Diving shallow on Nitrox.

[Subcooled]

A clarification: When carbon based fuels (be it hydrocarbons or coal) burn, combine with oxygen that is, two types of exhaust gases are generated: carbon with two oxygens C O2 or carbon with a single oxygen C O. The latter has a place free for more bindings and will thus attach to (the hemoglobin of) blood very tightly. While CO2 can be vented away, CO sticks and blocks oxygen from entering the blood stream. Hence, it is far more lethal. Both can cause head ache or death.

a group of 3 buddies (...) If Co2 was the issue, we would have noticed similar issues with other fills

These gases are apparently not the cause of head ache then.

 

[DustyC]

I'm one of them. I can't tell you if it's "real" or "placebo". When a dive trip costs 80ish dollars plus gas plus food for a dive day, the $2 extra I pay for a tank of nitrox at my LDS is totally not significant. I do believe I feel less tired after diving on nitrox, even at shallow depths. I can't quantify it better than that, and given the miniscule extra cost, I really don't care too much to look into it.

I'll only dive air if I'm somewhere like key largo where they have the bizarre practice of vastly more (by the cuft for example) or if I just can't get it at all.

Me too. A friend of mine had never done any dive trips and got nitrox for Bonaire. He didn't have any frame of reference until he went to the Caymans for a week, on air. Diving less, he felt worse. He'll be back in Nitrox in Dec for Bonaire again

 

[cmulvaney]

A couple of years ago I sent an email about the nitrox placebo effect that some continue to quote to IBUM. I posted this in a previous thread. Here it is...


I sent an inquiry on this subject to The International Board of Undersea Medicine (IBUM).
International Board of Undersea Medicine | Hyperbaric Medicine | Undersea Medicine Training & Education | Diving Medicine
This is my exchange with them thus far.

Jeffrey Bertsch jeffbertsch@earthlink.net via christophermulvaney.com	8:40 AM (5 hours ago)
to cm

Christopher, there is a lot of empirical information about how a diver feels using enriched air nitrox (EANx). Feelings are difficult to quantify in scientific studies and that is probably why there is so little literature on the subject. It would stand to reason that when there is less of a narcotic gas (nitrogen) in a breathing mix that one would feel less "fatigued" after a dive. I have not performed a recent literature search but when I worked at Duke we did a lot of studies involving EANx and the use of O2 for decompression. Among the test subjects, there were a lot of reports that divers felt less fatigued after these types of dives. By using key words for authors in a search like Richard Moon, Richard Vann, Caroline Fife or Claude Piantadosi you may have better luck in finding some pertinent literature. I personally do not agree with the study you cited and am a little skeptical of its conclusions if it was truly a double-blind, peer reviewed study. The sampling of only 11 divers is certainly not enough to support the author's conclusion. In the early days (1980's) there was some misinformation published about the use of EANx--mostly based on the fear of the unknown.

Dick Rutkowski and Dr. Morgan Wells pioneered the use of EANx while still at NOAA. You may find some of their published papers on line or at Dick's websitewww.hyperbaricsinternational.com

I have worked with Dick and Morgan for many years and was in the soup with them early on by advocating the use of EANx for it's many benefits to divers along with the safe use of oxygen for decompression and the first aid for decompression illnesses. I still advocate its use and still dive using EANx to this day.

Hope this helps in your quest for accurate information. ~jeff




-----Original Message-----
>From: cm@christophermulvaney.com
>Sent: Jul 9, 2014 9:52 PM
>To: jeffbertsch@earthlink.net
>Subject: Web Form Submission
>
>The following information was submitted on July 9, 2014 @ 8:52 pm:
>
>-------------------------------------------------------
>
>Name: Christopher Mulvaney
>
>Email: cm@christophermulvaney.com
>
>Subject: O2 Question
>
>Comments: Hello, I have a question I hope you can answer. I have been scuba diving for almost 35 years. I am looking for research on Nitrox diving. Specifically on whether feeling better after a nitrox dive vs an air dive and the physiological responses differentiating the two different kinds of diving. I did find a study that only included 11 divers and said it was a placebo effect and did nothing but waste money. I dive nitrox 90% of the time and do feel better. Any help would be greatly appreciated.
>
>-------------------------------------------------------
>
>

Thank you very much for your time and help. Chris

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[Storker]

Me too. A friend of mine had never done any dive trips and got nitrox for Bonaire. He didn't have any frame of reference until he went to the Caymans for a week, on air. Diving less, he felt worse. He'll be back in Nitrox in Dec for Bonaire again

Before we go down that road - again - it might be a good idea to check e.g. this thread to see if your arguments haven't been stated, discussed, countered, supported and re-hashed before. They probably have. Once, twice, thrice, ad nauseam...

 

[tamas970]

I was lazy to read all the comments, I personally would dive nitrox <10m/30' (c'm on, do you people call this a dive?) if I had a very deep dive before and I want to decrease my N2 level because I want a third dive or I want to do some hiking/driving in the mountains (happens in Croatia where I dive almost every year). Just for "fun" I can't be bothered anymore...

 

[Diving Dubai]

As others. Tanks filled post dive. I have a couple of of tanks at 28% the rest are 32% So I'd dive a 32. Nitrox fill here is $5 so not worth worry about

 

[archer1960]

I have heard this, but your body metabolizes some % of the o2, where as the n2 builds up. I understand planning for Narcosis the same, but I am still skeptic on this.

The analysis I read said that O2 is actually more narcotic than N2, but because some of it is metabolized, that brings its overall effect to be very close to that of N2.

 

[archer1960]

Several have hit on the point of tanks with nitrox bands. I have a site that will not fill air in a nitrox tank without charging for nitrox. IE any tank is 8 for air and 16 for nitrox. If the tank has a nitrox sticker that is what they charge. Another site will scrape the sticker if they put air in the tank so you get nitrox or pay the nitrox processing to simplify the process. One site I go to says they do not know if they have air that is e or hyp e. They just get a pass or no pass on the air testing. Since the shop does not deal in nitrox they have no idea, when the air analysis comes back, if it meets hyp e or not. Another site claims that their liability ins does not cover filling nitrox tanks. There are shops that say nitrox is nitrox so 23% is the same as 32% when pricing. Others say banked is one price and custom is another. Nitrox is a hassel in many cases, especially if you own your own tanks.

A final kicker a site with 25' water does nitrox fills. Why cause you cant put air in a nitrox tank. Go figure....................

You really should be sure you're putting oxygen-compatible air in a nitrox-labeled tank, to ensure you don't get crap in the tank. My shop's fill rig has an extra filter on the side where they make nitrox, and that's also what they use for filling tanks labeled nitrox, with air.

 

[Caveeagle]

..My shop's fill rig has an extra filter on the side where they make nitrox, and that's also what they use for filling tanks labeled nitrox, with air.

..So if I stop by for a 21% fill with an un-labeled tank.. I will get the low grade, crappy air? Maybe it's just me but if the air is not good enough for your >21% fills, I don't really want to breath it.

 

[NAM001]

..So if I stop by for a 21% fill with an un-labeled tank.. I will get the low grade, crappy air? Maybe it's just me but if the air is not good enough for your >21% fills, I don't really want to breath it.

Its not crappy air. It is as good as it comes and meets all standards. because of the higher O2 in nitrox, the allowed hydrocarbons and things are required to be lower to meet EAN standards. If you get an air fill in a shop that does not provide nitrox you get grade E air. They don't buy the extra filtering to get hyper E air. To get an EAN fll they use hyperfiltered grade E air. The band tells the filler that the tank can be used as a EAN tank and will call for hyperfiltered E air as the lowest quality air in it. Most times air from an E system will exceed the HYPER E requirements (by air testing). but as the compressor ages its quality degrades to grade e. Kinda like your car tires that will get 50k miles. they actually get 60k on interstaates but when you drive it on gravel roads the tire only lasts 50k. firemen air packs were reiquied grade D min air for many years. There is a fill station at a site I go to that will not fill my tank because it has a Nitrox band on it. If they fill it they have to remove the nitrox band from the tank to insure that if any contaminates get into the tank it will not be a problem when you put nitrox in it next time. Kinda of a crap excuse but the other is that they are not covered (INS) to do nitrox fills. They also do not top off nitrox tanks they empty them remove valve and then refill with air and remove the nitrox band and O2 vip sticker do a vip and replace with an air vip sticker. There is nothing crappy about grade E air. Many fill stations only have one fill line and that is hyper E (it covers all bases). others have more than one and most of them have premixed nitrox in that line or a hyperfilter in that line to turn E into hyperfiltered E. Hyperfiltered air goes by many names. nitrox air, hyperfltered e air, safe air.