100% 02 during your SI?

[Deep South Divers]

That is both a wonderful insight and a delightful turn of phrase ... thank you. It is right up there with the child who killed both his parents and threw himself on the mercy of the court, after all, we was an orphan.

+1! Very nice.

 

[Deep South Divers]

Surface O2 is not going to help that much for reducing the nitrogen but it is great for when you have a hang over.

+1. I can also tell you that it helped negate the horrible effects of chemotherapy as well. Specifically, a 10 minute break on 100% helped negate the horrible effects of cisplatnin and etopicide in my cancer treatments.

O2 is great stuff!

 

[DaleC]

Very good Thal! I was listening to some protesters on the radio the other day complaining about corporate welfare. During the same newscast it was also noted that their protest was being sustained primarily by donations from others?

When I worked at a private ambulance service some years ago we could not figure out why the onboard 02 was always depleted and in need of replacing. It wasn't until we caught the mechanic sleeping in the bus with a mask over his mug that we realized he was using it to alleviate his hangovers.

As to breathing 02 during the SI. IIRC, I did a chamber tour about two years ago and the head of Hyperbaric medicine (also a diver) told us he sometimes huffed the magic gas between/after dives himself. Cost and access was not an issue (because he was a Dr.) and he was discussing this in relation to strategies for reducing DCS risk. He also was keen on backup computers too.

SeaJay, Glad to hear you refer to your chemo in the past tense.

 

[TSandM]

I really don't understand why anyone would recommend that a recreational diver, diving within no-deco limits (whatever his are), should do a gas switch and breathe O2 at 20 feet. Breathing it on the boat may not be of any enormous use, but it's virtually entirely safe. Doing a gas switch and breathing it underwater has a whole host of place where things can go wrong . . . yes, it's not THAT hard to learn to do it, and do it safely, and maintain the awareness that's required even when distracted. But why take the risk for so little benefit?

I think a lot of us who have done a lot of diving and had a lot of training, and who have asked a great deal of ourselves, forget how little tolerance for task loading recreational divers can have. I do remember the first time I tried to unclip an SPG to look at it -- I ended up in the silt. I remember spooling up after a bag shoot, and losing control of the ascent. Tolerating task loading underwater is LEARNED, and until you're reasonably good at it, I don't think you have any business on a high O2 mix in the water.

 

[DevonDiver]

Breathing it on the boat may not be of any enormous use, but it's virtually entirely safe.

Yeah - safety.

Isn't that what this was supposed to be about?

Breathe some O2 to possibly increase off-gassing, thus adding some conservatism/increased safety on subsequent dives?

And people are seriously suggesting that taking O2 to 20ft is the best way to increase that safety?

Substitute a potentially fatal risk for a potentially minor risk...

That's like suggesting the best way to prevent a wasp sting is to keep a funnelweb spider in your hat.

 

[Akimbo]

I really don't understand why anyone would recommend that a recreational diver, diving within no-deco limits (whatever his are), should do a gas switch and breathe O2 at 20 feet. Breathing it on the boat may not be of any enormous use, but it's virtually entirely safe. Doing a gas switch and breathing it underwater has a whole host of place where things can go wrong . . . yes, it's not THAT hard to learn to do it, and do it safely, and maintain the awareness that's required even when distracted. But why take the risk for so little benefit?...

I don’t think anyone is suggesting that anyone who makes a couple of dives that are nowhere near decompression limits and goes home “should” use O2 on an extended safety stop. The other extreme is someone on a liveaboard that makes 4-5 dives a day for a week. Let’s also say there isn’t a chamber within a day’s travel, they aren’t in the best of physical condition, and are over 60.

All these parameters are outside what tables and algorithms have been developed and tested against. Add the fact that there is an acceptable level of failure designed in. Keep in mind that the failure rate is acceptable by the developers, primarily the US and Royal Navies, because there is a chamber nearby or onboard.

In this case, the risk of getting bent without the ability to treat increased dramatically. IMO, that should be considered as unacceptable as running out of breathable gas. At some point the risk of DCS exceeds the risk introduced by the use of in-water O2.

Having used and administered tens of thousands of Ft³ of O2 to divers at water stops without incident, I can say the risk is minimal with very little knowledge and preparation. In fact, a 15-20' oxygen reped can be made shortly after returning to the boat rather than lug a stage bottle with virtually equal benefit — when used prophylactically as part of the surface interval rather than crediting towards your dive profile. See: http://www.scubaboard.com/forums/diving-medicine/402490-increasing-safety-margin.html

 

[Deep South Divers]

SeaJay, Glad to hear you refer to your chemo in the past tense.

Thanks, man. Chemo sucked. This March 11th, I go for my 5-year and final CT scan to make sure that they still don't see any cancer in my body. March 11th is both the anniversary of my diagnosis and my birthday. Yes, I was diagnosed with testicular cancer on my 37th birthday. Happy birthday to me.

This March 11th could be very happy, by comparison.

Actually, I'll have to ask the docs... They may use the "end chemo" date as a 5-year anniversary, rather than the diagnosis date, which isn't until September of 2012. We'll see.

...But my point of bringing this up is this: Since I had 100% O2 sitting around, and some of my mid-chemo symptoms felt very much like being hungover with the flu at the same time, I used it... That is, I self-administered 100% O2 a couple of times - and 50% a couple of times, when I ran out of 100% - at about 10 or 15 minutes at a shot. Of course, this was while bedridden, so at 1 ata.

The stuff definitely made me feel a lot better. I don't know why.

 

[Blue Sparkle]

... even Nitrox at 30 to 40 % mixes, is essentially increasing the amount of free radicals your body is exposed to enormously--this is what we take Vitamin C and Vitamin E, etc, to eliminate, due to the unhealthy nature of free radicals in your body.

Pardon me for the tangent, but could you please elaborate on this? I don't use (pure) oxygen in the water, but I do dive with nitrox at >30% mix. I hadn't heard or read this about an enormous increase in free radicals, nor did I know about taking Vitamin C and E to offset it. I really wasn't thinking about nitrox potentially harming me (if used according to MOD, etc.).

So... this sounds like something I would like to know more about, before I use nitrox again (so far I don't "have" to use it, but am doing so electively on some dives).

Thanks,
Blue Sparkle

 

[Moonglow]

Decent overview:

Oxygen Toxicity, Enriched Air Nitrox, and Scuba Diving - Oxygen and Scuba Diving

 

[danvolker]

Pardon me for the tangent, but could you please elaborate on this? I don't use (pure) oxygen in the water, but I do dive with nitrox at >30% mix. I hadn't heard or read this about an enormous increase in free radicals, nor did I know about taking Vitamin C and E to offset it. I really wasn't thinking about nitrox potentially harming me (if used according to MOD, etc.).

So... this sounds like something I would like to know more about, before I use nitrox again (so far I don't "have" to use it, but am doing so electively on some dives).

Thanks,
Blue Sparkle

You have heard of oxidation, or random oxidative metabolism....free radicals get created daily by random oxidative metabolism, but when we breathe 32 % or 36% or 40% Nitrox mixes, we are INCREAsing the free radical production....
Now I use Nitrox.....But I do it knowing it is NOT a healthy choice..it will create more free radicals, which accelerate aging, cause inflamation, and are bad for your immune system in high concentrations. It is healthier for you than getting DCS, or bubbling a lot after diving. It is a trade off. For that matter, when I go on a 40 mile bike ride trying to average 25 to 30 mph the whole way ( with a couple of friends taking turns pulling), this will drastically increase my production of free radicals, BUT I will be taking lots of vitamin C, E, selenium and Astaxanthin ( the new super antioxidant) before and after the ride to counter act this.....we often see athletes that look much older than they should--sometimes this is genetics, sometimes this is these people never taking anti-oxidants along with their big workouts.

So, I guess what I'm saying, is that if you are "trying to have a healthy lifestyle", then when you use Nitrox, two thousand milligrams of C every 3 hours( a mineral ascorbate form like Alacer's Supergram II or EmergenC.. a non acidic C that will not bother your stomach in dosages high enough to be effective), 1000 IU or so of Vitamin E, the D Gamma type is the ONLY type of E your body will use, don't buy the crappy Alpha tocopherol....and the Astaxanthin a couple of 4 mg pills before diving and again 6 hours or so later. Do this, and it is my guess/hope that the free radicals will be eliminated...I do know that I get no inflamation, even after extreme profiles when I do this.

This is contentious though,,,people like me believe that science indicates this is where we should direct ourselves....then you have the FDA, potentially the most evil agency of all in the US, trying to outlaw vitamins without a doctor prescribing them...