Question about Oxygen

[medic_diver45]

OK, all of you are probably aware, I am the one who threw the flashbang grenade into the hornet's nest that was "The Oxygen Administration" debate. I shot my mouth off before and stepped on some toes in my attempt to balance what I learned in regular clinical settings and what is the "norm" for dive accidents. I have a simple question for the dive medicine docs (I am no longer debating the points were brought up in the previous forum):

If you are far out (say 45 minutes from shore) and you only have a single D tank, is it preferable to give as high concentration of oxygen as possible for a short time (assuming that that is going to burn through the O2 tank faster) or maintain the patient on a lower concentration (say 70%) for a longer period of time?

What are the risks involved with potentially running out of O2 on a DCS patient (that is are they gonna crash or worsen because of a sudden drop in FiO2)?

I can't seem to get anyone to look at this question for me and look beyond the "JUST GIVE AS MUCH O2 AS YOU CAN" response. I'm new to dive medicine (but not to other forms of medicine) and I am trying to learn. Can any of the MD's on here give me honest answers (non-sarcastic) to this?

-Steve

 

[jbd]

What are the risks involved with potentially running out of O2 on a DCS patient (that is are they gonna crash or worsen because of a sudden drop in FiO2)?

I can't seem to get anyone to look at this question for me and look beyond the "JUST GIVE AS MUCH O2 AS YOU CAN" response. I'm new to dive medicine (but not to other forms of medicine) and I am trying to learn. Can any of the MD's on here give me honest answers (non-sarcastic) to this?

-Steve

Steve,

You might want to take a look at www.scuba-doc.com. You might find some answers there. Even if you don't find the answer to your specific question in this thread its still a good site to have bookmarked.

As for the scenario you give, the idea is to clear out the excess N2 as much as you can as quickly as you can. By giving 100% O2 you increase the gradient between the aveoli and the "air" thus increasing the out flow of N2.

Thats why you are getting the give as much O2 as you can answer.

 

[medic_diver45]

Steve,

You might want to take a look at www.scuba-doc.com. You might find some answers there. Even if you don't find the answer to your specific question in this thread its still a good site to have bookmarked.

As for the scenario you give, the idea is to clear out the excess N2 as much as you can as quickly as you can. By giving 100% O2 you increase the gradient between the aveoli and the "air" thus increasing the out flow of N2.

Thats why you are getting the give as much O2 as you can answer.

I understand the physiology behind why we do the high O2 concentrations. My question was just one of logistics and preparedness (worst case scenario kind of deal- running out of the thing you need the most). I'll check out that website and see what I can find there. Thanks for the tip.

-Steve

 

[Atticus]

I am not a doctor, but I can say that my training was to deliver as high an fiO2 as possible, even if it means not being able to deliver it long enough to hand the patient off to someone with a larger O2 supply.

Hopefully some of the more educated members can provide a more detailed explanation.

 

[jerrynuss]

Have you considered the option of the remo? Basically an oxygen administration rebreather? Since there is a large about of oxygen being wasted it is an option for trying to conserve gas while cutting back on the amount of gas carried on a boat or to a dive site.

Good question! How many O2 delievery devices should be carried on board and how much gas should be carried?

Jerry Nuss

 

[medic_diver45]

I think a good rule of thumb would be to carry enough O2 to get your butt to shore but that's not practical on a small boat if you're going more than an hour from the harbor and don't have the coast guard to come get your butt.

I don't know what to think about the REMO thing. I contacted DAN and asked for some more info about it so I can make an educated guess.

Atticus, thank you for your input. I didn't mean to discourage anyone with something positive/constructive to contribute- just to discourage certain persons with nothing but hateful things (badmouthing me and anyone else who asks why and doesn't blindly follow what DAN says) to stay out of my attempts to learn more about something that interests me. Thank you again for your input.

-Steve

 

[jerrynuss]

It is a tough question and a boat operator should put some thought into it. Being from Terre Haute you also run into the same situation I do. Some of our dive sites are remote and difficult to get medical support. I carry O2 with me to the dive site but a couple of them are in a dead zone for cell phone. DCS would not be a problem but near drowning or an over expansion injury could be a problem.

 

[underwater daphne]

well i don't really know, but thinking for example you're exausted and don't have enough air to breath. would you prefer to have not enough for a longer period or enough for a shorter period. not having enough for a longer period will keep you weak and will not help you get to shore or out of the situation. having enough will get you stronger and may help you get out of the situation.

i know it's not medical, but for me kinda logical.
i'd give as much o2 in a go, rather than ration it not knowing if my rations are a waste, coz it's just too little to have an effect.

 

[Wreckie]

It would seem that not only is the recomendation from the medical side to give all you have until you run out, but also that this is the way the equipment is designed.

All the O2 kits i have seen sold to divers do not have the option to reduce the flow rate, its a demand regulator for those who are breathing and a free flowing mask for those who arnt (with AV) or if they are incapable of keeping the regulator in their mouth.

One of my loacal clubs has 7L 200 bar cylinders (normal diving ones) filled with O2 and fitted perminantly to their boats, they then have a 5m(18ft) hose and reg attached so it can reach almost anywhere on the boat without moving the cylinder. This rig gives them over an hours worth of O2 on the boat and the life boats/helicopters are rarely further than that away.

Mike

 

[underwater daphne]

the oxygen tanks here are equipped with a free flow where you can choose the amount of oxygen. it's a thingy you can turn at the end of the valve. i think this is recommendable, because if you are doing mouth to mask you can attach the oxygen hose to the mask and let a bit of oxygen flow in additional to your own breathe. this way less o2 will be wasted and the patient will get more than just your breathe.