Alarming and Dangerous Incident please read

[Tigerman]

Without looking in my books (as its not very relevant to me, diving only on air), inst higher o2 mixes getting toxic at lesser depth than normal air?
IIRC 100% o2 can poison you at as low as 20 feet, while 21% o2 can get poisonous at like 180 or something? (Which is already 80% deeper than my certification).
Which would make me assume that 36% o2 could get you nice and wuzzy a fair bit earlier than 21% o2 would?
Nitrox is used to increase bottomn time, not depth?

As far as nitrogen narcosis goes, I only have two deep dives (85 and 100 feet).
The first one we where basically cruising around looking at the wildlife, swimming out from the shore and continuing down to 85 feet where we arrived after 14-15 minutes. We just hung out there for like 3 minutes before we followed a "pile of rocks" (with loads of crabs) back to shore. This never made me feel any narcosis, which can start from 80 feet or for some people even shallower.

The other dive im not so sure about..
It was a wreck dive at 75-100 feet. We ascended along a line to 100 feet, which we reached in 2 minutes. This is an old WWII 4-engine seaplane wreck and the parts are lying in a triangle and the parts are marked with lines between them. By the time we where turning the last point of the triangle to return to the ascent/descent line i was starting to get confused about the direction. This was 14-15 minutes into the dive (12-13 minutes of that time between 75 and 100 feet). Wether or not this was because of the fact that you couldnt see much without a flashlight and the reasonably frequent direction changes or narcosis, I cant say for sure..

 

[mstroeck]

Not a tight wetsuit and I wear a harness. I find it hard to breathe slowly and exhale fully while kicking at max force. I tend to go into a sprinter's breathing pattern. I used to run 10K. I definitely feel the CO2.

No, you probably can't. The military tested this extensively quite a while ago by letting people ride an ergometer while slowly turning up CO2 content in their breathing mix. By the time the test subjects noticed that "something was wrong", they could not even get off of the ergometer on their own power.

 

[cerich]

OK guys, a few observations here:



First, note how quick his symptoms appeared. Second, notice how quickly they relieved. Third, notice that they did not re-occur when he descended again.

If I was presented with this type of patient, at his age, and with a history of sudden physical exertion, I'd have to consider atypical coronary artery spasm, pulmonary artery spasm, pulmonary blood clots generally, pulmonary embolism or other cardiac issues. Although all of the "complex" explanations of narcosis, HVS and other stuff is plausible, I don't think any of them fully explain what occurred. Key point here is that his symptoms did NOT re-occur when he descended again.

I'd suggest that the original poster contact his physician, explain the situation and request a cardiac work-up, evaluation and stress test. If those come back clear, then we can debate narcosis, HVS and other more exotic stuff..

Rule out the worst-case stuff FIRST...

Just my thoughts...

The most logical post yet.

 

[Thalassamania]

How do you cope with depth plus hard exertion? I think I might be a bit of a CO2 retainer as I have a very low SAC. I don't get uncomfortably narced without fighting a current.

Working hard does not seem to effect the narc, but that may have to do with the mental focus that many "hard work" tasks require.

 

[lamont]

No, you probably can't. The military tested this extensively quite a while ago by letting people ride an ergometer while slowly turning up CO2 content in their breathing mix. By the time the test subjects noticed that "something was wrong", they could not even get off of the ergometer on their own power.

Not a good comparison. I notice CO2 creeping up on me because my mind starts to get wiggy and I get sensitive to dark/paranoid narcs. I'll also start to get perceptual narrowing when doing more complicated tasks. You aren't going to notice these effects running on a treadmill at 1 ata.