DCI in Thailand

[Taipeidiver]

Taipei,

Did you do anything strenuos during or after the last dive? My question is based on things Dr. Deco said at a presentation here in the Houston area.

Regards,

I hear you, I did nothing more or less strenuous than usual before or after the dive. There was a moderate current running during the dive but nothing I haven't dealt with before.

A possible explanation is dehydration, although I am always careful to stay hydrated I had suffered a little with an upset stomach in the morning. I took a couple of immodium and had drunk a fair bit of water but might still have been a bit dry. Who knows, I guess that its possible that the immodium might have been a contributing factor.

So many variables...

 

[clgsamson]

I did indeed meet Rowan, they dragged the poor guy out of his bed when I was admitted at 3am. He's a good guy and really looked after me during my stay.

As for Phuket, I am STILL not giving up on the place! I will probably be back in March or April for some sailing, and will probably have another go at diving Richelieu Rock sometime this year. I am nothing if not determined! Or is that stubborn?

you are..born to dive.

 

[MoonWrasse]

When you look back at that data..

4 dives all deeper than 24m. Last dive of the day deeper than the 2 previous dives to 28m, on which you reached to within 1 minute of the deco limit.

99.5% of the time, not a problem.

2 more questions.

Did you spend a lot of time in the sun on the liveaboard?

Did you drink lots of water?

In Thailand, and I am sure, other tropical environments, dehydration is a major factor in the cases of DCS, even if people are not aware of it. Then, a borderline dive profile can be enough. I used to advise people (when I was a tour leader on a liveaboard in Thailand) to drink a glass of water before and after every dive. Another tour leader I worked with advised people to basically drink a cup of water every time they walked past the water dispenser.

At least you say you were not drinking alcohol. In Phuket, you can well imagine, plenty of divers will have a few the night before diving, then factor in the heat, dry air from the tank, coffee for breakfast, coke for lunch...

Anyhow, in this case, no harm done, lucky to be in a place where you have very good hyperbaric services. Hope you'll come back and do a whole trip!

A glass of water???
I try to drink a liter between dives, and my fridge back at my hotel is mostly stocked with liters of water.
Also coffee will dehydrate you.

It took me a few visits over the years to finally realize how much the climate there will dehydrate you, diving or not.

 

[Taipeidiver]

When you look back at that data..

4 dives all deeper than 24m. Last dive of the day deeper than the 2 previous dives to 28m, on which you reached to within 1 minute of the deco limit.

99.5% of the time, not a problem.

2 more questions.

Did you spend a lot of time in the sun on the liveaboard?

Did you drink lots of water?

In Thailand, and I am sure, other tropical environments, dehydration is a major factor in the cases of DCS, even if people are not aware of it. Then, a borderline dive profile can be enough. I used to advise people (when I was a tour leader on a liveaboard in Thailand) to drink a glass of water before and after every dive. Another tour leader I worked with advised people to basically drink a cup of water every time they walked past the water dispenser.

At least you say you were not drinking alcohol. In Phuket, you can well imagine, plenty of divers will have a few the night before diving, then factor in the heat, dry air from the tank, coffee for breakfast, coke for lunch...

Anyhow, in this case, no harm done, lucky to be in a place where you have very good hyperbaric services. Hope you'll come back and do a whole trip!

As you say, 99.5% of the time - no problem - in fact that is by no means even close to what some people might do on a liveaboard. That said, it is very likely that my dive planning is about to get a whole lot more conservative!

I mentioned above that I could have been dehydrated... I do all of my diving in the tropics and am almost religious about water intake, but had suffered from an upset stomach that moring and popped a couple of immodium. I had drunk plenty of water afterwards but it is quite possible that I was still dehydrated. Oh, and I avoid the sun as much as possible.

I'll be back in town before too long... Especially now that direct flights from Taipei have started again. Between diving and sailing I normally manage two or three visits a year. I love that crazy town!

 

[Batfish]

A glass of water???

The idea was really to get people to think about drinking water. Back home in the cooler weather you don't think about it. If you don't remind people they may sit for 3 hours between dives reading a book and drink nothing. I would remind everyone daily.

 

[Rick Inman]

Glad you're alright, and welcome to the club! When I left the hospital, they even gave me a Hyperbaric Chamber tee-shirt.

Ya know, when they first re-compressed me - within about a minute of hitting 2 ATA - I felt immediately better. Did you notice an improvement as quickly as I did?

Also, I was in the same kind of chamber as you were. Did they let you watch movies?

 

[MoonWrasse]

I hear you, I did nothing more or less strenuous than usual before or after the dive. There was a moderate current running during the dive but nothing I haven't dealt with before.

A possible explanation is dehydration, although I am always careful to stay hydrated I had suffered a little with an upset stomach in the morning. I took a couple of immodium and had drunk a fair bit of water but might still have been a bit dry. Who knows, I guess that its possible that the immodium might have been a contributing factor.

So many variables...

Well, if you had diarrhea, that can cause dehydration and the immodium might make it worse.

I see you've been to Palau - how does diving there compare to Thailand? It's on my wish list of places to go

 

[bradshsi]

All dives were on air, using a single 15L steel tank.

Dive 1 - 0733hrs, 28.0 metres, 61 minutes (multi-level dive), following a surface interval of 12 hours, 13 minutes. 3 minute safety stop at 5 metres.

Dive 2 - 1031hrs, 27.4 metres, 54 minutes (multi-level dive), following a surface interval of 1 hour, 56 minutes. 3 minute safety stop at 5 metres.

Dive 3 - 1331hrs, 24.3 metres, 41 minutes (multi-level dive), following a surface interval of 2 hours, 5 minutes. 3 minute safety stop at 5 metres.

Dive 4 - 1704hrs, 28.0 metres, 49 minutes (multi-level dive), following a surface interval of 2 hours, 52 minutes. 3 minute safety stop at 5 metres.

Thanks for the info. On review, those are not the sort of profiles that I would attempt. Since I use tables, putting those kind of numbers into them would result in dive 1 exceeding my NDL's before even considering the other dives (20 minutes would be the max bottom time from the RDP for dive 1).

Of course the tables assume a square profile and you clearly noted you did multi level. If you have an average depth for your multi level profile it might be possible to judge how conservative it was (relative to the tables).



I don't mean to criticize your diving style since I am a relative beginner to scuba, but I will make these observations from my limited experience. Please feel free to correct any errors in my observations:

1) You say you came within 1 minute of a deco obligation. To me this sounds like you were "riding" the computer NDL curve as you ascended during your multilevel dive. That in itself may not cause DCS, it's just that your safety margin is a lot less than I personally would be comfortable with.

2) Your 4th dive was deeper (and longer) than the previous dive. This is not recommended practice.

3) If I were doing dives to that depth (around 90ft), I would have added a 3-5 minute deep stop at half maximum depth, say 45 ft. (You may have done this in your multi level, but it wasn't mentioned.) According to DAN this type of stop is very effective in reducing bubbles in the body when the diver reaches the surface.


In summary, I'd just point out that as you and others have said, DCS is contingent on many factors, some outwith our control. However diving a more conservative profile will ceteris paribus, reduce your chance of getting a hit. You may want to consider that on future dives.

Thanks again for sharing the details of your incident. I appreciate the chance to learn from it.

 

[Taipeidiver]

Hey Rick, I had no idea you had also been bent. Oh well, obviously happens to the best of us...

I felt much better even just breathing 100% O2 on the boat, though deteriorated as soon as I removed the mask. Once recompressed I felt as though I had fully recovered, even the skin rash went. Some, though not all, symptoms returned after the first treatment - the skin rash stayed until the third treatment!

I watched so many movies! The chamber operator was a big league of gentlemen fan, which was all right for the first three hours...

 

[Taipeidiver]

Hi bradshsi,

My average depths for the four dives were:

D1 - 14.6 metres
D2 - 15.8 metres
D3 - 16.4 metres
D4 - 14.0 metres

My dive profiles were obviously not the most conservative, though by no means unusual. Obviously if I had dived a more conservative profile then, all things being equal, my risk of DCI/DCS would have been less, but you'll be forgiven for stating the obvious

Deep stops can help with your deco profile and reduce the risk of bubble formation but this is best carried out at high PO2 values (nitrox - say a switch to EAN50 at 21 metres and then 100% O2 at 6 metres), carrying out a deep stop on air may just result in further gas absorption if the PN2 in your breathing gas is higher than the PN2 in your tissues.

You can plan deep stops using proprietary software, such as decoplanner, but I would not recommend trying to work them out on the fly. If you stay within the recommended NDL then, theoretically (and only theoretically - remember that this is a very inexact science), no stops are required only recommended - you should be able to ascend directly to the surface. However, the benefit of safety stops has been shown to the point where only the mad or desperate would omit them where they can be carried out.