Does 1 DCS hit increase probability of hit in future?

[ocpaul]

I took a DCS hit (knee joint pain) on a recent liveaboard. Utilized on-board O2 and pain was reduced - final diagnosis was DCS-1. I did a 2-1/2 hour Table 5 recompression. Pain did not immediately resolve, but did completely resolve about 6 hours after the treatment was completed.

My question: Does this DCS hit suggest an increased probability of DCS hits in future? I find liveaboard diving really fits my diving interests and am hopeful that I will not need to think seriously about scaling back my trips.

Thanks for your input.

 

[Dr Deco]

Hi ocpaul:

One case of DCS is a possible indication that you might be in the group of divers more prone to gas bubble formation and growth. If this is the case, then one DCS incident could indicate that smaller nitrogen gas loads would be advisable on future dives.

It is not necessary to reduce the number of dive trips, simple reduce the nitrogen loading. This means reduced bottom times, and increasing the surface interval. Also, it is good to wait a bit at surface (the hidden stop) before reboarding the boat [and safety stops in the water].

The other possibility is that you simply loaded nitrogen – and strained – too much on that one dive and had a consequential hit.

 

[ocpaul]

Dr. Deco,

Thanks for that information. This was my 6th liveaboard trip and according to my computers, it was actually the least aggressive nitrogen loading trip of all of them. However, on the day prior to observing symptoms, I did do 6 dives and on one of those dives was involved in a long hard swim trying to keep up with a large turtle. Maybe that was the specific combination that put me over the top.

Guess I will just scale back to no more than 5 dives a day and start to limit each dive to 60 minutes. Hopefully that will do the trick.

Thanks again.

 

[Damselfish]

and don't try to keep up with turtles - if it's not interested in hanging with you, you won't win

 

[DeepSeaExplorer]

I think most divers can return to diving. However, I know two divers that got bent and both can only dive to about 70ft, any deeper and headaches or other symptoms return. They both can do a lot of diving right up to 70ft, but it's wierd. Others divers can continue with no problems what so ever, even though they may have been bent more severly. It just depends.

 

[robertarak]

It is not necessary to reduce the number of dive trips, simple reduce the nitrogen loading. This means reduced bottom times, and increasing the surface interval. Also, it is good to wait a bit at surface (the hidden stop) before reboarding the boat [and safety stops in the water].

Forgive me for the hijack.
Dr. Deco, you mentioned "The Hidden Stop" on the surface. I have never seen any reference to this. Could you please explain?

Thank you

 

[battles2a5]

I think he is referring to the "quadruple whammy" that occurs when you end a dive. I think it is:
1- Going from rest to heavy exertion (from safety stop/deco to climbing the ladder, lugging gear)
2- Sudden drop in O2 in breathing gas (if utilizing rich deco gas/ nitrox)
3- Loss of hydrostatic pressure
4- Huge change in overall pressure from the safety stop to out of the water.

I think this is right, somebody correct me if I am wrong.

Most people finish their safety stop then climb right out of the water. I think what Dr. Deco is sugguesting is to take some time at the surface to readjust to 1 ATA before lugging your body and gear onto the boat.

 

[crpntr133]

Forgive me for the hijack.
Dr. Deco, you mentioned "The Hidden Stop" on the surface. I have never seen any reference to this. Could you please explain?

Thank you

If you didn't post it I was going to!
Always heard about taking your time on going from the safety to surface but nothing about boarding the boat. Makes sense though.

 

[ocpaul]

Fortunately I had no neurological symptoms - just the knee that felt like it had been severely sprained. I knew that I had not done anything mechanical to make it hurt, so I suspected DCS and reported the same to the Captain. He immediately suggested O2 therapy and called DAN. In retrospect that was absolutely the right thing to do. A good lesson to all to not ignore ANY symptoms of DCS.

 

[Dr Deco]

Hi:

The 'Hidden Stop' generally refers to holding at the surface for about five minutes, possibly finning a little, before starting to climb out of the water.