Ever Experienced Memory Loss By Narcosis?

[verona]

I was talking to someone on a boat at the weekend and he told me about a dive he made when he "lost" 10 minutes of the dive from his memory. He said it was caused by narcosis and that he can't remember from when he hit around 26m until he started to ascend.

I have to say that scares the **** out of me, the notion that you can be swimming around at 30m and not remember any of it.

The guy was kind of sanguine about it all but I was thinking, what could have happened if he had encountered a problem down there? Yikes. Obviously, he was a fairly competent diver in the sense that he was swimming around a wreck for 10 minutes without incident even though he can't remember it. HIs buddies didn't seem to notice anything either.

Have any of you experienced this or witnessed it in someone else?? Hope I never do!

 

[sharkmasterbc]

I was at 100ft counting psi and time to figure out SAC rate. I kept repeating the #'s in my head so I would remember but once I hit 60 ft I could not for the life of me recollect any of the data...and I was repeating these #s for 5 min.
I now know the value of wetnotes

 

[100days-a-year]

uh,I forget.Part of diving(unless on heliox)is learning to deal with and minimise impairment.Simplifying gear and plans can help.Repititive drills helps one to familiarize one to the given circumstances.Mix training for deeper dives is a good idea too.

 

[jbichsel]

narcosis on deep dives, just to different degrees. There are various factors that can have an effect: Physical conditioning, stress, how tired you are, number of recent dives, diving conditions, etc.
I know myself, I usually don't have much of a problem, however once I became tangled in fishing lines at about 120' in a current. Ended up beyond the 130' recreational limit, over time, under air by the time we got ourselves cut loose. I thought we were only tangled up for a couple of minutes, but it was actually about 15. It seemed so quick.
I have watched people attempt to share their air with the fish yet have no recollection of it when we surfaced.

 

[DA Aquamaster]

Simplifying your plan, writing things on a slate and using simpler techniques all help at depth.

The problem with doing things like repeating numbers in your head at depth to later figure a sac rate is that your focus becomes the numbers and not the dive. People vary in their ability to multi task even on the surface and these differences become more pronounced at depth. Forcing your self to uneccesarily increase your task loading is just asking for a problem.

It is also important to know your limitations and plan accordingly to accomodate them. For example I know that at 150 ft I cannot figure a reciprocal bearing in my head. While it is very easy to figure a recrprocal to 135 degrees in my head on the surface, I really struggle with it at depth unless I can write it on a slate. But from a practical stand point, all I have to do is dial 135 degrees in on the compass and follow the other set of hashmarks to go the opposite way. So with a little thought and pre-planning the math impairment is not an issue as math is just not required if I plan the dive to use a simple 180 out and back profile.

Same thing with turn pressures, I plan what I need for ascent and saftey/deco stops plus a 1/3 reserve and figure turn and ascent pressures on the surface and then just write them on a slate in case I forget them during the dive (which has not occurred to date).

Everyone gets impaired at depth but the impact this has can be greatly reduced on a well planned dive where the effort is made to accomodate for the impairments and to reduce task loading to the essentials of the dive.

 

[JDostal]

I've forgotten things before...and still occasionally do.

 

[BlueSky]

But it might have happened to me without me even knowing...

One of my buddies was once forced to start ascending by his buddy. He had no idea why... untill they compared their computers: they had reached 56 meters! The first one without knowing, the second one trying to get him back to shallower depth. The buddy I'm talking about had no recollection whatsoever of descending to that depth...
I don't wanna think about what could have happened if his buddy was just as narced as he was...

BlueSky.

 

[Mako Mark]

Back in the days when deep air diving to 200 ft + was not considered something to be flamed about, I noticed that I could look at my gauges/computer and register that I had checked them, but not have a clue what they said.

I often use this example when teaching, I tell people to look at my watch, then I hide it and ask them what time it said... we often filter out information that the brain consideres too much detail, and students that have just looked at my watch, did not register what the time was.

I have found that with narcosis, it does not so much affect you ability to make good or bad decisions, rather it affects the speed at which you can make them.

When narcosed divers try to make descisions or have thought processes at normal speed, they can fail.

 

[H2Andy]

"Ever Experienced Memory Loss By Narcosis?"

ah... not that i remember...

 

[verona]

ah... not that i remember...

I've been waiting for that one, Andy!! :dazzler1: