Narcosis

[xjeslesx]

Thanks for all the information! I think 'Devon Diver' hit my event right on. "When a diver has sufficient experience that their core diving skills are instinctive, then they are unlikely to notice that narcosis. This is because narcosis primarily effects problem solving and stress reactions."

I have done plenty of 100'+ dives without feeling any real signs of narcosis. These dives did not consist of something large and fast coming towards me at a high speed.
I'm glad this happend, it allows me to understand what will happen if I do come across an emergency at that depth and what 'odd' feeling I can expect to deal with.

To answer a few of your questions; our decent was controled, swimming down a line tied into the ship, using 28% nitrox. My guess is that the grouper was being territorial, his initial reaction to my presense and his aggresive charge towards me lead me to this conclusion. I've dove with many other speciess and been approach my many looking to be fed, mostly striped bass, it is an entirely different approach and posture.
The only other time I have been charged in the water was by a 4-5lb lump fish. The lump fish was guarding its eggs and certainly did not want me anywhere near. The lump fish charged me and actually crashed into my mask. It didn't cause any damage to my mask, but I got the point and continued on in a slightly different direction.

 

[dumpsterDiver]

You were narced at 120 feet but didn't know it.

The fish scared the crap out of you.

The narcosis magnified the fear and all of a sudden you are so freaked that you had to run up to 90 feet to get your head together even though you knew the danger (or at least the inital cause of your discomfort had been removed).

Narcosis is like that it; makes you do stupid things, but usually only when you are presented with a novel problem or stressful stimulus.

I've been freaked out myself; my threshold was charging bullsharks that devoured a 40 lb fish I speared and were suddenly totally out of control (while solo at 190 feet). I pressed the "up" button and ascended in a cloud of bubbles until I stopped myself at around 100 feet.

Note to self: When you ascend at 100 feet per minute, it is better to swim a little sideways (out of your bubbles stream) if you want to have any visibility or situational awareness.

 

[Bubbletrubble]

One small note for all: while it's true that increased CO2 levels will exacerbate nitrogen narcosis, it's very unlikely that this is what happened in the case of this diver. If a diver is hyperpneic (breathing rapidly), it would take very small, dead-space only ventilations to cause an elevation in blood pCO2. Think of a panting poodle. Most probably, the rapid breathing that the OP experienced from his unexpected encounter would have dropped his CO2 level, not increased it.

@Duke Dive Medicine: You're arguing that the grouper incident caused a decrease in blood pCO2. I don't know about that. The fight-or-flight phenomenon is a pretty complex physiological response. I don't think it can be simplified to: hyperpnea --> decrease in blood pCO2. It would be fun to attempt to monitor this in humans...specifically how breathing changes (spirometric parameters) and how arterial pCO2 varies in the short-term. I'm picturing some willing participants who'll watch scary movies (̀a la the Ludovico method in Kubrik's A Clockwork Orange) while investigators measure these things. Any chance that you've already conducted such studies on Duke undergrads? If not, perhaps you could hit up some of the students waiting in those K-ville tents. They'd probably do it for pizza.

 

[Duke Dive Medicine]

@Duke Dive Medicine: You're arguing that the grouper incident caused a decrease in blood pCO2. I don't know about that. The fight-or-flight phenomenon is a pretty complex physiological response. I don't think it can be simplified to: hyperpnea --> decrease in blood pCO2. It would be fun to attempt to monitor this in humans...specifically how breathing changes (spirometric parameters) and how arterial pCO2 varies in the short-term. I'm picturing some willing participants who'll watch scary movies (̀a la the Ludovico method in Kubrik's A Clockwork Orange) while investigators measure these things. Any chance that you've already conducted such studies on Duke undergrads? If not, perhaps you could hit up some of the students waiting in those K-ville tents. They'd probably do it for pizza.

I'd like to see them right now, it was 17 degrees here this morning. They'd probably do it for a cup of hot coffee and five minutes inside the gym. I agree, he wouldn't have necessarily dropped his pCO2, I just don't think it would have become elevated and exacerbated the narcosis in this case. A small footnote to an otherwise good outcome and a great picture in my head all day of a narced diver screaming through his reg as a giant, otherwise docile fish scared the bejabbers out of him (with apologies to xjeslesx).

 

[ctyhallcoolio]

Yep agree grouper was looking for a handout. They can be real fun to night dive, light dazzle hunt with. My odd nacr story is filming a shark for over a minute under the cranes on the Grove. Totaly forgot about it and wasnt till 2 weeks later reviewing video that i was like woa... After that suprise I took to letting the camera run thru whole dive and while I might be narc'd at least I see I am very good with checking of computer and air.

 

[beester]

Yep agree grouper was looking for a handout. They can be real fun to night dive, light dazzle hunt with. My odd nacr story is filming a shark for over a minute under the cranes on the Grove. Totaly forgot about it and wasnt till 2 weeks later reviewing video that i was like woa... After that suprise I took to letting the camera run thru whole dive and while I might be narc'd at least I see I am very good with checking of computer and air.

Funny that's basically one of my 'I'm really narced'-triggers. Starting to check my computer/gas excessively. Not remembering what I read just seconds ago.

I look at being narced as a physiological process that decreases my mental bandwith. Being able to dive reasonably comfortable to 130 feet does not mean I've conquered narcosis... no it just means I don't need so much bandwith to deal with normal diving. (buyancy, gas management, stay in contact with team, etc).

Certain factors in diving may increase the need for diving bandwith like low vis, current, cold water, etc. An emergency will probably push this so far as to going into total task overload. Not having enough mental capacity left to deal with the problem or needing so much that you get tunnelvision trying to solve the issue and disregard all other diving issues (gas, depth, buyancy, etc).