Hypertensive emergencies

The most common clinical presentations of hypertensive emergencies are

• cerebral infarction (24.5%),
• pulmonary edema (22.5%),
• hypertensive encephalopathy (16.3%), and
• congestive heart failure (12%).
• Others - intracranial hemorrhage, aortic dissection, and eclampsia, as well as acute myocardial infarction

The pathologic hallmark of malignant hypertension is fibrinoid necrosis of the arterioles, which occurs systemically, but specifically in the kidneys. These patients develop fatal complications if untreated, and more than 90% will not survive beyond 1-2 years.

1st step in management of hypertensive emergency is immediate BP control to 25% less than that of presentation over the first 2 hours

DOC include IV nitroprusside (needs constant monitoring in ICU)

2nd Labetalol  -preferred in patients with acute dissection* and patients with end-stage renal disease. Boluses of 10-20 mg may be administered, or the drug may be infused at 1 mg/min until the desired BP is obtained.

• beta-blockers must be started before nitropursside to protect against reflex tachycardia of nitroprusside, which will worsen shearing forces.

Fenoldopam, a peripheral dopamine-1-receptor agonist is given as initial IV dose of 0.1 μg/kg/min titrated every 15 minutes.

Clevidipine, a dihydropyridine calcium channel blocker, is administered intravenously for rapid and precise BP reduction.[8] It is rapidly metabolized in the blood and tissues and does not accumulate in the body. Initiate IV infusion of clevidipine at 1-2 mg/h; titrate the dose at short intervals (ie, 90 s) initially by doubling the dose.

As the BP approaches its goal, increase the clevidipine dose by less than double, and lengthen the time between dose adjustments to every 5-10 minutes. An approximately 1-2 mg/h increase produces an additional 2-4 mm Hg decrease in SBP. Typically, the therapeutic response is achieved with 4-6 mg/h, although severe hypertension may require higher doses. Most patients have received maximum doses of 16 mg/h or less; experience is limited with short-term dosing as high as 32 mg/h. Because of lipid load restrictions, do not exceed 1000 mL or an average of 21 mg/h within a 24-hour period; experience is limited with use beyond 72 hours.

Neurologic emergencies

Rapid BP reduction is indicated in neurologic emergencies, such as hypertensive encephalopathy, acute ischemic stroke, acute intracerebral hemorrhage, and subarachnoid hemorrhage.

In hypertensive encephalopathy, the treatment guidelines are to reduce the MAP 25% over 8 hours. Labetalol, nicardipine, esmolol are the preferred medications; nitroprusside and hydralazine should be avoided.

For acute ischemic stroke, the preferred medications are labetalol and nicardipine. Withhold antihypertensive medications unless the SBP is >220 mm Hg or the DBP is >120 mm Hg, UNLESS the patient is receiving IV or intra-arterial (IA) fibrinolysis; then, the goal BP is an SBP of < 185 mm Hg and DBP < 110 mm Hg. After treatment with fibrinolysis, the SBP should be maintained < 180 mm Hg and the DBP at < 105 mm Hg for 24 hours.