Oxygen toxicity and Hyperbaric Chambers

[stoney85]

First post here guys.

Very quick background which brings me to the question i have.

My trade background is in the automotive industry as a mechanic, mines as a drill fitter, hobbies include flying, cars and scuba diving.

Just recently i have changed career paths again, and will be working with my Dad in bringing Hyperbaric Chambers into Australia from the States.

This design has been around for 20 years, and we are in the process of getting these TGA (therapeutic goods administration of Australia) approved, similar to FDA in the USA.


One question i haven't been able to get a decent answer for is in regards to oxygen toxicity.

Having done a bit of diving, that was a big part in the max bottom depth of an advanced recreational diver, being 1.6ata's, around 50psi in old terms, anything after that and the extra pressure can cause hyperoxia, breathing roughly 160% oxygen levels, which can lead to seizures, and potential drowning from regulator loss and so on.

Now when it comes to Hyperbaric Chambers, which are used for medical treatments, oxygen toxicity is unheard of. Dad has done over 1000 (dives) treatments on patients with never an issue, these treatments last 90min and are at 2.6 atmospheres.

I'm aware that the safety risks of a convulsion whilst in a chamber will not have the same risks, i don't have a definitive answer to that question.

It was only recently a few divers i met recently asked me about oxygen toxicity, and i said id get back to them.

I'm sure i'll be asking a few more questions in the future, i love learning about things that interest me, and it helps knowing what you're fixing, even its its the science behind it.

 

[lisab]

Hi stoney85 - welcome to PF!

I can't answer your questions but I suggest you contact DAN (Divers Alert Network). They are active in research areas such as oxygen toxicity.

http://www.diversalertnetwork.org/

I did a search of the DAN site, and found this article:

http://www.alertdiver.com/Oxygen_Toxicity

Perhaps you could contact the author of that article. Here's his bio, from the link above:

Petar Denoble, M.D., D.Sc., is the senior director of DAN Research. After graduating from medical school, he joined the navy in the former Yugoslavia and specialized in naval and diving medicine. For 13 years he was involved with training, supervision and treatment of divers in open-circuit, closed-circuit, deep-bounce and saturation diving. His doctoral thesis focused on studying oxygen consumption in underwater swimming. Denoble has been at DAN for 20 years and has been involved in the development of the largest database of exposure and outcomes in recreational diving, the monitoring of diving injuries and the study, treatment and prevention of fatal outcomes and long-term consequences of diving accidents.

 

[SteamKing]

You can find out some things about oxygen toxicity here:

http://en.wikipedia.org/wiki/Oxygen_toxicity

Oxygen toxicity is not a problem in the therapeutic settings because doctors know about its effects and safety protocols have been developed so that patients undergoing hyperbaric treatment are protected. However, there have been recent accidents where injuries and deaths were caused not by oxygen toxicity, but by fires or explosive decompression. Fire is a serious threat anytime pure oxygen is present, even at normal atmospheric pressure.

 

[Borek]

these treatments last 90min and are at 2.6 atmospheres.

2.6 atm pure oxygen, or 2.6 atm total air pressure (so with oxygen partial pressure of around 0.55 atm)?

 

[stoney85]

I've read a bit about oxygen toxicity, and you're bang on the money 'Steamking' regarding the safety of being in a hospital environment and Doctors being present

Pure oxygen is used in this chamber design, there is still the residual air in the chamber from initial start up, but with flushing of the gases and just increasing pressure with O2, oxygen levels stay above 90%.

Patient comfort is one of the main reasons of using pressurised oxygen, instead of compressed air and an O2 mask, much less invasive of your personal space, costs a bit more for medical grade oxygen compared to a filtered air compressor setup, but with it being a monoplace chamber as opposed to a multiplace, the cost difference is negligible.