What to do if you ascend too quickly?

I'm a new diver - 1 year, 51 dives. I just read another post titled uncontrolled ascent in which the diver overinflated the bc at 90', couldn't dump air, and shot to the surface. Once surfaced, the diver dumped the air in the bc and went back down to 90' to meet buddies and then ascend under control and with safety stops.

I would have thought this a very big deal, and the diver should have gone straight to the boat or shore for 100% oxygen/medical attention. The last thing i would have thought the diver should do is go back down. But, I didn't hear this from many of the responses on the thread. Some even said the diver did the right thing by going back down.

Can you help me understand this? What should the diver have done? If you ascend too quickly, does diving back down and ascending properly helpful?

In most cases no. In Water Recompression is a controversial procedure and I don't know that any clear benefit has been established.

It's primarily used in extreme instances of blown off deco when medical equipment or chambers is not readily available.

I *think* that the general consensus from the medical community would be to get on O2 and monitor for signs of DCS. Seek additional help as appropriate.

More info:

DAN Divers Alert Network

The Rubicon Foundation: In-water Recompression

IWR.ed.1

http://www.anaspides.net/documents/...mpression. Undercurrent magazine artical.pdf

Trying to better understand the science of how our bodies absorb and release nitrogen - if a diver is at 80' and shoots up to 40', should the diver descend to 80' and ascend properly, or should the diver stay at 40' for an extended stop?

Or if a diver shoots to the surface from 40', is it better to go back down to 40' and come up properly, or is the damage done?

Beaufort:

Trying to better understand the science of how our bodies absorb and release nitrogen - if a diver is at 80' and shoots up to 40', should the diver descend to 80' and ascend properly, or should the diver stay at 40' for an extended stop?

Or if a diver shoots to the surface from 40', is it better to go back down to 40' and come up properly, or is the damage done?

Click to expand...

There is a lot of "what if" in decompression theory. IMO, I think that they would be better served to stay at 40' for several minutes, then make a slowwww controlled ascent to 15' and extend the safety stop by a few minutes as long as they have the gas to do so.

This article may shed some light on your question as well: Why We Do Not Bounce Dive After Diving in the WKPP | Global Underwater Explorers

In normal NDL recreational diving, it's unlikely this would be a problem, that's why they're called no decompression limits and why it's called theory. But there is always that one odd goat that gets bent...

* Counter point *

In light of the two questions you've asked, about IWR and rapid ascents I'd add this thought to it. If you had a rapid ascent to 40' and started to feel symptoms of DCS while you were still in the water, then *I* would attempt probably make an attempt at IWR, especially if I had enriched mix (nitrox) available to me.

If I felt symptoms at 40', surfacing might cause even more severe symptoms, so assuming I had the gas, and a buddy to keep an eye on me, I'd take my chances in the water rather than the surface.

If I've already surfaced and feel the symptoms, my plan of action would be to get medical treatment ASAP.

Thanks Cave Diver.

One factor that has not been considered in this scenario is the amount of nitrogen loading at the time of ascent. If at the beginning of the dive, there may not be significant nitrogen loading to be an issue, however, if towards the end of a dive getting close to NDL, then it may be more of an issue at this point.

I've been told that if you have no symptoms, and can get back down immediately, then do so, but avoid strenuous exercise. If you need to exert yourself... don't. DCS depends on nitrogen loading, speed of ascend, diver physiology, metabolism and quite often luck. If I can get back down and extend my safety stop for a minute or two, then that is better than swimming hard to get to a boat, because that will be more likely to cause issues. Don't ask me how I know.... All right then:

Plopped up at end of dive, fought hard to get back down (not enough weight), surfaced 5 minutes later. Headache and feeling tired - 1 hour on oxygen, back to normal.

About a year later: First dive with dry-suit, semi-controlled ascend in the third quarter of the dive. (got it slowed down to avoid broaching the surface with more than my head), immediately descended back to ~70ft, finished dive spending extra time in the shallows. No Problems.

Descending again with significant nitrogen loading is one of those dammed if you do, dammed if you don't situations. If I can limit my exposure (short time, little exertion), then I'll descend again
and give it extra time in the shallows.

My dive computer (Gekko) agrees with me here, and, if exceeding parameters (Ascend speed or ceiling), it gives me extra time on the shallow water stop and 3 minutes to get below the ceiling (followed by the extension of the stop). That's what the handbook says, anyway. I'm not going to try it experimentally.

Gerbs

One thing I didn't see mentioned - the trick is not to let the nitrogen come out of solution (ie form a bubble). Once a bubble forms, it is more difficult to force it back into solution, even by going down to depth. If you are truly that close to your NDL or ascend so quickly that bubbles form, you are likely to cause more damage by going back down because you are compressing the bubble to the point where it will be able to get into a smaller blood vessel (such as those in your brain) and not back into solution, only to have it expand again on ascent, totally blocking the vessel. It would be unlikely you have enough of the proper gasses to finish decompression underwater anyhow.