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A man who ran out of air at the bottom of the ocean

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Re: A man who ran out of air at the bottom of the ocean

#31
post #29

Related - David Blaine's world record of holding breath for 17 minutes: https://worldrecordacademy.com/stunts/longest_breath-holding... Which is probably already broken: https://www.reddit.com/r/IAmA/comments/132l2v/i_hold_the_gui...

I think this is the current record. 24 minutes and 3 seconds. It's hard to comprehend.

http://www.guinnessworldrecords.com/world-records/longest-ti...

Re: A man who ran out of air at the bottom of the ocean

#32
post #17

Question for the medical readers: a person dies when brain dies from lack of blood flow, right? So all those injuries, say a car crash where heart will stop soon. 1) Disconnect the head from body 2) plug it into a machine that supplies blood, etc 3) the body is repaired 4) reattach head to body. Overlooking the obvious trauma, is this possible? While extreme/traumatic, I think it could be more reliable as other facto…

That's what an ECMO is... a last-ditch effort to perfuse the brain and vital organs to see if the body can recover. It rarely does.

Head transplantation is still too "out there."

Re: A man who ran out of air at the bottom of the ocean

#33
post #28

> They now use emergency tanks that carry 40 minutes of air rather than five. Glad to see the change, but why even carry a tank with 5 minutes of reserve? Might as well just plan on holding your breath in that case.

This is just idle observation, but when you ascend the air in your lungs expands and you are supposed to continuously exhale to prevent lung rupture. Supposedly if you start with a full pair of lungs, you can ascend pretty much from the bottom of the ocean on just one breath because of this. Also somewhat related, the deeper you go the less time your tank lasts. From what I remember, at 100m, a "5 minute tank" is pro…

This is correct; scuba divers are trained to do a controlled emergency ascent while continuously exhaling, because your lungful of air at depth will last the whole way up, and the real risk is not running out of air, but embolism from overexpansion.

The limiting factor in ascent (and therefore the reason for the recreational dive limit of 60 feet) is the risk of decompression sickness. If it weren't for that, a diver at arbitrary depth could ascend on a single breath.

Re: A man who ran out of air at the bottom of the ocean

#34
post #17

Question for the medical readers: a person dies when brain dies from lack of blood flow, right? So all those injuries, say a car crash where heart will stop soon. 1) Disconnect the head from body 2) plug it into a machine that supplies blood, etc 3) the body is repaired 4) reattach head to body. Overlooking the obvious trauma, is this possible? While extreme/traumatic, I think it could be more reliable as other facto…

That's what an ECMO is... a last-ditch effort to perfuse the brain and vital organs to see if the body can recover. It rarely does. Head transplantation is still too "out there."

One problem with head transplantation that comes to me, is that of resources such as hormones and neurotransmitters produced by the body (i.e. intestines produce neurotransmitters).

Thence it is not only a problem of oxygenation of brain tissue.

Re: A man who ran out of air at the bottom of the ocean

#35
post #10

Earlier quoted context omitted.

Yeah even if the unmanned drones are too hard, having spare tanks at the work site sounds like an easy way to at least supply oxygen... however without the umbilical cord he loses the heat supply. Maybe its more pleasant to pass out while your body freezes.

Getting cold probably saved his life by reducing the metabolic burden. This is done intentionally during certain surgeries, such as aortic aneurysm repairs. It also informs the ER standard: you're not dead until you're warm and dead. Also, it's staggering how much oxygen can be dissolved into your system at depth. The Navy did some experiments where they put pigs in a chamber, pressurized them to something obscene, l…

That's also why hyperbaric oxygen therapy is an effective treatment for carbon monoxide poisoning. Even when all the hemoglobin receptors are bound to carbon monoxide, enough oxygen will diffuse into the blood to keep the patient alive.

Re: A man who ran out of air at the bottom of the ocean

#36
post #17

Question for the medical readers: a person dies when brain dies from lack of blood flow, right? So all those injuries, say a car crash where heart will stop soon. 1) Disconnect the head from body 2) plug it into a machine that supplies blood, etc 3) the body is repaired 4) reattach head to body. Overlooking the obvious trauma, is this possible? While extreme/traumatic, I think it could be more reliable as other facto…

It's not just the brain. All the body's organs require perfusion. The heart will also quickly die without perfusion. Other organs will survive a little longer.

Re: A man who ran out of air at the bottom of the ocean

#37
post #27
post #4

>If you lower the brain temperature down to 30C (86F), it can increase the survival time from 10 to 20 minutes. If you cool the brain to 20C (68F), you can get an hour. Wow, I actually didn't know this until now. Is this method used anywhere in medical procedures to resuscitate or prolong life?

So this may be the basis of cryogenics? If you just cool down in specific way, you can turn off metabolism and then turn back on again at later date?

Well not really. Cooling the patient down will give you a few hours at most under ideal conditions. Metabolism isn't turned off, just slowed down. If you freeze the patient the ice crystals damage the cells so much that revival becomes impossible.

Re: A man who ran out of air at the bottom of the ocean

#38
post #28

Earlier quoted context omitted.

This is just idle observation, but when you ascend the air in your lungs expands and you are supposed to continuously exhale to prevent lung rupture. Supposedly if you start with a full pair of lungs, you can ascend pretty much from the bottom of the ocean on just one breath because of this. Also somewhat related, the deeper you go the less time your tank lasts. From what I remember, at 100m, a "5 minute tank" is pro…

This is correct; scuba divers are trained to do a controlled emergency ascent while continuously exhaling, because your lungful of air at depth will last the whole way up, and the real risk is not running out of air, but embolism from overexpansion. The limiting factor in ascent (and therefore the reason for the recreational dive limit of 60 feet) is the risk of decompression sickness. If it weren't for that, a diver…

Recreational dive limits are usually set at about 100 - 130ft (30 - 40m) depending on the training standards in use.

Re: A man who ran out of air at the bottom of the ocean

#39
post #17

Question for the medical readers: a person dies when brain dies from lack of blood flow, right? So all those injuries, say a car crash where heart will stop soon. 1) Disconnect the head from body 2) plug it into a machine that supplies blood, etc 3) the body is repaired 4) reattach head to body. Overlooking the obvious trauma, is this possible? While extreme/traumatic, I think it could be more reliable as other facto…

step 4 is pretty hard.

Re: A man who ran out of air at the bottom of the ocean

#40
post #5

Reminds me of the fantastic movie The Abyss (1)...vaguely recall a similar scene where there's N tanks of oxygen for N+1 people, so they submerge 1 of the crew to lower her (i think) metabolic rate. Curious why they don't have emergency unmanned drones with the crew or why they don't have emergency tanks at their work site (which he was able to get back to) (1) - Not sure how well it has aged ( https://en.wikipedia.o…

At least for recreational diving each diver has two regulators attached to their tank, so if you have N tanks you can provide breathing gas to 2N people.
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