bent bad in Grand cayman

[divenut2001]

There are just so many possibile variables. I, too, would like to know what pushed Mike into the Hit=Zone, even though this may never be determined.

I'm 57 yo aggressive diver when I get a chance, but I try to take all the precautions I can:
Hydrate early and often - with sport drinks, not "empty" rev-oss water;
No free diving or excercise after.
Surface with both Oceanic computers in the Green. (I see this abused and misunderstood a lot - by divers who never read the manual. Surfacing in the Yellow, having never gone into Deco is not "fine" as it's often put!)

This certainly drives home the need for a plan with caca hits the fan. I shudder when I hear of divers without DAN insurance, and - once I called for Oxygen for a diver on a boat I was on in Coz, only to learn that the O2 bottle was empty. That diver had been DAN covered for 3 days after seeing a non-diving incident that was thought to be diving related at the ime, and we got him to the chamber quickly. He felt a lot better after I gave him a quart of sport drink, but wanted to be careful.

Anyway, how many times have we asked to confirm that the O2 bottle really works on a boat?

You make an excellent point Don. I have always "assumed" that the O2 bottle to be working. How would you tactfully go about having the captain or crew show you that it's working?

And ditto about reading the owner's manual. I too have seen my share of divers with their "brand new out of the box" computer browsing thru the manual for the first time on the way to the dive site. I even had one diver ask me what part of the manual she should read. I simply said "all of it". Note to MikeD: This is not to insinuate that you do not know how to use a computer.

A friend of mine took a hit on a recent trip we were on and they tested her for pfo and she was determined to be ok. I am hoping you have the same outcome Mike. Good luck, and thanks again for opening everyone's eyes that it can still happen to anyone

 

[MikeFerrara]

Thanks for the eye opener, Mike, and best wishes.

Perhaps this is not the place to ask but the question comes to mind: if the profile had been reversed, shallow dives first, might this not have happened?

I am by no means a techie, but it seems they shun the deep dive first standard so as not to recompress bubbles, allowing them to pass by tissues that would keep them from the brain, etc.

Didn't know what a pfo was either and grasping for knowledge. Need some better educated opinions here.


Don

The reverse profile workshop a couple years ago decided that for no-stop dives above 130 and a depth difference no more than 30 or 40 ft (I don't remember) that reverse profiles seemed to be ok.

If you do a search on the board you'll find some posts by Bruce W. (author of "Technical Diving in Depth" and developer of RGBM) On the subject. He clearily states that in his opinion reverse profiles on technical dives aren't the best idea.

There is a pretty thorough treatment of reverse profiles in his book "Technical Diving in Depth" as it relates to several different models, including bubble models like RGBM, as I recall.

George Irvine is the only person that I've ever heard seem to recommend reverse profiles for technical dives.

 

[MikeFerrara]

Reverse profiles...from the horeses mouth from this thread.

Folks,

Contary to what you might read/hear about RPs in general,
DATA suggests that RPs with decrements larger than 40 fsw are
not a good thing. Especially as you go deeper on both dives.
And SIs are within a few hrs. And profile times are in the
same ballpark. This came out of the Smithsonian RP Wkshp.

Deco RPs are a relative bad thing -- see my earlier posts and refs therein. On both rec and tec RPs within SIs of 1 - 3 hrs.

Bub mechanics contraindicates same as decrements and
depth both increase, and SIs are shorter than a few hours.
And profile times are the same scale

Shallow (no-deco) dives followed by much deeper extended
deco dives (RPs) within SIs of 3 hrs, and vice-versa, probably
fall into the forward and reverse yo-yo category, with the deep
deco dive the main concern and the shallower ones second order
so long as they are not too deep nor long. Maybe I can
quantify when I get back.

Bottom line overall is RPs, especially for deco regimes, are
not recommended. Data says same.

Odd ball cases (disproportionate bottom times) need some
further data and analysis.

Bruce Wienke
Program Manager Computational Physics
C & C Dive Team Ldr
__________________
BRW

Many dive magazines totally misrepresented the findings of the workshop and it was translated, in some publications, to say basically that it doesn't matter any more since we use computers rather than tables.

I haven't ever been able to figure out what GI is talking about half the time but in the above referenced thread I think a couple of people who know more than me took a stab at it.

In short in general and as a rule most technical divers don't go out of their way to do reverse profiles. If some do there doesn't seem to be any science to support the practice.

 

[RichLockyer]

Surprised no-one has asked what kind of computer you were using..............

With those profiles, it wouldn't have mattered. He would have been "clean" on table dives if using nitrox, and clean using multilevel planning on air.

Even with a Suunto computer, he would have been WAY clear. He did 1/2 hour with a max depth of 96ft... I do dives of 45-65 minutes with max depths approaching 110.

 

[RichLockyer]

Hell with that. I'm due for my yearly physical, and I'm gonna see what's involved in screening for PFO. Can't hurt.

No more than a prostate exam

Seriously, it is not pleasant, but it won't physically hurt you.
Make sure you have it done by a doctor who is familiar with technical diving and decompression. There are two or three different methods of testing, and the best seems to be the TEEG... Trans-Esophageal-EchoCardiogram.

It's similar to a sonogram, but they drop a probe down your throat, position it next to your heart, inject bubbles into your veinous system, and have you perform some mild work.
From everything I've read, the trans-thoracic type of test (non-invasive, through the chest wall) is not as good at picking up the defect, however, it MAY be enough. Put one way, if the TTEG picks up a defect, then you DEFINITELY have a problem. If it does not, then a TEEG might be in order.

I have not had either test done, but have recently found out that my mother suffers from an aortic aneurysm, which IS hereditary, but can be detected via a TTEG well before it grows to a dangerous level. I am planning on discussing it with my doc and getting a referral to a cardiologist. With the family history, I can probably have at least the TTEG covered by my HMO, and ask the doc to run the PFO test at the same time. If no defect is found there, then I'll continue diving as I always have. My feeling from day-1 was that I would not worry too much about PFO, but would have the TEEG run immediately after my first chamber ride.

 

[RichLockyer]

I have a Mares MC1-rgbm and I wonder if it's conservative compared to others.

RGBM models tend to be more conservative than others. The idea behind RGBM is to reduce the formation of bubbles in the first place, while older models allow them to form during ascent, then hold you shallow to allow them to disperse... sometimes referred to as "bend and treat".

Unfortunately, this gives people the impression that Suunto computers are overly conservative, but they really are not... it's just that they were the first computers released to use RGBM (and it has been modified slightly for more conservatism).

Put it this way... on my last dive trip, I did a dive to 108ft. Total dive time was 62 minutes. Average depth was 54 ft. On a table dive, the 54ft would be a 60ft dive... yet my total dive time was 62 minutes. This dive was NDL-limited, not air supply limited. My second dive, following a 2.5 hour SI, was to 94ft, average depth 52 (still a 60ft table dive) for 48 minutes. This dive was neither NDL nor air limited... it was called due to boredom, and the scooter batteries had just hit the yellow.

The remaining dives for that trip were shallow (<40ft) and were air-limited.

If I take the above two dives to a PADI table, using average depth for the table, I find that I blew NDL on the first dive. Dropping back to 50ft depth, the table has me surfacing as a "T". After 2.5 hours, the T drops to "B".
For the second dive, "B" would allow for only 44 minutes at 60ft. Again, to keep myself on the tables, I would be forced to back off on the depth and treat it as a 50ft dive.

 

[voop]

You make an excellent point Don. I have always "assumed" that the O2 bottle to be working. How would you tactfully go about having the captain or crew show you that it's working?

Divers, in general, are a pretty cool and direct bunch, and we all (should) know why O2 is important -- and why knowing the state of the O2 bottle is good for the piece of mind.

Think about it as nothing more rude than asking "where's the toilet?"

I therefore simply go smething like this: "Hey, mind if I check the O2 prior to heading off? - just for my own piece of mind" I always get a variation over "sure, it's over there, let me show you..." in return. If I brief a dive myself, I always end by "...and the O2 bottle is over there, let me know if you want to check it out so we can do it together".

A "no need to check that" or anything similarly rejecting has never happened. If it did happen, I would not dive, nor pay for the dive nor bring any busines back to that boat ever again.

 

[jimmyboy]

one question Mike, what did you do during your surface time between all dives and after dive 3?

 

[Mr. P]

Mike,

I feel like I know you. I'm at a cyber-cafe in the Grand Caymans, waiting for my 72 hours to pass before I can fly home tomorrow morning. I was in the hyperberic chamber last Friday night and the people told me that a recent diver (you) had been in for six treatments the week prior.

I was on the Aggressor last week - logging 23 dives over 6 days with only one of them over 90 feet. I did my safety stops, drank very little alcohol as we were there primarily to dive. I noticed discoloration on my stomach during the week that seemed to "come and go" as the week progressed. I continued to take a couple tylenol and go for a dive (my idea of a prescription). Before departing the boat Friday evening, the captain requested that since the discoloration continued to reappear, that I go to the local hospital and at least have it check out, which I did. It seems that I had a mild case of "Skin Bends" which I had never heard of. The doctor (different from yours) was very knowledgable and an avid diver himself. He told me that 23 dives in six days was way too many and that while it appeared my profiles and safety stops were well within recommendations, stuff happens to people who follow safe procedures. He highly recommended that I change over to Nitrox and in the future, never do more than two dives per day with every 4th day off. At least I can continue diving, but I'm going to have to be more cautious than ever. I can't dive for two months and then will visit a DAN doctor prior to attempting my next dive. After spending six hours in the chamber, I can't imagine doing six sessions like you did. I'm very happy for you that you are okay. That had to be extremely scarey for you. I'm glad you're fine now. Every day seems to be a learning experience for us, but that's what life is about, huh?

 

[Scubakevdm]

Hey, thanks Mike, and I'm sorry for you.
You know, whenever I read a post about someone taking a hit it seems that a good bit of the ensuing discussion is aimed at what was wrong about the profile, or the computer, or the hydration or the whatever. I guess probably people want to find something to blame the hit on so that they can be extra careful not to do it themselves. The sad and scary thing is that you can do everything right and take the hit, and even take a bad one like you did.
The hanging up of the fins scares me the most. In fact, it's not the possibility of permanent physical disability or death that motivates me to dive safely as much as the thought of having to hang up mine. I'm grateful to you for posting this, and again so sorry.