Transcription
There are so many different medications that we can use to treat hypertensive emergency. And I remember, as an intern, I struggled knowing how to choose between all the different agents that are available. So this is going to be my approach to hypertensive emergency, and this is also an excellent teaching topic that's very quick that you can do with your medical students and interns.
So starting off, we have a discussion of the difference between hypertensive urgency and hypertensive emergency. And I always like to ask my medical students, "What is the blood pressure cut-off for urgency and emergency?" The answer to that is greater than 180 systolic or greater than 120 diastolic for both hypertensive urgency and emergency. The only difference between urgency and emergency is that in hypertensive emergency, you're going to have signs of end-organ damage.
So what are some examples of end-organ damage? I'll usually ask them to come up with a few examples of end-organ damage, and then we'll go over things like encephalopathy, stroke, retinal hemorrhage, papilloedema, congestive heart failure, acute coronary syndrome, aortic dissection, renal failure, etc. With hypertensive urgency, you can actually have a mild headache, and that's not going to be a sign of end-organ damage. It's only really going to be if it's a severe headache that's making you concerned that they're having some kind of stroke, or if they're encephalopathic—they're altered—then you're going to consider it end-organ damage.
One other point I want to bring up is that you'll hear in the literature this term called hypertensive crisis. And from what I can tell, it's kind of an umbrella term for hypertensive urgency and hypertensive emergency. But these days, it's very outdated, so I would very much avoid using that term because it's very confusing to people. The other thing is that there's a big push to stop using the terminology hypertensive urgency and instead call it severe asymptomatic hypertension. Because when you call it hypertensive urgency, it makes people feel like they need to do something right away about it. But in all reality, there is actually no evidence that there's anything urgent about hypertensive urgency, and we just try to lower the blood pressure slowly over time.
All right, let's move on to treatment approaches for hypertensive urgency and hypertensive emergency. So first of all, for hypertensive urgency, you should really consider all of the common inpatient causes for why they may be having hypertensive urgency, because there's a lot of things that are very quickly reversible. And here we can see missing outpatient medications, drug withdrawal such as alcohol withdrawal or benzo withdrawal, anxiety, pain, delirium, and volume overload are all very common reasons that people can be hypertensive in the hospital.
In terms of a therapeutic approach, the first step is really to treat the above etiologies. So first, you need to make sure there's a thorough med rec, and then you restart home medications. For drug withdrawal, you want to make sure that the patients are on a CIWA-Ar protocol. Anxiety and pain: you want to treat this with anti-anxiety medications, putting them in a quiet room, also making sure they have an appropriate pain medication regimen ordered. Delirium: obviously reorientation, delirium precautions. And volume overload: you're going to diurese.
The next step is to do what Dr. Strong recommends, is a five-minute neuroscreen. And this is just to rule out that you're not missing hypertensive urgency. So you want to check their cranial nerves, you want to check their orientation and their speech, and also just a general strength exam, make sure that they're not having any focal deficits that you're missing. If they're not on any antihypertensives already, then you should really start them on something like amlodipine or lisinopril, which will take several days to go into effect. And then in terms of an acute treatment, some of the options you have are hydralazine, labetalol, and clonidine patches.
First of all, I would want to say that the evidence for doing all this is very poor, but a lot of times you're going to be asked by nursing to give some kind of blood pressure medication. And so if you do have to give something, really try to give them PO instead of IV, because there's going to be less of a chance that you're just going to acutely drop somebody's blood pressure a lot. The other thing is that with clonidine patch—you know, oral clonidine is definitely not a preferred medication because of the risk of severe rebound hypertension—uh, but the good thing about clonidine patches is that they kind of self-taper over time. I will say that I have not really chosen this this approach very often, but hydralazine is definitely the most commonly used one. Make sure you know that a side effect of that is going to be reflex tachycardia. And then for the labetalol, you're going to cause a little bit of bradycardia. So the overall treatment approach is that you want to lower their blood pressure over hours to days.
And the reason I wrote this is it contrasts with the initial goal for hypertensive emergency. And here is where I ask interns and medical students, "What is your goal blood pressure if somebody comes in with hypertensive emergency?" And the answer to that is going to be that you want to lower their MAP by about 10 to 20 percent in the first hour of their presentation, and then over the next 24 hours, you want it to be a goal of about 25 percent lower.
The next thing to go over, and this is something that should be included in any good hypertensive emergency talk, is that there are two situations that are exceptions where you would not want to lower the blood pressure with the same goal as we talked about before. And those two situations are going to be ischemic stroke and aortic dissection. So for ischemic stroke, we allow permissive hypertension in order to allow better perfusion to the brain and allow more parenchyma to be saved. So for ischemic stroke, if the patient has received tPA, then we actually allow them to have blood pressures up to 185 over 110, and you would only start treatment if they were starting to go above this blood pressure. And if the patient did not receive tPA, you even have a higher goal of letting them stay all the way up to 220 over 120, and you would only initiate treatment if they're above that. And for aortic dissection, we actually have a completely opposite situation where you actually want to rapidly lower the blood pressure to 100 to 120 systolic within 20 to 30 minutes, and you also want to achieve a goal heart rate of less than 60. So again, the two situations that are exceptions to the above blood pressure goal are ischemic stroke and aortic dissection.
Next, I like to go over the medications, and I kind of just quiz the medical students or the interns about which medications they know that can be used for hypertensive emergency. And we have a whole host of medications, uh, including nitroprusside, nitroglycerin, esmolol, labetalol, nicardipine, clevidipine, and phenoldopam. And this is the main reason I want to do this talk, because as an intern, I remember being like, "How do I choose between all these different medications?" So let's talk about these different medications.
So nitropruside and nitroglycerin are agents that will increase the levels of nitric oxide, leading to release of cyclic GMP and causing vasodilation. Esmolol and labetalol are obviously beta-blockers. Nicardipine and clevidipine are calcium channel blockers. And this medication, phenoldopam, is a dopamine agonist. I want to go over a few unique characteristics about some of these medications. So for nitroprusside, this is going to be both a veno- and arterio-dilator, whereas nitroglycerin is a pure veno-dilator. This is something that attendings may ask you about. In terms of beta-blockers, the advantage of esmolol—and this is something we've talked about in previous talks—is that it's ultra short-acting with a half-life of nine minutes, so it's rapidly titratable, and you can easily achieve the correct rate that you need to. Calcium channel blockers: the one thing to know about nicardipine is that it prevents cerebral vasospasm, so it's really good for stroke patients. And then for clevidipine, it's kind of like esmolol, it's ultra short-acting and rapidly titratable. Finally, for phenoldopam, this is the dopamine agonist, and this one is really good for patients who come in with an acute kidney injury because it maintains or increases kidney perfusion while lowering the blood pressure at the same time.
A couple more things to note about each of these individual agents. So say you have somebody on nitroprusside, and they're on day two of it, they're on a pretty high dose, and all of a sudden they start to become altered, their bicarb is going down, and they're developing a lactic acidosis. What is the reason this is all going on? That's going to be cyanide toxicity. So that's going to be one major side effect of nitroprusside, and one reason that people are afraid to use it. But one of the good things about nitroprusside is it's pretty good in patients with heart failure. For nitroglycerin, this is a pure veno-dilator. A couple things to note about it is that it has less of an antihypertensive effect compared to the other medications, so it's not going to be as effective at lowering that blood pressure. One of the biggest side effects of this is going to be headaches, and there's also tachyphylaxis with nitroglycerin, which basically means the longer you use it, the less effective it's going to be. Obviously, the good thing that it's going to be good for is acute coronary syndrome, because a lot of times we're going to give nitroglycerin to these patients anyways. For beta-blockers, the main thing you want to know is that uh, the best situation to use it is going to be aortic dissection, because remember you're trying to rapidly lower that blood pressure, but you're also trying to lower that heart rate to a goal less than 60. So this is the perfect situation when you have aortic dissection to do a beta-blocker, and a lot of times you want to lower it so quickly that you give both a beta-blocker and a calcium channel blocker. Some of the downsides to it are using it in heart failure because you're going to have negative inotropy, and also for reactive airway disease. Nicardipine is very good for stroke situations, uh, clevidipine is basically good for all situations. The main thing you want to know for this one is that it's contraindicated in severe aortic stenosis, and also if the patient has a severe allergy to eggs or soy, then this also cannot be given. And finally, like I mentioned before, the dopamine agonist you'll be giving in the situations where the patient has an AKI.
In general, I would say that most of the time it's going to be institution-dependent for which agent is going to be most frequently used, but at my institution, the most commonly used one is clevidipine, because it's really good for most situations. As I mentioned, it's very rapid titration, short-acting, and just a very good drug overall.
Now let's just do a quick table of all of the different medications you can use. So again, nitroprusside is going to be good for heart failure specifically, and the reason for that is because a lot of the other drugs are just not good for heart failure, and otherwise it's good for most situations, but the things it's bad for are cyanide toxicity. So for this medication, it's really advised to avoid use over 48 to 72 hours. The next medication is nitroglycerin, and this is going to be really great for acute coronary syndrome. The downsides again are that it has a lower antihypertensive effect compared to the other medications. One of the big side effects is severe headache, and it also has tachyphylaxis, which means it's not as effective over time. Next, we go on to the beta-blockers, esmolol and labetalol, and these are going to be really good for aortic dissection, as I mentioned before, but also good for situations where the patient is experiencing angina. The situations you want to avoid this in are heart failure, pulmonary edema, and reactive airway disease. Next, we have nicardipine; it's going to be the best one for stroke, either ischemic or hemorrhagic, because of that prevention of cerebral vasospasm; also good to consider in hypertensive encephalopathy uh situations. It's bad for—again, it's gonna be bad for heart failure because it's got negative inotropy. Clevidipine is good for most situations, again bad for heart failure, severe aortic stenosis, and soy or egg allergy. And lastly, we have phenoldopam, which is going to be really good for acute kidney injury. I'm not actually sure what it's bad for in terms of contraindications, but it's just not a very commonly used medication, so that's probably the main downside to it; it's just people are not going to be as comfortable using phenoldopam. So again, I'd really say at our institution at least, clevidipine is the most useful one, but especially if somebody's coming in with aortic dissection, definitely consider beta-blockers; acute coronary syndrome, you want to try nitroglycerin; heart failure, something like nitroprusside; and then stroke, nicardipine.
I hope this video was helpful in doing a brief overview of hypertensive urgency and hypertensive emergency and helping you know the differences between the different medications that are available and how to choose the best one for each individual situation and different patient. If you enjoyed this video or found it useful, please consider subscribing and leaving a comment for me down below, which I'll definitely reply to, and let me know that you would like more content like this, and I'll definitely continue to make more videos. If there are any corrections to this video, I will put it in the description box below the video, and I hope you really enjoyed it. Thanks again for watching, and I'll see you in the next one.