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Shallow Water Blackout (SWB) - and Terry Maas

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Periodically I re-read Dr. Terry Maas' paper on Shallow Water Blackout:
as a reminder of a particular danger of spearing, the warning signs and appropriate measures.

Terry Maas was so concerned about this that he also co-invented an automatic/self-rescue vest for spearos and freedivers:



Until today, I did not realize quite how personal and deep his motivation must be. Today I came across an old article on DeeperBlue.com, dated 2002, describing the tragic death of his son, Loren, while diving:

Some things to ponder ahead of the 2019 season.
 
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A more uplifting video on a family spearing, the Paxman's of Australia:
 
Periodically I re-read Dr. Terry Maas' paper on Shallow Water Blackout:
as a reminder of a particular danger of spearing, the warning signs and appropriate measures.

Terry Maas was so concerned about this that he also co-invented an automatic/self-rescue vest for spearos and freedivers:



Until today, I did not realize quite how personal and deep his motivation must be. Today I came across an old article on DeeperBlue.com, dated 2002, describing the tragic death of his son, Loren, while diving:

Some things to ponder ahead of the 2019 season.



A very poignant post for me seeing as fellow spearo and deeperblue member Marco van Wyk sadly passed away while spearfishing last week. Although still to be confirmed, it was presumably due to shallow water blackout.

I joined Marco at Cape Vidal on the Southern Coast a year or so ago on a epic spearfishing trip. He was a very very good spearo and even a better person - a true gentleman.... he will be sorely missed.
 
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He was a very good Spearo but he still died. I’ve owned every version of Terry’s Freedive Recovery Vest since the first one and won’t dive without it. I just can’t understand why more Spearos don’t wear the vest. It’s so sleek that you don’t even know you have it on. Many people say it’s too expensive but then many of these same people own spearguns that cost more than the vest.
 
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it's very sad that this kind of accident is still happening. Although everyone should know that you should not dive alone.
The vest is a great idea, the problem is only that if you have a blackout, the vest lifts you up, you can't breathe as long as your nose is covered. Also a reason never to do dry static with nose clip alone.
Here you can see and hear very clearly how the athlete can only breathe independently once the mask has been removed (at min. 0:30).
 
it's very sad that this kind of accident is still happening. Although everyone should know that you should not dive alone.
The vest is a great idea, the problem is only that if you have a blackout, the vest lifts you up, you can't breathe as long as your nose is covered. Also a reason never to do dry static with nose clip alone.
Here you can see and hear very clearly how the athlete can only breathe independently once the mask has been removed (at min. 0:30).


I may be missing something, but I don't see how the video proves that he can only breath independently after the mask is removed. His mouth seemed to be open. Couldn't he breath through it? He does seem to recover rapidly after the mask is removed, but could that just be a coincidence? Maybe he had just been breathing long enough through his mouth to get his oxygen levels up.

But putting that aside for now. We should all have a dive buddy who is doing nothing but watching us, but its a fact that we don't. Very few Southern California white sea bass hunters dive that way and there is a reason. The visibility is often poor and the kelp is thick. I've watched my buddy disappear into the kelp and immediately lost sight of him. After a while I think it must be time for him to surface, and I look 10 yards across the kelp bed and see him on the surface. If he had not surfaced I wouldn't have known where to look for him. If he had blacked out and been wearing a vest, it would have brought him to the surface where I at least had a chance to help him get that mask off.

Pure freedivers advocate rules that can be very difficult for spear fisherman to follow in actual ocean conditions. I've taken many graduates of freediving courses out on my boat, and even a few freediving instructors, and they don't follow those rules when spearfishing. I suppose that if we were all smart we would decide that it just isn't possible to dive for white sea bass in California in the conditions that prevail on most days in most locations. That would certainly be a rational choice. After all, how valuable is a fish? But if we are foolish enough to dive the way we do, at least the vest reduces the risk somewhat.
 
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Hey Bill,
Good thoughts and knowing how long you have been in the game I love that you are not set in your ways. It's awesome that you have adopted the vest and pioneered its use. But yes, a lot of spearos are on the fence about it.

I just found a note on my laptop saying I should buy one. That note dates back four years... I can come up will all sorts of monetary explanations/excuses for not getting it before - but the bottom line is I finally have one on the way. If you think rationally, there is no reason not to have one and I have just buried that fact for the past four years. But becoming a bit more experienced now, not only do I dive a bit deeper and longer and target bigger fish - I also know of many more spearos lost, some in places I have dived or are intending to and also recently one that I knew personally. So, I just couldn't keep telling myself that the FRV is a luxury item, when it's really a quite basic, potentially life saving device. But please be smarter than me and get one before someone you know disappears - that someone could also be you.

As for the video and the "mask off" comment - for some years now, it's been an established rule of freediving rescues to immediately remove the mask and blow on the face of a BO'ed diver. The thinking is that the receptors on the face "feels" the airflow and that the brain does the math and realizes that you are now no longer submerged and hence it is safe to start breathing.
This works because being blacked out doesn't mean your brain has totally shut down - it is kind of in a standby mode, preserving the last bit of energy/oxygen to stretch out your body's self-preservation mechanisms.
One of these is that as you black out, your glottis closes blocking water from reaching your lungs. This is why even though a diver has BO'ed and is submerged, he may not have water in his lungs yet. After a few mins(?) this last amount of reserve oxygen in the brain runs out and all systems shut down and the glottis opens - that's when you drown. So, even if a BO'ed diver has his head above the surface and an open mouth it is very likely that the glottis is still closed and that he is not yet breathing.

As for @3joern's comment that you can't breathe with the nose covered, I am not so sure. As mentioned above, it is likely helping a whole lot taking it off and it is standard procedure now. And no one really wants to let a BO'ed diver just come to himself with the mask on for the sake of seeing if it will happen so I don't think we have enough data to conclusively say a mask blocks recovery fully.
But more importantly, it is certainly not a valid counterargument against the vest. The vest will bring you to the surface, which will make you visible to your buddy who can then take your mask off and start a proper rescue. And in case you're buddiless, you might start breathing by yourself as your head is now above water - even with your mask on. At least it beats sinking to certain death.

I have spent a long time thinking about all possibly scenarios with the vest and I hate to say this, but say a diver suffers a fatal heart attack or something else that, sadly, proves fatal then at the very, very least the deceased will be on the surface if he was wearing a vest (bar entanglement). And though many of us wouldn't mind a seaman's funeral I think a lot of families would get some sort of comfort from not having to deal with all the unanswered questions that come with not even having a body...

As for whether it is expensive? Well, I have seen the argument that it is cheap if it saves your life, but when you are scraping by it's still not cheap. But hey,
a lot of guys spend way more money on boat upkeep, flights, spearo trips or on a new gun. Nowadays, the FRV is less than a C4 or Bleutec bluewater gun and way less than many wooden brand name guns or custom builds.
Also, even if you are a semi-broke student, artist, freelancer, etc - a lot of us burn a few hundred bucks a month on coffees, burgers, beers, takeout food or what not. So, cut down on that for a few months and there's your vest. Or just start talking about the wonders of it around your mum, GF or wife and pretty soon I bet someone will offer to pay half of it...

Dive safe,
David
 
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I'am not against the vest, I'am just think that "only" the vest can't save you live.
Maybe most of the spearfisher think dive alone with the west is save and they don't need a buddy.
If the vest brings you up, perfekt, but don't be alone.
 
Interesting point. I suppose a lone diver using the vest might just come round, depending on what ails them. The coast guard helicopter might spot them, they sometimes fly by when I'm spearing, or a passing boat/kayak. They might even drift into shore. But, yes, they might just drift out to sea or to some remote rocks. It could easily save your life but it's not a sure thing. It helps tips odds on your favor, significantly though.
 
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I'am not against the vest, I'am just think that "only" the vest can't save you live.
Maybe most of the spearfisher think dive alone with the west is save and they don't need a buddy.
If the vest brings you up, perfekt, but don't be alone.

Well, you are onto something, but the "sad" secret of buddy diving in spearfishing is that it is rarely done as strict as you do it in freediving. That is simply fact. Why not you may ask? Well, sometimes it's "greed"/eagerness, sometimes ignorance and sometimes just hard to do due to e.g. bad viz or strong currents. But honestly, mostly it's just viewed as less practical and less efficient... I know, I know - it's a bad argument when we are talking about life and death scenarios but it's the truth. Also, some people who do actually practice strict buddy diving don't always do it, e.g. they do it on deep dives but not on shallow ones.
I have seen freedive instructors spearfish deep with zero buddying up and honestly some of the world's best competetive freedivers spearfish, too without a buddy (they just don't talk about it much). So, I think it's fair to say that a lot of the people who know the "rules" don't abide by them once they are hunting.
In general, we know it is not ideal, but we choose to do it this way. Sometimes, you just get carried away but often it's definitely a conscious choice - I guess some would go as far as to call it a calculated risk. Mind you, very few spearos are ignorant enough to knowingly push their limits while spearing. I, personally, spear at around half my best bottom times and when spearing I get "nervous" when I reach half the depth I can do on the rope. But diving this conservatively is still not a 100% guarantee and I know that.

I freedived before I took up spearing so I know where both camps are coming from and I used to think like you, I used to be pretty adamant about it. But then I started spearing myself... In all honesty, it is naive to think that the majority of spearos will start doing perfect buddy diving or never dive alone and you can point your finger as much as you want - it wont change much and certainly not anytime soon. It's a bit like telling drivers never to speed on the highway.

The vest is not an excuse to dive stupid, but it is very, very nice extra layer of safety to have. Mind you, people have been dying for ages from spearing, so I think Terry Maas realized that if you can't make people do a perfect buddy system on every single dive (which you can't), then the FRV is probably the best backup system and it is certainly far superior to having nothing. I think Terry even calls it a backup buddy which is the ideal way to think about it. It shouldn't take the place of a great buddy, but it does make sure that if the buddy system fails, you are not left completely alone in the case of an accident.

We all know that the S in SWB stands for shallow and luckily, problems at depth are extremely rare. But if you do have an issue at depth (cramp, deep BO, down current, time lost to entanglement) then all of a sudden, even in a perfect buddy system, you might be relying on your buddy to perform a deep rescue. While this might sound speculative, after having just read how Terry's own son had an issue deeper than his spotting buddy could reach and having run into a few down currents myself by now, I think that's another area where the vest would be helpful. Speaking of deep rescues, I find it comforting to know that when I wear my FRV, if I ever have to do a deep rescue, I can inflate the vest and help our ascent (I intend to practice this as the vest does take up some space on the chest when inflated).
 
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I appreciate all the thoughts. And I want to thank Diving Gecko for mentioning the unthinkable- that any least the vest lets us recover a body even if it doesn't save the victim. That is no small thing. Loved ones want a body rather than just being told that the diver is lost.

I can relate when I recall the only time I'v lost a dive buddy. We were in Mexico and he didn't come up. Luckily the water was very clear and we could barely see him on the bottom at 90 feet. Its unlikely that he blacked out on the way up and was dragged back down by a fish. He was kneeling on the bottom with his head and shoulders under a ledge with his hands on the shaft as if trying to pull a fish out of the hole. There was no fish on the slip tip but earlier he had shot a couple of big pargo, so best guess is the he had shot another one but it came off.

A few points-
I wasn't as close as I should have been, but I was 60 years old and couldn't have retrieved him from 90 feet anyway.
The vest didn't exist them, but if he had been wearing one it almost certainly would have brought him to the surface.
We tried CPR but his lungs were full of water and foul-tasting bloody foam came out of his mouth and nose with every compression. We finally gave up and looked at his body for the hour and a half trip back to the dock.
The hardest thing I've ever done was pick up the phone and tell his wife that she was the single mother of five children. But at least I had a body to bring home. It would have been worse to tell her that he was just out there somewhere and then have her wait for some long period before someone ran across the body or he was finally declared dead.

So if I seem to be a big fan of the vest, now you know why.

But now to that question of removing the mask. Here is a discussion that I just cut out of the digital version of Terry Mass's book, Blue Water Hunting and Freediving.
Screen Shot 2018-12-14 at 10.13.39 AM.png


Notice that he says that we shouldn't waste time with blow and tap, but go straight to rescue breathing. I realize that his focus is on rescue of a diver in ocean conditions rather than someone who is samba in a controlled competitive freedive situation. It's unlikely that rescue breathing is going to be necessary in a situation like the one shown in that video in a previous post. But since we are talking about the vest, we're talking about victims of blackout in the ocean.
Screen Shot 2018-12-14 at 10.13.39 AM.png
 
Bill... that's a rough story and it creates some painful images.
Not only are whole families distraught when a diver is lost, but I bet there's still quite the jab of pain recalling it for you so thanks so much for doing it.
Part of creating awareness is sharing the pain, too. It's too easy to decide to forget about the cost of these losses when we weigh up what our next USD 1000 spearing gear buy should be.
One of my friends just lost his own best friend. They couldn't locate him and my friend was the one to organize days of searching to no avail - it was very important that he did it though. But he was also the one to make the phone calls and then return home to meet the girlfriend and parents. Just heartbreaking painful stuff.
I don't actually want to know the numbers but the more stories I hear about lost divers, the more I realize how many of them are never found - in some locations, it's just staggering.

As for the question on when to start rescue breathing, the freediving community used to be a bit split on this issue (don't know if there is consensus now). I think the argument being made was that if the glottis is indeed still closed and you do a rescue breath, then you might risk blowing a bit of water into the throat and the brain might register this as being submerged and thus postpone waking up to the fact that its host is on the surface. But on the other hand, if the glottis is open from complete shutdown, then you need to really start right away. And if the glottis is open because the diver is coming back, then there's no harm done helping him with a bit of assisted breathing.
But Terry's point is that you can actually blow strongly enough to overcome a closed glottis to no ill effect which is really interesting. I would speculate that if the throat feels air rushing through - that's a good a wake up call as any, too. But I will try to ask around on this.

Also, you are right in that a freediving comp is almost a laboratory compared to spearing in the ocean. I was a visitor at a freediving world championship and it's quite amazing to see how fast a blacked out diver snaps out of it just with tap and blow. But their blackouts are rarely more than just a few seconds long and that might very well be the big difference.

Thanks again Bill
 
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Great discussion, very good points all.

In my case, we use a tight buddy system when spearing or not. Vis is such that the diver down is almost always visible on the bottom and I don't wear my vest in those conditions. Its an older model and has small but noticeable drag. If the vis is poor or I don't have a well trained buddy (or if I was ever alone), the vest is on.

Bill makes a good distinction between BO situations. In all three instances where I either observed or played rescue diver, the victim came around with no rescue breaths, even in the face of some pretty poor rescue technique. These were all cases where the BO was observed, buddy was close, and the victim immediately recovered, more like what happens in a comp. In that case, I think resue breaths would be counterproductive, not to mention tricky since we were in open water, and maybe damaging . In a case where there may be significant time between BO and rescue, it probably makes sense to start rescue breaths immediately.
 
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Whatever rescue technique is used, it's going to be a hell of a lot easier with the diver supported by a vest with his face out of the water. And if you want to pull him back to the boat where you could do chest compressions, its far easier if he is supported by a vest.

BTW, I always remove my snorkel from my mouth as I start a dive, but I know that some people don't. So I wondered if the end of the snorkel would be in the water if a victim was supported on his back and started breathing again. I tried it, and was pleasantly surprised to find that the snorkel was well above the surface.
 
Thanks Bill, that is a question I had wondered about but not tested. I'm snorkel in on the way down, almost always snorkel out on the way up.
 
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