DCS? Advice please

[Bulit7]

I am starting this thread to gain more info regarding fast ascent and DCS after an incident this past Friday 02-08-08. I don't know if I got bent or not. I think I might have, though very slightly. Maybe the more experienced guys here can help me try to understand.

As background, I'm a 44 year old male, very fit, 6'01", 190 lbs. Been diving all my life, mostly freediving. Since I got to Florida in 2000, I have been doing more and more tank diving in order to catch fish on the deeper wrecks. My typical dives used to be three 80cf tanks, but lately I have been dropping 120cf topped off to 3000psi for 155cf. Lots of air and good down time, or bad depending how you look at it. Lately I have been doing deeper and repetitive dive profiles more so than ever before. I hydrate well before and after. No drugs or alcohol ever.

This Friday my profile is as follows: Started my day on a wreck at 120 ft. Max depth was 110 feet for 20 minutes with ean32. Slow ascent and stops at 70 for a minute, 50 for a minute, 35 for a minute and a SS at 20 for 3 minutes as per computer. Total dive time aprox 30 minutes. Not exactly sure. Maybe I need to start taking notes or downloading my profile into the laptop. I don't have the cables but can get them.

Next my friend dropped into 170 while I did my SI for about 1.5 hrs.

Second dive was shallow, max depth of 85-90 on this wreck area that allways holds fish. As I reach the bottom and start scanning the surroundings, I feel my friend approach my flag with the boat and tug on it. :eek: I was like WTF? Emergency of some sort? I start my slow ascent and reach 50 feet and hang there a little. A couple of minutes pass and I decide to drop back down. If it is that important, he can call me again. A few minutes later he does the same thing. Tugs my float line. At this point I'm pissed off. This better be fu#$ing important. HE is litterally pulling me off the bottom! I figure we have a MAJOR emergency on board and start my ascent at max ascent rate watching my computer. Depth guage flashed twice and I stopped to let it cool off. It stopped blinking the fast ascent warning both times. Blew my safety stop by a couple of minutes, in other words, I stopped for 1 to 1.5 minutes only. Never was I close to DECO.

As I reached the surface I asked him what was the problem. He told me that he confused the instructions for the drop and that I should swim in such and such direction. At this point I was pissed. I told him to NEVER pull me off the bottom unless the boat was sinking or his ass was on fire. WTF? I was right on the fokin wreck and he pulled me up for no reason. I would expect better from such an experienced diver. Who gives a shit! Missed the drop, hunt the reef. I had been down 9 minutes.

OK, after the exchange, I redropped since current was very light and completed my dive untill 800psi. Aproximately 30-35 minutes. No DECO was ever close to being reached. Ascended slowly and performed my safety stops as allways. I allways try to do a staged ascent, stopping for periods as I ascend.

Now here is the catch: As soon as I got to the surface when my dive was interrupted by him calling me, I felt a dull pain in the lower neck/upper back. I have some compressed disks, from all the boating and waverunner action over the years, so sometimes it aches. I just thought that the pain started coincidently as I breached the surface.

The pain stayed with me thru Saturday. Felt like I had slept on my neck in a bad position. I decided to wait it out. No other symptoms were present and today, Sunday, it has subsided quite a bit, and is almost gone. No numbness, dizzyness, headaches, etc. Just the stiff neck pain.

What do you guys think?

[desertdream]

Did you call Dan

[SpearMax]

Lee, sounds like maybe a slight Type I DSC hit that centered on an area already injured in the past. A good "acid test" mould have been whether high Oxygen relieved the pain. That is a pretty good indicator of DCS in my non-medical opinion. Had you called DAN, they probably would have advised you to head straight to the hospital for assessment there. Did you take Ibprophren or anything for pain relief? You might not have had a DSC incident at all and could have just strained an old injury. But, when concerned, it is always wise to call DAN for their expert assessment.

Bends preventative hydration is super important in my opinion. I constantly drink water before and after the diving. I also bring with me lots of water-rich fruit to consume off shore like apples, watermellon, pineapple, grapes, blueberries, and strawberries. I have no scientific evidence, but I feel that such fruit consumption helps raise my hydration level even higher than just the pure water.

If you read DAN diving accident reports in their Alert Diver magazine, you will see some DCS incidents from fairly reasonable profiles like yours. Thus, it appears you could get it just about anytime with slight variations as you mentioned. Sometimes there is just little ryhm or reason for the hit. Luckily, there are thousands and thousands of dives in the scuba world every day that do not yield DCS.

[Florabama]

It's always hard to determine if you're hit or if it's just aches and pains. I'm 52 and just about always have pain after a boat ride in rough seas or after hauling aboard heavy steel tanks. As I understand it, pain can be the only symptom, but it is often accompanied with numbness, disorientation as well as skin rashes and swelling. While any one symptom could indicate a hit, any combination of two would be a clear indicator.

I would dito both the call to DAN and the O2 therapy if you have the slightest suspicion that you've had a hit. On my hit back in Oct., my symptoms were relieved within about 15 minutes on O2. I had both numbness and pain in my leg and hip. Although it's frowned upon these days, in-water recompression also works for mild hits.

[Bulit7]

Thanks for the advice guys. Yes we do have O2 on board and Tony, your fruit and water therapy is what we do as well, to the T! Lots and lots of water.

I have after and during ascents felt my joints a little, like there is a slight amount of sand in them. I am sure that this is due to very small bubbles forming and enstering the bloodstream. I am allways very tuned in to how I feel and I can sometimes feel these things.

I have read some of the DCS stories on here of guys that did it right and got hit and it can be a debilitating thing that lasts for months apparently. Scarry shit when you have a family that depends on you.:( This has made me think and opt to change my dive profiles to be even more conservative in nature.

I think that at this point it would be too late to call DAN. The symptoms are almost gone and I feel great.

By the way Tony, I did take Tylenol at 300 pm yesterday and it did not help immediately, but after resting all day, that evening (Saturday) I was feeling a little better.

Thanks again guys!!

[Bulit7]

I found this text on a tek dive site refferenced in another thread after searching on DCS and air embolisms:

Why we Don't bounce dive after diving in the WKPP By George Irvine


Guys read this for once. WHY WE DO NOT BOUNCE DIVE AFTER DIVING IN THE WKPP It is ok to offgas from the tissues into the blood stream in bubble form in the later steps of decompression as it is a more efficient, faster way of getting rid of the remaining gas ( by reduced pressure ) than by elevated oxygen alone ( which starts taking exponentially more time with greater risk) . However, this depends on having a good lung filter and no shunts. All of you have been PFO tested if you are diving with us. The correct way to ascend from the last stop is one foot per minute for the bigger dives.

The greatest potential for offgassing in bubble form is when the pressure is totally removed back to one ATA out of the water. Now you get a real shower of bubbles , relative to what was happening in the water. A good , clean deco with the foot per minute ascent reduces this dramatically . In MOST people, the greatest bubbling occurs out of the water and continues for up to four hours, not even peaking for a couple of hours. In a well vascularized, fit person like me, it is over with in 30 minutes. Don't bet on that with most of you. In ALL people, the bubbles continue to grow in size after the pressure is off. They accumulate like gas into themselves from the surrounding blood or tissues ( if there are bubbles in the tissues or injury sites ) and they grow bigger. This is why you feel pain later rather than earlier if the bubbles are in joints or tissues - they get bigger before they begin to shrink. This is why what starts out as micro bubbles can get by the lungs and grow and get lodged downstream, and you get neurological symptoms later.
Now here is the important part. If you understand everything I have said above, then you know that bouncing to 20 feet or whatever to pick up a bottle and immediately returning to the surface is the like giving yourself a home-made PFO: the bubbles in the venous side compress enough to get past the lungs and then will reexpand on the arterial side and lodge in the worst places , the spine and brain blood supplies. You do not want this. If you dive after dive, stay down and let everything reset. Get the bubbles all compressed, and then deco out and ascend accordingly. I do not want support divers diving support within four hours of doing a real dive or deep support. This works out fine, since we have support activities lasting up to 18 to 24 hours and need to rotate everyone. Let me assure you that we have found this out the hard way in the past. Parker used to get hot as hell when it would happen. In those days we had "volunteers", and they would all get bent diving to 20 feet to pick up bottles. We have also seen some severe cases of this where dives were done away from the project with no support, and the players went back for bottles later and got hammered. Don't do it. Also, obviously, do not freedive after a dive. When you want to freedive, do that first and then go scuba diving. Any questions from WKPP guys?

[Bulit7]

Obviously these guys are talking about very deep drops and staged deco but the insight into the process that occurs within ones bloodstream that can be paralleled to shallower dives and not be emphsized enough. I knew that I could feel the bubbles in my joints on normal, controlled ascents and this exerpt of text verifies that.

Bear in mind that I do not have the experience or training that some of you guys have so if this is redundant or boring to some of you, please feel free to ignore this thread. On the other hand, if you feel you have something that you can contribute to some of us that are less experienced, please do so.

I have spent the whole weekend searching and reading incident reports and threads here in an effort to never have to deal with a DCS hit in any way, shape or form.

By the way, I am feeling 100% recupped by now and the lower neck pain is gone. I do feel that I ascended a bit fast and am convinced that caused the pain.

Tomorrow I will try to get a pc link to dcownload and review my profile and really look at the numbers for more insight into my AR.

Lee

[SpearMax]

By the way, I am feeling 100% recupped by now and the lower neck pain is gone. I do feel that I ascended a bit fast and am convinced that caused the pain.

Tomorrow I will try to get a pc link to dcownload and review my profile and really look at the numbers for more insight into my AR.

Lee

Glad the pain is over Lee. Good idea to download the data and check actual ascent rate and stop times. Tony

[Mobile Diver]

Glad you are OK. You will never know if it was mild DCS or not, but if it was a few minutes of O2 at 12-15fsw & then some on the surface might well have stopped it cold.

[Bulit7]

Glad you are OK. You will never know if it was mild DCS or not, but if it was a few minutes of O2 at 12-15fsw & then some on the surface might well have stopped it cold.


Yeah, I know. Hindsight is 20-20!

I am an advanced diver with a lot of water time in all kinds of conditions but allways kept my dives down to 60-80 feet. The last year, I met a friend that is a tech diver and I have been learning a lot from him and diving deeper and deeper. Still learning.

[jadairiii]

My .02 cents, sounds like you just wrenched your back a bit, based on your history. Very odd to get a Type 1 hit in the lower back muscles. The more normal “hit” for that area is called (slang) “slobbitist” were you get bruising and a “fat” look around the mid section. If it had been a true spinal hit, Type II, you would have none right away, as in not being able to walk, talk, breath, control you body functions. But that second profile is a high risk one.

John

[UaVaj]

Why we Don't bounce dive .... By George Irvine


IMHO - All it takes is one breathe at depth and the in-proper asend to get bend. Too many divers don't truly understand the two parts of asending properly. This is the time where you are most relaxed but where you should be breathing the most. Part 1 is asending slowly - slower than your smallest bubble. Part 2 is breathing alot while asending - you need to breathe alot so you can properly gas off. Part 2 is where most are not doing enough.



I've done my fair share of bounce dive in 40'-80' because of not landing right on top of the ledge or wreck.

Because of the way I asend - depending on the depth - a wasteful bounce dive can easily burn up 1000psi on a full hp120cf.

Even if I only spend 2 minuite at the bottom. Each and every time I do take my own sweet time asending and never asending faster than my smallest bubble. Plus a safety stop. While asending I do alot of deep breathe and breathe very frequently to help in gassing off.

Most of my profile are day trip with triple dive on hp120cf in various depth and I have never had a problem.

Either I have been lucky so far or my method is working. Disclaimer: Use this method at your own risk.

[Bulit7]

IMHO - All it takes is one breathe at depth and the in-proper asend to get bend. Too many divers don't truly understand the two parts of asending properly. This is the time where you are most relaxed but where you should be breathing the most. Part 1 is asending slowly - slower than your smallest bubble. Part 2 is breathing alot while asending - you need to breathe alot so you can properly gas off. Part 2 is where most are not doing enough.



I've done my fair share of bounce dive in 40'-80' because of not landing right on top of the ledge or wreck.

Because of the way I asend - depending on the depth - a wasteful bounce dive can easily burn up 1000psi on a full hp120cf.

Even if I only spend 2 minuite at the bottom. Each and every time I do take my own sweet time asending and never asending faster than my smallest bubble. Plus a safety stop. While asending I do alot of deep breathe and breathe very frequently to help in gassing off.

Most of my profile are day trip with triple dive on hp120cf in various depth and I have never had a problem.

Either I have been lucky so far or my method is working. Disclaimer: Use this method at your own risk.

Good post.

[jfjf]

I think a super slow ascent, heavy breathing and a safety stop might be a little over kill for 60 seconds of bottom time at 50-60 feet (and using 30 cu-ft of gas to ascend), but I'm sure you don't get bent from it.

On the other hand, I have started to do some light exercise during the deco/safety stops. A few years ago, my friend got a forearm hit in one arm. We were pretty convinced it was due to the fact that he drapes his heavy spearguns over his elbow on the stops, (arms through bands) . He tended to keep his elbow bent and his arm still and this appears to have reduced blood flow past the elbow.

Usually on a safety stop, my heart rate is still a little elevated from swimming and excitement and I feel that blood flow is good. But if I am doing any deco, by the time I finish a short "deep stop" my respiration and heart rate are way down. It is at this point that I try to swim gently a little and also move all the big joints, knees, hips, SHOULDERS and elbows and I also try to switch hands so the forearms are not locked up with a death grip on the gun etc. I might alternate between doing one minute of very light exercise and then 2 minutes of just resting. I will not usually try to conserve air on a deco stop in an attempt to promote gas exchange.

[Bulit7]

Good point Jim. I can tell you all this: I learned a lot from this incident.

My ascents will be taken way more seriously and with a LOT more planning in all future dives.


PS: Does anyone have a data link for a Oceanic computer I could borrow? I'm in Palm Beach.

[HeadHunter]

Hard to say at this time if you suffered a hit, but the profile of that second dive is one that could easily lead to a dcs problem.

My advice on these "yo-yo/up-down" type dives is never to do them unless you simply have no other option. I have seen quite a few hits over the years that could all be attributed to a redescent immediately following a normal completed dive.

Also, the fact that you were Po'ed is probably an additional factor. You get mad/irritated and your BP and HR increase. You aren't thinking/performing as well as you should be. Anger clouds everyones thinking. Ascent rates and safety stops are more likely to be compromised. IMO, anger brings on the same type of increased loading that hard effort does. Working dives always stress reduced bottom times and increased safety stops and deco.

If you ever find yourself in an unavoidable bounce/yo-yo type situation, heres what I'd do.

Calm down, stay focused on the big picture. Don't get angry, control your BP and HR. Treat the "bounce" like a very dangerous dive, not an inconvience. Double or triple your normal safety stops and deco. This is a must. Take an extended SI, give your body time to straighten itself out.

If you're normally diving the type of profile of your first dive, I'd def start wearing a pony with a 50%-60% mix in it to help with blow offs. The differences in your overall nitrogen situation would be vastly improved. Of course, high O2 blowoffs require advanced training. If you don't have the training, get it before you do it.

Please don't take anything I said as criticism, it's not meant that way at all. I've seen way too many problems arise from an up-down dive and hopefully this might help someone else avoid those same problems.

If I can be of any further help, PM me.

Dan

[Bulit7]

Hard to say at this time if you suffered a hit, but the profile of that second dive is one that could easily lead to a dcs problem.

My advice on these "yo-yo/up-down" type dives is never to do them unless you simply have no other option. I have seen quite a few hits over the years that could all be attributed to a redescent immediately following a normal completed dive.

Also, the fact that you were Po'ed is probably an additional factor. You get mad/irritated and your BP and HR increase. You aren't thinking/performing as well as you should be. Anger clouds everyones thinking. Ascent rates and safety stops are more likely to be compromised. IMO, anger brings on the same type of increased loading that hard effort does. Working dives always stress reduced bottom times and increased safety stops and deco.

If you ever find yourself in an unavoidable bounce/yo-yo type situation, heres what I'd do.

Calm down, stay focused on the big picture. Don't get angry, control your BP and HR. Treat the "bounce" like a very dangerous dive, not an inconvience. Double or triple your normal safety stops and deco. This is a must. Take an extended SI, give your body time to straighten itself out.

If you're normally diving the type of profile of your first dive, I'd def start wearing a pony with a 50%-60% mix in it to help with blow offs. The differences in your overall nitrogen situation would be vastly improved. Of course, high O2 blowoffs require advanced training. If you don't have the training, get it before you do it.

Please don't take anything I said as criticism, it's not meant that way at all. I've seen way too many problems arise from an up-down dive and hopefully this might help someone else avoid those same problems.

If I can be of any further help, PM me.

Dan

Dan. thanks for taking the time to write this up. I really appreciate it.

Just for the record, I was pissed off but not enough to really stress over it. More than anything I was mad that I had hit my intended target and was pulled off to tell me that initial instructions for the drop were incorrect.

Bounce diving is something I had done before and never realized that it could be dangerous. Is there a safe way to do two dives back to back with a minimal SI?

Also, if anyone knows the bio-mechanics involved in a very short SI redive, please explain.

Thanks again!!

[HeadHunter]

The general rule on my boat in water depths up to 130 or so, is 45-60 minutes between dives. In deeper waters with planned/staged deco than it's much more. Of course, an unusually long or short previous dive would influence these guidelines.

I know of at least half dozen instances that I've personally witnessed that made me a believer in not doing a yo-yo dive. I watched a diver on my big boat come up and get attacked by a shark at the surface. He PH'd the shark but the ph and spear stuck in it's head and the shark started swimming slowly back down. Not wanting to lose a shaft and ph, the diver pursued the shark back down (100'), retrived his equipment and followed his computers guidelines to return to the surface. Within 10 minutes his right shoulder was as big as a basketball. Despite his computer telling him he was good to go, he wasn't. Yo-yo dives are dangerous. And like I said, I've seen the same thing too many times to not believe it.

I call them yo yo dives instead of bounce dives because so many different divers have different ideas of what a bounce dive is. To a techie whos used to doing 40 minutes on a wreck in 250 and hours of deco, than a 5 minute spearing dive on the same wreck with 10 minutes of deco might seem like a bounce dive. And so on.

I def am not saying that just because you do a yo yo style dive that you'll get hit, but you're really increasing your odds. Kinda like playing Russian Roulette with 2 bullets instead of one. My partner won't even consider a yo yo style dive. And you're talking about a guy that will dive just about anything under any circumstances, and yet he won't even think about that style dive.

Anyway, glad you're OK! Like I said before If I can ever be of help, just Pm me.

Safe Diving, Dan

[Bulit7]

Thanks Dan!:thumps:

[jfjf]

.....If you're normally diving the type of profile of your first dive, I'd def start wearing a pony with a 50%-60% mix in it to help with blow offs. The differences in your overall nitrogen situation would be vastly improved. Of course, high O2 blowoffs require advanced training. If you don't have the training, get it before you do it....

Dan

So are you recommending that this solo diver use a single pony with a rich mix?

What about redundancy? Should he not worry about it?

Should he have two pony bottles (actually a stage and a pony/bail out bottle)?

Should he assume he can make do with 50-60% comming up from the bottom in an emergency and thus a single bottle provides deco and some degree of redundancy?

[Mobile Diver]

Great couple of posts Dan!!:thumps:

[HeadHunter]

So are you recommending that this solo diver use a single pony with a rich mix?

What about redundancy? Should he not worry about it?

Should he have two pony bottles (actually a stage and a pony/bail out bottle)?

Should he assume he can make do with 50-60% comming up from the bottom in an emergency and thus a single bottle provides deco and some degree of redundancy?

Jim....

#1 For the situation he described above, it'd be light years ahead of where he was. And of course, as long as he has the training it requires. It would also require a two gas computer to track his O2 saturation, but a diver trained for this would know that and should be already equiped with one.

#2 Adding a pony where nothing was being worn before except a main is a heckuva more redundant than just a main, don't you think? One single pony tank can't be everything..it's either a great BOB and a crappy deco tank, or it's a great deco tank and a fair BOB. It'd be up to the individual diver who only wants to wear a single pony to decide whats best for the style diving they do and whats best based on their own training and abilities.

#3 He easily could, a single pony on the side with 50-60 in it and a BOB tank with the reg bungied around his neck with the same mix as his bottom gas would work. It's almost impossible to confuse a side slung higher O2 reg with a BOB reg thats bungied around your neck. It all comes down to the individual diver. Are you trained for this type of gear? How much stuff do you routinely want to wear? Like I've said before, if it's a pita to wear, fill and screw with, most people won't. And by the way, theres no disputing the superiority of a 80% deco mix compared to a 50-60% mix. But thats for planned staged deco requirements. If you're only wearing a single pony and want to use it for a little blow off and possibly a BOB in a bad situation, then 50-60% is where you want to be. If you have to use it as a BOB, it sure is nicer to be able to start breathing at 60 feet than at 20, big difference. I am NOT suggesting putting higher O2 mixes in a BOB tank...A diver using a tank ONLY for a BOB, and never for higher O2 blow offs should NEVER have a higher O2 % in it than his main...EVER.

#4 Depends on the divers skill level, in some instances, yes, in other cases, no, def no. It all depends on that Divers skill and training.

Thanks for the questions, I liked your advice about light exercising on deco stops.

Dan

[Bulit7]

Good points Jim and thanks Dan for clarifying. I understood what you said Dan, though one can never be clear and repetitive enough at the risk of someone misinterpreting what was said with bad consequences.

[jfjf]

.... One single pony tank can't be everything..it's either a great BOB and a crappy deco tank, or it's a great deco tank and a fair BOB. It'd be up to the individual diver who only wants to wear a single pony to decide whats best for the style diving they do and whats best based on their own training and abilities....

Thanks for the response.

I think that your characterization of the utility of a single pony bottle is excellent.

The more difficult question is to evaluate what is "best" for the individual.

I always dive with air in my pony. I am more worried about the danger of drowning or taking an oxygen hit (both of which are fatal) rather than gaining the benefit of an accelerated (or safer) deco. But I have to admit that the bottle with a rich mix could provide the diver a significant benefit on every dive, while the pony with air in it might provide a "real" benefit only once in a thousand dives.

I am comfortable with my decision primarily because I do not accrue significant deco on a typical dive (when I have only a primary tank and a single pony/BOB bottle).

I might have to give the 50-60% single bottle some more consideration, I am pretty confident that I could get from 130 to 60 feet pretty fast and with little or nothing to breath.

I think that this is an important issue for everyone to consider.

[Shark Tales]

I have enjoyed this dialog very much and have been reminded of things I learned while taking much of my tech training. As we know, unless someone is willing carry 3 bottles on every dive we have to choose which is the best set up for our individual comfort level and training. Here is what I have chosen for most of my diving over the last few years. First let me say that most of my dive days consists of 3 to 4 deep dives. By deep I mean 100 to 180 feet. I only do the 180 a few times a month but routinely dive 150 every dive day and then usually do a 130 and then finish the day with a 100 to 110. I have chosen to use a 13cf offgas bottle of 95% 02. I use a multi-gas computer and switch over to 02 on my hang on almost every dive. I also carry in my BC a H2Odyssey 6cf tank. I know it is not much air but I have tested it on two occasions at 130 ft doing a slow assent of 1 ft per sec and made it to 30ft on one test and 20 on the other. I understand that those were tests and I was not under any stress and breathing hard. I also manually inflated my BC for the ascent. My thinking is that if I have an emergency at depth I will use my 6cf to get as close to 20 ft as possible and then switch to 02. If you had to switch to 95% at 40 feet...how much risk is there? I am always looking to tweak what I am doing to be the safest I can be while still enjoying being streamline underwater for hunting. Sometime that balance is difficult. I would appreciate any input.

[Bulit7]

I have enjoyed this dialog very much and have been reminded of things I learned while taking much of my tech training. As we know, unless someone is willing carry 3 bottles on every dive we have to choose which is the best set up for our individual comfort level and training. Here is what I have chosen for most of my diving over the last few years. First let me say that most of my dive days consists of 3 to 4 deep dives. By deep I mean 100 to 180 feet. I only do the 180 a few times a month but routinely dive 150 every dive day and then usually do a 130 and then finish the day with a 100 to 110. I have chosen to use a 13cf offgas bottle of 95% 02. I use a multi-gas computer and switch over to 02 on my hang on almost every dive. I also carry in my BC a H2Odyssey 6cf tank. I know it is not much air but I have tested it on two occasions at 130 ft doing a slow assent of 1 ft per sec and made it to 30ft on one test and 20 on the other. I understand that those were tests and I was not under any stress and breathing hard. I also manually inflated my BC for the ascent. My thinking is that if I have an emergency at depth I will use my 6cf to get as close to 20 ft as possible and then switch to 02. If you had to switch to 95% at 40 feet...how much risk is there? I am always looking to tweak what I am doing to be the safest I can be while still enjoying being streamline underwater for hunting. Sometime that balance is difficult. I would appreciate any input.

According to the O2 partial pressure formula, 95% at 40 feet, would give you a PPO of 2.10. That is pretty high. Probably not worth the risk unless it is an emergency and even then, for a breath or two, just to get you to 20 feet.

Consider that the maximum exposure limit reccomended is 1.4 and the contingency limit is 1.6. From what I understand, some people can tollererate it more than others.

One of my friends sucked down the wrong gas once and almost passed out. It started with auditory halucinations in the form of a chatter in the back of his head, then tunnel vision. No bluuring of the mind. He was able to punch his inflator and ascend and it cleared up. Lucky...

Maybe we should start a thread for those who have had DCS or air embolism to relate their stories so we all could learn from it. That would make for insightfull reading.

[Bulit7]

Thanks for the response.

I think that your characterization of the utility of a single pony bottle is excellent.

The more difficult question is to evaluate what is "best" for the individual.

I always dive with air in my pony. I am more worried about the danger of drowning or taking an oxygen hit (both of which are fatal) rather than gaining the benefit of an accelerated (or safer) deco. But I have to admit that the bottle with a rich mix could provide the diver a significant benefit on every dive, while the pony with air in it might provide a "real" benefit only once in a thousand dives.

I am comfortable with my decision primarily because I do not accrue significant deco on a typical dive (when I have only a primary tank and a single pony/BOB bottle).

I might have to give the 50-60% single bottle some more consideration, I am pretty confident that I could get from 130 to 60 feet pretty fast and with little or nothing to breath.

I think that this is an important issue for everyone to consider.


My only concer with the single bottle train of though would be in the case of not being able to leave the bottom and get to a "safe" depth for a richer gas mixture fast enough. Let's say an entanglement or the shooting of a large fish. Now you are out of air and your only option is to suck down a mixture that will most likely knock you out.

My prefference is to dive with a 30cf bottle of the same mix as my primary.

One way we could use a scrubbing mix would be to ascend to 20 feet and send up a marker float adjascent to the float line. At that time, the guy on the boat could pull up, tie your float line of to a cleat and lower a 80cf bottle with a scrubbing mix. What do you guys think of that methode? It would save one from having to carry a third bottle around...

The reason I say 80cf,is because one tank could be used for multiple dives.

[jfjf]

My only concer with the single bottle train of though would be in the case of not being able to leave the bottom and get to a "safe" depth for a richer gas mixture fast enough. Let's say an entanglement or the shooting of a large fish. Now you are out of air and your only option is to suck down a mixture that will most likely knock you out.

My prefference is to dive with a 30cf bottle of the same mix as my primary.

One way we could use a scrubbing mix would be to ascend to 20 feet and send up a marker float adjascent to the float line. At that time, the guy on the boat could pull up, tie your float line of to a cleat and lower a 80cf bottle with a scrubbing mix. What do you guys think of that methode? It would save one from having to carry a third bottle around...

The reason I say 80cf,is because one tank could be used for multiple dives.


I do something similar to what you describe above, but it has a huge liability in that the diver could potentially be put in a position of NEEDING the boat to find them to deliver the necessary deco gas.

Most people will be much more comfortable taking the gas they need to get to the surface with them rather than reliance upon a boat and it's operators (and the weather) to complete a safe dive. Plus it falls apart if two people are diving and they get separated; who will the boat support?

Dropping a deco bottle seems like a viable plan B (emergency back-up plan) rather than a SOP.

[SpearMax]

One of my friends sucked down the wrong gas once and almost passed out. It started with auditory halucinations in the form of a chatter in the back of his head, then tunnel vision. No bluuring of the mind. He was able to punch his inflator and ascend and it cleared up. Lucky...

Good comments on this thread everyone!

I do alot of deep tech spearfishing and take two 19 cube ponies back mounted with special in-line shutoff valves. One is an emergency bail-out bottle with straight air which did save me once on a 200+ foot failure of two regs. The other bottle is 80% oxygen used for cutting deco time by over 50% at the 30 foot and shallower levels. There are lots of configuration possibilities out there and it is great we can all learn from each other through these posts. I have modified many things I do over the years based on the excellent feedback from this board's members. On deep trimix dives, I have two side-mounted aluminum 80 deco bottles.

Lee, concerning your buddy's situation..............it brings to mind that acromyn from my tech courses. the signs and symptoms of oxygen toxicity:

CONVENTID

Con= Convulsion (maybe too late unless your buddy saves you)

V= Visual impairment (tunnel vision)
E= Ears (auditory disturbances)
N= Nausea
T= Twitching
I= Irritability
D= Dizziness

Here is a link to some good reading on the Ox-Tox subject:

http://dir-diver.com/en/knowledge/nitrox_2.html

[Bulit7]

I do something similar to what you describe above, but it has a huge liability in that the diver could potentially be put in a position of NEEDING the boat to find them to deliver the necessary deco gas.

Most people will be much more comfortable taking the gas they need to get to the surface with them rather than reliance upon a boat and it's operators (and the weather) to complete a safe dive. Plus it falls apart if two people are diving and they get separated; who will the boat support?

Dropping a deco bottle seems like a viable plan B (emergency back-up plan) rather than a SOP.


Under my plan, the diver would have enough mix to complete his deco in case something happened to the surface support team on his regular mix. Just would be a way of cutting down deco and filling less tanks and carrying less tanks. Not a dependency, but an option.

[100days-a-year]

bulit,find a free download of GAP somewhere and set up the parameters of several dives similar to your normal day and then the day you felt you may have been hit.
The graphical representation of gas load in the GAP program can help to point out potential dangers in our methodology.

[Bulit7]

bulit,find a free download of GAP somewhere and set up the parameters of several dives similar to your normal day and then the day you felt you may have been hit.
The graphical representation of gas load in the GAP program can help to point out potential dangers in our methodology.


Sounds interesting. What is GAP? Where can one find it?

Thanks!

[Shark Tales]

http://www.gap-software.com

[EmbolizedDiver]

You didn't have DCS! type one is dull pain in the arms legs shoulders. say you where wearing a T-shirt, area that isn't covered by the t-shirt would be type 1 DCS. type 2 is the head heart lungs or the area covered by the T-shirt. In my opinion you had mediastinal emphysema, maybe subcutaneous emphysema if it was lower neck/back. 100% o2 on surface for an hour and you should be fine. no diving for 3-4 weeks!! you are lucky! blowing your deco can have serious effects along with a fast ascent. you are lucky you didnt a.g.e. yourself. even if the boat is on fire, if you a.g.e. yourself you wont be able to help, as a.g.e can result in paralysis, convulsion, death. So the deco is extremely important.

[EmbolizedDiver]

Bounce diving is something I had done before and never realized that it could be dangerous. Is there a safe way to do two dives back to back with a minimal SI?

Also, if anyone knows the bio-mechanics involved in a very short SI redive, please explain.

Thanks again!!

There is no bio-mechanics involved in a very short SI. You surface interval is there so your body can off gas the RN (residual nitrogen) still in your body. minimizing your SI is not a good idea unless you enjoy increased odds of omitting decompression and therefore giving you a head start to getting bent. my advice is follow the repetitive dive table. (you can pick one up from PADI or local dive shop) and do not follow your computer as we all know technology can and will fail. use your computer as a back up to a planned dive and you will never have this problem. if you plan to dive like this a lot, get familiar with RNT and repet diving, alittle knowledge can carry you a far way, but if you dont have the formal training for 02 at depth then it is not wise as you are going into a whole new world of diving where the consequences outweigh the benefits. CNS 02 toxicity, convulsions just to scratch the surface. Sorry but there is no way of getting around the surface interval.


Who said light exercise at a deco stop? . hydrate at a deco stop if you are going to do anything. juice boxes work.. the ones with the straw you poke in the stop. what is the reasoning behind light exercise at a deco stop, I would seriously like to know!! workload at depth is a contributing factor to getting bent. you want to stay relaxed and warm at deco stops not light exercise. I dont mean to be an ass but that is not a wise thing to do especially after a long dive at a depth beyond recreational limit.

[Benthos]

A lot of good comments in this thread. Sounds like you recovered
from a mild hit. These are more common than you think.

As I have aged I realize I am not as resilient as I use to be
when I was younger. About five years ago I decided to enter
into deep technical diving. I am now a firm believer in rich O2 mixes
for deco (with the caution of watching the O2 time and depth limits).
Now I use O2 deco even on relatively shallow dives (<60 ft).
I have a small pony that allows me to use O2 for the safety
stop for a non-deco dive. Carrying the pony also keeps the
technical skills sharp. For safety stops or short decos you do not
have to worry about a mixed gas computer just use the computer as
you would for air or nitrox and you get an extra safety margin by using
O2 at your safety stop. Even on the surface a lot of tech divers will
breath O2 for a while in the boat, which is actually your last deco stop.

If you do not want to carry O2 just hang it on your down line at 15 or 20 ft.

Safe diving,

[juno]

Breathing O2 on the boat is a definite yes if you have any concerns at all about your dive or ascent.

Everyone has given some great info on hydration, SI's, and stuff. Good thread.

To me, I treat a bounce dive as a deco dive whether I go into deco or not. it helps me maintain discipline during the dives.

On any deco dive in a cave (which are about 95% of my cave dives) I spend at least 20 minutes (usually longer) just hanging out when I get near shore, doing nothing stressful. On dives with an hour or more of deco, I take much longer. I take my sweet time getting out and taking off the gear.

Boats are harder. The work involved just getting back on the boat is a contributor to a dcs hit. If you are not in a situation where you can hang out for at least 5- 10 minutes on the surface before getting on the boat, it is a risk.

Even when not in deco, your ascent from your 10-15 foot safety stop should take several minutes, 5 feet a minute is about as fast as you want to go. Take longer if you can.

Anything you can do to reduce the amount of work you do when the dive is finished will help. I would definitely try to avoid getting on the boat wearing any gear except for your wet suit. Everything else should be handed on board or hung on a line.
If you are working at all during your ascent or stops, you need to extend the times, or cut the ascent rate in half.
Your ascent rate should never exceed 30 feet a minute. I keep it to 20 fpm max above 100 feet, 10 fpm about 30, and 5 fpm above 20. Those are about as fast as I go, slower if the situation allows.

Oxygen is king, if you can carry a bottle of 100% or 95% to use at 20 and above it will make a big difference in how you feel. But, it takes discipline to use it, O2 will kill you faster then anything if misused.
I would recommend taking a deco course from a respected instructor.
Or make a habit of breathing pure O2 for 5 minutes on the boat after a dive.

Deep stops will help also. I do not remember your profile, but one old rule of thumb is stopping at half your max depth for half your time at depth, plus some stops between there and your safety stop will help you tremendously. Say you spend 10 minutes actually at 130 feet. You should try to stop for 5 minutes at 60 -70 if you can. At least stop for a few minutes.

Another thing you must remember on any dive, you should feel as good or better after your dive as you did before. If not, your doing something in your profile, routine, gas choice, whatever, that may contribute to a DCS hit eventually.

Edit: I forgot to add that slowing your ascents and increasing the duration and number of ascents will require you to leave the bottom with enough gas to account for the extra time in the water. Sounds self-explanatory, but some folks don't get it and you never know who might read this thread.

[Bulit7]

Thanks ED and Juno for your comments. Yes this is a great thread and I learned a LOT from it and the situation I got myself in. Nothing serious but could have been worse.

Dive safe everyone!

Lee

[Bottom Dweller]

To me, I treat a bounce dive as a deco dive whether I go into deco or not. it helps me maintain discipline during the dives.

Boats are harder. The work involved just getting back on the boat is a contributor to a dcs hit. If you are not in a situation where you can hang out for at least 5- 10 minutes on the surface before getting on the boat, it is a risk.

Even when not in deco, your ascent from your 10-15 foot safety stop should take several minutes, 5 feet a minute is about as fast as you want to go. Take longer if you can.

Your ascent rate should never exceed 30 feet a minute. I keep it to 20 fpm max above 100 feet, 10 fpm about 30, and 5 fpm above 20. Those are about as fast as I go, slower if the situation allows.

Say you spend 10 minutes actually at 130 feet. You should try to stop for 5 minutes at 60 -70 if you can. At least stop for a few minutes.



Good god juno, how would we ever have time to get 8-10 drops in to 110-135ft in a day?:D We also have to gut fish, ice fish, change/whip tanks, and get to another spot. Most drops are only 15 minutes start to finish and they would double if we did your ascent. I do agree with the no greater than 30ft ascent and some form of a deep stop, just not as conservative as yours. 5ft a minute is going backwards.

[juno]

Good god juno, how would we ever have time to get 8-10 drops in to 110-135ft in a day?:D We also have to gut fish, ice fish, change/whip tanks, and get to another spot. Most drops are only 15 minutes start to finish and they would double if we did your ascent. I do agree with the no greater than 30ft ascent and some form of a deep stop, just not as conservative as yours. 5ft a minute is going backwards.


Yeah, that's a perfect world. Not in harmony with heavy duty spearfishing or shitty circumstances!! Stuff happens out there. :D
Folks have to be aware of the contributors to a hit, at least. You just have to do the things you can and hope ones luck holds out!

[bmoore]

I am glad you feeling better. Can I ask you a question though? Do you actually attach a line to yourself and have a float you are dragging around on the surface? I have never heard of this in 26 years of diving. I might be wrong but it kinda sounds like a bad idea. For obvious reasons listed not to mention entanglement ect. I guess if this is the case you have to do a cost benefit analyis. What are some benefits? Surface communication?

[Bulit7]

No, My surface float is attatched to my gun and the gun has a reel on it.

[cary]

I don't have alot to add here but if the pain went away is was not the bends. A true bends incident would not have resolved itself. There is still alot we don't understand about compression injuries but the fact remains we feel alot of aches and pains after excercise as we get older. No matter how in shape we feel.
Yours could have been a compression injury, "niggles" (look it up), but not DCS.
I have been treated three times for DCS in thirty years of dive employment. I was only diagnosed once with true DCS.
Back in 1988 I did a 100' dive over the NAVY table limits and rushed to the first decomprssion stop. I did three stops totalling 13 minutes. I had tingling in two finger tips within twenty minutes after surfacing and a 'locked ' knee within 6 hours. Being young and dumb I waited 2 days before getting treatment. No money, no insurance was the reason for waiting till the pain was too excruciating. Treatment was six and a half hours.
The moral of the story is if you have any doubts about pains after diving, see an expert.
Don't post your question to a bunch of 'know it alls'. The only true method of determining the DCS is to recompress the injury. The Oxygen trick is a myth. Oxygen treatment will cause all kinds of aches and pains to go away, including a hangover.
It is by no means an acid test, nor will it cure DCS.
I'm not trying to stir the pot, just adding my two cents like everyone else.

Slow ascents, safety stops, lots of fluids, don't dive when your fatigued.

[Scotty]

I don't have alot to add here but if the pain went away is was not the bends. A true bends incident would not have resolved itself. There is still alot we don't understand about compression injuries but the fact remains we feel alot of aches and pains after excercise as we get older. No matter how in shape we feel.
Yours could have been a compression injury, "niggles" (look it up), but not DCS.
I have been treated three times for DCS in thirty years of dive employment. I was only diagnosed once with true DCS.
Back in 1988 I did a 100' dive over the NAVY table limits and rushed to the first decomprssion stop. I did three stops totalling 13 minutes. I had tingling in two finger tips within twenty minutes after surfacing and a 'locked ' knee within 6 hours. Being young and dumb I waited 2 days before getting treatment. No money, no insurance was the reason for waiting till the pain was too excruciating. Treatment was six and a half hours.
The moral of the story is if you have any doubts about pains after diving, see an expert.
Don't post your question to a bunch of 'know it alls'. The only true method of determining the DCS is to recompress the injury. The Oxygen trick is a myth. Oxygen treatment will cause all kinds of aches and pains to go away, including a hangover.
It is by no means an acid test, nor will it cure DCS.
I'm not trying to stir the pot, just adding my two cents like everyone else.

Slow ascents, safety stops, lots of fluids, don't dive when your fatigued.


A neurological examination(you will know in the first 10 minutes if it is a.g.e. or DCS or something else) is used to determine a diving related injury, along with dive profile and so on and so on, also a doppler, tear film sample and a few others. a.g.e. and dcs are the only diving related injuries that re compression is used to treat. mediastinal emphysema, pneumothorax, other p.o.i.s.'s 100% o2 on surface for an hour or two is used. but you're right find someone who know's what they are talking about. better to be safe then sorry.

[Louis Rossignol]

Alot of times it's all in your head, when in dought, 2 Excedrins and a Beer.

I came up from a 250ft. dive, 8th dive of the day and I told Stan keep an eye on me, I'm pretty damn sure I'm bent. I was dizzy and feeling alot of tingling. I took 2 Excedrins and slamed a beer, then I had to go to the bathroom, #2, It shot out of my ass and almost blew the back of the toilet out. When I got up, I was fine, dizzyness went away and tingling went away.

I'm 44 too and I feel aches and pains all the time, whenever I know I had just done something stupid and my self conscience is making me feel all kinds of pain, I take 2 Excedrins and drink a beer. It deffinately relaxes me and I may do some in water decompression if I was really stupid, but to this day, I've never been clinically bent.

On that in water decompression thing, I make it a point to go to 60' for a minute and then come up the pipe real slow with a stops at 30, 20 and 10.

I know this advise is far fetched, but it works for me, this is what I have been doing for many years. It may not work for you.

[dr.ed]

Alot of times it's all in your head, when in dought, 2 Excedrins and a Beer.
I know this advise is far fetched, but it works for me, this is what I have been doing for many years. It may not work for you.


What brand of beer?:lol:

[Louis Rossignol]

What brand of beer?:lol:

Dude, I'm being truthfull............

[dr.ed]

Dude, I'm being truthfull............

IT was an Honest Question. What brand of beer?

All beers are not created equal!:D

Stay SAFE!!! 250ft is Scary deep for me.

[Louis Rossignol]

Lately I drink Guenness, but any brand will do.

[dr.ed]

Lately I drink Guenness,

Good/Great choice!:thumps: One of a few beers one can chew.:D

[goldfinchs1]

I take minor hits all the time now after taking a major hit years ago. They usually occur in the same place (shoulder) and begin aching at 15 feet up to surface and stay with me for a couple days until it slowly subsides. The pain is slight and has some numbness with it. It is easy to recognize as you can descend again and feel the pain subside. Once at the surface and the pain starts, or the pain has already started during the last part of your safety stop/deco stop, take a minute to come back down to safety stop/deco stop depth and see if the pain stops. I now dive with a 50% or higher deco bottle on every dive which seems to help with the scrubbing, even if the dive is shallow, (100'). Point is, minor DCS is recognizable if you simply descend to 20 feet. The pain should subside, and at that point it becomes obvious its not just a pulled muscle. At that point, its up to you whether you self-medicate with high 02 at safety stop depth or you go to chamber.
Hope my misfortune can help someone.

[ezequiel]

instead of sending a signal, and wait for the cap to send a tank with a mix,
why not just prepaare and leave this speacial deco tank at 20ft with a regulator ?
we do this all the time on recreational diving , on deep dives, so NO one has to avoid a deco stop for not having air.

[divethewetrocke]

There had been a lot of good suggestions on this thread and as a DMT(Paramedic) I am glad to see that in general the majority of you out there are well informed and have done you research and have sought out proper training as far as anything else goes you can't dispute the theraputic effect of O2 @ depth the 50/50 mix is the one that is most used although you could start using a lower % of 02 deeper 50% @ 20' is about the craziest I would go in the chamber we would use 100% @ 60' as Hyperdick ( dick Rutouski) would say Oxygen Oxygen Oxgen and that nothing clears the bubbles out faster than 100% at 60' I reiterate this is in the chamber @ the start of this thread someone metioned calling DAN when you are in doubt that is your 1st move and the smartest thing I have heard as for the rest it all gets into more training you can never have enough knowledge when you are dealing with deeper dives and as far a yo yo diving it is unwise to think that you can cheat the odds they will catch up with you there have been many "undeserved hits" so basically keep it safe guys and hopefully I will never see any of you in my chamber anytime soon

[Bulit7]

instead of sending a signal, and wait for the cap to send a tank with a mix,
why not just prepaare and leave this speacial deco tank at 20ft with a regulator ?
we do this all the time on recreational diving , on deep dives, so NO one has to avoid a deco stop for not having air.

Ezequiel, problem with that is that we usually dive in current and it is not feasable to have a tank waiting at 20. If you are anchored on a wreck that would be the best approach.

[TheBrazilNut]

It's been more then 7 months since you posted this thread. Have you figured out if you have been bent yet?

[Bulit7]

It's been more then 7 months since you posted this thread. Have you figured out if you have been bent yet?


Nope and I guess I never will. My belief is that it was a small hit.:confused:

[TheBrazilNut]

Nope and I guess I never will. My belief is that it was a small hit.:confused:


Well, when you F-up on deco from a 200' dive the problem will be a little greater then "a small hit".

[Bulit7]

Well, when you F-up on deco from a 200' dive the problem will be a little greater then "a small hit".

No shit? Man you are a wealth of knowledge. Stick around some people here might learn something from you after all!:thumps:

[Scotty]

you guys are so silly. you get DCS mixed up with all the the other diving related injuries. they are different..... small hit? never heard of it. type 1 DCS yeah, type 2 you better be finding the closest chamber. you guys do crack me up though. I've done some stupid shit before, but at least I know what I am doing and how to fix myself. And if I can't fix myself my friends over at NEDU so know how to. dive safe guys and if it doesn't hurt when you go down then you aren't going deep enough. just kidding.