How does anesthesia work? - Steven Zheng

翻译人员: Claire Zhang 校对人员: Chen Zou

If you've had surgery,

如果你做过手术，

you might remember starting to count backwards from ten,

你也许会记得 开始从10倒数

nine,

9

eight,

8

and then waking up with the surgery already over before you even got to five.

在你还没数到5的时候 你就苏醒过来，发现手术已完成了。

And it might seem like you were asleep, but you weren't.

也许看起来像是你睡着了， 可事实并非如此。

You were under anesthesia,

你被麻醉了

which is much more complicated.

这更为复杂。

You were unconscious,

你不仅陷入了昏迷状态，

but you also couldn't move,

而且你也动不了，

form memories,

不能形成记忆，

or, hopefully, feel pain.

当然，你也感觉不到疼痛。

Without being able to block all those processes at once,

如果不能在同一时间 阻止上述的发生，

many surgeries would be way too traumatic to perform.

许多手术会十分痛苦 而难以进行下去。

Ancient medical texts from Egypt, Asia and the Middle East

来自埃及，亚洲和中东的 古代医学书籍，

all describe early anesthetics

都有描述早期的麻醉药，

containing things like opium poppy,

包括罂粟

mandrake fruit,

曼德拉草果

and alcohol.

以及酒精。

Today, anesthesiologists often combine

如今，麻醉师通常会结合

regional, inhalational and intravenous agents

局部麻醉，吸入麻醉 和静脉注射麻醉的方法，

在手术中获得合适的平衡点。

to get the right balance for a surgery.

Regional anesthesia blocks pain signals from a specific part of the body

局部麻醉可以阻止 从身体某一部位发出的疼痛信号

from getting to the brain.

传输到脑部。

Pain and other messages travel through the nervous system as electrical impulses.

疼痛感与其它感觉在神经系统中 就好像电脉冲一样传输。

Regional anesthetics work by setting up an electrical barricade.

局部性麻醉剂可以 设立一个电子路障。

They bind to the proteins in neurons' cell membranes

它们结合到神经元 细胞膜的蛋白质上，

that let charged particles in and out,

这些蛋白质让里子进出，

and lock out positively charged particles.

并保持正电荷的粒子不能进入细胞。

One compound that does this is cocaine,

可卡因是这种类型的化合物的一个例子，

whose painkilling effects were discovered by accident

当一位眼科实习生不小心把它弄到舌头上，

when an ophthalmology intern got some on his tongue.

它的止痛效果被偶然发现。

It's still occasionally used as an anesthetic,

它仍然偶尔被用作麻醉剂

but many of the more common regional anesthetics

但许多更常见的局部麻醉剂

have a similar chemical structure and work the same way.

具有类似的化学结构和工作方式。

But for major surgeries where you need to be unconscious,

但对于大部分需要昏迷的手术

you'll want something that acts on the entire nervous system,

你要的是可以针对 整个神经系统的药物，

including the brain.

包括大脑。

That's what inhalational anesthetics do.

这就是吸入麻醉药的用处。

In Western medicine, diethyl ether was the first common one.

西药里，乙醚是最先常见的一种，

It was best known as a recreational drug

它以前是以娱乐性药物而闻名

until doctors started to realize that people sometimes didn't notice

直到医生开始认识到 人们有时没注意到

injuries they received under the influence.

他们在乙醚的影响下受的伤。

In the 1840s, they started sedating patients with ether

在19世纪40年代 他们开始将乙醚麻醉

during dental extractions and surgeries.

用在拔牙和手术中。

Nitrous oxide became popular in the decades that followed

几十年后， 一氧化二氮开始变得普遍，

一直沿用到今天。

and is still used today.

although ether derivatives, like sevoflurane, are more common.

虽然醚衍生物， 像七氟醚，更常见

Inhalational anesthesia is usually supplemented with intravenous anesthesia,

吸入式麻醉剂通常在 静脉麻醉的补充下运作，

which was developed in the 1870s.

它源于19世纪70年代。

Common intravenous agents include sedatives, like propofol,

常见的静脉注射剂包括镇静剂， 比如异丙酚

which induce unconsciousness,

镇静剂可以导致昏迷状态，

and opioids, like fentanyl, which reduce pain.

以及阿片类药物 可以减轻疼痛的芬太尼。

These general anesthetics also seem to work

这些普遍麻醉药似乎也能

by affecting electrical signals in the nervous system.

影响神经系统的电信号工作。

Normally, the brain's electrical signals are a chaotic chorus

通常情况下， 大脑的电信号是一个混乱的大合唱

as different parts of the brain communicate with each other.

因为大脑的不同部位会互相通信，

That connectivity keeps you awake and aware.

那种连接使你保持清醒。

But as someone becomes anesthetized,

但当一个人被麻醉

those signals become calmer and more organized,

这些信号变得平静， 更有条理，

suggesting that different parts of the brain

这表明大脑的某些部分

aren't talking to each other anymore.

不能互相交谈了。

There's a lot we still don't know about exactly how this happens.

关于麻醉， 仍有有很多我们不清楚的地方。

Several common anesthetics bind to the GABA-A receptor in the brain's neurons.

几种常见的麻醉药 绑定到大脑的神经元GABA-A受体，

They hold the gateway open,

它们开着大门，

letting negatively charged particles flow into the cell.

让着带负电荷的粒子进入细胞

负电荷积聚和作用就像一个塞子

Negative charge builds up and acts like a log jam,

keeping the neuron from transmitting electrical signals.

不让神经元传输电信号。

The nervous system has lots of these gated channels,

神经系统有很多门控通道

controlling pathways for movement,

它们控制运动通道、

memory,

记忆，

and consciousness.

以及意识。

Most anesthetics probably act on more than one,

大多数麻醉剂可能作用于不止一个，

and they don't act on just the nervous system.

而且不只作用于神经系统。

Many anesthetics also affect the heart,

许多麻醉药也影响心脏

lungs,

肺

and other vital organs.

以及其它重要器官。

Just like early anesthetics,

就像早期的麻醉剂

which included familiar poisons like hemlock and aconite,

其中包括熟悉的毒药一样 铁杉和附子，

modern drugs can have serious side effects.

现代药可能有严重的副作用。

So an anesthesiologist has to mix just the right balance of drugs

因此，一个麻醉师必须搭配好药物 之间的平衡，

to create all the features of anesthesia,

才能发挥出麻醉的所有功能，

while carefully monitoring the patient's vital signs,

同时密切监测患者的生命体征

and adjusting the drug mixture as needed.

并根据需要调整药物。

Anesthesia is complicated,

麻醉是复杂的

but figuring out how to use it

但弄清楚如何使用它

allowed for the development of new and better surgical techniques.

允许了新和更好的 外科技术的发展。

Surgeons could learn how to routinely and safely perform C-sections,

外科医生可以学习如何 系统化地和安全地进行剖腹产，

reopen blocked arteries,

打开阻塞的动脉，

replace damaged livers and kidneys,

替换受损的肝脏和肾脏，

and many other life-saving operations.

以及许多其它可以拯救生命的手术。

And each year, new anesthesia techniques are developed

而且每年，新的麻醉技术在被开发

that will ensure more and more patients survive the trauma of surgery.

这将确保越来越多的患者 经受得住痛苦的手术过程。