Rescue of an Unconscious Diver Underwater

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Hello,

The original post appears to be a reference (with a few misinterpretations) to an initiative by the UHMS Diving Committee to produce guidelines for the rescue of an unconscious diver. Several of you have linked to the paper that was published as a result of that project in posts above . If you are interested in this subject, I would suggest you read the paper, and as the coordinator of that project I would be happy to answer any questions / comments that arise.

Simon M
 
Hello,

The original post appears to be a reference (with a few misinterpretations) to an initiative by the UHMS Diving Committee to produce guidelines for the rescue of an unconscious diver. Several of you have linked to the paper that was published as a result of that project in posts above . If you are interested in this subject, I would suggest you read the paper, and as the coordinator of that project I would be happy to answer any questions / comments that arise.

Simon M
Thank you for the offer.

In this thread right now, the issue in which some are interested is raising a diver who is undergoing a seizure. As you know, some contend that the diver should not be raised during the tonic or clonic phases, but the study disagrees. I wonder if you could go into that in more detail.
 
I don't get this part, was this ever recommended and how is it possible?
It's possible. It requires a lot of strength and it's as stupid as it is equally ineffective. I had to do this on the side of a wall when I became a climbing instructor way, way back. One hand behind the victim (being on their left side is best), and then use the other hand to do the compressions.
 
Thank you for the offer.

In this thread right now, the issue in which some are interested is raising a diver who is undergoing a seizure. As you know, some contend that the diver should not be raised during the tonic or clonic phases, but the study disagrees. I wonder if you could go into that in more detail.


Hello John,

This was one of the more difficult issues. As you correctly point out there is a long standing belief that bringing a diver to the surface during a seizure is dangerous because the glottis (the airway at the larynx) will be closed and the airway will be blocked. This would create a risk of pulmonary barotrauma because air would be prevented from escaping from the lungs during the ascent. That is the basis for the long held belief that one must wait until the seizure has finished before bringing the diver to the surface.

However, there are some other facts that are important.

First and most importantly, the assumption that the glottis is inevitably closed during a seizure is incorrect. We see sometimes see non-diving patients suffering "status epilepticus" which essentially means a seizure that does not terminate, and which may continue for a long time. If the airway were closed in this setting it would be a non-survivable event but the vast majority of patients survive prolonged seizures. Moreover, I (and many of my anesthesia or ER colleagues) have been able to manually ventilate such patients with a bag - mask during a seizure which, again, means that the airway is not completely closed. In addition, we obtained a video of the glottis in pigs during a seizure which showed that although there is certainly a partial and rapidly fluctuating obstruction of the glottis during a seizure, it is also open on a rapidly fluctuating basis.

Second, the first thing that a patient starts to do after a seizure (but while still unconscious) is to start breathing heavily. If they did that with an unprotected airway underwater, then they will inhale water and drown.

If you put these two facts together, then it is possible to draw the conclusion that the period when a diver is seizing but not breathing may actually be the correct time to bring them to the surface, because if you hold them underwater until the seizure finishes and they start to breathe, then they will almost certainly drown. This is particularly true if the airway is unprotected (regulator out) and our conclusion was that in this setting the risk of pulmonary barotrauma in bringing them to the surface was less than the risk of drowning by holding them underwater until the seizure had finished.

We gave different advice if the regulator or mouthpiece or full face mask was still in place. We could argue about how much "airway protection" is provided by a regulator held in place, but we thought that if the reg / mouthpiece remained in place and the rescuer could hold it there, then the balance of risk would shift in favour of waiting until the seizure had finished before bringing the victim to the surface. In this setting, it is anticipated that if the victim starts breathing then they are much less likely to drown because the reg / mouthpiece is still in place.

That is the logic behind the recommendations around seizures.

Simon M
 
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Why when rescuing an unconscious diver is part of BSAC core training:
* Ocean Diver from 6m,
* Sports Diver from 10m,
* Dive Leader from 15m,
* Advanced Diver from 20m.
 
Hello John,

This was one of the more difficult issues. As you correctly point out there is a long standing belief that bringing a diver to the surface during a seizure is dangerous because the glottis (the airway at the larynx) will be closed and the airway will be blocked. This would create a risk of pulmonary barotrauma because air would be prevented from escaping from the lungs during the ascent. That is the basis for the long held belief that one must wait until the seizure has finished before bringing the diver to the surface.

However, there are some other facts that are important.

First and most importantly, the assumption that the glottis is inevitably closed during a seizure is incorrect. We see sometimes see non-diving patients suffering "status epilepticus" which essentially means a seizure that does not terminate, and which may continue for a long time. If the airway were closed in this setting it would be a non-survivable event but the vast majority of patients survive prolonged seizures. Moreover, I (and many of my anesthesia or ER colleagues) have been able to manually ventilate such patients with a bag - mask during a seizure which, again, means that the airway is not completely closed. In addition, we obtained a video of the glottis in pigs during a seizure which showed that although there is certainly a partial and rapidly fluctuating obstruction of the glottis during a seizure, it is also open on a rapidly fluctuating basis.

Second, the first thing that a patient starts to do after a seizure (but while still unconscious) is to start breathing heavily. If they did that with an unprotected airway underwater, then they will inhale water and drown.

If you put these two facts together, then it is possible to draw the conclusion that the period when a diver is seizing but not breathing may actually be the correct time to bring them to the surface, because if you hold them underwater until the seizure finishes and they start to breathe, then they will almost certainly drown. This is particularly true if the airway is unprotected (regulator out) and our conclusion was that in this setting the risk of pulmonary barotrauma in bringing them to the surface was less than the risk of drowning by holding them underwater until the seizure had finished.

We gave different advice if the regulator or mouthpiece or full face mask was still in place. We could argue about how much "airway protection" is provided by a regulator held in place, but we thought that if the reg / mouthpiece remained in place and the rescuer could hold it there, then the balance of risk would shift in favour of waiting until the seizure had finished before bringing the victim to the surface. In this setting, it is anticipated that if the victim starts breathing then they are much less likely to drown because the reg / mouthpiece is still in place.

That is the logic behind the recommendations around seizures.

Simon M
Thank you very much. That is extremely helpful.
 
I will need to borrow a half dozen divers, give them seizures, and then see what happens when a regulator is stuck in their mouths before I can really evaluate the original post.

I'm thinking that if a diver has seized and lost their regulator, their mouth and portions of their airway are now filled with water. If I stick a regulator in the mouth and air comes out...isn't it going to push that water into their lungs? I'm not sure what inserting the regulator accomplishes, unless the seized diver has kept their throat closed and then awakens [sic] again, willing and able to purge the flooded regulator and resume breathing.

Confused. And not at all certain I'd agree with futzing around with the regulator instead of just getting the victim topside in the fastest safe manner.
 
Confused. And not at all certain I'd agree with futzing around with the regulator instead of just getting the victim topside in the fastest safe manner.
Darned good point.

Back in the Bronze age, when I was starting my undergrad studies, we had a course on lab safety. "If this, and provided that, do so. If that, and provided this, do si. Etcetera, etcetera, etcetera." Our TA got a little peeved when I insisted that no-one will be able to remember all those ifs and hows if SHTF. I'm a firm believer in KISS. And the simpler, the better. The less options, the better. If SHTF, it's better that someone does something sub-optimal than no-one doing anything since they can't remember what-when-if.

Discussing what to do with an unconscious diver if this and provided that seems to me to be somewhat like discussing how many angels can dance on the pin of a needle. Having someone able to do anything close by should be seen as a bonus, and they're probably going to be stressed out of their minds anyway, so KISS.
 
Some of the situations with unconscious divers prohibit direct ascents. So what do you do until then?

Unless they are running a ffm it's almost certainly not going to be a happy ending, but it's a possibly useful course of action.
 
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