Examples of truly titratable agents include: Clevidipine, nitroglycerine, and esmolol.
Examples of quasi-titratable agents include: Nicardipine and diltiazem.
Examples of bolus agents include: Labetalol and metoprolol.
Pitfalls in the management of hypertension include:
1. Over-diagnosis of hypertensive emergencies in patients with alarmingly high blood pressure but without any damage to target organs. Such cases do not qualify as hypertensive emergencies.
2. Overly aggressive treatment of hypertensive emergencies, which can lead to excessively rapid and significant reductions in blood pressure.
3. Over-reliance on oral antihypertensive agents with unpredictable onset and effectiveness may pose a risk of dose-stacking.
4. Avoid intravenous hydralazine since its effects can be inconsistent and may occasionally cause a drastic drop in blood pressure.
5. Avoid intravenous metoprolol since it may cause severe bradycardia.
Special considerations in the management of hypertensive emergency include: 1. Aortic dissection.
Traditional teaching is to lower the systolic blood pressure to 100 to 120 millimeter mercury. Intravenous beta-blockers, most commonly esmolol, are first-line treatments due to their ability to lower blood pressure while avoiding reflex tachycardia and increased shear stress to the aortic wall.
Using nitroprusside to treat aortic dissection has become an infrequent practice due to its association with rapid and profound hypotension, tachyphylaxis, as well as the potential for cyanide toxicity.
Nicardipine with the addition of a beta-blocker would also be a reasonable choice.
2. Acute hemorrhagic stroke.
In acute brain hemorrhage, reduction of systolic blood pressure below 140 mmHg may improve functional outcomes.
This requires an aggressive approach with rapidly titrated intravenous anti-hypertensives, and extreme vigilance is necessary to prevent hypotension, which causes decreased cerebral perfusion pressure and adds to the ischemic insult.
Easily titratable medications with rapid onset and short duration of action, such as nicardipine, are recommended.
3. Acute ischemic stroke.
Stroke patients eligible for thrombolysis should have blood pressure controlled to systolic blood pressure below 185 millimeter mercury and diastolic blood pressure below 110 millimeter mercury.
For those not receiving thrombolytics, only levels of systolic blood pressure above 220 millimeter mercury or diastolic blood pressure above 120 millimeter mercury should be treated as hypertension in acute stroke is usually transient and may be protective.
A reasonable goal is about a 15% decrease in mean arterial pressure.
4. Preeclampsia or eclampsia.
Preeclampsia or eclampsia is a particularly troubling and difficult to manage hypertensive emergency since there are two patients to consider.
The first-line therapy is magnesium sulfate, administered as a 4 to 6 gram loading dose followed by 1 to 2 gram per hour infusion.
Care must be taken to monitor for urine output, deep tendon reflexes, and respiratory status.
If further antihypertensives are needed, beta-blockers can be used, but only to treat systolic blood pressure higher than 160 millimeter mercury.
Hydralazine was once touted as the preferred agent in pregnant patients;
however, its delayed onset of action, prolonged duration, and unpredictable hypotensive effects make it a less than ideal choice.
Regardless of the agent, the patient is likely to need close monitoring in a critical care setting.