Congestive heart failure exacerbation management

Most of the third years, and probably the second years at this point, know pretty well how to manage CHF exacerbations. However, there are differences in managing the normotensive vs. hypertensive vs. hypotensive exacerbation, and I’ll try to provide some tricks in managing your run-of-the-mill CHF exacerbation as well (credits to Amal Mattu and Scott Weingart).

 

First, try to determine the cause of the exacerbation. Determining the cause of the exacerbation, however, can be difficult – most patients aren’t honest about their salt/food/drug intake or medication compliance, or do not understand their disease process. The most common cause of an exacerbation is dietary or medication non-compliance. However, in all cases, ischemia needs to be considered. More rare cases can be valvular dysfunction such as rupture (auscultation or BSUS), myocarditis (check a troponin if it fits the clinical scenario), arrhythmias (check HR and an EKG), hypertensive crisis (often secondary to medication and dietary non-compliance, or drugs), or high-output failure (such as anemia, sepsis, AV-fistula in a dialysis patient, thyrotoxicosis). (1)

 

Next comes diagnostics. There are debates on whether troponins and BNPs need to be ordered on every CHF exacerbation. For example, many of these patients will have chronically elevated troponins and BNPs, and you’ll be stuck trending them. A BNP is of limited value in the ER except in maybe determining is the patient’s dyspnea secondary to a COPD exacerbation or CHF exacerbation, or if the BNP is normal then it should make you consider alternative diagnoses. Amal Mattu suggests that if you’re going to admit the patient, get everything (CBC, CMP, BNP, trop, EKG, CXR) because the inpatient teams like to trend trops/BNPs (even if the evidence doesn’t really back up trending BNPs). If it’s simply diet or medication non-compliance, you might only need to check electrolytes, because diuretics can cause electrolyte disturbances. ABGs aren’t typically helpful unless the patient is hypoxemic. Overall, not much other testing needs to be done for your non-critically ill patients. (1)

 

As for management, this becomes tricky because it depends on many things. What is the patient’s blood pressure? What is the cause of their exacerbation? Are they volume-overloaded, euvolemic, or dry? Are they septic? In general you have three goals: decrease the preload, decrease the afterload, and (in some cases) increase LV function. PLEASE watch this Amal Mattu lecture and you will master CHF exacerbations (2). For management, let’s start with the classic hypertensive patient.

 

Hypertensive patient: The patient’s heart is straining against a high amount of SVR and can’t perfuse their kidneys. Fluid backs up into the lungs. Don’t immediately jump to your loop diuretics (it’s debatable, and should only be done if hyper or maybe euvolemic). We fix this problem by fixing two problem: decreasing the SVR in order to perfuse the kidneys, and decreasing preload to “turn off the faucet” that’s overflowing a bathtub (lungs). Lasix won’t work if you aren’t perfusing the kidneys. One of the best and quickest agents we have is nitroglycerin. You have three options: 0.4mg sublingual tab, nitro paste, and a nitro bolus and drip. Scott Weingart (3) recommends the nitro drip, starting with a bolus of 400 mcg (that’s one sublingual nitro tab) over 2 minutes, and then drop to 100 mcg/min and titrate up until SVR is decreased. Your nurses will often question if you want to start the rate that high, and the answer is yes, but you MUST monitor your patient closely because high doses of nitro can tank your patient’s BP if you aren’t careful. Also, nitro also decreases preload, which can prevent fluid from backing up into the heart and therefore the lungs. (Nitro often gives patients a headache – give ‘em some Tylenol.) This can fix patients in minutes, because you’re redistributing fluid out of the lungs and into the vasculature or the rest of the body! BiPAP will save these patients by pushing fluid out of their lungs and can prevent intubation. The other thing to consider is IV ACE Inhibitors. Enalapril (enalaprilat) is the only IV form we have, and it has to come from pharmacy, but ACE Inhibitors are very good at afterload reduction and will help move the fluid from the lungs into the rest of the body. If nitro isn’t working, consider adding on enalapril.

 

Normotensive patients: just because their BP isn’t high doesn’t mean you can’t use nitro. However, be judicious, because you don’t want to cause hypotension, but remember that even normotensive patients can tolerate a sublingual nitro without issue. Lasix if clinically volume overloaded. BiPAP as needed for respiratory difficulties. Otherwise, nothing too tricky here.

 

Hypotensive patients: these are actually your cardiogenic shock patients. They are sick as snot. They could also be septic (! Hi Dr. Shoff), or could be having an MI. Your management of these patients is very difficult and much different than your typical CHF exacerbation management. First, determine if the patient is “warm” or “cold” (feel their extremities), and then determine if “wet” or “dry” (pulmonary edema). (4) The most common presentation is “cold and wet”, but removing fluid from them will make them worse. Obviously, if they have pulmonary edema, do not give them fluid.  HOWEVER, norepinephrine is the best agent to use and is proven in many studies. Epinephrine is your second-line agent. Avoid dopamine (SOAP-II trial demonstrated harm of dopamine vs. norepinephrine). Get basic labs, troponin, BNP, EKG, CXR, lactic acid level, blood cultures, and get reliable access. Get a digoxin level if they’re on dig, or if they can’t tell you if they are. Use BiPAP early for their respiratory status. Your BSUS can greatly aid you in what is going on and how to treat it. If the heart isn’t squeezing well, give drugs to make it do so. If it’s hyperdynamic, maybe the heart isn’t the problem. You can provide inotropic support (epi, milrinone) if on BSUS you see their EF is terrible, and if it’s caused by an MI they need urgent revascularization. Be careful – milrinone can cause hypotension. Digoxin is actually an alternative and can be given IV.

 

If you want a checklist version in treating the cardiogenic shock patients, Weingart supplied this: https://i2.wp.com/emcrit.org/wp-content/uploads/2016/11/chflist.jpg

 

Note: A study published in 2017 (5) tried to see if “time-to-furosemide” was beneficial. Initially, the study looks grossly positive (2.3% vs. 6% mortality in the “early” treatment vs “late” treatment arms, respectively), however, “early” was defined as <1 hour and “late” was defined as all furosemide given after 1 hour. You can see the potential issues with this.

 

(1) https://www.emrap.org/episode/emrap2018august/cardiology

(2) https://www.youtube.com/watch?v=AEKzT98EZHQ

(3) https://emcrit.org/emcrit/scape/

(4) https://emcrit.org/ibcc/chf/

(5) https://www.ncbi.nlm.nih.gov/pubmed/?term=time-to-furosemide

 

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