Panic and the Hypercapnic Alarm Response

[TONY CHANEY]

Good points GJC. The problem here seems that the diver only had a single wing BC and when it failed and was filling up with water her kit now has become an anchor pulling her down. She starts for fight the weight and the water. She is working her butt off just trying to stay on the surface and over breather the reg. So she takes the reg. out because she is air starved. How she is air starved in a rather hostile environment breathing bad air in the dome. CO2 is building up due to inadequate breathing and a decrease in O2. IMO, she should have either used her dry suit to help her stay afloat and relax and breath properly from the reg. or go back down and relax and allow the team to assist her. Seldom are weights used in caves that can be ditched because they can damage the cave and also put you pinned against the ceiling and you can't get back to say a deeper restriction.

 

[Schwob]

Good points GJC. The problem here seems that the diver only had a single wing BC and when it failed and was filling up with water her kit now has become an anchor pulling her down. She starts for fight the weight and the water. She is working her butt off just trying to stay on the surface and over breather the reg. So she takes the reg. out because she is air starved. How she is air starved in a rather hostile environment breathing bad air in the dome. CO2 is building up due to inadequate breathing and a decrease in O2. IMO, she should have either used her dry suit to help her stay afloat and relax and breath properly from the reg. or go back down and relax and allow the team to assist her. Seldom are weights used in caves that can be ditched because they can damage the cave and also put you pinned against the ceiling and you can't get back to say a deeper restriction.

I get and am with that there may be situations where some form of (tunable) reserve buoancy may be desirable over ditching weights, e.g
like a drysuit. I think so does she at least while she has not lost her wits and paniced, which I think she may have done already well underwater ... otherwise things would have gone calmer and less hectic and the ascend would have been less work, more controlled and less CO taxing.

Wondering:
There sure was a reason to ascess the situation and abort the dive after the malfunction. Had that been done calmly, controlled, step by step, then there sure was a reason to abort the dive, but would ascending right here and there have been mecessary?

BTW, why does everyone appear to make it sound like a wing filled with water is heavy? I would think it would weigh (UW that is) exactly the same as an empty wing... Who cares if it is or isn't filled with water. The point is the air, the lift is out. It being filled with water makes no additional difference... Not UW, only when trying to be at the surface... which seemed her only focus during her panicked reaction. So yeah, I guess in that sense the wing was heavy...

 

[Kevrumbo]

Reviewing the first video a few more times:

After her wing failure, she may have been having problems operating her drysuit inflator for redundant surface buoyancy -she says something about, "Can't get my drysuit inflator to ~open~(?)", as a teammate initially reaches her to donate with a long hose primary reg. Could also be the drysuit exhaust valve automatically and inadvertently dumping the added air she needed for surface buoyancy if it wasn't fully clockwise-closed-off. . .

Again, note the narrowed cognitive perception and goal oriented drive of hypercapnic panic: trying to "get out of her gear" which is pulling her down, and rejecting the regulator because of its high WOB and her "air hunger" -even if it meant taking in the "easier breathing" air of the dome room which she may not have realized was noxious and hypoxic.

As she says in the video: ". . .If you let things snowball, even the best diver can get into a bad situation. . ."

In terms of treating hypercapnia, the time-honored “PADI advice” for an out-of-breath diver to “stop, breathe deeply, and rest” remains valid, but should be appended with “... as soon as you feel symptoms of hypercapnia” because it is often not followed until it is too late by highly motivated technical divers. . .
https://www.diversalertnetwork.org/files/Tech_Proceedings_Feb2010.pdf, p.33

 

[sea_otter]

CO2 does weird things to your brain. I had one dive where I was working fairly hard at a depth of around 85 ft. I suddenly felt an overwhelming urge to get to the surface ASAP.

My rational brain managed to take over, I stopped swimming, took a few breathes, checked my gas, realized that all okay, and I really didn't want to go to the surface. It probably took 15 seconds in total, but it was actually quite a scary experience.

I can't imagine the same thing happening in a cave with non-breathable air at the surface. That's quite a terrifying situation.

 

[TONY CHANEY]

I am not too sure about her dry suit. She said, “I can’t keep my dry suit inflated.” That might mean that the over pressure dump valve was fully open or when vertical often the gas will blow out your neck seal. I often find that when vertical in a dry suit that the extra gas around my neck adds pressure or a constricktive

 

[TONY CHANEY]

I am not sure what happened to her dry suit but maybe the over pressure dump valve was fully opened, or it failed or often when vertical the gas was blowing out of the neck seal. A dry suit, which appears to be a bag style, when it will not hold air adds additional difficulty in kicking due to the squeeze.
The flooded BC is not the problem but not holding air is. No lift.
We don’t know about the air in the dome. Someone said that this air is bad but some of them keep their regs. Out of their mouth and are talking while breathing this “bad air.” We have no idea unless the air was analyzed. Personally, I find the air on the surface in Mexico rather bad in some places. When we were in Cozumel and wanted to analyze our tanks at the dock, the outside air was reading 4 ppm CO. When I placed the analyzer on the tanks it went to zero. That was at the waters’ edge. I can not imagine what the CO is in the city.

 

[TONY CHANEY]

Sorry but doing this on my phone.

 

[Kevrumbo]

Had that been done calmly, controlled, step by step, then there sure was a reason to abort the dive, but would ascending right here and there have been mecessary?

IMO -and apparently by the video editing- they surfaced right then and there just to "sight see" this dome room without anyone initially aware of Jeanna's cascading problems.

There were at least three other teammates with plenty of planned redundant volume for a gas share if necessary. The priority at that moment was to give Jeanna good gas to breath and have her recover. Obviously they had enough time to troubleshoot her wing and drysuit as needed, and form a contingency plan to use the drysuit for Jeanna's buoyancy on the egress from the dome room & cave system.

 

[lermontov]

well we know she did one thing right - Mask on forehead!!

 

[KevinNM]

I had an instructor describe a CO2 hit on a rebreather. It didn't cause any obvious breathing issues, what it caused was bizarre behavior. Like bouncing off the floor and ceiling and not recognizing that something was seriously wrong. There was awareness that 'today is not a good buoyancy day', but what caused bailout was the other divers persistently and increasingly urgently urging bailout.