Why no N2 bubbles?

[fisherdvm]

So, in theory, Dr. Deco, if you don't have a decompression chamber, theoretically, you can treat the bends by taking the patient back down to 100 ft, and gradually bringing him back up. Assuming that no cell death has resulted from the nitrogen bubbles???

 

[H2Andy]

yeah.. in theory...

but in-water deco has other problems... boy, that's a hole new can of worms

 

[60feet]

So, in theory, Dr. Deco, if you don't have a decompression chamber, theoretically, you can treat the bends by taking the patient back down to 100 ft, and gradually bringing him back up. Assuming that no cell death has resulted from the nitrogen bubbles???

Wouldn't in-water recompression treatment also take hours just like a hyperbaric chamber on land? And wouldn't that require using helmet diving with long air/gas hose from a source at the surface? Unless a rebreather is used, but is that doable if the diver needing recompression therapy has not been rebreather trained? Either way, other divers would be required to be there to supervise, right? There would have to be "shifts" of divers to replace one another as each approaches deco limit or gas limit. Also, underwater is not as a controlled environment as a hyperbaric chamber for recompression treatment. Seems a lot of work, coordination, and more risks than using a hyperbaric chamber.

Edit: oopps, just noticed that your question was addressed to Dr. Deco. Sorry to both fisherdvm and Dr. Deco for jumping in like I did.

 

[Charlie99]

So, in theory, Dr. Deco, if you don't have a decompression chamber, theoretically, you can treat the bends by taking the patient back down to 100 ft, and gradually bringing him back up. Assuming that no cell death has resulted from the nitrogen bubbles???

Doing in water recompression on air takes lots of air and lots of time. Doing it on O2 at 30'/9m (yes, that's 1.9ata ppO2) has had pretty good success. A google search on Richard Pyle and IWR or maybe Australian IWR should bring up some info.

THe general concensus is that IWR is something that is appropriate for expeditions far, far away from hyperbaric treatment. In addition, it is something that should be planned, equipment (lot and lots of O2, full face mask, support divers, etc.) in place, and hopefully some drills or exercises run. Hypothermia is another potential problem as even using O2 the diver will be spending another hour or two in the water.

Ad hoc, unplanned IWR, particularly when a diver with symptoms goes back down alone has a pretty bad record for both fatalities and possibility of worsening the DCS.

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In water recompression is NOT the same as a symptomless diver returning to depth to complete omitted decompression within 5 minutes of blowing the deco stop. That is generally a pretty good idea if the situation is under control -- the diver has adequate gas, is symptomless, isn't panicked, and hopefully has a buddy/safety diver.

 

[Dr Deco]

Hello fisherdvm:

Yes, theoretically you could treat the bends by in water recompression (IWR). Most often, this is not really a practical alternative to calling for help and returning to shore. :shakehead Others mentioned this.

When in the water, the injured diver needs a tender, and this makes at least two people who are now at risk for DCS. Additionally, you would need several tenders.

If you are recompressing on nitrogen, you need a lot of it and a slow ascent to the surface. If breathing oxygen, the injured diver must be monitored for toxicity problems.

Last, the diver in the water for a long time will begin to develop hypothermia – even in warm water.

Dr Deco :doctor:

 

[ReefHugger]

Apologies for this late thank you for your comprehensive response. Internet went AWOL.

Much appreciated.