Divetech Cayman
Contributor
Hello Scubaboard.
I wrote this article for our website blog, but when we peer reviewed it, it was felt it was too intense for our website, and we didn't want to turn new folks off to the idea of diving. But I did want to make it public, and felt this was a better forum to release it here as post. The moral of this post is about safe diving practices.
Several of the Divetech staff members volunteer at the Cayman hyperbaric chamber. Chamber volunteers are on-call 24/7 to serve as operators or attendants when patients arrive for treatment of decompression illness. A typical diver treatment is 5 hours, and to avoid fatigue and keep exposure limits reasonable, chamber operators and attendants are rotated ever hour. This means up to 15 volunteers are needed for each treatment. (There is also a senior operator present who oversees the mechanical room, and the entire treatment.)
There are hundreds, if not thousands of articles, blog posts, and research papers which discuss DCS; what causes it, and the current thinking on how to prevent it. That is not what this post is about.
This article talks about the real-world component, which is often overlooked, and I'd like to share with you.
I was called out for my most recent patient at 12:30 in the morning a few nights ago. I'm going to call him David. When I arrived for my attendant session with him, David was in his fourth hour of treatment. He was unable to move his legs and left arm. His right arm had a horrible 'pins and needles' feeling in it. He kept having bouts of nausea, and was unable to do anything for himself, including sit up or drink water. For him to urinate, it required the attendant to physically assist him in all aspects. At hour 5, I watched his wife crying silently, as she peered in through the viewing port to watch her husband. As I write these words, David is undergoing his fourth table 6 treatment, and while his symptoms are improved, they have not resolved completely. He will likely never dive again.
Recompression therapy is a horrible way to end your dive vacation. Aside from the medical issues you may be having, the chamber is small, noisy, and not terribly comfortable. Lay a few phone booths on their side, and crawl into them with a total stranger. If you are even close to claustrophobic, you're going to have a tough time without a sedative. If you are much taller than 6 feet, you wont be able to stretch out completely. The descent phase is swelteringly hot, and humid. At depth it becomes freezing cold. The bare walls of the chamber are hard, cold, and covered in freezing condensation. If you have to urinate, (if you are even able to do so,) you must do so into a urinal or bed pan with your knees literally touching the attendant while wearing an ill-fitting hospital gown. Many times this is with an attendant of the opposite sex. There's no modesty here. Even the slightest metal-on-metal contact results in a loud sound like being in a bell. Did I mention it's noisy? Hearing protection sits on a rack by the patient's head for those who just can't take the constant hissing of gas. You're not allowed to sleep. To mitigate fire risks, you can not take in your phone, tablet, or even a paperback book. There is no TV, even one outside you can watch. You have an oxygen mask on, which makes it difficult to even have a conversation. What you do, is lay on a bench, and stare at the hatch - for 5 hours. If you're lucky, your symptoms will subside and you'll only require a single treatment.
No diver I've ever met in the recompression chamber thought they would be bent. decompression sickness is one of those things that divers think just can't or won't happen to them. But it does. Chamber volunteers are called out on an average of twice per month for diver treatments. When you consider the numbers of divers Grand Cayman has every year, this is statically not a huge figure. But every year there are are 20 or so divers who end up having a miserable experience on what should be a fun-filled vacation, and you could be one of them.
All chamber patients agree - it's much better to be drinking rum punch on the beach with your spouse, then to be locked in a steel pipe, peeing in a cup next to a total stranger.
Decompression illness can strike you after any dive - whether it's your 5th dive, or your 5,000th, so of course the best approach is to be cautious and conservative. As a boat captain and dive instructor here in Grand Cayman, myself and my co-workers see lots of risky dive practices. So we've come up with a list of tips to help keep you out of the pot, and into the water.
Dive nitrox. Especially if you are over the age of 40. Enriched air means you are absorbing less inert gas during your dive. When you dive nitrox and use an air profile, this makes your dive safer.
This may sound ridiculous to some of you, but know and understand that your bottom time is governed by your no-decompression time. Several times per year, we have guests who just do not understand this concept. Most recently, a co-worker and I literally pulled a guest from the bottom to his safety stop because he was minutes away from his NDL time, with no intention of leaving the bottom anytime soon. When we informed him on the boat of why we did this, he looked at us puzzled and said "Why did I have to come up? I had air left in my tank."
Know and understand your dive computer. I cannot tell you how many times I hear a dive computer beeping on the boat, usually because you missed a mandatory decompression stop. When asked, the customer will shrug and say something like "Yeah it was beeping, I'm not sure why." An easy rule to remember, is if your computer is beeping, it's trying to tell you something important. Know your dive computer, how to read and understand what it is telling you.
Watch your depth. This may seem to be common sense, but sometimes customers are so taken by the beauty of the wall diving in Cayman, they simply forget to look at their depth, or fail to realize how deep they actually are. Sometimes chasing marine life gets a diver far deeper than they intended. Be aware of how deep you are and remember - the deeper you go, the more risk you are incurring.
Pay attention to your dive briefing. The briefing your boat captain or divemaster gives you is important. He or she is reminding you about your depth limits, time limits, local conditions, safety procedures, performing your safety stops, and watching your no-decompression time limits. These are not things the dive say just to be difficult - they are telling you these things for your own safety.
Avoid overexertion at depth. The harder you work, the more your circulatory system pumps blood. If you are at depth, this means you circulatory system is pumping blood with compressed nitrogen to your tissues. When you stop working as hard, your circulatory system slows as well (typically during your safety stop,) leaving more inert gas in your system. Slow down when at the bottom, and adopt a zen-like approach to diving.
Stay warm. The same issues with circulation apply with thermal changes as well. When you are warm, your blood flows freely to your extremities. When you get cold, your body begins to shunt blood to your core, restricting it from your extremities. If you start off your dive warm (typically the deep phase of your dive) and end it cold, you have likely on-gassed more nitrogen than you have off-gassed.
Dive conservatively - many hits are "undeserved." It's the same reason you drive slowly, or invest money conservatively. You're trying to mitigate risk. The more aggressive you are in any facet of life, the more likely you are to get in trouble. You don't need to be crawling in the sand for your entire dive. Some of the best time I have diving, is floating at 20 feet watching all the activity below me.
Do your safety stop - for 5 minutes. Divetech staff always recommend doing a 5 minute safety stop - 2 minutes longer than the industry standard. This is just another layer of conservatism. Surely you have 2 extra minutes.
Get your buoyancy under control - or use the ascent line. Rapid changes in buoyancy, especially when shallow, can lead to problems. Poor buoyancy can lead to rapid ascents which can be a big risk. Get yourself weighted properly, and get your buoyancy under control to mitigate these risks.
I hope when I see you in Grand Cayman, it's on the dive boat and not in the chamber!
Safe diving!
Tony
I wrote this article for our website blog, but when we peer reviewed it, it was felt it was too intense for our website, and we didn't want to turn new folks off to the idea of diving. But I did want to make it public, and felt this was a better forum to release it here as post. The moral of this post is about safe diving practices.
Several of the Divetech staff members volunteer at the Cayman hyperbaric chamber. Chamber volunteers are on-call 24/7 to serve as operators or attendants when patients arrive for treatment of decompression illness. A typical diver treatment is 5 hours, and to avoid fatigue and keep exposure limits reasonable, chamber operators and attendants are rotated ever hour. This means up to 15 volunteers are needed for each treatment. (There is also a senior operator present who oversees the mechanical room, and the entire treatment.)
There are hundreds, if not thousands of articles, blog posts, and research papers which discuss DCS; what causes it, and the current thinking on how to prevent it. That is not what this post is about.
This article talks about the real-world component, which is often overlooked, and I'd like to share with you.
I was called out for my most recent patient at 12:30 in the morning a few nights ago. I'm going to call him David. When I arrived for my attendant session with him, David was in his fourth hour of treatment. He was unable to move his legs and left arm. His right arm had a horrible 'pins and needles' feeling in it. He kept having bouts of nausea, and was unable to do anything for himself, including sit up or drink water. For him to urinate, it required the attendant to physically assist him in all aspects. At hour 5, I watched his wife crying silently, as she peered in through the viewing port to watch her husband. As I write these words, David is undergoing his fourth table 6 treatment, and while his symptoms are improved, they have not resolved completely. He will likely never dive again.
Recompression therapy is a horrible way to end your dive vacation. Aside from the medical issues you may be having, the chamber is small, noisy, and not terribly comfortable. Lay a few phone booths on their side, and crawl into them with a total stranger. If you are even close to claustrophobic, you're going to have a tough time without a sedative. If you are much taller than 6 feet, you wont be able to stretch out completely. The descent phase is swelteringly hot, and humid. At depth it becomes freezing cold. The bare walls of the chamber are hard, cold, and covered in freezing condensation. If you have to urinate, (if you are even able to do so,) you must do so into a urinal or bed pan with your knees literally touching the attendant while wearing an ill-fitting hospital gown. Many times this is with an attendant of the opposite sex. There's no modesty here. Even the slightest metal-on-metal contact results in a loud sound like being in a bell. Did I mention it's noisy? Hearing protection sits on a rack by the patient's head for those who just can't take the constant hissing of gas. You're not allowed to sleep. To mitigate fire risks, you can not take in your phone, tablet, or even a paperback book. There is no TV, even one outside you can watch. You have an oxygen mask on, which makes it difficult to even have a conversation. What you do, is lay on a bench, and stare at the hatch - for 5 hours. If you're lucky, your symptoms will subside and you'll only require a single treatment.
No diver I've ever met in the recompression chamber thought they would be bent. decompression sickness is one of those things that divers think just can't or won't happen to them. But it does. Chamber volunteers are called out on an average of twice per month for diver treatments. When you consider the numbers of divers Grand Cayman has every year, this is statically not a huge figure. But every year there are are 20 or so divers who end up having a miserable experience on what should be a fun-filled vacation, and you could be one of them.
All chamber patients agree - it's much better to be drinking rum punch on the beach with your spouse, then to be locked in a steel pipe, peeing in a cup next to a total stranger.
Decompression illness can strike you after any dive - whether it's your 5th dive, or your 5,000th, so of course the best approach is to be cautious and conservative. As a boat captain and dive instructor here in Grand Cayman, myself and my co-workers see lots of risky dive practices. So we've come up with a list of tips to help keep you out of the pot, and into the water.
Dive nitrox. Especially if you are over the age of 40. Enriched air means you are absorbing less inert gas during your dive. When you dive nitrox and use an air profile, this makes your dive safer.
This may sound ridiculous to some of you, but know and understand that your bottom time is governed by your no-decompression time. Several times per year, we have guests who just do not understand this concept. Most recently, a co-worker and I literally pulled a guest from the bottom to his safety stop because he was minutes away from his NDL time, with no intention of leaving the bottom anytime soon. When we informed him on the boat of why we did this, he looked at us puzzled and said "Why did I have to come up? I had air left in my tank."
Know and understand your dive computer. I cannot tell you how many times I hear a dive computer beeping on the boat, usually because you missed a mandatory decompression stop. When asked, the customer will shrug and say something like "Yeah it was beeping, I'm not sure why." An easy rule to remember, is if your computer is beeping, it's trying to tell you something important. Know your dive computer, how to read and understand what it is telling you.
Watch your depth. This may seem to be common sense, but sometimes customers are so taken by the beauty of the wall diving in Cayman, they simply forget to look at their depth, or fail to realize how deep they actually are. Sometimes chasing marine life gets a diver far deeper than they intended. Be aware of how deep you are and remember - the deeper you go, the more risk you are incurring.
Pay attention to your dive briefing. The briefing your boat captain or divemaster gives you is important. He or she is reminding you about your depth limits, time limits, local conditions, safety procedures, performing your safety stops, and watching your no-decompression time limits. These are not things the dive say just to be difficult - they are telling you these things for your own safety.
Avoid overexertion at depth. The harder you work, the more your circulatory system pumps blood. If you are at depth, this means you circulatory system is pumping blood with compressed nitrogen to your tissues. When you stop working as hard, your circulatory system slows as well (typically during your safety stop,) leaving more inert gas in your system. Slow down when at the bottom, and adopt a zen-like approach to diving.
Stay warm. The same issues with circulation apply with thermal changes as well. When you are warm, your blood flows freely to your extremities. When you get cold, your body begins to shunt blood to your core, restricting it from your extremities. If you start off your dive warm (typically the deep phase of your dive) and end it cold, you have likely on-gassed more nitrogen than you have off-gassed.
Dive conservatively - many hits are "undeserved." It's the same reason you drive slowly, or invest money conservatively. You're trying to mitigate risk. The more aggressive you are in any facet of life, the more likely you are to get in trouble. You don't need to be crawling in the sand for your entire dive. Some of the best time I have diving, is floating at 20 feet watching all the activity below me.
Do your safety stop - for 5 minutes. Divetech staff always recommend doing a 5 minute safety stop - 2 minutes longer than the industry standard. This is just another layer of conservatism. Surely you have 2 extra minutes.
Get your buoyancy under control - or use the ascent line. Rapid changes in buoyancy, especially when shallow, can lead to problems. Poor buoyancy can lead to rapid ascents which can be a big risk. Get yourself weighted properly, and get your buoyancy under control to mitigate these risks.
I hope when I see you in Grand Cayman, it's on the dive boat and not in the chamber!
Safe diving!
Tony
