死是一种什么感觉？（电死、坠死、吊死...） (1177/28150)

触电而亡
心脏和大脑都完了
在触电事故中，肇事者经常是家用的低压电，最常见的致死原因是点击造成心率不齐使心脏停止跳动，跟着就会失去直觉。芝加哥拉什大学的心脏病专家richard trohman说。来自加拿大蒙大拿的一份调查报告显示，92%的死者都是因为触电引起的心律不齐。
高压电流会使人迅速的失去直觉。电椅就是这么设计的，迅速、无痛、有效。这比以前的绞刑可文明多了。
要达到这一步可不容易。1950年在狗身上做的试验发现，把电极放在头的两侧能让电流更快的通过脑部，迅速导致死亡。在这之前被电死的罪犯可没这么走运，他们往往需要被电好几次才能安息，有的被电的头上光芒四射，有一次一个被浸湿的人造海绵被放到犯人的头上，这个法子是不错，可是海绵是个糟糕的导体，没一会犯人头上就烧着了。
2005年一份针对验尸报告做的研究显示在43名被电死的罪犯中，他们最明显的伤口是在头和腿被放置电极的地方。这个报告的资深医学专家william hamilton总结说，因为死亡只在一瞬间，这些伤口是在死后才造成的。
然而，范德比尔特大学的生物学家john wikswo补充说道，人体又硬又厚的骨骼是绝缘的，它们可能会阻止电流抵达脑部，这种情况下犯人可能死于脑部过热或者呼吸肌肉麻痹造成的窒息。但不管是哪种情况，反正不会是什么好事。
高空坠落
如果可能的话，尽量让脚先着地
从高空坠落也很可能迅速的死去。从145米以上的高度掉下来到地面时能达到200公里的时速。德国汉堡一份坠落而死的统计显示，75%的遇难者在落地后几秒或几分钟后死去。
坠落的死因得取决于地面情况和人落地的姿势。不管是10米以下还是25米以上，一旦你的头先落地，那一般来说就不用去医院了。1981年的分析报告调查了 100个在旧金山金门大桥上的自杀者，大桥75米高，落水时的时速120公里，迅速致死的原因包括肺部大面积淤血、肺部塌陷、心脏爆裂、大动脉伤害和肺被肋骨刺穿。
一些幸存者描述这一过程时候说：时间好像停止了。跌落时本能的挣扎着想双腿落地，这样经常导致腿部骨折、挤压脊椎和致命的骨盆破裂。落地时的冲力通过身体破坏大动脉和心房。尽管冲力被集中在双脚上，这依然是最好的一种落地方式：脚和腿可以行程一个“弯曲地带”，这样保护了内在主要器官不受太大的伤害。
一些有经验的登山者和高空跳伞者提供了一些高空坠落事故中求生的心得，集中精神，保持警觉，尽量以最好的姿势着地：放松，腿部弯曲，如果可能做好后续的翻滚准备。这也许能有些帮助，但如果你不幸从高空坠落，记住最重要的一条，要使自己尽量“软着陆”。一份1942年的报道说，一个妇女从她28米的公寓摔了下来，可幸运的是她落在一片刚犁过的土上，只是断了根肋骨、扭了一下腰。
吊死
死的速度取决于行刑人的技巧
老式的自杀和行刑都是用绞刑，绳子勒紧通往大脑的气管和动脉。这能让人在10秒钟里失去知觉，但如果绳打的不对那就得多花点时间。绞刑的旁观者经常提起死者在绳套上痛苦的“舞蹈”，在窒息的时候剧烈的挣扎。在真正死去之前还会有好几分钟，有不少人被救下之前甚至已经吊了15分钟。
在1868年的英国，当众行刑是违法的，行刑人员不得不找个人少的地。为了快点完事，他们想出了“长落”的法子，他们故意把绳子弄的稍微长一点，这样犯人就会靠下落的冲力快一点死去。但这也有门道，如果绳子太长犯人的重量可能会把绳子拉断，对于一个专业的刽子手来说，没有比这更丢脸的了。
尽管十九世纪末的英国有不少自诩高明的刽子手，但一份1992年的报告对34名犯人的死亡报告的分析表明，大约一般的人完全或部分死于颈椎伤害，只有五分之一的人死因是典型的绞死症状--即第二与第三根颈椎间隙碎裂。其他人相当程度上死于窒息。
加拿大西安大略大学伦敦分校的人类学家michael spence发现在美国的死者也是这样。他总结道，窒息致死甚至占到很大一部分，坠落的冲击可以造成所有人失去直觉。行刑者都在找一种可以迅速了解的方法，他说。犯人们都知道自己死定了，没有人心存侥幸，他们害怕的不是绞刑而是被砍头。
安乐死
美国政府许可 但它真的安乐么？
安乐死1977年出现在俄克拉荷马州，相比于坐电椅来说，它被看作一种更人道的方法。医疗审查者和麻醉学机构确定了安乐死的三个步骤。首先用戊硫代巴比妥麻醉，让人快速失去痛感，接下来用叫做溴化双哌雄双酯的作用物使人停止呼吸。最后注射氯化钾致人死亡，氯化钾很毒，被注射者几乎在瞬间就死了。
每一种药物的计量都能致命，剩下的部分会使人死的更快也更人道。然而，目击者也说，受刑者在注射期间会发生抽搐、起伏并试图做起来。看来致命鸡尾酒不总是有效。
关于个中原因，迈阿密米勒医学院的Leonidas koniaris说，是因为戊硫代巴比妥的问题。他和他的同事分析了41个北卡罗来纳和加利福尼亚的安乐死病例，并比较了麻醉剂在动物比如猪身上的效果。不同体重的人接受同样计量的注射，比较重的人对麻醉剂的反应要轻一些。
“我认为很大一部分接受安乐死的人是有知觉的”这种知觉可能包括肺部麻痹造成的窒息和氯化钾注射造成的灼痛。然而，麻痹的作用应该是让目击者差距不出受刑者有任何痛苦的迹象。
最高法院现在正在考量这种死刑方式是否合法。
爆发性减压
它让你窒息
身处真空中而死亡是科幻小说中常见的情节，不管是从气压过渡仓被扔了出去还是抓破了自己的太空衣。
在现实生活中只有一起致命的太空爆发性减压事故。它发生于1971年苏联的Soyuz-11计划中，当飞行器入口处被暴露在地球大气层时，封闭仓发生破裂，降落后发现三位宇航员死于窒息。（when a sealleaked upon re-entry into the Earth's atmosphere; upon landing allthree flight crew were found dead from asphyxiation.也许有错误）
大部分减压的知识来自动物试验和飞行员在高海拔地区发生的事故。当外部的压力突然降低，肺里的空气会急速膨胀，撕裂脆弱的气体交换组织。如果遇难者只顾摒住呼吸而忽视了吐出空气平衡压力，那尤其危险。你血液和肺中的氧气会迅速流失。
上世纪50年代在狗身上做的试验显示。失去外部压力30-40秒钟后，尽管人紧密的皮肤可以避免水份"爆裂”但不可避免的，肺组织中的水开始蒸发，人的身体开始浮肿。心率先是加快，然后大幅减速。血液中的水分迅速蒸发，然后通过循环系统波及全身，阻塞血液流动。一分钟后，你的血液循环系统结束了。
从急速减压事故中幸存下来的人中包括一名飞机突然失压的飞行员和NASA一个脱掉宇航服进入真空仓勇敢的技工。他们事后描述说感觉到一种像被人猛击胸部的疼痛，然后空气迅速脱离他们的肺，以致不能呼吸。在15秒钟内就能让人失去知觉。
美国军方位于新墨西哥州的航空医学研究实验室60年代中期的时候做了一个试验，他们发现大猩猩在缺氧之后11秒钟它们依旧意识清醒。
让人惊讶的是，经过了这么多人类的折磨，只要90秒钟内恢复压力，动物们通常会完整无缺的活下来，简直可以说是若无其事。

Electrocution

The heart and the brain are most vulnerable

In accidental electrocutions, usually involving low, household current, the most common cause of death is arrhythmia, stopping the heart dead. Unconsciousness ensues after the standard 10 seconds, says Richard Trohman, a cardiologist at Rush University in Chicago. One study of electrocution deaths in Montreal, Canada found that 92 per cent had probably died from arrhythmia.

Higher currents can produce nearly immediate unconsciousness. The electric chair was designed to produce instant loss of consciousness and painless death - a step up from traditional hangings - by conducting the current through the brain and the heart.

Whether it achieves this end is debatable. Studies on dogs in 1950 found that electrodes had to be placed on either side of the head to ensure sufficient current passed through the brain to knock the creature out. There have been many botched executions - those that required several jolts to kill, or where flames leapt from the prisoner's head, in one case due to a damp synthetic sponge being attached to the electrodes on the prisoner's head, which was such a poor conductor it was heated up by the current and caught fire.

An analysis in 2005 of post-mortem remains from 43 prisoners sentenced to death by electrocution found the most common visible injuries to be head and leg burns where the electrodes were attached. The study's senior author, William Hamilton, a medical examiner in Florida, concluded that these burns occurred post-mortem and that death was indeed instantaneous.

However, John Wikswo, a biophysicist at Vanderbilt University in Nashville, Tennessee, maintains that the thick, insulating bones of the skull would prevent sufficient current from reaching the brain, and prisoners could instead be dying from heating of the brain, or perhaps from suffocation due to paralysis of the breathing muscles - either way, an unpleasant way to go.

Fall from a height

If possible aim to land feet first

A high fall is certainly among the speediest ways to die: terminal velocity (no pun intended) is about 200 kilometres per hour, achieved from a height of about 145 metres or more. A study of deadly falls in Hamburg, Germany, found that 75 per cent of victims died in the first few seconds or minutes after landing.

The exact cause of death varies, depending on the landing surface and the person's posture. People are especially unlikely to arrive at the hospital alive if they land on their head - more common for shorter (under 10 metres) and higher (over 25 metres) falls. A 1981 analysis of 100 suicidal jumps from the Golden Gate Bridge in San Francisco - height: 75 metres, velocity on impact with the water: 120 kilometres per hour - found numerous causes of instantaneous death including massive lung bruising, collapsed lungs, exploded hearts or damage to major blood vessels and lungs through broken ribs.

Survivors of great falls often report the sensation of time slowing down. The natural reaction is to struggle to maintain a feet-first landing, resulting in fractures to the leg bones, lower spinal column and life-threatening broken pelvises. The impact travelling up through the body can also burst the aorta and heart chambers. Yet this is probably still the safest way to land, despite the force being concentrated in a small area: the feet and legs form a "crumple zone" which provides some protection to the major internal organs.

Some experienced climbers or skydivers who have survived a fall report feeling focused, alert and driven to ensure they landed in the best way possible: relaxed, legs bent and, where possible, ready to roll. Certainly every little helps, but the top tip for fallers must be to aim for a soft landing. A paper from 1942 reports a woman falling 28 metres from her apartment building into freshly tilled soil. She walked away with just a fractured rib and broken wrist.

Hanging

Speed of death depends on the hangman's skill

Suicides and old-fashioned "short drop" executions cause death by strangulation; the rope puts pressure on the windpipe and the arteries to the brain. This can cause unconsciousness in 10 seconds, but it takes longer if the noose is incorrectly sited. Witnesses of public hangings often reported victims "dancing" in pain at the end of the rope, struggling violently as they asphyxiated. Death only ensues after many minutes, as shown by the numerous people being resuscitated after being cut down - even after 15 minutes.

When public executions were outlawed in Britain in 1868, hangmen looked for a less performance-oriented approach. They eventually adopted the "long-drop" method, using a lengthier rope so the victim reached a speed that broke their necks. It had to be tailored to the victim's weight, however, as too great a force could rip the head clean off, a professionally embarrassing outcome for the hangman.

Despite the public boasting of several prominent executioners in late 19th-century Britain, a 1992 analysis of the remains of 34 prisoners found that in only about half of cases was the cause of death wholly or partly due to spinal trauma. Just one-fifth showed the classic "hangman's fracture" between the second and third cervical vertebrae. The others died in part from asphyxiation.

Michael Spence, an anthropologist at the University of Western Ontario in London, Canada, has found similar results in US victims. He concluded, however, that even if asphyxiation played a role, the trauma of the drop would have rapidly rendered all of them unconscious. "What the hangmen were looking for was quick cessation of activity," he says. "And they knew enough about their craft to ensure that happened. The thing they feared most was decapitation."

Lethal injection

US-government approved, but is it really painless?

Lethal injection was designed in Oklahoma in 1977 as a humane alternative to the electric chair. The state medical examiner and chair of anaesthesiology settled on a series of three drug injections. First comes the anaesthetic thiopental to speed away any feelings of pain, followed by a paralytic agent called pancuronium to stop breathing. Finally potassium chloride is injected, which stops the heart almost instantly.

Each drug is supposed to be administered in a lethal dose, a redundancy to ensure speedy and humane death. However, eyewitnesses have reported inmates convulsing, heaving and attempting to sit up during the procedure, suggesting the cocktail is not always completely effective.

The reason, say Leonidas Koniaris at the University of Miami Miller School of Medicine, is insufficient thiopental. He and his colleagues analysed 41 executions by lethal injection in North Carolina and California, and compared anaesthetic doses to known effects in animal models, such as pigs. As the same dose of thiopental is used regardless of body weight, the anaesthesia produced in some heavier inmates might be inadequate, they concluded.

"I think that awareness is a real possibility in a large fraction of executions," says Koniaris. That awareness might include feelings of suffocation from paralysed lungs and the searing, burning pain of a potassium chloride injection. The effect of the paralytic, however, might mean that witnesses never see any outward signs of pain.

The Supreme Court is now going to review whether this mode of execution is legal.

Explosive decompression

It takes your breath away

Death due to exposure to vacuum is a staple of science fiction plots, whether the unfortunate gets thrown from an airlock or ruptures their spacesuit.

In real life there has been just one fatal space depressurisation accident. This occurred on the Russian Soyuz-11 mission in 1971, when a seal leaked upon re-entry into the Earth's atmosphere; upon landing all three flight crew were found dead from asphyxiation.

Most of our knowledge of depressurisation comes from animal experiments and the experiences of pilots in accidents at very high altitudes. When the external air pressure suddenly drops, the air in the lungs expands, tearing the fragile gas exchange tissues. This is especially damaging if the victim neglects to exhale prior to decompression or tries to hold their breath. Oxygen begins to escape from the blood and lungs.

Experiments on dogs in the 1950s showed that 30 to 40 seconds after the pressure drops, their bodies began to swell as the water in tissues vaporised, though the tight seal of their skin prevented them from "bursting". The heart rate rises initially, then plummets. Bubbles of water vapour form in the blood and travel through the circulatory system, obstructing blood flow. After about a minute, blood effectively stops circulating.

Human survivors of rapid decompression accidents include pilots whose planes lost pressure, or in one case a NASA technician who accidentally depressurised his flight suit inside a vacuum chamber. They often report an initial pain, like being hit in the chest, and may remember feeling air escape from their lungs and the inability to inhale. Time to the loss of consciousness was generally less than 15 seconds.

One mid-1960s experiment by the US Army Aeromedical Research Laboratory in New Mexico found that a chimpanzee had a period of useful consciousness of just 11 seconds before lack of oxygen caused them to pass out.

Surprisingly, in view of these apparently traumatic effects, animals that have been repressurised within 90 seconds have generally survived with no lasting damage.