'Do we drown or rocket to the surface?'
Ouch: Disability Talk
Rich Osborn had the perfect summer job as a scuba diving instructor in Cyprus - but it would become a job which led to him becoming paraplegic.
On a day off, the then 21-year-old and three instructor friends decided to go for a carefully planned deep-dive.
At 40m under the ocean's surface the group ran out of air.
With nothing left in the tanks they had a decision to make - drown there and then, or rocket to the surface and risk catastrophic injuries from the [bends].
Presented by Beth Rose with Rich Osborn
Full Transcript (written): https://www.bbc.com/news/disability-44811673I'm only going to review the point where everyone ran out of air... the planning that failed all four of them.
Beth Rose interviews Rich Osborn his time as, "a perfect summer as a scuba diving instructor in Cypress when he was 21."
There's a lot of great things about being a scuba diving instructor but the "dream job" or the "dream summer job" is not like a swim in the shallow end of the pool. Don't get me wrong, I love teaching and I love diving, but there's a lot of responsibility that comes with teaching people to scuba dive not to mention just taking divers on "tours." There are several things that bother me about the cavalier attitude of these guys. It perpetuates cutting corners during training. I've seen it first hand. When classes are large, the only way to get everyone done at the same time is to accept the outcomes (abilities) from everyone as being the same.
Additionally, diving beyond the scope of one's training and ability is abundant in the industry. PADI certifies divers to 60ft and only in conditions from which the divers were trained in. That means that one doesn't dive deeper than 60ft without additional training and it also means that divers that earned their certification at tropical destinations are not prepared for cold water, low-visibility dives. Some agencies and instructors also lead divers to believe they are more qualified than they really are. In particular, labels like "advanced diver" or "rescue diver" categorize ability and experience where none exists.
Until a diver takes technical or professional courses, ALL courses are "recreational." All classes are recreational and leisure at one's dive destination. Recreational dive limits mean no in-water decompression obligations, no penetration dives or overhead environments and not diving beyond the scope of the training you received and regularly practiced. If a diver takes years away from diving, skills will degrade.
BETH - "...but his summer came to an abrupt nightmarish end when during a deep dive with three friends their oxygen ran out. The group had a decision to make: drown there and then or rocket to the surface and face the consequences of the bends."
The water can be a really bad place to make split decisions. In fact, even when one makes the best decision at that particular moment the outcome might not be as desired. Similarly, one can do everything wrong while nothing bad happens. Beth's description of the position Rich was in was real although somewhat exaggerated. Drowning is the last thing on the diver's list and it is not a dichotomy of "rocket to the surface" or "drowning". There is a large spectrum between what you can do and decompression sickness is not a result of a fast ascent, but can be the outcome of one. As we'll hear later on in the podcast, Rich was the only one that was injured.
One must be ready at anytime to perform: air sharing ascent; buddy breathing ascent; emergency swimming ascent; emergency buoyant ascent; and emergency buoyant ascent while orally exhaling into the BCD. Ironically, PADI instructors teach a lesson called the CESA, Controlled Emergency Swimming Ascent and as I've talked about before, it's very often taught to never be practiced due to potential injury. Nevertheless, even when it's utilized, it's often done in a manner that is unrealistic and more often unsuccessful. Getting to the surface is the next place you'll be taking your next breath. You have to know how you'll get there, what you'll do when you arrive there, and especially what to do if others don't make it back up with you.
Rich reports that he learned how to dive when he was 14 and took his instructor examination when he was 18. Many divers do make a quick transition into the professional side of scuba especially if they have an opportunity to make some money doing it. The interesting part about young instructors is not their ability to perform the skills and tasks necessary to scuba dive or teach others to dive, it's that most 18 year-old's don't make good decisions. Partner dangerous activities to an immature attitude, limited experiences and poor decision making, and scuba diving becomes a lot more dangerous than it should be.
Scuba diving has risk, but reducing the risk is the goal of every diver not just instructors. As Rich found out, while most dives are a balance between risk and reward, death is NOT the worst thing that can happen. Rich's attitude about life with a spinal cord injury after the fact and how he lives with it are also not typical for most teens or young adults if not most adults. He reports that he still has a "fire for outdoor activities" including for scuba diving. The ability to play the cards we are dealt is a difficult ability to master. In this regard, his injurious outcome has only become a speed bump in the highway of his life -- unfortunately not typical.
As Beth continues to interview Rich, he describes teaching pool sessions, "confined water, so you can practice it in a safe environment" and the open water sessions, "so practicing the skills you learned in the safe environment in an open water environment."
These statements seem like there is a emphasis on safety after the fact and that safety is a tenet of what is always practiced. A couple of things stand out in PADI's culture, particularly. One such leader in the diving industry, Bret Gilliam found, "...that no effective attempt is made within some agencies to interdict and restrict instructors who consistently breach standards that lead to unacceptable accident records." This is the phenomenon called, "Just Culture." Just culture is a practice in which front-line operators and others are not punished for actions, omissions or decisions taken by them which are commensurate with their experience and training, but where gross negligence, willful violations and destructive acts are not tolerated. Interestingly, when nothing happens over the course of one's career, another phenomenon occurs, "Normalization of Deviance." Normalization of deviance is defined as, "The gradual process through which unacceptable practice or standards become acceptable. As the deviant behavior is repeated without catastrophic results, it becomes the social norm for the organization." Nothing bad has ever happened before, so why will it happen this time...?
Herein lies the problem when education is inadequate. If you learn by poorly written material and have an instructor that only follows the materials provided, it's hard to recall that material when you need it. I call that process "teaching to the lowest common denominator." Why devote extra time and energy if only one or two in the group are going to benefit from it or continue with it. Programs that only teach the minimum and only emphasize getting a passing score on tests or in recollection are prone to losing those students. So much so that skills can never be correlated to test scores. Students that pass a test with 80% also mean that they didn't pass 20% of it. What 20% did you miss? Why would someone want to miss 20% of a program that is designed to train in skills necessary to reduce risk and injury and can result in death? Not only is that contrary to risk reduction, but the review of what was missed is often followed by blank stares or glazed looks while the student nods their head in agreement when wrong answers are being reviewed. Sometimes the instructors aren't well versed in the materials either. When this happens, throwing it over your shoulder or under the rug happens. "PADI doesn't put a lot of emphasis on that," I've heard. Or, "Once you're certified, no one remembers that stuff anyway." Students that understand the material get the correct answers on tests. If the goal is comprehension, missing anything is inappropriate.
Scuba diving already has an incredibly high dropout rate. Divers will also take years off between dives and feel that a couple of hours of remediation in the pool will make up for years of lost experience. There isn't a substitute for ongoing training. That doesn't mean that practice makes perfect... people make mistakes, however, practice makes permanence! Surgeons that don't perform surgeries regularly are not on my list of surgeons to perform my operations. The last thing I ever want to hear is, "I've haven't done this operation in three years but I watched it done on a YouTube video and feel like I got it!"
BETH - "So, you were obviously having a great summer, and then one day something a bit unusual happened. Tell me what happened," says Beth.I understand that this is an interview and Beth is facilitating the interview to move in a fluid and forward motion so the podcast is successful. It's possible that the English connotation and expression interprets differently than an American one. However, I believe that listeners (English, American and others) are tuning in to find out what happened and why. Going on a scuba dive is not unusual for scuba divers, but doing anything and it resulting in being paralyzed from the waist down, is definitely unusual!
Rich accounts the dive and the day of the accident.
Here are the bullet points:
- it was their day off so Rich and a couple of others he works with (turns out to be three) are going to go diving
- tells Beth, "they were all dive professionals"
- someone said, "let's try this"
- they wanted to go a little bit deeper than normally
- everyone was trained in deep diving and "stuff like that"
- Rich admits that being young, "you kind of want to push the limits a little bit"
- BETH - "How deep are we talking?" RICH - "So, about 40 metres or so."
- Rich states that 30 meters is like the usual depth in recreational scuba diving
- additionally mentioning that at 40 meters, "you need to be deep dive trained for that"
- Rich states, "we all planned thoroughly before the dive"
- RICH - "But what happened was a disparity between what was planned in terms of breathing rates and what actually happened on the dive. So, a couple of people ran out of air before they'd planned to run out of air, if you know what I mean."
- BETH - So, it was a surprise was it? RICH - "Yeah, it was an absolute surprise."
This description reminds me of the meme that shows a guy saying to his buddy, "Hold my beer. Watch this."
Four divers are going on a dive together. They were all together so I'm not sure how gas management escaped all of them. I teach students that running out of air is a misconception, but I guess these guys had to prove this theory inaccurate. I tell my students that nobody wakes up in the morning and decides to run out of air, BUT these four guys did! It seems improbable, but they actually did it... Wow! I wonder what the odds are that four divers would enter the water together and that each of them would run out of air? Rich called everyone "dive professionals." The definitions of "professionals" are all over the board so I don't know which one to take, but I'll go with the way I define it, "A person that follows standards and guidelines set by the greater community in a paid capacity and is expected to perform at the highest level aptitude and integrity."
It'd be fair to say that they didn't approach this day as dive professionals. As far as professional attitudes, I'm not sure that was there either. Interestingly, I'm sometimes told that I have to let bad divers make their own mistakes but there is a harsh reality that comes with that philosophy. I think it's important to speak up. Being sure to say something when another is making (or going to make) a bad decision, especially when scuba diving is involved, is just being compassionate -- and as far as professional, I'm always an instructor. Scuba divers are a group of individuals that share this great activity in common; a group of people that make up a community. Communities have a responsibility to watch out for each other. We might even belong to many communities. Imagine what the world would be like if someone in the communities we belonged to always had our back. Now, put that in an activity that is inherently dangerous -- it's a win-win-win-win, Rich...!!! If you'd like to see how numerous failures on a dive boat lead two down to 149ft and if somebody didn't eventually do something, they would have not made it back, watch this video: https://youtu.be/1LyocSGiXdU
40 meters (130ft) is a long way down, but the depth itself is not any more dangerous than 4 meters (13ft). Deep dives require specialized training and definitely the right attitude. Thorough planning DID NOT happen in this case and here's why. Rich put is quite eloquently when he said there was, "...a disparity between what was planned in terms of breathing rates and what actually happened on the dive." Even with proper planning, gas management only works when the plan has considered all the things that can go wrong. Let's run through a rudimentary dive plan and see if that matches up to what happened.
I use V-Planner, dive software, when planning dives (especially deep dives). If the parameters of the dive change, like less time at depth or a shallower maximum depth, that will only give more of a cushion to fall back on if needed. This example will only be hypothetical as there are several factors we just don't know. The primary ones are everyone's "Respiratory Minute Volume" or RMV and "Surface Air Consumption" or SAC rate. Additionally, we don't know if they have any special considerations that can effect RMV/SAC (like health issues) and dive conditions (current, visibility, equipment, emotional, physiological, or environmental factors). It seems like all of them where young and probably healthy. If we go with these assumption then their numbers might be a little lower.
The assumptions of the plan I created are below. I picked a dive plan in V-Planner that would closely resemble a 130ft dive with a 3-5 minute safety stop between 20ft and 10ft and an average diver's air consumption with an average dive computer with an average conservancy (whatever average means). The math is also below. And remember, this is a RECREATIONAL DIVE...!!! If you'd like to calculate your own, you can use my RMV/SAC calculator by following this link: https://jcaelitescuba.com/rmv-sac/calc.htm
Dive# 1, VPM-B +2
Depth = 130ft
Profile = Square
Elevation = 0ft
CNS = 4%
OTU's = 11
Gas = 21% = 51cuft required
Gas density = 5.9g/l
Decozone start = 69ft
SAC = 0.80cuft/min
Ascent/Descent rate = 30ft/min
Cylinder = Aluminum 80 (77.4cuft)
Descent/Ascent
(130ft) / (30ft/min) = 4.33 minutes
Atmospheres Absolute
(130ft) / (33ft) = 3.93atm + 1atm = 4.93ata
Rule of Thirds
51cuft / 2 = 25.5cuft x 3 = 76.5cuft
Baseline
77.4 / 3000 = 0.0258
.0258 * 500psi = 12.9cuft
10.82cuft / .0258 = 419psi required to get to surface -- ROCK BOTTOM PSI
Schedule
------ Time Depth Notes (below)
start 0:00 0 1)
descent to bottom 4:20 130 2)
stay at bottom 6:40 130 3)
ascent to safety stop 3:50 15 4)
safety stop 3:00 15 5)
ascent to surface 0:30 0 6)
So, how deep is 130ft? It's somewhat rhetorical, but it really isn't that straight-forward. Let's look at it this way. 130ft of water is above your head and you have to swim back to the surface. That is a long way up. Additionally, 130ft is a 4 minute and 20 second descent and ascent at 30ft/min. 130ft is also 4.9 atmospheres absolute and that means breathing about five times the amount of air at that depth. You remembered to add the atmosphere above the water into your calculations, right?
1) Before you get into the water, do you know how much gas you need to do the dive? Let's figure out what we need following the "rule of thirds". 51cuft of air is going to be required (see above). That's the descent; 6 minutes and 40 seconds down there; the ascent; a 4 minute safety stop; and then the exit. But that wouldn't leave us with any gas left over. When we use the rule of thirds it means that 1/3 of the gas is left for emergencies or contingencies. If we know how much we need, and that comes from our RMV at different depths, usually every 10ft, we can calculate what we should take with us. take that 51cuft, divide the 51cuft by 2, then multiplying that number by 3. 51/2=25.5x3=76.5 that means that a full AL80 with 77.4cuft at 3000psi will be adequate for this dive and leave enough gas for emergencies.
We should also calculate how much gas we need before we have to turn around immediately to get back to the surface on your last breath. Let's figure that out also... if they stuck to the plan and air consumption stayed the same, "Rock-Bottom" psi is how much air needed to get to the surface without a safety stop and nothing getting in the way of (or slowing down) that ascent. HOWEVER, Rich mentioned that breathing rates changed. Was that not planned for? Cave divers make it a point that breathing has to remain constant and consistent. Getting out of the cave still happens when one hits their first third (turn psi), but if one's goal is to get to a particular site to see something in particular, then constant and consistent must happen. We'd have to know what the new breathing rate changed to in order to know when everyone should have turned around. in the light of the recent cave rescue in Thailand and the death of one of the dive team, air consumption is particularly critical. Some interesting insight also comes into view by doing the actual written work.
https://jcaelitescuba.com/articles/SAC_RMV_calculations.pdf
2) Some might say that you can just descend faster, but that is problematic by itself. Not only do you have to equalize, regularly and often, but you have to stay with your dive buddies for the dive plan and schedule to work. failure to equalize could cause traumatic barotrauma as well. Descents are a perfect time to decide to end the dive as well. I call this a "jumping off point." Divers have a tendency to check their air too much, not at all, or think they'll never run out of air. This doesn't mean that someone should expect to run out of air at some point in their scuba diving career, but if it happens, one knows exactly what they will say to themselves, what they will do, and they know what will happen once they get to the surface.
A jumping off point is the place in the beginning of a dive where the diver reaches their destination (in this case their planned depth) and stops to ask everyone if their air is okay. giving a number to everyone isn't the same because that only reflects a moment in time. the question to answer is, "Do I have enough air to complete this dive?;" "Do i have enough air to get the attention of my dive buddy and tell them i am out of air, please share air;" "Do i have enough air to safely swim to the surface and power inflate my BCD?;" "Do I have enough air to get to my dive buddy, share air towards the surface and go back to my own air supply to finish the rest of the dive?"
3) This is probably the most interesting part of this plan! New divers often think that an 11 minute bottom time is the same as dive time -- the clock starts once you hit the bottom. Once you get there, you'll know how much time you have if using a dive computer, but not until then. NDL's are not correlated to the amount of gas a diver has left. It is possible that a diver may have more time, but not enough gas... some dive computers have planning modes but they only work on square profiles. In reality, after the 4 minute and 20 second descent, the divers only have 6 minutes and 40 seconds at depth. When I used V-Planner, everything longer than 11 minutes went into decompression. The 1:20 at 20ft and the 3:00 at 10ft are technically a required decompression, but instead of a recommended stop, this one you can't skip but it as closely matches the safety stop everyone should be doing.
Realistically, most follow the guidelines that a safety stop is required, so that's a good thing. So, here's is the reality of this dive! Why did 4 divers agree to spend a whopping 6:40 at 130ft. that's the whole dive! There are costs to all dives and if there was something amazing down there, perhaps advanced nitrox and/or decompression procedures programs would be a better option. Perhaps diving with larger cylinders or two tanks? All these calculations are what every technical diver considers and uses. Most of this is done electronically, V-Planner in my case, but the fundamentals and nuances of being "deep diving trained" is something that these 4 instructors should have known. If one was leading the group into this dive, why did everyone go so easily? Of course, there are questions that no can except these guys can answer, so we'll never know. As far as what he said during the podcast interview, it's very likely to be abbreviated or even carefully scripted to protect everyone involved.
4) PADI ,SSI, and SDI consider the total dive time in the water not the same as actual bottom time. PADI, SSI, and SDI consider that the clock starts when you leave the surface, but it stops when you are making your final ascent. The physiological reasons why this is not accurate can be read in chapter 14 of diving medicine for scuba.
http://www.divingmedicine.info/Ch%2014%20SM10c.pdf
NAUI considers that total dive time is the same as total bottom time. Most tech divers follow this rule also because they will often follow a schedule of stops to do decompressions at, all of them being consider required! chapter 14 for more information on decompression and tissue compartments. So, is a safety stop required? No, it is recommended. anything one can do that can minimize the risk of decompression sickness is typically a good thing. With that said, one can do everything right and still get bent. On that same point, one can do everything wrong, and not get bent. I always tell students when talking about the "what ifs," I remind them that death is not the worst thing that can happen -- as we can see by this discussion. This isn't based on an assumption that paralysis could be a good thing or a bad thing, but there is a strong probability that one doesn't wake up in the morning and say, "this is a good day to get paralyzed," just like one doesn't wake up in the mornings and say this is a good day to run out of air...
5) and 6) So you decide to do a safety stop. There should be more happening than waiting 3-5 minutes. Absolutely! Work on your buoyancy, confirm you know where and how to get to your weights to ditch them, that you know where your alternate is, check your air, watch your breathing, relax, confirm that everyone else is there with you, that everyone is ready to ascend and that you get the actual confirmation of that readiness, maybe deploy your SMB and finger spool, and most importantly that when you get to the surface, leave the reg in your mouth, your mask on your face, and look around to make sure it's safe to be there (i.e. boat traffic, surface conditions, where your exit point is, how you'll get out of the water WITH your dive buddy).
Bonus) RBS -- There are a lot of divers that dive with an RBS, a redundant breathing system. There are some misconceptions about this device that should be addressed and clarified as well. Since divers don't expect to run out of air, have you practiced using it? Equipment that the diver carries with them yet they never practice with will not be useful to them in an emergency. Do you know how much air is in that other cylinder? Systems that are kept on the back have a chance to be leaking, empty, or never turned on -- consider slinging the bottle. If not, when entering the water, consider an "s-drill" and your buddy confirming that the valve is on...
No comments:
Post a Comment