Podcast 1016: Hypokalemia

这里是《急诊医学一分钟》，由CarePoint和HCA HealthONE赞助播出。

This is the Emergency Medical Minute sponsored by CarePoint and HCA HealthONE.

太好了。

Great.

好的。

Okay.

早上好。

Good morning.

昨天我们讲了高钾血症。

So yesterday, we did hyperkalemia.

今天我们要讲低钾血症，主要因为这样我就能聊聊我最喜欢的两件事。

Today, we're gonna do hypokalemia, and mostly because it lets me talk about two of my favorite things.

首先，我们说说它是怎么发生的。

So first of all, how we get it.

关于低钾血症，昨天我们提到了一些药物，这些药物可以帮助那些可能肾功能不全、因此血钾升高的患者降低血钾。

So hypokalemia, we talked about some drugs yesterday that will help us lower the potassium in patients who have probably some renal dysfunction and therefore have gotten some increased potassium.

其中一种就是利尿剂，速尿。

One of those was a diuretic, Lasix.

所以利尿剂和药物可能是导致血钾降低最常见的原因。

And so diuretics and meds are probably the most common way that you start dropping your potassium.

我们还顺便聊了一下，有些因素会让体内的钾离子发生转移。

We also talked, just for a fun sidebar, about how some things can shift your potassium.

沙丁胺醇就在那些因素之列。

Albuterol was on that list.

它不会明显排出任何钾，所以这种情况是暂时的。

It doesn't meaningfully excrete any of it, so it is temporary.

但如果病人是因为呼吸窘迫入院，并且我们给他用了持续性的沙丁胺醇雾化，这就是一种导致钾离子转移的方式，你会看到血钾水平略有下降。

But if you have a patient who's come in with respiratory distress and we have them on, say, continuous albuterol, that's one way that the potassium can become shifted, and you can see a slight drop in that.

再说一遍，这是暂时的。

Again, it's temporary.

我们通常不需要针对这种情况进行治疗。

We don't usually treat that.

对于胃肠道丢失比较多的病人，比如在肠胃炎高发季节，如果有人因为肠胃炎来就诊，任何胃肠道丢失都可能导致钾降低。

In patients who have high GI losses, so a lot of times in gastro season, if somebody comes in with gastroenteritis, any kind of GI loss can cause your potassium to go low.

比如大量呕吐、大量腹泻。

So lots of vomiting, lots of diarrhea.

我们也会在慢性情况下看到这种情况，比如病人因为化疗而恶心呕吐，或者因为其他原因长期腹泻。

We also will see it in a more kind of chronic sense in patients who have, like, chemotherapy that makes them really sick to their stomach or just chronic diarrhea for other reasons.

所以胃肠道丢失肯定会导致钾下降。

So GI losses will definitely cause your potassium to go down.

所以一旦你确定病人是低钾血症，他们会出现的一个变化就是心电图上的改变。

So once you have identified somebody as being hypokalemic, one of the changes that they get, is on their EKG.

在心电图上，T波后面会出现一个很小的U波。

And so you can end up with this tiny u wave that happens on the backside of their t wave on their EKG.

我在医学院的时候，在国立犹太医院上过一门心脏病学课程，那里有一位老心脏病专家，他会坐在那里跟你讲心电图，把他知道的所有关于心电图的知识都倾囊相授。

And I did when I was in medical school, I did a cardiology class over at National Jewish, and there's this old cardiologist who, like, sits there and talks to you about EKGs and spills everything he knows about them.

那门课真的非常有趣，特别吸引人。

And it's, like, such a fun and fascinating class.

但他说过，当你看心电图时，如果在T波后面看到一个小凸起，你心里会想：这是U波吗？

But what he said was if you're looking at somebody's EKG and you see this little bump after the t wave and you go, is that a u wave?

这时候你的语调会在句尾上扬，这就说明是U波，因为你其实不太确定。

And your voice sort of goes up at the end, that's how you know it's a u wave because you're not really sure.

你会心想：这到底是U波吗？

You're like, is that a u wave?

然后你就会确认那就是U波。

And then that's a u wave.

这就是判断依据。

That's how you know.

它们可能会融合在一起，形成所谓的T-U复合波，这确实更难识别，挺让人头疼的，因为这时候情况就已经很危险了。

Those can actually fuse together and become this t u complex, and that can actually be a lot harder to identify, which is a bummer because that's when it becomes dangerous.

T-U复合波一旦融合，就会让间期明显延长。

The t u complex can fuse, and it puts you it actually does prolong meaningfully.

这可不是光靠肉眼看看那么简单的事。

It's not just like a visual thing.

这会延长心脏的复极，延长QT间期，让你面临室颤、室速、尖端扭转性室速的风险。

It prolongs the repolarization of your heart, prolongs that QT prolongation, and puts you at risk for, you know, V fib, V tach Torsades.

所以到那时就不只是伪影了。

So not just a not just an artifact at that point.

我们经常遇到低钾的患者。

We see patients that come in with low potassium all the time.

钾水平大概在3.5到2.5之间，这些患者可能可以通过口服补钾。

Anywhere from kinda like 3.5 to 2.5, those can probably be repleted orally.

同时还要考虑，如果补钾的话，需要同时补充镁。

And also need to think if you're repleting them, you need to give them magnesium at the same time.

低钾往往伴随低镁。

Hypo k is hypo mag.

所以你经常会看到这两种情况同时发生。

So you'll oftentimes see that, happening at the same time.

当钾水平低于2.5时，这些患者确实需要静脉补钾，你可能会看到我们考虑让他们住院，而不是试图在急诊室就把他们完全治好。

When they get to be below 2.5, those are patients who really do need IV potassium, and you probably see us sort of flirt with the idea of bringing them in at that point, as opposed to trying to, like, treat them, to completion here in the emergency department.

还有其他一些情况，比如低钾性周期性麻痹。这类患者会经历血钾突然下降的时期，从而导致瘫痪，症状主要集中在下肢，但上肢也会受到一定影响。

Other things so other things that can cause hypokalemic periodic paralysis, which is patients who end up with just these periods of dropping their potassium, and it creates this paralysis, mostly concentrated in the lower extremities, but their upper extremities do tend to see some effects.

这是一种离子通道病，简单来说，就是他们的细胞处理钾离子的方式出了问题，从而引发了这种状况。

It's a channelopathy, so it's actually just a way that their cells deal with potassium that causes this.

网上关于这个病的视频真的特别有意思。

And the YouTube videos of this are very, very fun.

好在这些患者的手臂通常还能动，他们会把口服补钾的药（比如那种橙色的）放在床边备用。

So these patients will, thank god, sometimes have some mobility in their arms, and they will keep these little cups of, like, the the oral potassium, like the orange one, next to their beds.

所以如果他们某天早上醒来，发现自己得了这个病，完全动弹不得，他们就能伸手去够一些口服钾盐，喝下去，然后等一会儿，接着又能重新活动了。

So if they end up waking up one morning and realizing that they have this and they're completely stuck in bed, they can reach over, hopefully fumble for some oral potassium, drink it, and then wait a spell, and then be able to start moving again.

患者第一次来就诊时，通常是为了首次确诊这个病。

When patients come in for the first time, they usually only come in for the first diagnosis of this.

而且初次就诊的患者，年纪一般都在二十多岁。

And when they come in for the first time, they tend to be, like, in their twenties.

所以他们通常是独自来看病，不会带着父母一起来。

So it's like they don't really come in with their parents.

这就像他们第一次独自生活，然后某天早上醒来，突然动不了了。

It's like the first time they're living alone, and they just wake up one morning and can't move.

这真的很震撼。

It's really profound.

那些YouTube视频值得一看。

The YouTube videos are worth a watch.

这种情况最常见于亚洲男性。

Happens in Asian males most commonly.

我在其他一些男性身上见过，但我不记得见过女性患者。

I've seen it in some other males, but I don't think I've ever seen it in a lady.

至少我印象中没有。

I don't not that I remember.

但这确实是一个非常有趣的疾病过程。

But it's a really interesting, disease process.

我们之前提到过，QT间期延长，或者说，这种QT间期延长如何导致危险的心律失常，现在这让我可以谈谈我对这个话题第二喜欢的内容，那就是难治性室颤。

We talked about how this QT or sorry, how this pro QT prolongation can lead them to dangerous arrhythmias, which now lets me talk about my second favorite thing to do with this topic, which is refractory V fib.

昨天我们遇到一个心脏骤停的病例，抢救了好一阵子，有一次出现了可电击的心律。

Yesterday, we had a cardiac arrest that we were coding for a while that had a shockable rhythm one time.

所以，很不幸，那个病人不是他。

So, unfortunately, that wasn't him.

但是对于那些室颤患者，每次检查时他们都在室颤，我们反复电击，却始终无法让他们恢复正常心律。

But in patients who have this V fib where, like, every time you're checking, they're in V fib and we're shocking, over shocking, we just can't get them out.

针对难治性室颤，你可以尝试三种方法来帮助纠正。

Three things that you can try to do for refractory V fib to help fix it.

第一种是艾司洛尔。

One is esmolol.

有一项规模非常小的研究显示，这可能有帮助。

There's low very, very small study that shows that maybe that is helpful.

所以通常是一次比较大的负荷剂量，有时随后会持续滴注，但这可能有助于心脏重新启动。

So it's a a pretty big bolus sometimes followed by a drip, but that might be a helpful reset for the heart.

另一种方法是双重除颤，我们昨天讨论过这个。

And then the other thing is a double defib, which we were talking about yesterday.

电极片贴在常规位置，也就是前侧和左侧位。

Pads go in your normal position, so anterior and lateral.

然后一片放在背部，另一片贴在你正在使用的前侧电极片旁边。

And then one goes posterior and the other one goes just to the side of the anterior pad that you're using.

目的是尽量让两次电击的位置靠近一些。

The goal is to kinda try and get the shocks close together.

这两次电击几乎不可能完全同时发生，所以通常是顺序进行的联合除颤，而不是真正意义上的同步同时放电。

It's almost never exactly at the same time, so it tends to be sort of a sequential double defib as opposed to a truly, you know, concomitantly shocking them at the same time.

所以值得试一试。

So worth a try.

然后，今天早上我们稍微提到过的最后一件事是，对于难治性室颤，可以尝试使用ECMO（体外膜肺氧合）。

And then the last thing that we already mentioned slightly this morning was that for refractory V fib, you can end up trying ECMO.

如果发生这种情况的原因仅仅是因为心肌细胞因为心肌梗死导致缺氧而处于应激状态，那么通过ECMO让心脏暂时休息，恢复给心肌细胞供氧，同时给自己争取时间去开通病变血管，这可能是解决问题的关键。

So if the reason that this is happening is just that the myocytes are angry because they're not getting enough oxygen because of their MI, Giving them some oxygen back, kind of taking them off, you know, of their normal, circulation, putting them on ECMO, giving back oxygen to the myocytes, and then giving yourself a chance to go in and open up the, affected vessel may be the thing that helps.

就像我们之前说的，虽然我们现在还没这么做，但这项技术很快也会在瑞典的医院普及。

So like we said, not something that we're doing right now, but coming soon to a Swedish near you.

非常好。

That's very good.

有什么问题吗？

Any questions?

那好，就这样。

And then Alright.

祝大家今天愉快。

Let's have a good day.

这里是急诊医学一分钟。

This has been the emergency medical minute.

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