Nitrogen Narcosis

[DCBC]

Bubbletrubble, you're discussing an individual's measurable performance decrease when dealing with nitrogen narcosis in repetitive dives over a five day period. I'm discussing how performance for these tasks are increased through years of experience dealing with nitrogen narcosis.

 

[DCBC]

I think it's unfair to compare inert gas narcosis to alcohol intoxication.

As I mentioned, this was an analogy of testing that was undertaken and I had previously described. I'm aware that drunkenness and nitrogen narcosis are different.

If your personal experience suggests that adaptation might occur, I'm not saying that's wrong. I'm just saying that your subjective assessment might not be the best indicator of adaptation, since it's easy to confuse learning with adaptation. I think the door's still open for the possibility of adaptation...especially in tasks that are unrelated to reaction time.

I have been involved in many hyperbaric tests over the years (not subjective assessments). Not all of these are in electronic format, nor are all available on the Internet. I would also not expect that all of them would be made available to the public sector. I think I've described my experiences.

Notwithstanding peer reviewed journals, there are things that are commonly known by many people. Several people have experienced themselves becoming more accustomed to nitrogen narcosis. Historically divers increased their depth over time and were able to accomplish jobs like underwater welding at ever increasing depths. Individuals that understood their inability to complete a task eventually gave way to something that was doable for them.

If this is not your experience, I understand. Safe diving.

Wayne

 

[Bubbletrubble]

Bubbletrubble, you're discussing an individual's measurable performance decrease when dealing with nitrogen narcosis in repetitive dives over a five day period. I'm discussing how performance for these tasks are increased through years of experience dealing with nitrogen narcosis.

It really depends on what kind of tasks you're talking about. If those tasks are heavily reaction-based, then even an experienced diver will still be impaired. AFAIK, one cannot increase his reaction time through practice.

With regard to adaptation to narcosis, perhaps the commercial diving community is focused on performance in tasks that do not rely on reaction time.

I am completely ignorant about what a commercial diver does. I can only draw conclusions based on what's been published.
Are most/any of your under water tasks reaction-based?
Could under water welding be considered a reaction-based task?
I suspect that deep sea welding is something that one can practice. If so, then I can definitely see the value in doing deep dives to acquire that skill.

 

[Diver0001]

So you mean that the tests were done using tasks requiring high levels of reactive action?

That's not like diving at all.

A good test for diving would be to test divers for slower reaction times while engaged in walking meditation.

That's the problem with comparing apples with oranges. You can conclude whatever you want to see .....

R..

 

[Bubbletrubble]

@Diver0001: Wait a sec. Did you read the paper? Read the Methods section for a description of the reaction-time task.

I'm only interpreting what was in the article.

Of course, one can argue that a different type of task might not yield the same results.

FWIW, I do think that reaction time is relevant to sport diving.

Consider the following scenario: You are at 150 fsw, and your buddy has an entanglement issue at that depth. Do you think that the time it takes for you to recognize and resolve the situation will be longer or shorter than if you had experienced the same situation at 10 feet? To isolate the depth variable, let's assume that all other things are equal (light, temperature, can't surface to get help, gear, distance between divers, etc.). I'm not offering this as proof...just that reaction time may be relevant to sport diving under certain circumstances.

 

[Bubbletrubble]

DCBC and Diver0001, I owe you guys a beer.

 

[Diver0001]

DCBC and Diver0001, I owe you guys a beer.

Can't object to that, eh?

As for your scenario.... yeah. I understand that it's the internet and we can always invent a scenario that can't be handled and I would fully agree with you that nobody wants to die gruesomely.

On the other hand, maybe one of the things that separates highly experienced divers from teh ones who "die gruesomely" is their ability to recognise danger (despite, in the case of narcosis, their depth) and the handle that adequately. (ie. situational awareness).

I think you said before that the tests are relevant. But they are not. They measure the wrong variable. They need to measure judgement (or common sense) and situational awareness and not just pure choice reaction time.

The latter (what they measured) is like measuring calculation speed.

The former (what I'm saying) is measuring making the *right* calculations.

The difference is that someone making the wrong decision quickly isn't as effective as a diver as someone who makes the right decision but takes 10 seconds longer. Hardly anything happens during diving that is so threatening and immediate that "calculation speed" is the determining factor for survival. 99.99998% of situations require the *right* decision, not the *fastest* decision.

R..

 

[Bubbletrubble]

I didn't say that reaction time is the only important variable in effecting a rescue. I also didn't say that it was the most important factor in effecting a rescue. I stand by my statement that it does contribute to resolving the situation.

Of course, good judgment, planning, training, experience, situational awareness, and many other things go into making the rescue in the given scenario. Something to consider is that some or all of those things might be impaired simultaneously along with reaction time.

Reaction time is easy to measure. It's quantifiable and was known to be affected by narcosis. That's why it was used in the study in question.

I realize that we all want a simple, clear-cut answer. Unfortunately, this rarely happens in science.

If one read the article, it would probably be incorrect to conclude that adaptation to narcosis is a myth. It's probably better to phrase it as follows: "The findings of the study suggest that reaction-based tasks do not show adaptation in the context of inert gas narcosis." After all, adaptation can occur in many different kinds of tasks. And not all of those tasks were tested.

It's up to the reader to decide the relevance of the study to sport and/or commercial diving. I would hope that people would take a look at the methodology and understand the limitations of the findings.

Is it happy hour yet?

 

[DCBC]

Are most/any of your under water tasks reaction-based? Could under water welding be considered a reaction-based task? I suspect that deep sea welding is something that one can practice. If so, then I can definitely see the value in doing deep dives to acquire that skill.

Yes. In this example, the diver has to maintain control of the torch, in-that he doesn't cut his umbilical, support lines, a piece of his equipment, or his leg. You often work in high current and varying visibility and have to react to unplanned movement or loss of vision. The commercial diver works in a construction site which is fraught with hazards over and above the "diving aspects" of the job.

When communicating topside, the diver may have to give moment-by-moment information to a crane operator which involves movement of a load that presents a potential danger to the diver or the construction being undertaken. Setting or removing explosive charges is another action that requires a high degree of diver situational awareness. As does hot tapping a natural gas line. Not a lot of room for error.

 

[DCBC]

I agree with Diver0001. In the military and commercial field if nitrogen narcosis is a factor, it's understood that the performance of the diver will be degraded. Through increased experience and exposure, the goal is to increase situational awareness and improve the decision making process.

The area of recognition of nitrogen narcosis isn't stressed enough in sport diving imo. The time it takes to react to a situation may be decreased by preparation.

One example is an inexperienced "driver" sees a red light, realizes he's close to the intersection and slams on his brakes (the reaction time is the time it takes him to recognize the problem and move his foot off the gas pedal to the brake).

An experienced "driver" pays more attention to the light as it cycles and can predict that it will turn red. He may have to brake as well, but his "critical reaction time" has been eliminated. This is a result of experience.

I think a diver who's attuned to himself, his equipment and the environment is better prepared to deal with a situation than another diver who's caught by surprise, or never knew what hit him until it was too late.