Today we discussed an interesting case of hypertensive emergency. Identifying hypertensive emergency remains fairly straightforward: 1) Elevated blood pressure (systolic ≥180, diastolic ≥120), and 2) ends-organ damage as a result of point (1). The management of emergency is difficult primarily because a) blood pressure are tissue necrosis are both continuous variables which we are managing as discrete processes, and b) there is little evidence to inform appropriate therapy of emergency. Bearing that in mind, we come across several different problems over the course of hypertensive emergency treatment (CHEST 2007; 131:1949–1962.).
If hypertensive emergency is just high blood pressure with organ injury, what kind of organ injury am I looking for? In general, there are 5 principle organs (or systems) that can be injured by an acutely elevated blood pressure. Knowing the injured system affects management, so it is important to be precise in understanding where in the body hypertension has run amok.
- CNS: Stroke (usual principle of 25% SBP reduction over 60-120 minutes falls apart here), Hemorrhage, Hypertensive Encephalopathy
- Cardiac: ACS, Acute Heart Failure
- Vascular: AAA (Blood pressure control is far more aggressive in this instance)
- Renal: Hypertensive Nephrosclerosis
- Hematologic: MAHA
What agents are appropriate for the acute management of hypertensive emergency? This is one of those topics where medical (specifically physician) judgment exceeds medical knowledge. There are a tremendous number of very strong opinions on the right agents to use without much literature to guide decision-making. In these circumstances, using your medical knowledge of pharmacodynamics and pathophysiology will guide decision-making (not to mention institutional standards of care). The following table can help get you started (in general, nicardipine and labetalol are favored).