Fatal dive accident - Lake Werbellin, Germany

[cathal]

"We" read it in posts #1 and #6 of this thread.

From post 1 "According to the dive computers they were at max. 38 m and spent approx. 20 minutes at 6 m depth, when they were found."

Post No.1 indicates that both divers spent 20 minutes at 6 meters before their bodies were located. In this post there is no information indicating that both deceased were swimming at this depth.

Regarding rapid ascents from shallow depths, I personally have had to call a chopper to transport a diver to a chamber who had a rapid ascent from 12m (36ft) while diving on air, while dehydrated. He was paralysed from the waist down by the time the chopper got to him, (approx 1 hour wait). I believe he was able to walk out of the Hospital after 3 days of treatments, resolution of symptoms was not 100%. Rapid ascents from shallow depths can be serious. A rapid ascent from 38M is a whole different level if that occurred.

There are other extraneous factors that have not been discussed that could have played a role in this.

 

[KevinNM]

As a young engineering student living in dismal housing in northern England, one of my friends suffered mild CO poisoning from a faulty gas heater. She experienced extreme disorientation and vivid, frightening hallucinations - not symptoms I've heard discussed with reference to CO.

The symptoms with most medical things are generally somewhat to hugely more variable than the books suggest. The two people I know who have had CO2 issues on a rebreather both had symptoms different than the classic ones. Both basically looked drunk to their teammates but felt pretty good if maybe a little clumsy (as they bounced off the ceiling and floor of the cave). But no rapid breathing. And both were sure everything was fine and had no idea why people were shoving regulators at them.

 

[Duke Dive Medicine]

It's worth mentioning again that there is a big difference between carbon DIoxide (CO2) and carbon MONoxide (CO). CO2 is a byproduct of metabolism and can cause toxicity in divers. CO is a byproduct of incomplete combustion and can also cause toxicity in divers, though by an entirely different mechanism. CO2 toxicity generally resolves very quickly on the surface. CO toxicity does not.

I don't think anyone here is going to speculate Carbon Dioxide as it's generally not an issue as long as there is enough Oxygen in the mix.

@DandyDon , that is not the case. CO2 retention can be a significant issue in divers regardless of the amount of O2 in the mix. Risk increases with increasing gas density (which increases as a function of depth). Work of breathing, physical condition, and individual hypercapnic ventilatory response (how one's body responds to increased levels of CO2) also contribute.

Best regards,
DDM

 

[Duke Dive Medicine]

"Apologies in advance for my ignorance, but can I ask what are the precise circumstances about the incident that are leading to the hypothesis of Co2 poisoning?"



Then is there any chance the Admin could split this thread off, as we are learning nothing about the actual incident, its specific trigger factors and the COD?

Rarely are the full details of an accident made public, so speculation is part and parcel of the A & I forum. Still, the conversation is often valuable to newer divers. I do understand that it can be a distraction, and A & I threads are full of rabbit holes where speculation is debated as fact. Mods only step in if the conversation goes way off topic or becomes uncivil.

Best regards,
DDM

 

[DandyDon]

@DandyDon , that is not the case. CO2 retention can be a significant issue in divers regardless of the amount of O2 in the mix. Risk increases with increasing gas density (which increases as a function of depth). Work of breathing, physical condition, and individual hypercapnic ventilatory response (how one's body responds to increased levels of CO2) also contribute.

Alright, thanks. I stand corrected.

It's worth mentioning again that there is a big difference between carbon DIoxide (CO2) and carbon MONoxide (CO). CO2 is a byproduct of metabolism and can cause toxicity in divers. CO is a byproduct of incomplete combustion and can also cause toxicity in divers, though by an entirely different mechanism. CO2 toxicity generally resolves very quickly on the surface. CO toxicity does not.

I think that the risks of 100 ppm CO = 0.1% is tremendously far greater, but it's still an apples vs kumquats comparison.

 

[leadduck]

As a young engineering student living in dismal housing in northern England, one of my friends suffered mild CO poisoning from a faulty gas heater. She experienced extreme disorientation and vivid, frightening hallucinations - not symptoms I've heard discussed with reference to CO.

The symptoms with most medical things are generally somewhat to hugely more variable than the books suggest. The two people I know who have had CO2 issues on a rebreather both had symptoms different than the classic ones. Both basically looked drunk to their teammates but felt pretty good if maybe a little clumsy (as they bounced off the ceiling and floor of the cave). But no rapid breathing. And both were sure everything was fine and had no idea why people were shoving regulators at them.

Early CO poisoning symptoms usually include strong headache, dizziness, nausea... That's good because, unlike O2 or CO2, you have a good chance to notice the effects of CO early enough before it gets dangerous. But you must take the symptoms seriously and immediately tell your buddy, and call the dive. Whereas to people who hope that the headache wears off, swim behind, or leave the group to return to the boat alone, bad things have happened.

One of my friends once signalled her buddy she isn't well, then passed out under water and her buddy brought her to the surface. The air in the tank was smelly, so not CO but probably some cleaning stuff residue (had hydro testing just before the dive). CO testing will not protect you from everything. Most importantly always tell your buddy and call the dive when you feel sick.

 

[Duke Dive Medicine]

I think that the risks of 100 ppm CO = 0.1% is tremendously far greater

One conclusion that can be reasonably drawn is that divers should proactively mitigate the risks of both CO and CO2 toxicity. You're a passionate advocate for testing air for CO, which is great. Divers should also be aware of risk factors for CO2 toxicity and work to control them. Like you said, apples to kumquats.

Best regards,
DDM

 

[leadduck]

A report on this accident got published:
Defekte Tauchflasche könnte zum Tod geführt haben (in German)

Their dive computers showed a fast ascent from 34m to 23m, and then a very fast ascent from 23m (77ft) to the surface taking just a few seconds. After 5min on the surface, they both sank to 6m were other divers found them unconscious. The very fast ascent caused lethal injuries and they died in hospital. The initial problem was probably that the connection of her drysuit inflator hose to the tank became loose and lost gas. There's no evidence of third party involvement.

 

[leadduck]

A report on this accident got published:
Defekte Tauchflasche könnte zum Tod geführt haben (in German)

Their dive computers showed a fast ascent from 34m to 23m, and then a very fast ascent from 23m (77ft) to the surface taking just a few seconds. After 5min on the surface, they both sank to 6m were other divers found them unconscious. The very fast ascent caused lethal injuries and they died in hospital. The initial problem was probably that the connection of her drysuit inflator hose to the tank became loose and lost gas. There's no evidence of third party involvement.

My interpretation would be: unsuccessful attempt at in-water recompression (IWR). Nothing to do with CO.

 

[Raphus]

My interpretation would be: unsuccessful attempt at in-water recompression (IWR). Nothing to do with CO.

Yes IWR was my first though after reading the article aswell..
Very sad