Potassium: The Heart’s MVP – Essential Electrolyte for Nursing Students | Episode 2 of Electrolytes 101

Hey everybody, and welcome back to Nursing School Week by Week. We are diving into part two of our electrolyte series, and today we're talking all about potassium. If you listened to part one, you know how important sodium is for fluid balance and nerve function. But potassium, this one is a game changer.

It keeps the heart beating, the muscles moving, and when it's out of whack, bad things can happen fast. Have you ever seen a patient's heart rhythm go from normal to a deadly arrhythmia in seconds? Chances are, potassium was involved. That's why we have to know exactly how to recognize hyperkalemia and hypokalemia before they turn into an emergency.

So, grab your coffee, your notes, or whatever helps you focus, and let's break down potassium. What it does, why it matters, and how to spot trouble before it's too late.

Alright, potassium is the heart's MVP. This is the one that can send your patient into a deadly arrhythmia if you don't catch it in time.

It is absolutely essential for keeping the heart beating at a steady rhythm, but let's break it down a little bit more. Potassium doesn't just sit around doing nothing. It actually helps control the electrical signals of the heart. I want you to picture an orchestra, the violins, the trumpets, the drums, each section has to come in at exactly the right moment for everything to sound smooth.

But what happens if the conductor loses control? The trumpets blare at the wrong time, the violins are playing offbeat, and suddenly the whole thing turns into chaos. That's exactly what happens to the heart when potassium levels are too high or too low. The electrical signals get out of sync, and that's when things get dangerous.

Alright, so the normal potassium level, the normal range, is 3. 5 to 5. 0. Just like sodium, potassium has a narrow range where it likes to stay. Too low, the heart struggles to send signals. Too high, the heart gets overwhelmed and can even stop altogether. Even a small shift outside this normal range of 3. 5 to 5 can cause serious symptoms.

So as nurses, we have to be on high alert for any potassium imbalances. Let's start with hypokalemia, which means low potassium.

So hypokalemia, that would be under 3. 5. What causes potassium to drop too low?

Think about anything that might drain potassium from the body. Like diuretics or water pills. These are one of the biggest culprits. Some diuretics like furosemide or Lasix, or hydrochlorothiazide, make the kidneys flush out extra fluid. But when the body loses fluid, it often loses potassium too.

And we would call these potassium wasting diuretics. Other causes of hypokalemia include excessive vomiting or diarrhea. When the body is losing fluids rapidly, it's also losing electrolytes like potassium, and then sweating too much. If someone is sweating a lot but not replacing electrolytes, potassium levels can drop.

And then just not getting enough potassium in the diet. This one is less common, but it can happen in patients who are malnourished or on long term IV fluids without potassium. All right, so let's put this into a real life situation. You're on the floor in clinicals and you have a 72 year old patient with heart failure Who's been on furosemide? You walk into the room and they say, I don't know what's wrong, but I feel really weak. My legs keep cramping and I just feel off. Red flag, right? Your nursing brain should immediately start thinking, could this be hypokalemia?

You check their vitals and their heart rate is irregular. You pull up their latest labs, potassium is 3. 0. This patient is showing classic signs of hypokalemia. So how do we know when potassium is too low? Some common symptoms of hypokalemia are muscle weakness and leg cramps. And just now in our real life situation, she was complaining about her legs, her legs kept cramping, right, and she felt really weak.

So a common symptom is muscle weakness and leg cramps. The muscles don't have enough potassium to contract properly. Then you also might see fatigue and slowed reflexes. Potassium is crucial for nerve function, so when it's low, everything slows down. And then irregular heart rhythms, or arrhythmias, the electrical activity in the heart gets thrown off.

So, we're gonna see EKG changes, that's the classic sign. The classic sign is flat T waves or U waves. The last one is really important. If you ever see flat T waves on an EKG, think hypokalemia. And then in severe cases, hypokalemia can cause life threatening cardiac dysrhythmias. Scary stuff.

Alright, so what's the game plan when a patient has low potassium? What are we going to do about it? Number one, we are going to replace the potassium. If it's mild, the provider may order oral potassium supplements.

If it's severe, they're going to need IV potassium. But here's the big rule. Never ever push potassium through the IV. This is because pushing potassium too fast can stop the heart immediately. Instead, IV potassium is always diluted and given slowly via an IV infusion.

If it's severe, they'll need IV potassium. But here's the big rule. Never ever IV push potassium. That's because pushing potassium too fast can stop the heart immediately. Instead, IV potassium is always diluted and given slowly via an IV infusion. Then second, we're going to monitor the heart rhythm. If the patient already has an irregular heart rate, they may need to be placed on a cardiac monitor to watch for arrhythmias.

And third thing we're going to do for these patients is encourage potassium rich foods. If the patient can eat, suggest potassium rich foods like bananas, oranges, potatoes, and spinach. So the key takeaway is if you see a patient with muscle weakness, Leg cramps or an irregular heart rate, check that potassium level.

Hypokalemia can lead to life threatening arrhythmias, so early recognition is key.

Alright, now that we've covered low potassium, let's talk about the opposite problem, hyperkalemia. Because if low potassium can mess up the heart, too much potassium is even worse.

Remember how I said potassium is like the conductor of the heart's electrical symphony? Well, when there's too much potassium, that symphony doesn't just get a little messy, it turns into complete chaos. The electrical signals in the heart fire out of control, and if we don't catch it in time, it can be life threatening.

So what actually causes potassium overload? Well, unlike sodium, where we mostly lose it through fluid imbalances, potassium is primarily controlled by the kidneys. The kidneys are responsible for regulating potassium levels in the blood. If they aren't working properly, potassium starts building up to dangerous levels.

That's why one of the biggest causes of hyperkalemia is kidney failure. When the kidneys can't filter out excess potassium, it stays in the bloodstream, raising potassium levels to dangerous heights. But kidney failure isn't the only cause. Certain medications can also send potassium through the roof, such as ACE inhibitors like lisinopril and enalapril.

These meds are used for high blood pressure, but they can also increase potassium levels as a side effect. And then also potassium sparing diuretics like Spironolactone. Unlike other diuretics that flush potassium out, these ones hold onto potassium, which can lead to dangerously high levels. All right, let's look at another scenario.

You're in clinicals and you get assigned to a 65 year old patient with kidney failure. Their latest labs just came back and you see that their potassium is 6. 3. That is dangerously high, right? Do you remember the Normal range was 3. 5 to 5. 0. So, you rush into their room to assess them. What symptoms are you looking for?

 The symptoms of hyperkalemia. Hyperkalemia affects muscles first. And guess which muscle is the most important? The heart. Here's hyperkalemic patient. You're going to see tall peaked T waves on an EKG. This is one of the biggest red flags for hyperkalemia. Instead of a normal T wave, you'll see a sharp, pointy peak, like a mountain.

And then, the next thing we're going to see is muscle cramps and weakness. Too much potassium messes with nerve signals, making the muscles spasm and weaken. And then, we may see irregular heart rhythms. As potassium keeps rising, the heart is going to start beating out of sync. And in severe cases, hyperkalemia can lead to the scariest complication of all, which is heart failure.

cardiac arrest. When potassium gets too high, the heart's electrical system shuts down and the heart can completely stop. This is a medical emergency and you need to act fast.

So what do we do when potassium levels skyrocket? Luckily, we have a few tools in our nursing arsenal to combat this potassium crisis. The first tool we have is KXolate. This medication binds to potassium in the intestines and helps the body get rid of it through the stool. And the downside is it takes a few hours to work and can cause diarrhea.

But really, I mean, diarrhea or cardiac arrest, I mean, come on. Alright, and then the second tool we have to treat hyperkalemia is insulin plus a glucose combination. This is one of the fastest ways to lower potassium. Insulin moves potassium back into the cells. Remember, insulin is like a key that unlocks the cell.

So insulin is going to move the potassium back into the cells out of the bloodstream where it's dangerous. And then glucose is given alongside insulin to prevent hypoglycemia. And then the third tool we have is calcium gluconate. This doesn't actually lower potassium, but it protects the heart from its dangerous effects.

Think of it like a shield. It helps stabilize the heart while we work on actually lowering the potassium. This is used in severe, life threatening hyperkalemia. And in really severe cases, the patient might even need dialysis to completely remove the extra potassium from their blood. All right, so key takeaways.

If you see tall, peaked T waves, muscle cramps, or an irregular heartbeat, think hyperkalemia. Hyperkalemia can be fatal, so early detection and intervention are critical.

Alright, so time for another pod quiz

to test your knowledge on potassium. And I will read the question and the possible answers, and then I will pause and let you have a little time to think. Okay, question one. Which specific EKG change is a classic sign of hyperkalemia?   A. ST segment depression.  B. Peaked T waves.

 C, prolonged QT interval,  or D, wide QRS complex.

 And the correct answer is B, peaked T waves. And that's because hyperkalemia affects the electrical conduction of the heart, leading to characteristic EKG changes. One of the earliest and most classic signs is tall, peaked T waves. As potassium levels continue to rise, other abnormalities like widened QRS complexes and even V fib can occur, making hyperkalemia a life threatening condition.

Alright, question two. Why is it absolutely forbidden to give potassium as an IV push?  A. It is not absorbed effectively in the bloodstream. B. It can cause severe pain at the injection site. C. It can lead to fatal cardiac arrhythmias. Or D, it has a very short half life and would not be effective.

You guys better get this one.  Alright, correct answer is C, it can lead to fatal cardiac arrhythmias. Potassium plays a critical role in cardiac function. Giving potassium as an IV push causes a sudden, dangerous increase in serum potassium levels, which can lead to lethal arrhythmias, such as a systole or cardiac arrest.

This is why potassium must always be diluted and administered slowly via IV infusion. All right, question three. What medication can we use to rapidly lower potassium levels in an emergency situation?  A. Calcium gluconate.  B. Ferrosamide  C. Sodium polystyrene sulfonate or D. Insulin with dextrose

 Alright, the correct answer is D. Insulin with dextrose. In an emergency, insulin with dextrose is used to shift potassium from the bloodstream into the cells, temporarily lowering serum potassium levels. Calcium gluconate does not lower potassium, but helps stabilize the heart. And then furosemide is a diuretic.

And sodium polystyrene sulfonate, or Kaexolate, help remove potassium from the body, but act more slowly.

All right, so today we tackled potassium, one of the most critical electrolytes to monitor in our patients. We broke down what happens when levels get too high or too low, and how to quickly recognize those warning signs. But we're not done yet. In part three next week, we'll cover calcium and magnesium, and tie it all together with some case studies to help you apply what you've learned in real world scenarios.

So be sure to tune in. In the meantime, if you want to reinforce what we covered today, head over to my YouTube channel, Nursing School Week by Week,

where I've got some more videos that you'll definitely find useful. And if you're enjoying this series, don't forget to subscribe and leave a review. It really helps more nursing students find the podcast.

Alright, thanks for listening and have a great week.