What to do if you ascend too quickly?

[Bubbletrubble]

The diver should be put on Oxygen immediately for 3X the missed decompression or 20 minutes whichever is longer. They also need to be monitored for signs of DCS.

@NetDoc: OK. I have to ask. How did you arrive at your "3X the missed decompression or 20 minutes whichever is longer" rule? I would think that as long as the oxygen is being delivered at 1 atm (and not endangering the patient by approaching oxygen toxicity limits) it would be best to continue with oxygen treatment for as long as supplies will allow.

 

[The Chairman]

NAUI NitrOx manuals. You can give oxygen for as l-o-n-g as your want. The minimum is 3X the missed decompression or 20 minutes, whichever is longer.

 

[lowviz]

Considering the OP:

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?

This is a new diver with a bit of experience asking a good question. A lot of possibilities were discussed.

That's precisely what I didn't say. The diver should be put on Oxygen immediately for 3X the missed decompression or 20 minutes whichever is longer. They also need to be monitored for signs of DCS. ...................

Apologies, I should have explicitly said "breathe oxygen and wait to see what happens".

So how to best answer the OP? (via Seaduced's question)

In this forum, I can only say: To hell with the drama, if extended O2 treatment is required (rapid ascent through a deco ceiling), seek medical assistance afterward. I'm not challenging your expertise, just cautioning the OP that anyone coming at you with oxygen isn't necessarily the last word in medical advice or diagnosis. Do all DCS symptoms present within 20 min?

I'm out. I respect you experience and previous posts too much to keep butting heads over this.

 

[Seaduced]

Negative. You do not need to seek medical attention if you are asymptomatic.

Okay, seek medical attention if symptoms present themselves, and the O2 should be used?

A man I respect very much, was a boilerman on the Oriskany, back in the Korean War era. I would love to dive the boilers and get a picture of me next to them, but that training path may take too long. So, I have settled on an interim goal of diving the props in a year to get that picture.

I'm starting to go down the tech path and there are a lot of classes in my future, but these threads really help me know, there is a lot I don't know (sorry for the butchered cliche). There are a ton of concepts and references presented, that glue my nose to the books (and I wouldn't even know which books to look for). It isn't a substitute for formal training, but it sure helps me ask the right questions.

Thanks for the posts!

 

[DCBC]

Scenario #1: Uncontrolled ascent from greater than 20 fsw with no deco obligation and asymptomatic
Course of action: observe for one hour
-------------------
Scenario #2: Uncontrolled ascent from greater than 20 fsw with missed deco obligation at depth shallower than 20 fsw and asymptomatic
Course of action (a): with less than 1 minute surface interval: return to depth of stop and increase stop time by 1 minute.

Yes, so it's a matter of interpretation. Did the diver consider the safety stop as a missed decompression obligation?

Some may say that a ND dive does not require a safety stop, as it has no decompression obligation. Others may say that every dive is a decompression dive because you have a maximum ascent rate and a safety stop that's required on all dives within the NDL.

It's worthwhile to note that as long as the diver was asymptomatic, he could have just left the water. If he had a higher amount of N2 absorption and required decompression, the USN Manual instructs that he descend and follow the profile adding the stated penalty. In other words, the diver who has a higher gas absorption would be deemed safe to descend to complete the profile. Surely by descending the diver, in this case, would be better off than sitting on the surface.

I can appreciate the concerns you've made. The OP did not provide inclusive information on the dive. I did however assume that the diver was experienced (evidenced by the 90' depth) and that this was his first dive of the day (90' NDD).

During my tenure at DCIEM and in the commercial field, I have considerable experience with decompression and saturation diving. All I can say is that as far as DCS is concerned, the body tolerates much more that one would initially suspect. That's why I personally wouldn't be concerned of DCS on a PBA from 90' on a no decompression dive). My concern would have more to do with AGE than DCS, but this wasn't the case. I'm not saying that DCS is an impossibility, nor should the possibility be treated lightly, but IMO it would be highly unlikely. I believe what the USN Manual has to say about the protocol is sound.

 

[The Chairman]

Apologies,

None needed. I just wanted to clarify my plan of action as just that and not a plan of inaction or complacency. Nothing in the world says we have to dive in precisely the same manner and that's why there are so many agencies around. The treatment I gave is straight out of the NAUI NitrOx manual... at least the old one. I didn't make it up and I believe it to be efficacious in dealing with this scenario.

I would like to add, that once I am out of the water, I would not go back in. Exits can be strenuous and doing them twice does not seem like a good idea. However, if I am still in the water, had enough gas and the conditions were fine, I would signal "OK" to the boat, gently descend and do my stops. In fact, I do this whenever I do a boat recon while on my safety stop. Gradually ascend, take a quick peek to get a bearing, give the "OK" and descend back down. I would pop a surface marker if I didn't have the flag as well.