From the latest American Heart Association (AHA) guidelines for the management of stroke, we have the following: Although severe hypertension may be considered an indication for treatment, there are no data that define the levels of hypertension that require emergency management. However, data do suggest that the systolic blood pressure level that would prompt treatment would be over 180 mm Hg. A systolic blood pressure over 185 mm Hg or a diastolic blood pressure over 110 mm Hg is a contraindication to intravenous administration of rtPA.13
Explore This IssueACEP News: Vol 31 – No 09 – September 2012
Still, it is not clear whether those values should be the threshold for starting emergency treatment outside the setting of administration of rtPA.
In the absence of other organ dysfunction necessitating rapid reduction in blood pressure or in the setting of thrombolytic therapy, there is little scientific evidence and no clinically established benefit for rapid lowering of blood pressure among persons with acute ischemic stroke.13 The current AHA guidelines recommend the use of labetalol or nicardipine as the initial vasoactive medications if blood pressure does indeed need to be reduced in a patient with ischemic stroke.13
Patients with intracerebral hemorrhage (ICH) often have marked elevations in blood pressure. Several physiologic mechanisms likely contribute to this, including stress activation of the neuro-endocrine system and increased intracranial pressure causing reflex systemic hypertension. Several studies have shown that systolic blood pressures over 140-150 mm Hg within 12 hours of the onset of ICH are associated with more than double the risk of death or dependency.14 The INTERACT and ATACH trials are both relatively large clinical trials that support the safety and efficacy of rapid blood pressure lowering in ICH.
Still, per the latest guidelines on the management of intracerebral hemorrhage, the issue of blood pressure management remains a controversial one. Although studies have shown that intensive blood pressure lowering is clinically feasible and potentially safe, the blood pressure target, duration of therapy, and whether such treatment improves clinical outcomes remain unclear.15 Emergency physicians should make decisions regarding blood pressure management in ICH in close consultation with a neurosurgeon. When blood pressure reduction is indicated, nicardipine is recommended as a drug of choice.
Persistent elevation of blood pressure in cases of aortic dissection serves to increase the shearing force across the interface of the intimal flap and can cause further propagation or extension of the dissection.2 Rapid blood pressure reduction, often beyond the general goal of a reduction in mean arterial pressure (MAP) of about 25%, is recommended for acute aortic dissection. The goal of blood pressure reduction is for the systolic blood pressure to be reduced to a level between 100 and 120 mm Hg. A drug of choice for this scenario is labetalol. Alternatively, a combination of a beta-blocker and vasodilator can be used.16 Blood pressure management decisions should be made in close consultation with a vascular surgeon.
Hypertension complicates more than 10% of pregnancies and is responsible for as many as 13% of maternal deaths in the United States.17 Though delivery is the definitive treatment for severe pre-eclampsia and eclampsia, ED management usually entails administration of magnesium sulfate for seizure prophylaxis and aggressive blood pressure control. Systolic blood pressure over 160 mm Hg has been shown to be the most important factor associated with a cerebrovascular accident in patients with pre-eclampsia.2,18 ED management focuses on aggressively reducing blood pressure to a systolic blood pressure less than 160 mm Hg and/or a diastolic blood pressure under 110. Traditionally, a drug of choice for use in this particular hypertensive emergency has been hydralazine. Recent evidence shows that hydralazine should likely not be used as a first-line agent in pre-eclamptic or eclamptic patients. Hydralazine’s latent period of 5-15 minutes is usually followed by a progressive, unpredictable, and often precipitous fall in blood pressure that can last up to 12 hours. Labetalol and nicardipine have been shown to be equally efficacious and ultimately preferable drugs for this population.1,2
The modern-day emergency physician has a vast armamentarium of antihypertensive medications at their disposal for hypertensive emergency. Accumulating evidence has resulted in older mainstays like hydralazine and nitroprusside largely falling out of favor except in cases that fail to respond to other therapies. A review of the basic properties and indications for use of some of the most commonly utilized medications can be found in Table 2.