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

在你甚至數到五之前，你已經完成手術而甦醒了。

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

你可能覺得你睡著了，但不是這樣的。

You were under anesthesia, which is much more complicated.

你被麻醉了，這比 「睡著」複雜多了 。

You were unconscious, but you also couldn't move, form memories, or, hopefully, feel pain.

你失去意識而且無法動彈，無法產生記憶或，但願，不會感到疼痛。

Without being able to block all those processes at once, many surgeries would be way too traumatic to perform.

如果無法同時阻斷那些過程，許多手術可能會因身心創傷太大而無法執行。

Ancient medical texts from Egypt, Asia and the Middle East all describe early anesthetics, containing things like opium poppy, mandrake fruit, and alcohol.

來自埃及、亞洲及中東古老的醫學文稿都有描述早期的麻醉藥含有像罌粟、 曼德拉草果實、及酒精的成分。

Today, anesthesiologists often combine regional, inhalational and intravenous agents to get the right balance for a surgery.

現今，麻醉師常結合局部、吸入性及靜脈注射藥物以獲得手術需要的正確組合。

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

局部麻醉阻斷身體特定部位的疼痛訊號傳遞至腦部。

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

疼痛及其他訊息以電子脈衝運行於神經系統。

Regional anesthetics work by setting up an electrical barricade.

局部麻醉劑是藉著設立電流屏障而產生作用。

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

它們與神經元細胞膜的蛋白質結合而使得帶電粒子能流進與流出，並將帶正電粒子阻擋於細胞外。

One compound that does this is cocaine, whose painkilling effects were discovered by accident when an ophthalmology intern got some on his tongue.

古柯鹼就是執行這種機轉的一種化合物，其止痛作用是一位眼科實習醫師舌頭沾到一些，而意外發現的。

It's still occasionally used as an anesthetic, but many of the more common regional anesthetics have a similar chemical structure and work the same way.

至今它仍偶爾用作麻醉劑，但現在有許多更常用的局部麻醉藥具有相似的化學結構與作用機轉。

But for major surgeries where you need to be unconscious, you'll want something that acts on the entire nervous system, including the brain.

但對於病人需要昏迷無知覺的重大手術將需要能作用於整個神經系統 - 包括大腦 - 的藥物。

That's what inhalational anesthetics do.

吸入性麻醉劑就有這樣的作用。

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

在西方醫學中，乙醚就是最早普遍使用的一種。

It was best known as a recreational drug until doctors started to realize that people sometimes didn't notice injuries they received under the influence.

過去它以娛樂性藥物而聞名，直到醫師們開始察覺到有些人因服用乙醚後受傷而卻渾然不知。

In the 1840s, they started sedating patients with ether during dental extractions and surgeries.

在 1840 年代，醫師開始用乙醚來鎮靜拔牙及手術的病患。

Nitrous oxide became popular in the decades that followed and is still used today.

在其後數十年，一氧化二氮（笑氣）變得普遍至今仍使用中。

Although ether derivatives like sevoflurane, are more common.

然而乙醚的衍生物，如七氟醚更為常用。

Inhalational anesthesia is usually supplemented with intravenous anesthesia, which was developed in the 1870s.

吸入性麻醉常會額外加用靜脈注射麻醉，後者是在 1870 年代研發出來。

Common intravenous agents include sedatives, like propofol, which induce unconsciousness, and opioids, like fentanyl, which reduce pain.

常用的靜脈注射麻醉劑包括鎮靜劑，如異丙芬可導致昏迷無意識狀態，以及鴉片類如芬太尼可減輕疼痛。

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

這些全身麻醉劑也似乎是藉著影響神經系統的電子訊號發生作用。

Normally, the brain's electrical signals are a chaotic chorus as different parts of the brain communicate with each other.

通常，當大腦不同部位之間互相交流時，大腦的電子訊號就像一個失序的合唱團。

That connectivity keeps you awake and aware.

這種連結方式讓你保持清醒、有知覺。

But as someone becomes anesthetized, those signals become calmer and more organized, suggesting that different parts of the brain aren't talking to each other anymore.

但是一旦被麻醉那些訊號就變得較平靜、較有秩序，意謂大腦不同部份之間不再彼此溝通。

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

這倒底是如何發生的，我們仍有許多地方不清楚。

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

許多常用的麻醉劑會與大腦神經元的 GABA-A 受體結合。

They hold the gateway open, letting negatively charged particles flow into the cell.

它們維持通道開放讓帶負電的粒子流入細胞內 。

Negative charge builds up and acts like a log jam, keeping the neuron from transmitting electrical signals.

負電堆積就好像原木堵塞阻斷神經元電子訊號傳送 。

The nervous system has lots of these gated channels, controlling pathways for movement, memory, and consciousness.

神經系統有許多這種門控通道用來控制運動、 記憶、 及意識的路徑 。

Most anesthetics probably act on more than one, and they don't act on just the nervous system.

大多數的麻醉劑可能不只一種作用，而且不只作用在神經系統而已。

Many anesthetics also affect the heart, lungs, and other vital organs.

許多麻醉劑也會影響心臟、肺臟、 及其他重要器官 。

Just like early anesthetics, which included familiar poisons like hemlock and aconite, modern drugs can have serious side effects.

就如早期的麻醉劑包括熟悉的毒物，如鐵杉與烏頭以及現代的麻醉劑也有嚴重的副作用。

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

所以麻醉師必須以最恰當的比例混合藥物以產生麻醉的所有作用，

while carefully monitoring the patient's vital signs, and adjusting the drug mixture as needed.

同時小心地監測病人的生命徵候及視需要調整混合的藥物 。

Anesthesia is complicated, but figuring out how to use it allowed for the development of new and better surgical techniques.

麻醉是複雜的，但了解如何使用它讓新的及更好的外科技術得以發展。

Surgeons could learn how to routinely and safely perform C-sections, reopen blocked arteries, replace damaged livers and kidneys, and many other life-saving operations.

外科醫師能學會如何例行且安全地執行剖腹產手術、打通阻塞的動脈、 置換損傷的肝臟及腎臟以及許多其他挽救生命的手術。

And each year, new anesthesia techniques are developed that will ensure more and more patients survive the trauma of surgery.

每一年，新的麻醉技術都在進步，這將確保更多病人會熬過手術的身心創傷。