Monoplace seizure

[LubaScuba]

Seizures tend to be self-limiting, so it should not be necessary to remove the O2 to get it to stop. Besides that, breathing tends to stop for a short time during seizure. Also, the large amout of muscle action during a seizure tends to metabolize a lot of the O2 already in the person. Point is, there shouldn't be a huge rush to vent the O2 or to "ascend" the patient.

What's the big deal anyway?? It's my understanding that hyperoxic seizures are not that common in hyperbaric chambers and when they do occur, at least you know the patient isn't gonna drown. The probability of drowning when breathing resumes, not the seizure itself, is the primary reason hyperoxic seizures are such a serious concern for divers.

I thought the O2 concentration to the mask the patient breathes from could be adjusted to any percentage? Even if not, from others more knowledgable posters, it seems the O2 can be flushed from the chamber in 10 seconds if necessary.

Dear Snowbear,

I am sorry to tell you that contrary to your opinion there is a well documented scientific evidence that hyperoxic seizure does not stop as long as high level oxygen delivery is not discontinued or the patient eventually dies. Please be more careful when publicly claiming your personal opinions as some 'welknown facts' because it can be misleading to others such as the claim that "it is possible to flush the oxygen in the chamber in just 10 seconds" was obviously misleading to you. The oxygen seizure in the monoplace chamber is a serious, potentially life threatening emergency so i guess it is a bit of a 'big deal'.

Take care


PS Here is my little personal opinion. Loving both jazz and diving medicine i'd say that diving medicine seems to be rather opposite from the jazz music in some aspects. In jazz it is more important how you say something than what you actually say, whereas in diving medicine, if you pay too much attention on how to say things instead of what exactly you are saying it just might not swing hard enough!

 

[pipedope]

Dear Snowbear,

I am sorry to tell you that contrary to your opinion there is a well documented scientific evidence that hyperoxic seizure do not stop as long as high level oxygen delivery is not discontinued or the patient eventually dies.

Can you give us some pointers to the documentation?
Is this from clinical treatments (not DCI) or from DCI treatments related to diving?

I don't know of any cases of O2 tox of a diver being treated for DCI. That doesn't mean it hasn't happened, but I don't know any cases. I know lots of divers who have been on chamber rides.

It is clear that if someone does tox in the chamber action needs to be taken but the point is that it doesn't require "instant" action.

Taking the wrong action would be much worse than doing nothing until you are sure of the right action. Surfacing the patient would be extreemly dangerous and much worse than doing nothing for a short period of time.

While a monoplace chamber is not the best for treating an injured diver it is FAR better than no treatment for a diver with DCI.

 

[Snowbear]

Dear Snowbear,

I am sorry to tell you that contrary to your opinion...

Please be more careful when publicly claiming your personal opinions as some 'welknown facts' because it can be misleading to others

Please reread my post.... I said "it's my understanding" not, "it's my opinion" and represented nothing as "well known facts"

(The part where I said seizures tend to be self-limiting was as typed... I said seizures, not hyperoxic seizures) As for the well-documented scientific evidence you stated..... please answer pipedope's post.

Any seizure is potentially life threatening if not stopped (see the not breathing part ) By not a big deal and the rest of what I said - Are you saying that it's such a big immediately life-threatening deal that it's more important to "ascend" the non-breathing patient with a potentially closed airway than it is to take a couple minutes to stop the seizure first?

 

[LubaScuba]

Seizures tend to be self-limiting, so it should not be necessary to remove the O2 to get it to stop. Besides that, breathing tends to stop for a short time during seizure. Also, the large amout of muscle action during a seizure tends to metabolize a lot of the O2 already in the person. Point is, there shouldn't be a huge rush to vent the O2 or to "ascend" the patient.

What's the big deal anyway?? It's my understanding that hyperoxic seizures are not that common in hyperbaric chambers and when they do occur, at least you know the patient isn't gonna drown. The probability of drowning when breathing resumes, not the seizure itself, is the primary reason hyperoxic seizures are such a serious concern for divers.

I thought the O2 concentration to the mask the patient breathes from could be adjusted to any percentage? Even if not, from others more knowledgable posters, it seems the O2 can be flushed from the chamber in 10 seconds if necessary.

I think you should read your own first sentence. It is either related to oxygen seizure so the conclusion is totally wrong or it is a very arbitrary extrapolation of normoxic seizure over a hyperoxic one. Either way it is invalid and was claimed bluntly as a fact without the slightest mark that it just might not be the case or that it was your own understanding, opinion or whatever. So forgive me to put it this way saying that there is a reason why medically untrained people should sometimes leave the subject to professionals as misleading others can eventually adversely affect their wellbeing. (same as reading my English) What i just said might look arrogant but believe me, ignoring someones years and years of studying and experience by trying to participate in the science easy way is much more arrogant than that.


As for the sources you asked me to support what i said i would tell you first that the phenomenon in question even has its own name in diving medicine (it is called Bean effect) but you really don't have to know it as you are not a doctor. If you are still keen to read here you go:



Balentine JD. Pathogenesis of central nervous system lesions induced by exposure to hyperbaric oxygen. Am J Pathol 53: 1097-1109, 1968.[ISI][Medline]
Balentine JD. Dendritic degeneration following hyperbaric oxygen exposure. Adv Neurol 12: 471-481, 1975.[ISI][Medline]
Balentine JD. Pathology of Oxygen Toxicity. New York: Academic, 1982.
Balentine JD and Gutsche BB. Central nervous system lesions in rats exposed to oxygen at high pressure. Am J Pathol 48: 107-127, 1966.[ISI][Medline]

Bean JW. Effects of oxygen at increased pressure. Physiol Rev 25: 1-147, 1945.



Good look going through it.


(there are some potentialy disturbing parts about torturing animals which i don't recommend you to read but the rest should be OK)

 

[Snowbear]

Funny, these guys said pretty much the same thing I did....

O2 seizures per se resulting from acute exposure to hyperbaric hyperoxia are not believed to be harmful.

...there is a reason why medically untrained people should sometimes leave the subject to professionals as misleading others can eventually adversely affect their wellbeing. (same as reading my English)...

This discussion board (and this forum), are open to professionals and non-professionals to participate in. Do you seriously think anything I said is going to inluence anyone running a monoplace chamber for treating DCI??

...What i just said might look arrogant...)

Very much so.

...the phenomenon in question even has its own name in diving medicine (it is called Bean effect))
...
Good look going through it.

Actually, I would like to look through it. I wouldn't have asked if I wasn't interested.
Since you once again condescendingly assumed I should have no need to know stuff, and since you seem more inclined to "put me in my place" than actually educate me, I looked up what I could....
From the same reference quoted above:
...continued exposure to HBO2 can result, first, in permanent neurological damage and paralysis (i.e., the "John Bean effect") and eventually death with prolonged exposure (12).

Since you seem more inclined to point out my ignorance and stupidity than answer my question (Or perhaps you again think it is not for me to know, since I'm not a doctor?), I'll ask it again:
Are you saying that it's such a big immediately life-threatening deal that it's more important to "ascend" the non-breathing patient with a potentially closed airway than it is to take a couple minutes to stop the seizure first?

 

[Table6A]

Any thoughts?

As I reread all our posts, I believe we are thinking of different chamber configurations and using different schools of thought. I say always treat your DCI in the best setting possible and be prepared to work in an imperfect one. There's not much more you can do than that.

 

[LubaScuba]

"The chamber does not need to be brought to 20.9% O2 (AIR), though that is preferred. The seizure may subside at 60% O2 or 40% O2."



60% at 60ft gives 1.68ATA of O2. Would you really consider that as a very efficient 'drug' to 'treat' a hyperoxic seizure? Me neither. Even if sufficiently low it would still take considerable amount of time to reach that percentage, wouldn't it? So far we could not see any realistic answer in this thread about how long would that take. Anyway you put some very good points like the one about monoplace being a second choice when it comes to DCI treatment which is something all divers should be well aware of! As lot of people say different things it is very easy to mislead someone which can have even tragical consequences. Monoplace and multiplace facilities very often coexist in the same area which is a completely different situation from having only a monoplace at the site where measuring risk of treatment against risk of leaving the diver untreated can justify using this type of chamber in DCI case. It is really essential not to confuse the 'final decision makers' (whoever happened to decide the destination of divers with possible DCI) in diving emergencies and expose the injured diver to unnecessary risks of treatment in a monoplace chamber where multiplace chamber was perfectly available! Oxygen toxicity is certainly not the only reason why monoplace should always be the second choice, but it is one of the most important reasons.

 

[LubaScuba]

As I reread all our posts, I believe we are thinking of different chamber configurations and using different schools of thought. I say always treat your DCI in the best setting possible and be prepared to work in an imperfect one. There's not much more you can do than that.

Could not agree more for example.

 

[LubaScuba]

Dear Snowbear,
First of all i do not think you are ignorant or stupid and had no intention to judge you only to criticize your claim which i believe was a bit rushed. If you look how i started this thread you'll see it was addressed to all, so i am not a priori against anybody's participation.
I totally agree with you that ascending immediatelly is not the best thing to do but i wanted to check the existing alternatives which didn't seem too much brighter. I am more keen to say that O2 seizure in a monoplace is a lose-lose scenario than to suggest some particular correct action.

Take care

 

[Table6A]

It seems this has turned from a friendly discussion to something else. As such, I am going to extract myself at this time. Enjoy yourselves...

~ Kip