麻醉是如何起作用的？- Steven Zheng：英语精读讲义

If you've had surgery, 語法

如果你做过手术，

you might remember starting to count backwards from 10, 短語搭配

你可能还记得从10开始倒数，

9,

9，

8,

8，

and then waking up with the surgery already over 語法

然后醒来时手术已经结束了，

before you even got to five.

你甚至还没数到5。

And it might seem like you were asleep, 表達脈絡

看起来你好像睡着了，

but you weren't.

但其实并没有。

You were under anesthesia, 用詞

你处于麻醉状态，

which is much more complicated.

这是一个复杂得多的过程。

You were unconscious,

你失去了意识，

but you also couldn't move,

同时你也不能移动，

form memories, 短語搭配

无法形成记忆，

or hopefully feel pain.

并且理想情况下也感觉不到疼痛。

Without being able to block all those processes at once, 語法

如果不能同时阻断所有这些过程，

many surgeries would be way too traumatic to perform. 語法

许多手术就会因为创伤太大而无法进行。

Ancient medical texts from Egypt,

来自埃及、

Asia,

亚洲，

and the Middle East all describe early anesthetics containing things like opium poppy, 短語搭配

和中东的古代医学文献都记载了早期的麻醉剂，它们含有罂粟、

mandrake fruit,

曼德拉草果实，

and alcohol.

以及酒精等成分。

Today,

如今，

anesthesiologists often combine regional, 用詞

麻醉师通常会将局部麻醉剂、

inhalational,

吸入性麻醉剂，

and intravenous agents to get the right balance for a surgery. 短語搭配

和静脉注射麻醉剂结合使用，以达到手术的合适平衡。

Regional anesthesia blocks pain signals from a specific part of the body from getting to the brain. 短語搭配

局部麻醉会阻断身体特定部位的疼痛信号传递到大脑。

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

疼痛和其他信息以电脉冲的形式在神经系统中传递。

Regional anesthetics work by setting up an electrical barricade. 講解

局部麻醉剂通过设置电气路障起作用。

They bind to the proteins in neurons' cell membranes that let charged particles in and out 講解

它们与神经元细胞膜上控制带电粒子进出的蛋白质结合，

and lock out positively charged particles. 短語動詞

并将带正电的粒子挡在门外。

One compound that does this is cocaine,

一种能做到这点的化合物是可卡因，

whose pain-killing effects were discovered by accident when an ophthalmology intern got some on his tongue. 短語搭配

它的镇痛作用是一位眼科实习生不小心弄到舌头上时偶然发现的。

It's still occasionally used as an anesthetic,

它现在偶尔仍被用作麻醉剂，

but many of the more common regional anesthetics have a similar chemical structure and work the same way. 短語搭配

但许多更常见的局部麻醉剂具有相似的化学结构，作用原理也相同。

But for major surgeries where you need to be unconscious, 語法

但对于需要你失去意识的大型手术，

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

你会需要一种作用于整个神经系统的药物，

including the brain.

包括大脑。

That's what inhalational anesthetics do. 表達脈絡

这就是吸入性麻醉剂的作用。

In Western medicine, 文化背景

在西医中，

diethyl ether was the first common one.

乙醚是第一种常用的吸入麻醉剂。

It was best known as a recreational drug 短語搭配

它作为一种消遣性药物而广为人知，

until doctors started to realize that people sometimes didn't notice injuries they received under the influence. 習語

直到医生们开始意识到，人们在受其影响时有时察觉不到自己受的伤。

In the 1840s,

在19世纪40年代，

they started sedating patients with ether during dental extractions and surgeries. 用詞

他们开始在拔牙和手术期间用乙醚给病人进行镇静。

Nitrous oxide became popular in the decades that followed 短語搭配

笑气在随后的几十年里开始流行，

and is still used today,

并且沿用至今，

although ether derivatives like sevoflurane are more common. 語法

尽管像七氟醚这样的乙醚衍生物更为常见。

Inhalational anesthesia is usually supplemented with intravenous anesthesia, 短語搭配

吸入性麻醉通常辅以静脉麻醉，

which was developed in the 1870s.

后者研发于19世纪70年代。

Common intravenous agents include sedatives like propofol,

常见的静脉注射剂包括像异丙酚这样的镇静剂，

which induce unconsciousness, 用詞

它可以导致无意识状态，

and opioids like fentanyl,

还有像芬太尼这样的阿片类药物，

which reduce pain.

它可以减轻疼痛。

These general anesthetics also seem to work by affecting electrical signals in the nervous system. 表達脈絡

这些全身麻醉剂似乎也通过影响神经系统中的电信号来发挥作用。

Normally,

通常情况下，

the brain's electrical signals are a chaotic chorus 習語

大脑的电信号就像一场混乱的大合唱，

as different parts of the brain communicate with each other.

因为大脑的不同部分在相互交流。

That connectivity keeps you awake and aware. 語法

这种连通性让你保持清醒和意识。

But as someone becomes anesthetized, 語法

但当人被麻醉时，

those signals become calmer and more organized,

这些信号变得更平静、更有条理，

suggesting that different parts of the brain aren't talking to each other anymore. 表達脈絡

这表明大脑的不同部分不再相互对话。

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

关于这到底是如何发生的，我们还有很多未知之处。

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

几种常见的麻醉剂会与大脑神经元中的GABA-A受体结合。

They hold the gateway open, 習語

它们保持通道敞开，

letting negatively charged particles flow into the cell. 語法

让带负电的粒子流入细胞。

Negative charge builds up and acts like a logjam, 講解

负电荷不断积累，就像堵塞的原木一样，

keeping the neuron from transmitting electrical signals. 語法

阻止神经元传递电信号。

The nervous system has lots of these gated channels, 用詞

神经系统有许多这样的门控通道，

controlling pathways for movement,

控制着运动、

memory,

记忆，

and consciousness.

和意识的通路。

Most anesthetics probably act on more than one,

大多数麻醉剂可能作用于不止一种通道，

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

而且它们不仅仅作用于神经系统。

Many anesthetics also affect the heart,

许多麻醉剂也会影响心脏、

lungs,

肺，

and other vital organs,

以及其他重要器官，

just like early anesthetics,

就像早期的麻醉剂一样，

which included familiar poisons like hemlock and aconite.

它们包含了熟悉的毒物，如毒芹和乌头。

Modern drugs can have serious side effects. 短語搭配

现代药物可能有严重的副作用。

So an anesthesiologist has to mix just the right balance of drugs to create all the features of anesthesia 短語搭配

所以麻醉师必须混合出刚好达到平衡的药物，以创造麻醉的所有特性，

while carefully monitoring the patient's vital signs 語法

同时仔细监测病人的生命体征，

and adjusting the drug mixture as needed.

并根据需要调整药物混合比例。

Anesthesia is complicated,

麻醉是复杂的，

but figuring out how to use it allowed for the development of new and better surgical techniques. 語法

但弄清楚如何使用它，促成了新的、更好的外科技术的发展。

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

外科医生得以学会如何常规且安全地进行剖腹产、

reopen blocked arteries, 短語搭配

重新打通阻塞的动脉、

replace damaged livers and kidneys,

移植受损的肝脏和肾脏，

and many other life-saving operations. 短語搭配

以及许多其他拯救生命的手术。

And each year,

每年，

new anesthesia techniques are developed that will ensure more and more patients survive the trauma of surgery. 講解

都有新的麻醉技术被开发出来，这将确保越来越多的病人能在手术创伤中幸存下来。