Re: Drug induced comas?

On Mon, 30 Jul 2007 20:28:56 -0000, STJensen
<RecreationalPoker@xxxxxxxxx> wrote:

<snip>

Didn't you ask something like this back in 2002?
On Fri, 30 Aug 2002 11:26:08 -0500, "Scott T. Jensen"
<stj@xxxxxxxxxxx> wrote:

Has NASA or someone else done any research on how long we can keep someone
asleep and yet they'll be mentally healthy after they're woken up? Perhaps
some sort of controlled coma? As for the atrophy of muscles that would
result, has any research been done on the stimulating of muscles via some
type of web suit with electric contacts so the long-term sleeper doesn't
lose muscle tone?

Answers:
Can humans be safely put into a coma by way of drugs?
Yes, it's called general anaesthesia.

If so, what drugs would be used and how long can they be safely kept in a coma?

There's several different classes of drugs that are potential
candidates: benzodiazepines, opiates, barbiturates, ketamine,
propofol, volatile anaesthetic agents, neuromuscular blocking
agents...

Duration is limited by the complications of immobility and having
foreign bodies in your trachea and other places (IV lines, urinary
catheters etc).

With scrupulous care, people can be maintained for several weeks. This
is the bread and butter of Intensive Care medicine.

Complications of immobility include:
Pneumonia
Bone demineralisation
Muscle atrophy (skeletal and cardiac)
Reduction in blood volume
Formation of blood clots in leg and pelvic vessels
Pressure areas (bedsores)

If there's a time limit, how long do they need to be out of the coma
before being safely put back into one?

As far as sedation and anaesthesia are concerned, this question makes
no sense. You might want to lighten sedation to see if the patient can
wake up or assess their neurological state. With regard to
anaesthesia, you might want to turn the drugs off at the end of a
procedure.

If they need to be sedated or anaesthetised again (for another
procedure, say) you just get on and do it.

Essentially, astronauts doing this to themselves to save on oxygen,
water and food (people sleeping consume less of all three) as well as
to just make the space trip fly past faster for them.

You're only going to reduce metabolism to ~80% of resting with
anaesthesia alone. Cooling *and* something like hydrogen sulfide will
be required to get a big reduction in nutritional requirements.

Suzanne Blom wrote:
So far though, a rather large support team is needed to keep a person in a
theraputic coma alive & potentially well.
Yes. Welcome to ICU.

James Nicoll wrote:
There was something about being able to trigger low-metabolism
states in a wide variety of organisms by exposing them to hydrogen sulfide
about two years ago.

Yep, 'Science' April 22, 2005. Roth et al at the 'Hutch' in Seattle.
As you go on to say, it 'only' reduces metabolism (albeit to ~10% in
mice)- which may not enough to get the effect that Scott might want.
If it works in humans.


Dr. Robert O'Connor
.

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