DCS incident after wreckdive

[wgw04024]

If you had taken another hit shortly there after, would DAN insurance covered that too?

 

[islanddream]

If you had taken another hit shortly there after, would DAN insurance covered that too?

Most likely not. DAN looks at the recommendation from the attending physician at the chamber as to when the person can dive again. When I took a chamber ride last October (skin bends), I was told not to dive for six months. The paperwork sent to DAN has all the information the physician has given the patient and that includes "time out of water." What I was told was if I got bent from diving within the six months, DAN wouldn't cover the costs. Chamber rides are very expensive.

 

[Dr Simon Mitchell]

may be Going tech - Patent Foramen Ovale (PFO) testing? ?

There is no association between musculoskeletal DCS and PFO. A PFO test is not indicated on the basis of this episode. The forms of DCS associated with PFO are cerebral, spinal, inner ear, and skin.

Miyaru,

I would not spend too much time ruminating on the cause of this event. I personally have had two episodes that were virtually identical to yours over the years, and both occurred with longish, intermediate depth repetitive dives. This makes sense because musculoskeletal DCS is almost certainly a manifestation of localised bubble formation in pain-sensitive slow tissues that will accumulate inert gas in this sort of diving. It is one of those things that can happen. Personally, these days, if I get deep (notionally over 50m) for a longish bottom time I generally only do one dive per day, or make the second dive very shallow. That would probably be my primary advice if you are looking to avoid another event of this nature.

The problems you encountered at the hospital (being placed in a queue etc) are common, and have occurred many times with divers much sicker than you were and where delay to recompression was more problematic. I am one of the doctors covering the NZ equivalent of the DAN line you called. If I take a call about a diver and refer them to a hospital, then I always call the hospital, speak personally to the duty consultant emergency physician, and let them know the diver is coming and what I believe needs to happen with them. Communication is the key to smooth management of diving casualties. However, despite best efforts by diving doctors on DAN lines, problems can still occur when divers arrive at hospitals that are not accustomed to seeing divers.

Simon M

 

[rossh]

.... as planned (15/45 trimix, EAN50 and O2, GF40/75). Computer profiles where compared from my SW and a team member's SW, the chamber staff concluded that I was simply unlucky on this dive..

In MultiDeco, we can take an existing dive graph log image, and re-plan that dive, to test and check what the underlying planning really amounts too. This gives you a cross check on the dive computer and verifies what the dive computer says it provided for deco conservative or GF settings.

Here is your dive #2:

It computes closer to about a GF 50/70 plan.

Note the 14m /min ascent rate from 50 to 24m

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[rossh]

Another handy tool in MultiDeco, is the ability to quickly chart your Supersaturation or tissue gradients values through the ascent.

Again here is your dive #2.

From these, we can see that fast and middle tissues are the dominant ones in your dive. The slowest tissues are not significant.


Why are we looking at this? Because somewhere in your ascent, an excessive pressure occurred, that lead to an injury. These graphs can provide some guidance on what to look out for.

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[ajduplessis]

Maybe stop a bit deeper next time and slow down your ascent.

But then again, some professionals promote “shooting” for the shallows as staying deeper increase DCS risks.

 

[Beau640]

There’s two competing things: staying deep to keep bubbles small vs getting shallow fast to avoid further ongassing. The sweet spot is about 30ft per minute. That’s for optimal deco though not necessarily to avoid DCS. Up to 60ft per minute although not ideal should still be safe. I doubt his ascent rate caused his DCS hit.

 

[Beau640]

Ross, how do those graphs help us figure out where the profile went wrong for him? It shows us max supersaturation but he never crossed critical supersaturation for his profile. How can we use those graphs to figure out where his personal critical supersaturation may have been (in other words where in the profile it didn’t work for his body even though he followed it) and where he exceeded it to avoid it next time?

 

[Miyaru]

I ascended from 50.2m to 25m in 110s. That's 13.63m/min.
One buddy ascended from 50.9m to 23.9m in 120s. That's 13.5m/min.

In this case, it's both helium and nitrogen offgassing. Critical supersaturation might have been reached in my tissues, while two other divers had no issues.
Anyway, if slowing down to the planned 9m/min makes a difference, I'll take it.

 

[rossh]

Ross, how do those graphs help us figure out where the profile went wrong for him? It shows us max supersaturation but he never crossed critical supersaturation for his profile. How can we use those graphs to figure out where his personal critical supersaturation may have been (in other words where in the profile it didn’t work for his body even though he followed it) and where he exceeded it to avoid it next time?

These graphs show the theoretical gas kinetics of the ascent. This parallel mono-exponential model is the most widely accepted and tested method for tissue gas exchange monitoring.

Supersaturation is a required condition for bubble formation and growth. Supersaturation occurs when the sum of all inert gas pressures at the tissue, exceeds the ambient (water) pressure.

Where, when and how far those supersaturation levels become, is the basis of most model's ascent limits and deco decision points.

The supersaturation graphs help because it measures and compare all types of ascents in a generic, scientific and model independent way. After using them a little, one can quickly identify various attributes of a specific model, or compare any changes in ascent plans for their effects. The interaction of inspired gas swaps is a consideration too.

****

This dive is a relatively short decompression dive where the shorter / faster tissue compartments are the ones in control. This diver reported the pain started at 7m in ascent, so that narrows the search further towards the peak levels of supersaturation.

It is also possible he created the injury site micro-bubble seeds, from the previous surface interval activity, and this ordinary looking ascent with its modest supersaturation levels, was the final part needed to create the DCI.

****

Precisely what caused his injury? There at least 20 possible contributing risk factors to be considered for the cause:

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