High PO2 Hits - Tell us your story

[Bulit7]

Just wanted to start this thread so we have some kind of a record and data for O2 hits suffered under the circumstances we dive in. Helpfull info would be:

Depth
Time on bottom
Mix
PO2
What happened

[Tyler Durden]

Just wanted to start this thread so we have some kind of a record and data for O2 hits suffered under the circumstances we dive in. Helpfull info would be:

Depth
Time on bottom
Mix
PO2
What happened

UMmmmm, nearly all people who suffer O2 hits at depth don't make it. Therefore, I suggest posting this using a ouija board.

[willembad]

Wait.... What???

I thought I logged on to the ouija board....

Damned crossed link :D

Willem

[Bulit7]

Well, it would be helpfull to have accounts of those dives by someone that was there.

Some people have made it.

If the diver died, it is regreatable, but I think the benefits outweigh the downside. We could keep it factual and unemotional and it would serve as a refference point for everyone as to what can happen and under what conditions.

Some people think that if you keep it at 1.4, all is well. Some guys take it up to 1.6.

I know of at least one guy on here that took a hit and passed away. I'm sure there are more, maybe even some that survived.


Here, I'll go first:

This is second hand so it might not be 100% accurate.
A buddy of mine by the name of David, dropped down and ended up taking a tank witha wrong mix. Not too sure about the details but the symptoms I remember clearly and are what is important here. This was also a dive with Jim Mimms. He got to a certain depth and started hearing a stutter sound that he thought was coming from his first stage. Thought it was strange and kept on diving and a few seconds later he developed tunnel vision but was fully aware of what was happening. He told me that he hit the inflator and as soon as he ascended a few feet, it was gone. That is all I have but the symptoms are key and his presence of mind to "eject" were what saved him and might save someone else here. He was lucky.

[Bulit7]

Here's another and I will try to get more info on it. Guy was diving the Hydro with a group of divers from Dixie Divers and took a hit. He drifted down and was caught by another diver and saved. I will try to get more info on this one and add latter. It was a deco class. This happened in that last few weeks.

[TheBrazilNut]

UMmmmm, nearly all people who suffer O2 hits at depth don't make it. Therefore, I suggest posting this using a ouija board.


Exactly! It just boggles the mind about your lack of knowledge Lee! Yet another post that you should have PM 'ed someone!

[Bulit7]

Exactly! It just boggles the mind about your lack of knowledge Lee! Yet another post that you should have PM 'ed someone!

Read before inserting foot in mouth.

[Chad Carney]

DAN publishes a report of fatailties and serious injuries every year going way back on scuba, and it just started a year ago freediving.

It's accurate and it's for the purpose of learning.

Chad


http://www.diversalertnetwork.org/medical/report/index.asp

[Mullins]

I did some reading on this a while back as I was concerned about the risk of Ox Tox while freediving - some of the symptoms I was getting sounded a lot like those you get with high pp02. We've since decided due to the short time at depth the symptoms (metallic taste, visual distortions, numb face, shaking) are more likely to be caused by the combination of ppN2 and ppCO2 but still haven't ruled it out completely.

It was a scary thought - you don't get a lot of warning (sometimes none, though red-tinged visual distortion was mentioned as a good indicator) and a siezure is very likely to be fatal whether you're on scuba or freediving. It's unpredictable and the US Navy found some would have a seizure after a couple of minutes at 1.8 while others can happily swim around for half an hour at 2.0 and above with no ill effects. Very nasty. If I was a scuba diver I'd want to stay the hell away from it.

[Hank49]

I did a dive to 210 feet (air), up to about 140, drifted down the reef, and back down to 165 into a little cavern. After the dive I asked what made that cavern all red inside. Everyone else said it's not red. That's the only time that every happened. I dont' remember feeling anything more than being narced but it was like looking through rose tinted sun glasses. We ascended at that point.

[Tyler Durden]

Look Lee, here is my observations from your posts in various threads over the past few days. I see a lot of piecemeal, different questions from you that, in whole, seem to attempt to encompass what should be proper training.

You obviously have a yearning to learn to dive deeper, which I can fully understand. My recommendation to you is: save money and get the best training and certification you deserve. Take your time, learn from the best, and when you fully understand the principles involved, then get onto the internet and debate the details and ambiguities. If you demand to dive in this fashion, then you owe it to yourself and your family to get the proper training.

What I do not recommend is getting in the middle of a technical diving debate, and asking questions with the intent to immediately apply to your near-term diving. You should get proper training first, first, foremost, and above all. Nothing wrong with asking questions, but it helps to have the proper training first.

Several people have been lucky enough to know something wasn't right before an O2 hit began to manifest itself, but the numbers of survivors are INCREDIBLY SMALL. Among the reports, symptoms most often included the "wah-wah" sound and tunnel vision. O2 hits are known to happen swiftly and nearly always fatally, especially among spearfisherman who cannot dive the buddy system the way it was intended. Not sure if you are nitrox certified, but if you were, you will understand. Lastly, the comment about hitting the inflator button could have led to other serious problems, as uncontrolled ascents usually do. Everyone is responsible for their own lives while diving, not people on the internet. You'll learn a few things in nitrox class that will help prevent you from ever getting an O2 hit.

[Bulit7]

Look Lee, here is my observations from your posts in various threads over the past few days. I see a lot of piecemeal, different questions from you that, in whole, seem to attempt to encompass what should be proper training.

You obviously have a yearning to learn to dive deeper, which I can fully understand. My recommendation to you is: save money and get the best training and certification you deserve. Take your time, learn from the best, and when you fully understand the principles involved, then get onto the internet and debate the details and ambiguities. If you demand to dive in this fashion, then you owe it to yourself and your family to get the proper training.

What I do not recommend is getting in the middle of a technical diving debate, and asking questions with the intent to immediately apply to your near-term diving. You should get proper training first, first, foremost, and above all. Nothing wrong with asking questions, but it helps to have the proper training first.

Several people have been lucky enough to know something wasn't right before an O2 hit began to manifest itself, but the numbers of survivors are INCREDIBLY SMALL. Among the reports, symptoms most often included the "wah-wah" sound and tunnel vision. O2 hits are known to happen swiftly and nearly always fatally, especially among spearfisherman who cannot dive the buddy system the way it was intended. Not sure if you are nitrox certified, but if you were, you will understand. Lastly, the comment about hitting the inflator button could have led to other serious problems, as uncontrolled ascents usually do. Everyone is responsible for their own lives while diving, not people on the internet. You'll learn a few things in nitrox class that will help prevent you from ever getting an O2 hit.


Tyler, thanks for your thoughtfull post. Yes I'm Nitrox certified.
I am just attempting to bring into discussion the subjects that interest me. I am in no way trying to self teach myself how to deep dive thru these forums. If I wanted to self teach, I would go out and buy the course materials and read and apply them to diving. I know a lot about the general theory of deep diving but do not have trimix math and mix advantages down(nor do I care to learn trimix due to cost/rewards ratio being out of whack for the SE Florida Area). I do have an interest in learning more about O2 hits, DCS, air diving deep, Nitrox mixes for deep diving(Ex:EAN28), etc...

I will make this clear to anyone on here: I will not do deco dives or dives that I am not qualified for untill I get training. Period.

I am just preparing the groundwork for the task at hand(deco proceedures course) by trying to learn as much about it so that when I take the course, I canmake the most of it.

I relly appreciate you phrasing your post the way you did and not trying to talk down to me. :beer:

If you all don't mind, I will continue to take part in these discussions. I think they benefit us all.

Lee

PS. Can anyone recomend a good instructor in Palm Beach/Broward that is spear friendly and spear knowledgeable for my deco proceedures course. Thx!

[headhunter561]

It sounds to me like he just wants to hear of some real world examples. Its an interesting topic, I'd like to hear them too.

[jadairiii]

Wreck dive years ago on air/EAN with an extremely convoluted gear set-up (made Tony look DIR, I was still learning :D), max depth was 200’, I am swimming into the current at 165’ on EAN 28, lips begin to tingle, agitation sets in, I hit the line and head for the surface, feeling cleared as I got shallower. Not a CO2 issue, I was diving a Poseidon odin at the time (I still think they suck, but it did deliver the gas!)

John

[Daddy_Jeffy]

"Tyler, thanks for your thoughtfull post. Yes I'm Nitrox certified.
I am just attempting to bring into discussion the subjects that interest me. I am in no way trying to self teach myself how to deep dive thru these forums. If I wanted to self teach, I would go out and buy the course materials and read and apply them to diving."

But on 15 August:

"Yep. I have no cards. I am open water only. I self taught myself Nitrox thru books and diving with people who wanted me to use Nitrox so we could dive together. I am very cautious and calm in the water. I am very comfortable as well."


You are dangerous. We will read about you soon, and foot the huge bill for the Coast Guard having to search for your corpse.

[Bulit7]

"Tyler, thanks for your thoughtfull post. Yes I'm Nitrox certified.
I am just attempting to bring into discussion the subjects that interest me. I am in no way trying to self teach myself how to deep dive thru these forums. If I wanted to self teach, I would go out and buy the course materials and read and apply them to diving."

But on 15 August:

"Yep. I have no cards. I am open water only. I self taught myself Nitrox thru books and diving with people who wanted me to use Nitrox so we could dive together. I am very cautious and calm in the water. I am very comfortable as well."


You are dangerous. We will read about you soon, and foot the huge bill for the Coast Guard having to search for your corpse.

I mispoke. Initially I was taught by an instructor friend of mine and dove for a long time without it and recently got the cert so I could get fills in places where people don't know me. What I meant is that I never took any courses beyond OW.

Besides, Nitrox course is something that can be learned thru reading and formulas. PO2, MOD, Contingency Depth, EAD, EAN Tables. Nothing complicated there. Just need to understand the risks and advantages and manage them. Way different then creating a dive plan for a 150-200 foot dive. What mix? How long? What PO2, what MOD, etc. They even offer these courses online and some agencies do not have nitrox certification dives, just class work.
It's pretty straight forward.

[Daddy_Jeffy]

You got the cert in the last week?? Your post was pretty clear not "mispoken".

It is always the guy without a formal cert who says the class is unecessary.

"A buddy of mine by the name of David, dropped down and ended up taking a tank witha wrong mix."

Had your "buddy" taken a course, he would have checked his owned mix and written it on the side of the tank, one way to "manage" the risk...

[jfjf]

Had your "buddy" taken a course, he would have checked his owned mix and written it on the side of the tank, one way to "manage" the risk...

No amount of education or training is an antidote for stupidity;)

[Bulit7]

You got the cert in the last week?? Your post was pretty clear not "mispoken".

It is always the guy without a formal cert who says the class is unecessary.

"A buddy of mine by the name of David, dropped down and ended up taking a tank witha wrong mix."

Had your "buddy" taken a course, he would have checked his owned mix and written it on the side of the tank, one way to "manage" the risk...

I explained the post, I was taught by an instructor that no longer teaches proffessionally. He was taught by Jim Mimms(I think).We covered all the course materials at his home and I used his Padi literature(that I still have). I began diving Nitrox and using pony bottles based on his advice and instruction. Nitrox is pretty straight forward. It's not brain surgery as long as you are not pushing the limits.

As far as the O2 hit, I don't have the details, exactly. More imporatnt, to me, were the symptoms he had. Maybe the awarness generated thru reading what I wrote will save someone who encounters the same symptoms.

Not lookin for an inet argument. Getting tired of those. Too busy, not enough time. More important to me is to keep this thread on track regarding O2 hits and maybe we can generate more awarnes regarding this. Maybe you could join us with something positive here.

[Daddy_Jeffy]

I'm positive you are a tool

[Bulit7]

I'm positive you are a tool

I'm positive you are an ass..

[Daddy_Jeffy]

Touche

[Bulit7]

Lol!

[GUNRUNNER]

A couple of years back I took a minor O2 hit (i think) at around 155 ft on 29%. It felt like my lips and the area around were tingling or asleep. the feeling was kinda like the after affect of being stung in the face by a jellyfish. The feeling went away after rising up around 60ft or so and leveling off. The current was ripping and I had kicked hard all the way down to get to the jug line. I decided after that to get further training before i ended up on the RIP thread. Several more experienced divers said it was likely an O2 hit and I was lucky to be telling about it? If they were wrong I would like to hear other explanations.

[Bulit7]

Thanks for sharing that gunrunner. Glad you are ok.

[TheBrazilNut]

You got the cert in the last week?? Your post was pretty clear not "mispoken".

It is always the guy without a formal cert who says the class is unecessary.

"A buddy of mine by the name of David, dropped down and ended up taking a tank witha wrong mix."

Had your "buddy" taken a course, he would have checked his owned mix and written it on the side of the tank, one way to "manage" the risk...


Lee said he took an informal Nitrox Class. The only problem I have is the liability side of the Instructor. Are you referring to "the open water dives" that need to be completed along with the class to get a Nitrox card?

I have no idea why any student would have to complete two dives on Nitrox to complete the class! Can an Instructor from one of those Training Agencies give me me any type of answer as to why the two dives are necessary?

[jfjf]

A couple of years back I took a minor O2 hit (i think) at around 155 ft on 29%. It felt like my lips and the area around were tingling or asleep. the feeling was kinda like the after affect of being stung in the face by a jellyfish. The feeling went away after rising up around 60ft or so and leveling off. The current was ripping and I had kicked hard all the way down to get to the jug line. I decided after that to get further training before i ended up on the RIP thread. Several more experienced divers said it was likely an O2 hit and I was lucky to be telling about it? If they were wrong I would like to hear other explanations.

Possibly oxygen, but I have been pretty narced, especially while working hard and ended up with numb lips and tongue (but it was somewhat deeper). Either way, if you don't feel right, you did the right thing and got on the inflator.

[Mullins]

It was the same feeling (see my last post) that had me worried I was close to ox tox on deeper dives, but I found out from talking to tech divers over here that you can also get it with high nitrogen/CO2.

[Ydiveman]

Another great thread:thumps: Love it or hate it, information is being shared and discussed:beer:.

Since we are looking at medical related I have a question. Last dive of the day, usually after 3 or 4 dives, towards end of dives alot of times I get cramps in quads. I have been reading up on it, and I believe it is related to dehydration. Is this a solid assumption?? Usually during safety stops at end of dive.

[Mobile Diver]

Another great thread:thumps: Love it or hate it, information is being shared and discussed:beer:.

Since we are looking at medical related I have a question. Last dive of the day, usually after 3 or 4 dives, towards end of dives alot of times I get cramps in quads. I have been reading up on it, and I believe it is related to dehydration. Is this a solid assumption?? Usually during safety stops at end of dive.

Probably dehydration or just lack of fitness. I would drink some Gatorade next dive trip & see if that doesn't help. If not, do some time in the gym.

[TheBrazilNut]

Another great thread:thumps: Love it or hate it, information is being shared and discussed:beer:.

Since we are looking at medical related I have a question. Last dive of the day, usually after 3 or 4 dives, towards end of dives alot of times I get cramps in quads. I have been reading up on it, and I believe it is related to dehydration. Is this a solid assumption?? Usually during safety stops at end of dive.

You should be taking a piss on every dive!:D

[Bulit7]

One thing I learned with this guy I used to dive with is that you can do all kinds of shit wrong with your body but seems that as long as you hydrate the hell out of yourself, you will stand a better chance of avoiding DCS.

We would foce liquids down, even as we were about to flip over the gunnel, we would be drinking up tonsof water. This guy smoked and did some other things and his dive profiles were not the safest, yet he never got bent. I think it is due to how heavily he hydrated.

Take it for what its worth.

.

[shcubasteve]

Check out PADI's Encyclopedia of Recreational Diving... The physiology section has a very detailed description of diving injuries and related problems, including how and when oxygen becomes toxic

[Daddy_Jeffy]

One thing I learned with this guy I used to dive with is that you can do all kinds of shit wrong with your body but seems that as long as you hydrate the hell out of yourself, you will stand a better chance of avoiding DCS.

We would foce liquids down, even as we were about to flip over the gunnel, we would be drinking up tonsof water. This guy smoked and did some other things and his dive profiles were not the safest, yet he never got bent. I think it is due to how heavily he hydrated.

Take it for what its worth.

.
I think it is due to dumb luck. "Did some other things??" I can't crack that code. You are lucky you didn't have to retrieve this guy from an accident, or expect him to watch your back.

Post more examples. You are an ambassador of the sport. I hope everyone is taking the advice you put forward.

[diverlen]

Check out PADI's Encyclopedia of Recreational Diving... The physiology section has a very detailed description of diving injuries and related problems, including how and when oxygen becomes toxic

Steve, good post. Regardless of our diving experience, we all should learn more about oxygen toxicity.

[Mobile Diver]

I think it is due to dumb luck. "Did some other things??" I can't crack that code. You are lucky you didn't have to retrieve this guy from an accident, or expect him to watch your back.

Post more examples. You are an ambassador of the sport. I hope everyone is taking the advice you put forward.

Your posts are BS & contribute nothing to the discussion. I think the mods should delete them.

[Bulit7]

I think it is due to dumb luck. "Did some other things??" I can't crack that code. You are lucky you didn't have to retrieve this guy from an accident, or expect him to watch your back.

Post more examples. You are an ambassador of the sport. I hope everyone is taking the advice you put forward.



Hey, I cut him off and don't even speak to him anymore because of his substance abuse and quirky personality. I tried to be a friend and steer him in a better direction to no avail. It was time to move on. Sad thing is the dude inherited millions from his dad and is wasting away. Nice guy, sad... Let me tell you: I don't even drink, work out almost every day, bike, run. It is what it is. Doesn't embarass me. I don't have time for druggies, alcoholics or whatever.

Seems like you are making a point in trying to ridicule me. Good luck.

At least I am honest and try to post things that others can benefit from. What have you brought to the table? Bunch of negative shit that probably stems from you being some low life dipshit. Why don't you quit wasting everyones time with your lame ass coments.

Seems that you hide behind a screen name. Who are you? Post a pic and your real name. Lets hear about your accomplishments. See some of your fish. I think it will be a more positive contribution to this site than the dumb shit you have been posting.

.

[Ydiveman]

:yup::yup::yay:

[Toledo970]

:d

[Scotty]

First of all is that all I can say about this tread is WTF. Second of all most of you if not all have not a damn clue about O2 hits. I think the one thing most understand is an O2 hit can kill you. Mostly because of a convulsion. It takes a lot more than just a damn PADI class to understand how this stuff works. Try taking an inside tender course at a local hospital that has a re compression chamber. you will learn all about PPO2 and treatment tables.

Most of what this thread is advocating is "well i learned how to do it online from so and so, so it must work. Or I will ask a question on how to do and maybe some people will tell me. I am a firm believer in asking questions but they should be asked in a class room where you are learning this shit and not while you sit at your computer and then try it the next day at 200'. Most of these questions are way beyond your experience level. that goes for the idiots that are bashing each other as well. if you have to ask then you shouldn't be doing it, because sooner or later you will end up killing yourself or someone else. I see diving accidents all the time. I have seen guys that know what they are doing and have 10+ years as a navy diver get bent. I have seen idiots bypass 2 hours of decompression and only get a very mild type 1 . I treat idiots and professionals alike. have fun be safe and like any other sport play within your limit.

[Bulit7]

First of all is that all I can say about this tread is WTF. Second of all most of you if not all have not a damn clue about O2 hits. I think the one thing most understand is an O2 hit can kill you. Mostly because of a convulsion. It takes a lot more than just a damn PADI class to understand how this stuff works. Try taking an inside tender course at a local hospital that has a re compression chamber. you will learn all about PPO2 and treatment tables.

Most of what this thread is advocating is "well i learned how to do it online from so and so, so it must work. Or I will ask a question on how to do and maybe some people will tell me. I am a firm believer in asking questions but they should be asked in a class room where you are learning this shit and not while you sit at your computer and then try it the next day at 200'. Most of these questions are way beyond your experience level. that goes for the idiots that are bashing each other as well. if you have to ask then you shouldn't be doing it, because sooner or later you will end up killing yourself or someone else. I see diving accidents all the time. I have seen guys that know what they are doing and have 10+ years as a navy diver get bent. I have seen idiots bypass 2 hours of decompression and only get a very mild type 1 . I treat idiots and professionals alike. have fun be safe and like any other sport play within your limit.

Scotty, wtf are you talkin about?

This thread is not advocating anything.

So knowledge should only be shared in a classroom?

"Most of these questions are beyond our experience level" How is that? Learning about oxigen toxicity is one of the fundamental aspects of diving safely on Nitrox.

"If you have to ask, you shouldn't be doing it". Only thing asked on here was to hear anybodys experiences with O2 toxicity. Though rare, they do occur as ilustrated earlier. Read the whole thread.

" I have seen guys that know what they are doing and have 10+ years as a navy diver get bent. I have seen idiots bypass 2 hours of decompression and only get a very mild type 1 " WTF does DCS have to do with High PO2 hits?

Do us all a favor and re-read the thread. Then delete your post or edit it so it fits within the context of what is being discussed. In other words, we want to hear about PO2 hits. Close calls with oxigen toxicity.

[Scotty]

Scotty, wtf are you talkin about?

This thread is not advocating anything.

So knowledge should only be shared in a classroom?

"Most of these questions are beyond our experience level" How is that? Learning about oxigen toxicity is one of the fundamental aspects of diving safely on Nitrox.

"If you have to ask, you shouldn't be doing it". Only thing asked on here was to hear anybodys experiences with O2 toxicity. Though rare, they do occur as ilustrated earlier. Read the whole thread.

" I have seen guys that know what they are doing and have 10+ years as a navy diver get bent. I have seen idiots bypass 2 hours of decompression and only get a very mild type 1 " WTF does DCS have to do with High PO2 hits?

Do us all a favor and re-read the thread. Then delete your post or edit it so it fits within the context of what is being discussed. In other words, we want to hear about PO2 hits. Close calls with oxigen toxicity.

real world scenario:

O2 hits mostly happen in chambers during a TT. where 02 is the main breathing medium. and if it does happen in the water with out a FFmask. the person that got the hit likely didn't survived due to drowning. Diver's reg falls out of mouth during a convulsion.

Why so angry. What I said is the truth. most people have no idea what an O2 hit feels like anyways. so most people think they got a hit when in fact could be something else like a little carbon monoxide in their tank, or over breathing their rig due to chasing fish. the symptoms are about the same. the end result is if you are having an o2 hit a convulsion is likely going to happen. Im not saying that it happens every time but that is the underlying symptom of an O2 hit. besides the correct term would be CNS 02 toxicity. and there is also pulmonary 02 toxicity which happens when in a chamber after breathing o2 for long period of time or a rebreather that is 100% o2. My post was more or less to get the point across to stick to what you know. and learn what you don't from a qualified professional. not your buddy down the street who says he's a tech instructor or whoever. I am preaching safety not stupidity.

[Bulit7]

Oh, ok....:rolleyes:

[dirtbroker]

142' 21% fighting a 50# aj. when i later downloaded the dive log off the computer, to analyze it showed a p02 1.10 i defer to you gentlemen with a lot more experience and deeper dives than i. was i within respectably acceptable limits

[hammerhead786]

Acording to sport diving standards throughout the world no. 1.6 is it. If you were a US navy diver potentially. At that depth to get that PO2 on 21% you were either down a long time or did multiple dives that day? Diving 21% on a PO2 1.6 you get max 45 miutes at 218fsw. The thing is what doesn't harm you one dive may kill you the next. It's a habit bro... you gotta know when to say when.

Depth, Mix & PO2 Chart









~ Captain Ed ~

[Bulit7]

142' 21% fighting a 50# aj. when i later downloaded the dive log off the computer, to analyze it showed a p02 1.10 i defer to you gentlemen with a lot more experience and deeper dives than i. was i within respectably acceptable limits

What are the symptoms you experienced...

[dirtbroker]

didnt experience any symptoms, dive went just fine

[xstephenx]

I don't know if he edited his post, but he was at a pO2 of 1.11 at 142' on air. There is absolutely no reason he should have experienced any symptoms. 1.11 is perfectly fine, so I don't know why people are assuming anything out of the ordinary should have happened.

[dirtbroker]

the p02 of 1.10 at 142' on air is correct, I was resonably sure that since I got the fish up fine, with no problems except running a little shorter on air than I would have liked with an 80 cft tank, that all was well, thats just the deepest I d ever been before and that was the reason for the post, wondered if that p02 level would have been about right for that depth

[qleem]

Acording to sport diving standards throughout the world no. 1.6 is it. If you were a US navy diver potentially.

I know this can be hard but.... 1.10 < 1.6(0)

I hate to be that guy, but seriously shit math errors like that can get you killed.

[POL]

..

[Doc]

Ive never had on O2 problem myself, but have sp[oken to several people who did;

CAse 1 is an old friend who was living in the Yucatan in the 1980's, cave diver mostly, He also worked as a chamber attendent during this time, and was very knowledgable about the signs and sympoms of bends/co2/narcosis. He later trai ned as a commercial diver. Anyway, for kicks would do drops off one of the walls to seee howdeep he could go... classic macho bullshit that unfortunately too many youg divers get sucked into, any way on one of his deep drops at about 280' he got the tunnel vision, numb lips, feeling of intense agitation... and the thing that really wireded him out was a visual hallucination of a ball bouncing around in his mask that that old atari game. His symptoms went away on ascent, but he states flatly that he thought he was going to die and was amazed when his head cleared up. As this was a straight drop down a wall, there was no exertion so co2 is unlikely. Obviously he was narced on air at this depth, but was used to getting narced and he know this was much different. His mantra was "when the balls start bouncing, its time to go home".

I talked to another friend that came in very rattled after a day of diving. He was an experienced diver at something like 150 feet and had been at this depth many times, but never had a serious problem., and was convinced he was so narced that he had majopr problems getting back up; piecing the dive back together, his choice of mix put him a bit over 1.6 02 ata. He had dove hot mixes before with no problems,so did not think this was the issue. His symptoms were severe tunnel vision "almost totally blinding me" , strong anxiety and agitation and what he described as flashing lights("when the balls start bouncing, its time to go home!")... he knew this was all bad and ascended and the symptoms cleared on the way up.

Digging deeper as to why hos 02 tolerence may have changed, I found that He had a bad cold, so was hopped iup on several tabs of sudafed (major cns stimulant). He was also having some deppresion, so was on wellbutrin and his dose had just been increased, (Raises not only seretonin levels but norepinephrine levels on the brain, therefore lowers siezure threshhold) Due to his cold he had very poor sleep, so was drinking coffee most of the day, another CNS deppressent.

Anyway these are two cases of people who did some very stupid things, one on purpose one on accident both of whom almost ox-toxed and died but recognized symptoms and got out of dodge before the siezures hit. I think that this type of information is what this thread was meant to bring to light, and i think it is very improtant to share. Please dont dive deep without the training, and if anyone reading this was suprised to find out that common medications like antideppressents, stimulants, and cold medicines, anti spasm medications, pain medications and various others CAN KILL YOU doiing high po2's, then YOU DONT HAVE ENOUGH TRAINING to be making these dives. Very few doctors will be aware of these effects and will likely give bad advice on taking them while diving deep.

[Doc]

A very short and totally incmplete list of very common medications that might kill you diving deep, by acting as CNS stimulants and lowering seizure threshold. THis is off the top of my head from no database, but based on basic pharmacology are drugs I would be very weary of...

cold meds: Sudafed is the most dangerous
Psychiatric meds: Any stimulant (like ritalin or diet pills amd many others), just about any tri-cyclic antideppressent (ALso note many uses other than deppression), any drug that raises norepinephrine levels (wellbutin, effexor, many others)
Pain meds: Tramadol/ultram is the worst, also narcotics to some extent
Spasm: Flexeril/cyclobenzparine is the biggest offender, several others

I, and I would think no one else could tell you what Po2 is safe to dive at when on these meds... Would a 1.4 be safe? or a 1.0? Ive never heard of anyone on the meds seizing when placed on 100% oxygen, but then again these meds sometimes make people seize( only those predisposed) without the aid of any oxygen at all. Anyone on more than one of these types of meds is at an especially high risk, as the seizure lowering effects may be synergistic.

[Doc]

One last thought on the subject before I head to sleep; I am not saying this to embolden a rogue diver to expect warning signs to avoid ox-tox , but to empower those diving deep who dont feel right to consider aborting or at least ascending if they dont feel right.

While it is true that many epileptics seize without any warning, the physiology in seizures from oxygen is a bit different, And I would not be surprised of warning symptoms of an ox-tox are fairly common... divers at risk for ox-tox are typically task loaded, narced, hyped on adrenaline and often in a team where they dont want to let their partners down by aborting or ascending from a dive and I think prone to ignore or overcome warning symptoms of danger or attribute them to something else. If you dont feel right, no matter what the symptoms are, dont ignore it. If your buddy is close let him know, if he is not around stop exerting yourself, start ascending until you feel better

[aue-mike]

FWIW, most of the examples offered sound like classic narcosis IMHO. When you get seriously narced, strange shit can happen (e.g., tunnel vision, loss of color vision, visual distortions, auditory distortions, etc.). Sometimes this can be compounded with CO2 retention, and sometimes you can experience this stuff from CO2 alone such as when you over-breath a reg at depth. I have had severe tunnel vision leading directly into crazy purple spots when I worked way too hard in strong current on a 300-foot dive (using a depth-appropriate gas). Definitely not a fun experience and I am not too proud to say I was scared shitless. It hit that hard and that fast.

As someone else tried to mention, O2 toxicity is a different beast. I know some people who have said they believed they felt the onset of an event (e.g., lips twitching) and believe they escaped a close call. Whether or not it was true oxtox is probably debatable. However, for many situations if you indeed could feel an oxtox event coming on, physiologically the train has probably already left the station and the power is about to be turned off. At that point, you better be able to breathe water or have someone nearby get you to the surface.

Also, it might be worth noting that lip and tongue numbness can also be from narcosis, and not just limited to nitrogen narcosis. I was subjected to a not-so-fun episode of serious toluene narcosis from tainted gas at a depth of only 100 feet. Tongue numbness was one of the first symptoms followed by a very weird amnesia-like dreamy state. Not cool to experience that underwater (especially considering it was in a cave and I had to be helped out).

Anyway, here is a entertaining case of serious narcosis (and stupidity):
http://www.cisatlantic.com/trimix/AQUAcorps/wahwah/WahWah.htm

Dive safe (and within your training and limits),
Mike

[aue-mike]

Sorry - wrong article. This was the one I meant to link:
http://www.cisatlantic.com/trimix/AQUAcorps/wahwah/Wah-Raimo.htm

[float 'n stalk]

Sorry - wrong article. This was the one I meant to link:
http://www.cisatlantic.com/trimix/AQUAcorps/wahwah/Wah-Raimo.htm

good read. Interesting commentary about feeling so good, but at the same time being so scared.

[Spear CR]

Awesome Reads.

[Doc]

Mike I had almost the exact same symtoms as you on the only (really) close call of my diving career... it was the end of a dive and I was chasing that one last fish, a very sizable hog who was swimmimg up-current with two of my sharts in him Just as I would get into range with my last shaft he would scoot another 20 feet. I know I was "over breathing" my reg but figured Id stop and breathe once I had him strung. I gave one last sprint to get him, and as I was swimming the co2 hit me like frieght train... sudden and severe tunnel vision then I remember my vision essentially closing off and getting brown, dark and mottled. I Remeber thinking I was done, and I just stopped and sat on the bottom and concentrating on slow steady deep breaths while holding my regulater in my mouth with both hands. Right before I thought I was gonna pass out my vision started coming back like a little port hole of light in the center of my vision that expanded and brightened until my vision was back and soon it was bright again, I was alive and well and still on the bottom... kept breathing deep another minute or so, Grabbed my gun, said sorry to the fish I killed (that almost killed me) and ascended with one VERY humbling experience under my belt.

I remember thinking about jabbing my inflater and bolting for the surface so that they might recover my body if I went out; and thinking better bent on the surface than dead down below, but even while it was happening I knew this was co2 and stayed put and just breathed until it passed and Im glad I did.
.
I dont know if those two cases I mentioned above were 02 related or severe narcosis, not sure I ever will but there definatly stories to learn from... both divers had significant deep experience and said these symptoms were totally unlike anything they had experienced before (or since in the case of the cave diver). The interesting symptoms to me are the agitation and visual disturbance they described... Im not sure severe narcosis would do that but who knows.

My lips always get numb and tingly when Im narced, kicks in at an EAD of 110-120 feet almost like clock work and foreshadows that warm narc feeling that takes over when Im deeper.

[Doc]

Just googled this up; VERY interesting info on Pre-seizure ox-tox symptoms:

THis study seems to support that there are in fact warning symptoms in many or even most cases. I like the conclusion:



CONCLUSION: Awareness of any unusual sensation can prevent a potentially dangerous situation from arising.

That I think is the answer Built-7 was asking for in this thread.



Article below:


Aviat Space Environ Med. 2006 Nov;77(11):1153-7.

CNS oxygen toxicity in closed-circuit diving: signs and symptoms before loss of consciousness.
Arieli R, Arieli Y, Daskalovic Y, Eynan M, Abramovich A.

Israel Naval Medical Institute, IDF Medical Corps, Haifa, Israel. rarieli@netvision.net.il

INTRODUCTION: There is a dearth of information regarding CNS oxygen toxicity accidents in closed-circuit oxygen diving. The aims of the present study were to report the sensations and symptoms that accompany CNS oxygen toxicity accidents, and to evaluate whether loss of consciousness can occur without any warning signs. METHODS: We documented 36 CNS oxygen toxicity accidents in closed-circuit oxygen diving. The full accident inquiry included the first report from the diving unit, an interview of the victim and his buddy by the researchers, and an examination of the diving equipment. RESULTS: The symptoms that appeared before termination of a dive, as reported by the victim or his buddy, were as follows (in descending order of frequency): limb convulsions; hyperventilation; difficulty maintaining a steady depth; headache; and visual disturbances. The symptoms that appeared after detachment from the mouthpiece were, in descending order of frequency: headache; loss of consciousness; confusion; weakness; dizziness; and facial muscle twitching and limb convulsions. A high inspired CO2 [mean 4.2 kPa (29.9 mmHg)] was connected with loss of consciousness. No dive was terminated before at least two symptoms (mean 3.4) had been noted a minimum of 5 min before termination. DISCUSSION: Symptoms that are accepted as being related to CNS oxygen toxicity, as well as others such as headache, difficulty maintaining a steady depth, hyperventilation, weakness, and a choking sensation, were more frequent among the O2 accident victims compared with divers who did not interrupt their dives. CONCLUSION: Awareness of any unusual sensation can prevent a potentially dangerous situation from arising.

[jmhardingjr]

Rebreather trimix instructors sometimes use med grade nitrous oxide to simulate extreme nitrogen narcosis so that students can learn to recognize and differentiate narcosis symptoms from hypercapnia (CO2) or oxtox. There are subtle differences. If you fill a ballon with nitrous and then empty your lungs and breathe in from the balloon at sea level it simulates an air dive to approximately 300 fsw. In short, you are so f***ed up from the narcosis that you learn very quickly why diving very deep on air or any high nitrogen gas is literally gambling. You are gambling that you will have the wherewithall to deal with any problems when you are basically drunk. It's like driving while intoxicated except that you are underwater. Sound safe? That's because it's not.

The surface nitrous oxide exercise is valuable from the point of view of leaning to recognize the different effects of nitrogen versus elevated O2 or CO2. Try it if you get a chance, it will teach you something. My experience that nitrogen narcosis makes you feel great and at the same time anxious, tingly, have tunnel vision, and have other sensory distortions (numbness or pulsing in extremities, burning sensation in the thin skin of my ears, etc). These symptoms are all nitrogen narcosis for me and not associated with O2 and or CO2 because I have had them on the surface while doing a narcosis simulation as well as at depth (much shallower than oxtox range). I've also had a full blown hypercapnia (CO2) hit on a failed rebreather that almost took my life, and those symptoms need to be recognized and differentiated from oxtox symptoms. In short, if you are diving deep enough to worry about oxtox (on open circuit gear), you need to be diving the appropriate gas and that gas is not nitrox, it's heliair or trimix. Or you could switch to a rebreather and have full control your PO2.

I'm consistently amazed at the way people mistakenly think that nitrox is for diving deep. Nitrox is for extending bottom times at RECREATIONAL depths (0-130 fsw) and for speeding up nitrogen/helium flushing during decompression. An earlier comment about wanting to discuss EAN 28 for deep diving is indicative of someone being misinformed. From an oxtox point of view nitrox is more dangerous at moderately deep depths. And, again, if you are diving deep enough to care about oxtox on air, then you should be diving trimix so that you aren't swimming around essentially drunk from narcosis. If you are worrying about oxtox on nitrox, then you aren't calculating or paying attention to the MODs of your mix. I realize that oxtox is not an exact science and that some people tox much sooner that others - but the diving agencies have realized that as well and the PPO2 of 1.6 rule is designed to work for the majority of the population. It's conservative, believe it or not (US Navy has dive tables for PPO2 up to 2.4!!). And it's not instant. You don't reach 1.6 and tox. It takes time. So, if 1.6 is conservative, and it takes time to tox even at that level, then IF you do tox you are either unlucky or you are pushing the envelope. I would venture that most people who oxtox were either pushing the limit or weren't aware of the limit. Either way it might have been preventable. For all others who toxed under abnormal circumstances, they were just unlucky and how do you account for that? Plan a safe dive, dive to your plan, and remember that the dive you are on is not nearly as important as the hundreds or maybe thousands of dives that you plan to do throughout the rest of your life. When in doubt, bailout.

These are just my thoughts and opinions, actual mileage may vary.

Good luck and dive safe.

Jay

[mohalk]

For what it's worth, I've was at 140 feet on a nitrox blend that put me at 1.7 or 1.8 po2 and had no problems whatsoever. I slowly descended to that depth because there happened to be a rig crossmember there that I could hold on to.

I shot an amberjack and stoned it but I was prepared to hold on to the crossmember or just let go of the riding rig if it wanted to bring me deeper.

That's my anecdotal two cents. FWIW I don't dive nitrox much on the rigs just because the depth is so much greater than your po2 floor.

[Bulit7]

Thanks for the coments guys!!

Rebreather trimix instructors sometimes use med grade nitrous oxide to simulate extreme nitrogen narcosis so that students can learn to recognize and differentiate narcosis symptoms from hypercapnia (CO2) or oxtox. There are subtle differences. If you fill a ballon with nitrous and then empty your lungs and breathe in from the balloon at sea level it simulates an air dive to approximately 300 fsw. In short, you are so f***ed up from the narcosis that you learn very quickly why diving very deep on air or any high nitrogen gas is literally gambling. You are gambling that you will have the wherewithall to deal with any problems when you are basically drunk. It's like driving while intoxicated except that you are underwater. Sound safe? That's because it's not.

The surface nitrous oxide exercise is valuable from the point of view of leaning to recognize the different effects of nitrogen versus elevated O2 or CO2. Try it if you get a chance, it will teach you something. My experience that nitrogen narcosis makes you feel great and at the same time anxious, tingly, have tunnel vision, and have other sensory distortions (numbness or pulsing in extremities, burning sensation in the thin skin of my ears, etc). These symptoms are all nitrogen narcosis for me and not associated with O2 and or CO2 because I have had them on the surface while doing a narcosis simulation as well as at depth (much shallower than oxtox range). I've also had a full blown hypercapnia (CO2) hit on a failed rebreather that almost took my life, and those symptoms need to be recognized and differentiated from oxtox symptoms. In short, if you are diving deep enough to worry about oxtox (on open circuit gear), you need to be diving the appropriate gas and that gas is not nitrox, it's heliair or trimix. Or you could switch to a rebreather and have full control your PO2.

I'm consistently amazed at the way people mistakenly think that nitrox is for diving deep. Nitrox is for extending bottom times at RECREATIONAL depths (0-130 fsw) and for speeding up nitrogen/helium flushing during decompression. An earlier comment about wanting to discuss EAN 28 for deep diving is indicative of someone being misinformed. From an oxtox point of view nitrox is more dangerous at moderately deep depths. And, again, if you are diving deep enough to care about oxtox on air, then you should be diving trimix so that you aren't swimming around essentially drunk from narcosis. If you are worrying about oxtox on nitrox, then you aren't calculating or paying attention to the MODs of your mix. I realize that oxtox is not an exact science and that some people tox much sooner that others - but the diving agencies have realized that as well and the PPO2 of 1.6 rule is designed to work for the majority of the population. It's conservative, believe it or not (US Navy has dive tables for PPO2 up to 2.4!!). And it's not instant. You don't reach 1.6 and tox. It takes time. So, if 1.6 is conservative, and it takes time to tox even at that level, then IF you do tox you are either unlucky or you are pushing the envelope. I would venture that most people who oxtox were either pushing the limit or weren't aware of the limit. Either way it might have been preventable. For all others who toxed under abnormal circumstances, they were just unlucky and how do you account for that? Plan a safe dive, dive to your plan, and remember that the dive you are on is not nearly as important as the hundreds or maybe thousands of dives that you plan to do throughout the rest of your life. When in doubt, bailout.

These are just my thoughts and opinions, actual mileage may vary.

Good luck and dive safe.

Jay

For what it's worth, I've was at 140 feet on a nitrox blend that put me at 1.7 or 1.8 po2 and had no problems whatsoever. I slowly descended to that depth because there happened to be a rig crossmember there that I could hold on to.

I shot an amberjack and stoned it but I was prepared to hold on to the crossmember or just let go of the riding rig if it wanted to bring me deeper.

That's my anecdotal two cents. FWIW I don't dive nitrox much on the rigs just because the depth is so much greater than your po2 floor.

[BIG C]

jmhardingjr, what a great post. I thought I knew alot about gas and depths, but I really learned something form reading your post. Thanks so much.
As for planning a dive on nitrox that puts you at 1.7 to 1.8 is, well I dont want to type what I am thinking, but maybe my explanation will change your mind about doing it again.
Consider this:
1. If you are diving a rig that is 150 fsw, dive a mix that is good to 150. reason being that aj can easily pull you to 200 then you are way past the 1.6 rule. Never dive a 200' rig with a 150' mix.
2. by descending slowly, does not slow o2 absorption. if you are on the edge of having a seizure, it can come on in seconds. It may take a full minute to leave the leg and start coming up. by that time, its too late
3. if you shoot that aj at 1.8, your heart will immediately rev up, you will spend more time that you think fighting the fish, and more time tryin got pull it up. Essentially, you will spend alot more time than you planned at 1.8 than you were hoping. by the time you realize whats going on, its too late to ascend. even if you ascend to a 1.6 atmosphere, its not immediately helpful on the cns. it takes time for the pressure to relieve and if you get a seizure, you are screwed.

aj are so plentiful, please consider not diving deep rigs on a mix that can kill you.

[FishMasterT]

Nitrox is a luxury for most shallow water divers in florida and other states that have many areas shallower than 150ft. Nitrox is great for those that have shallower water, but in extremely deep waters like Louisiana (mainly venice) it's dangerous b/c you may be diving at an acceptable depth and shoot a fish and end up deeper than you are suppose to be....before you know it you receive a big hit and become immobilized. I've used nitrox in florida but never will i use it on the oil rigs in louisiana unless i am only doing shallow water diving. It's just really risky. It's all about what risks you're comfortable taking. For me it's not worth the risk(s).

Be safe seriously! That goes for everyone be safe and remember "NO FISH IS WORTH LOSING YOUR LIFE OVER". Think about your family and friends before you make a decision.