Anaesthesia and respiration

[specialspack]

not sure if this is really ADD stuff...

I was just reading an article in New Scientist this week, about hypnosis used for anaesthesia, which mentions that patients under general anaesthesia (drug induced) have to be ventilated with a respirator.

The article talking mainly about halothane and its derivatives, and alkylphenols.

Surely patients anaesthetised with nitrous or ketamine don't need respirating? or do they?

If anyone knows any good book about anaetheisology (technical or historical) I'd be interested.

S.

 

[fastandbulbous]

With nitrous, you don't get the same depth of surgical anaesthesia (the mixture being inhaled has to be min 20% oxygen and 80% nitrous just doesn't get deep enough) and with ketamine you don't get sufficient muscle relaxation. You can get the muscle relaxation by also administering a neuromuscular blocking agent (tubocurarine or something like one of the acetylcholine based depolarizing agents), but then you need ventilation as it paralyses the intercostal muscles and the diaphragm, which are needed to ventilate the lungs

 

[BilZ0r]

^The Ket anasthesia is hardly general anyway... isn't it? It's all the twilight anaesthia business.

 

[Giza]

Is there anything somone could take along with an opioid analgesic to help respiration? Aside from the obvious caffeine cut.

Would a bronchialdilator or vasodilator be helpful?

 

[fastandbulbous]

No - opiates reduce the sensetivity of the medulla oblongata to the concn of CO2 in the blood - that's how they act as respiratory depressants. I suppose you could try increasing the level of CO2 in the inspired air, but if you've ever tried breathing air with higher concn.s of carbon dioxide, it's a ereally unpleasant feeling (courtesy of a physiology practical at uni, I got a chance to breath air with 5% CO2 and 25% O2. It is really distressing and unpleasant - probably the way asphixiation feels. Def not recommended for someone receiving anaesthesia)

 

[Giza]

So then why is most heroin cut with caffeine? Is it for the heart if not the lungs?

 

[fastandbulbous]

The Ket anasthesia is hardly general anyway... isn't it?

Ketamine anaesthesia is just as good as inhalation anaesthetics in terms of depth, pain relief etc., but is unsuitable for any abdominal surgery as it does not cause any reduction of muscle tone. For surgery on limbs it is every bit as efficient as inhalation anaesthetics. It also has the drawbacks of only lasting for 30mins and of producing major freakouts in people recovering from it (several people here will be well acquainted with that feeling!). It is good enough to allow for limb amputation, so I'd think that it's classed as a general anaesthetic.

So then why is most heroin cut with caffeine?

It's not for any reason to do with pharmacology. The caffeine is included as the heroin will be intended for smoking - the caffeine vapourizes first, forming a protective layer around the heroin as heating heroin to it's boiling point in the presence of oxygen will result in a fair amount of the opiate being destroyed/oxidized (a bit like the nitrogen or argon atmosphere produced to surround a mig/arc welder - it prevents atmospheric oxygen from oxidizing, and therefore weakening the weld). The caffeine isn't needed if the heroin isn't intended for smoking

 

[Survival0200]

with ketamine you don't get sufficient muscle relaxation. You can get the muscle relaxation by also administering a neuromuscular blocking agent (tubocurarine or something like one of the acetylcholine based depolarizing agents)

Would someone want to combine ketamine and d-tubocurarine (dTC) on recreational purpose? I just saw a movie (Basic Instinct 2) where one guy had been taking ketamine and dTC. (He died.)

P.S. This was the only thread about tubocurarine I could find.

 

[hussness]

No unless you own a ventilator.

 

[fastandbulbous]

Would someone want to combine ketamine and d-tubocurarine (dTC) on recreational purpose? I just saw a movie (Basic Instinct 2) where one guy had been taking ketamine and dTC. (He died.)

P.S. This was the only thread about tubocurarine I could find.

Absolutely no reason whatsoever for combining them for recreational/ketamine therapy use