Anxious at Nine Feet

[TSandM]

Sorry, quoting Boyle's law in Latin again . . .

 

[do it easy]

Perhaps you are sensitive to pulmonary oxygen toxicity? Did you do any other dives earlier that day? Your dive profile doesn't add up to a lot of OTUs, but I just thought that I would throw my latest conspiracy theory into the ring. If this happens again, switch back to a leaner gas for a few minutes and see if it gets better.

EDIT: The pulmonary toxicity doesn't explain the anxiety, but the part about not getting a good breath makes me suspicious.

 

[Rick Inman]

Rick, no idea on your anxiety, but I do want to ask a couple of questions about your dive.

1. Why didn't you do the switch to EAN50 at 70ft?

As per the V-planner I posted on the origional post, I did switch at 70'.

2. Why the 10ft final stop? I see you didn't use oxygen, but I'm wonderig if you might have had a shorter TAT with an extended stop on EAN50 at 70ft.

Maybe. Planned the dive based on V-Planner VPM-B.

3. Why no Oxygen?

This class allows a max O2 of 50%.

4. 28/16???

Sorry, not sure what your question is here.

Perhaps you are sensitive to pulmonary oxygen toxicity? Did you do any other dives earlier that day? Your dive profile doesn't add up to a lot of OTUs, but I just thought that I would throw my latest conspiracy theory into the ring. If this happens again, switch back to a leaner gas for a few minutes and see if it gets better.

Yes, my instructor suggested I could have tried going back to the leaner backgas. Good idea.

 

[gcbryan]

My guess would be TS&M's adrenaline rush explanation or just general anxiety that hit you once the stress of the dive was over. The fact that you enjoyed the dive and didn't feel stress doesn't mean that you weren't under stress.

 

[Kayla]

This happened to me too, but not after a dive like yours. I was so stressed about my OW check out dive that just before I got to the surface it was like all of that tension just released, and it was similar to the panic attacks that I had had when I was younger. Hard to breathe, a little panicky, just not feeling right, and then it just went away. Sounds like thats kind of what happened to you... but I have absolutley nothing to stand on to prove that...

Either way, glad you enjoyed yourself, and I hope that there aren't any issues on the next one!!

Take it easy!
K

 

[PerroneFord]

Rick,

I think I misread your V-Planner time. I think what confused me was that you did not extend the stop at 70ft to take advantage of the higher pp. Since the asc to 70 and the asc to 60 both show at 26 minutes, but the gas switch happens, I am assuming that you just did a gas switch and continued the ascent without a stop. I was just curious about it.

I was also going to mention that the bottom mix was a bit rich perhaps, as I was taught not to go above 1.4, and preferably keep things at 1.3 if possible.

What class was this? It seems strange (to me) that someone could take a trimix class but not be allowed to carry oxygen. But it would have given you two gas switches on a 45 minute dive. Maybe not the best idea. And if you're sensitive to high oxygen partial pressures as has been suggested, it might have made things worse rather than better.

Thanks for sharing this real world example. It's been very helpful.

 

[Rick Murchison]

Hmmm... interesting event... unexplained anxiety can lead to anxiety wondering why
Possibilities, in no particular order (TS&M has covered much of this, but I'll be using the common tongue...):
(1) Blood sugar crash - not uncommon after excitement and adreneline rush
- When was your last meal/snack before the dive and what was it?
(2) Some sort of CV event - some folks have an occasional "cold induced" irregular heartbeat that can lead to anxiety; sometimes otherwise perfectly healthy folks just have a little bout of it.
(3) Drug side effect - decongestants in particular can do the anxiety thing. Were you taking any kind of prescription or OTC medicines?
(4) Self induced - sometimes the tiniest bit of unexplained anxiety can quickly and exponentially expand due to worry over what caused the little anxiety in the first place; failing to figure it out blossoms into full blown anxiety.
(5) Sometimes - sometimes, the Dragon just crawls up your spine. You just have to kill it..

Barring contaminated gas, I do not think that what happened to you had anything to do with CO2 buildup - extremely unlikely after a series of low-to-no exertion deco stops, or with O2 toxicity, which, if you were going to have a problem, would have surfaced at higher PPO2 and exertion level.

The only post-dive critique I have for you is the same as what your instructor suggested, in that any physiological weirdness should dictate a change of gasses if you have another suitable one handy. As for calling the dive, that was a good call On the plus side, now that you've had a bit of the Dragon you can better recognize him and kill him should he ever come your way again under less benign conditions.

The lesson learned for all of us is that any of us can have a period of anxiety for no apparent reason at any time and we need to keep a level head in spite of it. Plan for it; decide now that you will continue to operate in a controlled manner, follow the plan and keep your priorities straight. The ability to do so is an absolute prerequisite to any activity like overhead diving or IFR flying.
Rick

 

[Rick Inman]

Hmmm... interesting event... unexplained anxiety can lead to anxiety wondering why
Possibilities, in no particular order (TS&M has covered much of this, but I'll be using the common tongue...):
(1) Blood sugar crash - not uncommon after excitement and adreneline rush
- When was your last meal/snack before the dive and what was it?
(2) Some sort of CV event - some folks have an occasional "cold induced" irregular heartbeat that can lead to anxiety; sometimes otherwise perfectly healthy folks just have a little bout of it.
(3) Drug side effect - decongestants in particular can do the anxiety thing. Were you taking any kind of prescription or OTC medicines?
(4) Self induced - sometimes the tiniest bit of unexplained anxiety can quickly and exponentially expand due to worry over what caused the little anxiety in the first place; failing to figure it out blossoms into full blown anxiety.
(5) Sometimes - sometimes, the Dragon just crawls up your spine. You just have to kill it.

Barring contaminated gas, I do not think that what happened to you had anything to do with CO2 buildup - extremely unlikely after a series of low-to-no exertion deco stops, or with O2 toxicity, which, if you were going to have a problem, would have surfaced at higher PPO2 and exertion level.

The only post-dive critique I have for you is the same as what your instructor suggested, in that any physiological weirdness should dictate a change of gasses if you have another suitable one handy. As for calling the dive, that was a good call On the plus side, now that you've had a bit of the Dragon you can better recognize him and kill him should he ever come your way again under less benign conditions.

The lesson learned for all of us is that any of us can have a period of anxiety for no apparent reason at any time and we need to keep a level head in spite of it. Plan for it; decide now that you will continue to operate in a controlled manner, follow the plan and keep your priorities straight. The ability to do so is an absolute prerequisite to any activity like overhead diving or IFR flying.
Rick

Banana 3 hrs prior and 12oz decaf mocha 1 hr prior. No meds of any kind.

Very good post, Rick. Thanks.

PerroneFord,

IANTD, which teaches 1.5 TOD and 1.6 MOD. The 140' was a touch with 130' cruising depth. My guess on why the 50% O2 limit is that HE is benign. It's O2 (too much or too little) that'll kill ya.

 

[CD_in_Chitown]

Rick,

I think I misread your V-Planner time. I think what confused me was that you did not extend the stop at 70ft to take advantage of the higher pp. Since the asc to 70 and the asc to 60 both show at 26 minutes, but the gas switch happens, I am assuming that you just did a gas switch and continued the ascent without a stop. I was just curious about it.

I was also going to mention that the bottom mix was a bit rich perhaps, as I was taught not to go above 1.4, and preferably keep things at 1.3 if possible.

What class was this? It seems strange (to me) that someone could take a trimix class but not be allowed to carry oxygen. But it would have given you two gas switches on a 45 minute dive. Maybe not the best idea. And if you're sensitive to high oxygen partial pressures as has been suggested, it might have made things worse rather than better.

Thanks for sharing this real world example. It's been very helpful.

Alot of agencies do things differently, IE a 10 ft stop is common in alot of circles, the value in extending the 20 ft stop is usually considered the length of time at 1.6 Po2 on 100%. Breathing 50% for the entire deco isn't going to penalize you more than 5 minutes as it starts the gradient earlier. My choice for a single deco gas is 50/50 everytime, I think the benefits of switching at 70 outweighg the 100%. Some guys doing deeper wrecks up here dive 100% on the first dive and then top it with air to come up with something near 50% for dive 2. For average dives in the 150-200FFW range 1 deco tank and surface supplied oxygen (situation dependant) are the norm for the guys I dive with.

Not sure what tech agency trained you but your grasps of Vplanner tables and comments regarding the acceptable PO2 are curious. Please expand on where those PO2 targets are and what deco ratios were deemed appropriate by your tech agency?

Rick sounds like a great time, other than the finale at 9 ft. Hope that you can pinpoint the cause to prevent further issues, I like to take in a few more calories on dive mornings but they aren't nearly as healthy as a bananna so that may not be it. Remember I'm no doctor, just some board smartalec and can only offer best wishes for figuring out the quandry.

Good Luck,
Chris

 

[jagfish]

What class was this? It seems strange (to me) that someone could take a trimix class but not be allowed to carry oxygen. But it would have given you two gas switches on a 45 minute dive. Maybe not the best idea.

Hi
Chris gave you some good feedback about your questions.

About the above, at 28% O2 in the bottom mix, it was triox, so without further elaboration from Rick, I'd assume it was a triox class of some kind. For this level of training, and even some recreational trimix courses, it is quite common to be limited to just one deco gas. These are entry level technical courses and for first time technical divers, two stages can be a lot of task loading and equipment.

For reference...
O2 greater than 21%, He and N2 = Triox (EDITED)
O2 21%, He, N2 = Normoxic trimix (sometimes called recreational trimix)
O2 less than 21%, He and N2 = Hypoxic trimix (the deep stuff)