I am on the cardiac care unit, which is a supposed intensive care unit. I say “supposed” because none of the patients I am caring for are actually sick; almost all of the patients in the “CCU” are in a holding pattern until something definitive can be done by another person. For instance, there are people awaiting heart transplants. Others are awaiting implantation of an implantable defibrillator.
Because most people in the unit have heart failure, we give them tremendous, massive doses of diuretics – intravenous versions of the ‘water pill’ you’ve probably heard of before. Lasix. Bumex. Metolazone. Diuril. Spironolactone. Torsemide. Eplerenone. All drugs to make you pee.
If you or I took the same quantity of diuretics that these patients take, you would have the approximate water content of a tumbleweed. You would also be dead, and strongly resemble a very small, raisin-shaped piece of turkey jerky.
I had originally planned on explaining how diuretics work, as the explanation is actually kind of int- actually, no, it’s horribly boring and has to do with very tiny tubes in your kidneys that no one knows the name of or cares to remember. In short, diuretics prevent your kidneys from reabsorbing salt, and water goes with the salt as you pee it out. So basically you pee out a lot more water than normal.
We do this because we want you to be dehydrated. In a really simple way, less fluid in the tank means less pressure for the heart to pump against. In a failing heart, this keeps you alive longer. Long enough to, say, receive a heart transplant.
Anyway. A side effect of the diuretic medicine is you also pee out potassium. What is potassium? I actually don’t know, except it is present in huge quantities in bananas, spinach, and pages from the nurses every day.
It is very, very important to maintain a normal or even high level of potassium in people with failing hearts. This is because of a very complex physiological balance that I can sum up with the answer, “I don’t know.” Thus it is very important to Always Be Repleting Potassium.
(Lest you think I am a danger to others, I actually do understand why these patients need normal to high levels of potassium – low potassium causes arrhythmias. High potassium also causes arrhythmias, but according to my attending supervisors the concept of a patient on massive diuretics developing high levels of potassium is less likely than discovering life on Mars. I am simply beyond caring about the details of either extreme at this point and have been reduced to a button-clicking monkey on the potassium order page.)
You Replete Potassium by, unsurprisingly, giving the patient potassium. Potassium, by the way, is abbreviated K (this will become important in a second, and yes, K is the elemental symbol for potassium on the periodic table, no I do not know why it isn’t just P). For this reason, low potassium is called “hypokalemia” and high potassium is called “hyperkalemia.”
There are pills of potassium, and there are IV infusions of potassium. I am assuming there is a suppository form, but every time I suggest this, people look at me strangely. You would think you could just give a patient a banana or two, but there are two reasons arguing against this:
– You would probably need to eat about 400 bananas to adequately replace your peed-out potassium losses;
– Most patients are on a “cardiac diet,” which translates to “you can’t eat anything except for some raw lentils.”
There are also Guidelines Posted All Over The Place so you can recall how much potassium to give, although I have learned that it quite honestly does not seem to matter how much potassium you give as your patient will simply pee it all out again by morning and be hypokalemic again.
I have experimented with different amounts of oral versus intravenous K, with divided dosing of K, with huge doses and tiny doses of K. It does not matter. The K is going to be what the K is going to be, and so in all likelihood your efforts are medically futile. My current guiding principle is, “give what seems like a shitload of potassium,” and it seems to be working okay.
However. If you follow your instincts and do not Always Replete K, your pager and eardrums will both spontaneously combust with the combined force of 500 pages being delivered all at the same time, all about potassium. This is because the nurses in the CCU are experts in the heart, and they have been trained by other experts in the heart, namely cardiologists with plenty of native repleted K, that the K Must Be Repleted or the patient will Suffer An Adverse Event, necessitating a great deal of charting.
(That was an inside joke at the expense of nursing. I am sorry and I do not mean it. Please don’t fire me.)
Because of their truthfully high level of training – they know far more than me, although that’s not saying much – the nurses react instantaneously when sets of morning labs come back on their patients. Because of a silly systematic oversight, the nurses – who again, know way more than me – need a doctor’s order to replete potassium, and thus must page me to Always Be Repleting K. I will, eventually, see the K lab value on my own and order repletion, but it is never too soon to be Repleting.
While googling around for funny images for this post I stumbled upon this slide:
I honestly laughed out loud to myself when I read that. I am in my apartment, wholly alone, at nine o clock at night after a long day, laughing like an insane person. If it took me “days to weeks” to correct potassium, my attending and charge nurse would simultaneously suplex me through a food tray table like the Dudley Brothers from the old-school World Wrestling Federation:
Because of oddities in lab timing, I have gotten so well-acquainted with this paging bomb that I can sometimes predict, down to the exact minute, which patient’s nurse is paging me about K. If the clock reads between 6:02 and 6:11, I know it is the nurse for Mr. P. The nurse for Mr. K pages around 6:18. The nurse for Mr. M reliably pages me at 6:30 on the dot, as if she has set a timer.
(She has, in fact, set a timer. I have caught her.)
I actually checked this today for educational purposes. I received 108 pages today from 5:30 AM until about 5PM when I signed off my pager. 91 of them were about potassium or its sister electrolyte, magnesium. We will not delve into magnesium here for purposes of time and sanity, but it is also thing that Always Needs Repleting.
I am not dumping on the nurses here. First of all, they have plenty of K. Second, they know far more about K, and why it matters, and many other things about the heart, than I do. They are doing their job, and doing it far better than I could. I am more than happy to follow their recommendations about potassium repletion and will put in the orders immediately when I can. I only wish, since they are so much wiser than I in matters of kalemia big and small, that they could fill potassium orders on their own without my own stupid input.
Excuse me. I have to go eat my banana. I leave you with a quote from the great Corey Slovis:
“I am not anti-kalemic. Many of my good friends… have potassium.”