Narcosis

[Gene_Hobbs]

any one know of anymore papers on the subject?

It's funny, Peter Bennett was asked about this at the DAN Tech Conference last year... He is one of three REAL experts on narcosis in the world. Might be worth a listen. (they are free after all)

...and to get you started on your reading:

Frankenhaeuser M Graff-Lonnevig V Hesser CM. 1960. Psychomotor performance in man as affected by high oxygen partial pressure (3 atmospheres) Acta Physiol Scand; 50:1-7 PubMed ID: 13701420

Frankenhaeuser M Graff-Lonnevig V Hesser CM. 1963. EFFECTS ON PSYCHO- MOTOR FUNCTIONS OF DIFFERENT NITROGEN-OXYGEN GAS MIXTURES AT INCREASED AMBIENT PRESSURES. Acta Physiol Scand; 59:400-9. PubMed ID: 14082611

Paton WDM (1967) Experiments on the convulsant and anesthetic properties of oxygen. Brit. J. Pharm. 29, 350-366. PubMed Central: PMC1557218

Thomas, JR. Combined effects of elevated pressures of nitrogen and oxygen on operant performance. Undersea Biomed Res. 1974 Dec;1(4):363-70. RRR ID: 2677

 

[Kern]

O₂ Narcosis fact or fiction.

Diving Doctor - Diver Magazine

Is there a definitive answer, beats me.

PS. By the way, is it just me, or are there others who couldn't even get an abstract on some of the above links.

 

[Gene_Hobbs]

PS. By the way, is it just me, or are there others who couldn't even get an abstract on some of the above links.

It's not you, Medline does not have abstracts available for many old journal articles. The database is great for finding where to look for the older stuff but not so much for anyone that does not want to take the effort to pull the whole paper.

Since I could finally find them in my office today:

Psychomotor performance (simple and choice reaction times and mirror drawing) of 10 subjects during exposure to oxygen at 3 atm was compared with performance under normal air breathing at 1 atm. No statistically significant differences in psychomotor performance under the two conditions could be demonstrated. Nor did performance show any tendency to deteriorate with time within the 30 min period employed. The possible importance of these observations as criteria of concomitant physiological events is discussed.

In order to differentiate and evaluate possible factors responsible for compressed air narcosis, changes in psychomotor performance (simple and four-choice visual reaction times and mirror drawing) induced through exposure to different nitrogen-oxygen gas mixtures at raised barometric pressures were studied in 12 subjects. By comparing data from five different experimental conditions evidence was obtained that, at rest, (1) nitrogen pressures up to 3.9 atmospheres absolute have but slight effects on objective performance, and (2) oxygen excess has a potentiating effect on the narcotic action of nitrogen at high pressure. It was concluded that oxygen excess acts indirectly by interfering with the elimination of carbon dioxide from the tissues, and that compressed air narcosis is not due to interference with oxidation in the tissues by nitrogen excess.

An older post by Simon Mitchell on RBW sums up what is known quite well.

Enjoy!



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[Tortuga68]

... and what did all of that teach you? How do you relate what it taught you to your dive planning and execution?

... Bob (Grateful Diver)

It taught me that even when you don't feel narc'd, you are

I relate it to my dive planning and execution by being aware that I will be narc'd, making sure that I know my run time and have it written on my slate, trying to remember to check my SPG regularly, and dealing with the effects of narcosis

 

[leadweight]

I can't let this pass

Everyone gets narc'd, no-one is immune

You may not notice any symptoms at the rec depths you mention; that doesn't mean they aren't there

How true.

Some of us do fall into that category where we don't notice at the deep end of rec depth, but after the dive its "why did I do that."

 

[CamG]

Greetings Jmarsland and good thread! I have enjoyed reading the information in the following posts. It has broadened my awareness and made me think / re-think my diving techniques. I would like to thank all who have joined in the posting process!
It has got me pondering different ways to manage / process narcosis. Obviously only under safe diving conditions while training!
I agree that ignorance or denial of the inevitable is more dangerous than the real perception of narcosis!
Educate yourself, research and continue to train gaining valuable dive experience!
There is value in problem solving and working through issues but there also are times to ascend a few feet and clear your head!
Great information, keep it coming!
CamG Keep diving....keep training....keep learning!