Simon Mitchell - Should divers treat DCS in-water?

[Vicko]

IWR is a therapeutic method, DAN and everyone else involved has a hard time recommending it as if something goes wrong they will be the ones giving medical advice leading to improper treatment, a big no no.
Recompression chamber requires a doctor and staff to use and maintaine, it's easy to kill or seriously injure someone when using it improperly. What dive resort can pay a full time medical team to be on standby in case someone gets bent?

 

[ginti]

How times have changed.

It is quite interesting that DAN Europe had sponsored the talks, since IWR (in water recompression or “decompression“ years ago) had always been verboten by the organization, "DAN strongly recommends that in-water decompression using either air or oxygen, should never be attempted," and had only previously encouraged onboard treatment of DCS with O2.

There had been a number of reasons for that proscription, including a potential increase of danger to the patient (paralysis or loss of consciousness) and to his or her attendants (DCS themselves, for one); the depths that were originally suggested for IWR (up to 50 meters); the long periods of time required (usually measured in hours); risks of hypothermia; the availability of a very large gas supply; a possible decline in the patient's condition — even unforeseen weather changes.

Shallow-water IWR on O2 seems to carry some real benefits, that not even DAN can really ignore, but is still a bit sketchy -- no added nitrogen debt and a large gradient for its excretion; a maximum depth reduced to less than 10 meters and a time reduced from around five hours, on air, to about three on O2; less of a threat to any attendants; and no nitrogen narcosis.

That use of positive pressure full face masks for shallow water IWR was also interesting, should a patient either convulse from O2 treatment or lose consciousness for some another reason . . .

DAN Europe actually sponsors a lot of this type of research, but as per my understanding it is more about promoting science and supporting very experienced divers (exploration level - deep sea, long cave penetration, etc). I doubt very strongly they will ever recommend these practices to rec divers or even tec divers outside exploration. But I might be wrong

 

[Searcaigh]

A few years back some of my tech buddies and myself did the IANTD IWR course and found it extremely informative.

However, one key takeaway is that the "victim" has to be compatible with all the criteria for IWR before jumping back into the water with but not limited to the following:

1. Trained personnel
2. Full Face Mask
3. Sufficient supply of gas for the "victim" and all the support divers.

Apart from the tech dives that we were doing at the time, when we started to carry with us the required gear and gases, it would be unlikely that any of the rec dives myself and others were doing at the time, that this would be an option, as it would be unlikely that the above three points would be fulfilled, and therefore the scenario of IWR would only be feasible in tech dive situation.

The nearest chamber is a good two hour drive from our area of diving as well as having to cross an altitude of approximately 360m (1,181ft) above sea level.

Prior to our IWR course we had one member of our group take a hit on a 72m dive, the symptoms had manifested once back onboard (pain on right shoulder joint) and were initially put down to hanging on to the shotline in current and choppy weather (?denial), but subsided once the "victim" was on 100% O2 at the surface.

The "victim" was driven to a chamber two hours away and there was an apparent increase in pain whilst crossing the relatively higher altitude (360m).

This latter point has always made me delay my return home after normal diving rather than drive straight home, generally we have lunch etc., and the drive back is usually two to there hours from surfacing, as well as diving with the richest Nitrox mix that I can use for my second dive without compromising myself and surfacing without hitting my NDL (usually EAN40).

That said, I would agree that IWR is an important tool for treatment of DCI assuming all of the criteria can be met to make it possible, but in reality perhaps it's not always practical.

 

[rob.mwpropane]

A few years back some of my tech buddies and myself did the IANTD IWR course and found it extremely informative.

However, one key takeaway is that the "victim" has to be compatible with all the criteria for IWR before jumping back into the water with but not limited to the following:

1. Trained personnel
2. Full Face Mask
3. Sufficient supply of gas for the "victim" and all the support divers.

Apart from the tech dives that we were doing at the time, when we started to carry with us the required gear and gases, it would be unlikely that any of the rec dives myself and others were doing at the time, that this would be an option, as it would be unlikely that the above three points would be fulfilled, and therefore the scenario of IWR would only be feasible in tech dive situation.

The nearest chamber is a good two hour drive from our area of diving as well as having to cross an altitude of approximately 360m (1,181ft) above sea level.

Prior to our IWR course we had one member of our group take a hit on a 72m dive, the symptoms had manifested once back onboard (pain on right shoulder joint) and were initially put down to hanging on to the shotline in current and choppy weather (?denial), but subsided once the "victim" was on 100% O2 at the surface.

The "victim" was driven to a chamber two hours away and there was an apparent increase in pain whilst crossing the relatively higher altitude (360m).

This latter point has always made me delay my return home after normal diving rather than drive straight home, generally we have lunch etc., and the drive back is usually two to there hours from surfacing, as well as diving with the richest Nitrox mix that I can use for my second dive without compromising myself and surfacing without hitting my NDL (usually EAN40).

That said, I would agree that IWR is an important tool for treatment of DCI assuming all of the criteria can be met to make it possible, but in reality perhaps it's not always practical.

Curious to know if everyone in your team dives the same settings on dc and if you set a little more conservative knowing you have to drive into the hills to get home?

I'm on the east coast, so I never even think about the altitude after a dive. Interesting.

 

[formernuke]

Interesting

 

[Searcaigh]

Curious to know if everyone in your team dives the same settings on dc and if you set a little more conservative knowing you have to drive into the hills to get home?

I've not heard of anyone getting a hit after driving over the hills after diving, but that doesn't mean it hasn't happened!

My current GF for rec diving is set at 40/85 and for my last tech dive in June 2022 was 45/75.

 

[100days-a-year]

Disclaimer. Do NOT construe this as advice.
I have seen IWR resolve issues from pain to partial paralysis when I was working on long range commercial spearfishing boats. We were always 6 hours to a day away from shore.
The dives were minimal if any deco but up to 40 dives a week in depths 80' to 180' will accumulate a lot of residual nitrogen in slow tissues.
We used a dedicated AL80 of 02 without an FFM but I would have preferred one.
A weighted tagline off the stern was set and the diver would hang or be held until the symtoms resolved and then a slow ascent was made. By treating within minutes of symptoms arising it appears to have taken far less time to "fix" the bent diver than most of the IWR protocols I've seen.
Maybe a half hour total time maximum was the most I ever saw including the guy who was partially paralyzed.
Most of these guys are dinosaurs with 5 to 10k dives or more and routinely did things that made me cringe but some did it until their 70s.

 

[rob.mwpropane]

Maybe a half hour total time maximum was the most I ever saw including the guy who was partially paralyzed.

1/2 hr from surface until IWR was administered or 1/2 hr total time spent IWR after symptoms occurred? Was the guy that was pertially paralyzed ok? Full recovery?

Really interesting. I know what the books say, but there are real world situations that don't fit.

 

[Vicko]

IWR or on board recompression chambers were also used in the Adriatic extensively by old school divers who were, ehm, fishing less than legally.
Everyone said the same thing, if you recompressed fast enough you would go back to work tomorrow like nothing happened.
The chambers were a thing to marvel. You would come up from the dive with no decompression done, just pop up slowly to the surface, then get your gear off as fast as possible and jump in the coffine sized chamber with a 12l tank of o2 and a 12l tank of air.
To pressurize the chamber you open the air tank, and there is a bleed valve to decompress, all the time breathing o2 from a regulator.

 

[100days-a-year]

Half

1/2 hr from surface until IWR was administered or 1/2 hr total time spent IWR after symptoms occurred? Was the guy that was pertially paralyzed ok? Full recovery?

Really interesting. I know what the books say, but there are real world situations that don't fit.

Half hour or less in the water resolved most cases completely.
This particular guy was back diving the next day. He'd been bent several times before.
They get in the water on 02 immediately if any symptoms occur or if any deco was missed because of annoying sealife.