular tachyarrhythmias and severe hypertension, but its use should be avoided in patients with low cardiac output 11.
• Nicardipine is a potent arteriolar vasodilator without a significant direct depressant effect on myocardium, but it should not be used in patients with severe aortic stenosis 11.