What happens when a scuba diver resurfaces too quickly and what is this called?
What is it called when a diver comes up too fast? Possibly one of the most important questions to answer for would-be scuba divers. Probably one of the most important aspects to scuba diving is to understand the impact of the pressure changes in water at depth. It’s also important to understand about ascending at the right speed from a dive. Stopping at the correct times to decompress, if applicable. Plus to take care and carry out a safety stop on all scuba dives.
When a scuba diver comes up too fast and has either mild or severe symptoms as a result, this is called decompression sickness. The other name for this is 'The Bends.' In the most severe cases of a scuba diver coming up too fast from a dive and getting the bends, the diver can die. The symptoms of decompression sickness vary. But are caused from the formation of nitrogen bubbles inside the body. This is due to the reduced pressure on ascent.
What is it called when a diver comes up too fast?
When a diver comes up too fast from a dive, this is called decompression sickness. The other name for it is the bends.
Divers breath compressed air that contains nitrogen. At high pressure underwater, the nitrogen gas is absorbed into the body's tissues. As a diver ascends, and the pressure of the water reduces, this dissolved gas wants to escape. What happens when a scuba diver comes up too quickly, bubbles form and this is what causes the bends or decompression sickness. See below for more of an explanation on this.
You should ascend from a dive at a rate which is slower than the smallest bubbles, which are formed when you breath out. The best way to ensure a safe ascent is to use a dive computer. All dive computers have a safe ascent monitor. If you begin to ascend too fast, an audible warning will be heard.
Something to note is all dives are decompression dives. Most, if not all diving organisations refer to dives that don't require decompression stops as no-decompression dives.' This is a mistake.
Why do they call decompression sickness the bends?
Most people understand the term 'The Bends,' which is the original name for decompression sickness. It is also referred to as Caisson disease.
Caissons were enormous compressed air boxes used to build riverine piers and abutments, which were first used to build the Brooklyn Bridge New York and Eads Bridge in St. Loius.
The workers who worked in these Caissons suffered from decompression sickness. This is why it is sometimes referred to as Caisson disease too.
It was called the bends because divers who were afflicted by this disease characteristically bent forward at the hips in pain. See below for more of the symptoms of the bends.
There is also the belief that the name 'the bends' was possibly characterised from the then popular women's fashion and dance maneuver known as the Grecian Bend.
Divers still refer to decompression sickness as the bends. But since the time when it was first discovered or understood, more is obviously known about it now.
Can the bends be fatal?
Scuba diving is a wonderful sport. But it is also regarded as a dangerous sport. There are a number of risks associated with scuba diving, but these risks are generally very low when divers get the proper training.
But having said that mistakes happen and scuba divers make errors. This is where the risks come into play and one of those is the risk of getting decompression sickness, or the bends.
The bends is a serious disease. It is also a potentially deadly disease too, with the most serious of cases of the bends can result in paralysis, coma or death.
How do you treat the bends?
Decompression sickness is treatable. If a diver has come up from a dive too fast and is either suffering from decompression sickness, or is likely to suffer due to the fast ascent rate, then there are options for treatment.
The best and most reliable option to treat a diver with the bends is to get them to a hyperbaric chamber. In a hyperbaric chamber they are re-pressurised down to a depth at least equal to their maximum depth or deeper. They are then returned slowly to atmospheric pressure.
The first stage of treatment when a diver returns to the surface where decompression sickness is likely, the diver should be put onto oxygen immediately. The oxygen administration will continue throughout their treatment, including when they are in the hyperbaric chamber.
There are many ways to mitigate the risk of getting decompression sickness (DCS). In this article on emergency decompression stop vs safety stop, I explain about the importance of safety stops and decompression stops.
The best advice I can give you, if you are new to scuba diving, is to respect the water. You must get certified to scuba dive and undertake all the relevant training. Don't dive beyond your capabilities, make sure you check and maintain your diving equipment and always dive with a dive buddy.
Also, take things slowly when you're learning to scuba dive. Get plenty of experience and build up your dives, before you go deeper than 18-20 metres (59-66 feet).
What does it mean when you get the bends?
To best understand what happens to your body when you get the bends, it's important to first understand the principles at play.
The majority of scuba divers breath normal atmospheric air. Whilst the air is breathed via a regulator from an air tank, the composition is still the same. This means that roughly 79% is nitrogen and 21% is oxygen.
The oxygen content of air during the dive is used in metabolism, as it is on the surface. But the nitrogen is not used by the body and is usually breathed out again.
But the nitrogen at pressure is dissolved into the bodily tissues, it's dissolved into the blood stream and so on.
The deeper you go, the greater the pressure, the more nitrogen is dissolved. Also, the deeper you go, the faster the nitrogen is absorbed by your body too.
In modern day scuba diving, this nitrogen build-up in the body is monitored by using a dive computer. A dive computer constantly monitors your depth, how long you've dived for and how long you have left before going into an ascent where decompression stops are a must.
But the majority of recreational scuba divers dive without going into decompression stop diving.
What happens to your body when you get the bends?
Above I've explained about how at depth and under pressure, the nitrogen in the air that scuba divers breath is dissolved into the body.
When this pressure is reversed by coming back to the surface, and if you were to return too quickly, the nitrogen would escape too fast. Fast escaping nitrogen would result in the formation of tiny gas bubbles. It's these bubbles that are the danger to you. Depending on where they form, how large they get and how many are formed, will depend on your fate.
This process is referred to as decompression, which is where the nitrogen gas is decompressing from your bodily tissues. If you were to ascend too quickly, and without the proper safety stops, you would simply 'fizz-up.' This 'fizzing-up' is referred to as either decompression sickness or the bends.
Decompression sickness can lead to to serious injury or in the worst case scenario can lead to death.
The parts of the body that can be affected by the bends includes your joints, your lungs, your heart, your skin and your brain and spinal cord.
What are some of the symptoms of the bends?
Some of the symptoms of the bends include fatigue and pain in the muscles and in particular the joints. The bubbles that form in the body can migrate to any part of the body. This includes vital organs like the heart or lungs, the brain and the spinal cord.
Decompression sickness produces many different symptoms. These symptoms will vary depending on the depth dived to. They will also be affected by how fast the ascent was. But also, the type and severity of a bend will vary from person to person.
There are a number of decompression sickness risk factors, of which include how well hydrated your body is, whether you smoke cigarettes, if you’re overweight and so on. These will all have an impact on DCS too.
The effects of DCS can range from joint pain and skin rashes, all the way through to to paralysis and death.
It is also possible to get what's known as a skin bend. A skin bend is where a small rash appears on the skin.
The symptoms of decompression sickness depends on the level of DCS you have. The levels of DCS fall into two categories, as follows:
Type I decompression sickness (low severity) - Affects the muscles and skeletal parts of the body
Type I decompression sickness is the least severe type you can have. The main symptom of type I is pain, which usually occurs in the joints of the arms, legs or back. Often times the location of this pain may be difficult to pin down.
The pain may start off to be mild, but will usually increase over time. The pain can sometimes become quite severe and lead to the casualty leaning over from the pain in their hips.
This is where the name for it came from, the bends. The pain is described as a sharp stabbing pain. It will feel like someone’s boring into your bones.
Other symptoms of Type I DCS might include loss of appetite, skin rashes and itching, skin mottling, swollen lymph nodes, and extreme fatigue.
The symptoms of Type I are not in themselves life threatening, but they may precede more dangerous problems. Type I symptoms may lead to Type II symptoms.
In all cases, medical attention should be sought and oxygen be administered immediately.
Type II DCS is the more severe type of decompression sickness. At this level of decompression sickness the spinal cord is particularly vulnerable. In the worst case of Type II decompression sickness the diver can become paralysed or die.
Type II symptoms can follow on from the above Type I symptoms. So always be aware that just because the casualty is only suffering from mild DCS symptoms, more severe symptoms may follow.
Spinal cord decompression sickness
Where the spinal cord is involved in the DCS symptoms, this has been caused by gas bubbles entering the spinal column. As the bubbles expand on the spinal cord, they can have a have a damaging affect.
This damage can lead to numbness, tingling like pins and needles, weakness, or a combination of all these in the arms, legs, or both.
The initial mild weakness or tingling can ultimately lead to irreversible paralysis. This can occur over a few hours from when the symptoms first began.
Other symptoms of the spinal cord being affected include the inability to urinate. Or to the other extreme the casualty may become incontinent and have the inability to control urination or defecation.
Back and abdomen pain are also common symptoms.
Brain affected decompression sickness
Where the symptoms of Type II DCS have affected the brain, this is caused from gas bubbles forming in the brain or where they've traveled through the veins. The symptoms would include a headache, double vision, confusion, difficulty in speaking or slurred speech and in some cases a loss of consciousness.
Inner ear decompression sickness
Where the symptoms involve the inner ear, where the nitrogen bubbles have formed in or around the inner ear. The symptoms present as the loss of hearing, severe vertigo and ringing in the ears or tinnitus.
Lung affected decompression sickness
Where the symptoms include the lungs, which is caused by nitrogen gas bubbles that travel through the veins to the lungs.
Symptoms of lung DCS would be a cough, mild or severe chest pain, and a progressively worsening difficulty in breathing. This in itself can lead to shock and death too.
How can DCS be avoided - Includes 17 tips on how to avoid decompression sickness
I wanted to finish this article on how DCS can be avoided. I have already touched on this subject, but I felt it important to reiterate this point.
17 tips on how DCS can be avoided:
1. Plan your dive and dive the plan
When you plan your dive, make sure you stick to the plan. Especially the depth of the dive.
2. Dive within your certification level and experience
Build up your experience slowly and never dive beyond the depth you are certified to dive to.
3. Make sure you can control your buoyancy
Be careful on the ascent that your buoyancy doesn't get out of control. As you ascend from a dive, the air spaces will expand and you'll become more buoyant. Make sure you dump air from your buoyancy control device on ascent to control your speed of ascent.
4. Always ascend slowly from a dive
A fast ascent is what causes the bends. Therefore slow ascents will keep you safe.
5. Adhere to safety stops
It's always recommended to carry out a safety stop. Most safety conscious scuba divers do a safety stop at 5-6 metres (16-20 feet) for three minutes. This is good safe diving practice.
6. Carry out decompression stops
If you are diving where you need to carry out decompression stops, make sure you do all deco-stops. Never think about missing a planned decompression stop.
7. Make sure you have enough air for your deco-stops
If you plan to carry out decompression stops, make sure you have enough air to do them.
8. Avoid yo-yo diving profiles
It's never been a good idea to yo-yo dive. This means you should always dive to the deepest part of your dive first and slowly ascend from there. Once you have ascended more than a several metres or feet, don't return to that depth again.
9. Make sure you don't run out of air
Running out of air is probably one of the top causes of a rushed ascent. Check your air regularly and always return to the surface with your reserve air.
10. Always dive with a buddy
Buddy diving is taught by all international dive schools. Always dive in buddy pairs.
11. Check and maintain your equipment
Equipment failure is one of the top causes of divers needing to ascend fast. Make sure you have your scuba equipment serviced and checked regularly.
12. Stay hydrated when you scuba dive
Being hydrated lessens the risk of getting the bends. Always drink plenty when you're scuba diving.
13. Never dive drunk
You should never mix alcohol and scuba diving. Even drinking the night before and diving on a hangover could affect you. If you have had a heavy session the night before, make sure you re-hydrate yourself well. Or better still don't dive until the after affects of drinking have passed.
14. Don't fly immediately after diving
You must leave at least 24 hours between your last dive and when you fly. This avoids you getting the bends on the flight.
15. Get checked for a hole in the heart or a septal defect
Many scuba divers with a hole in the heart or a septal defect can be susceptible to unexpected decompression sickness. Get this checked out at your local GP or hospital.
16. Always make sure there's oxygen on the boat
In the vent of a fast ascent, oxygen is a must have resource for immediate administration to the casualty.
17. Make extra plans when you're planning decompression stops
If your dive is to include decompression stops, make sure you carry out adequate planning for this. Make plans for the extra air consumption, noting that air is consumed faster the deeper you go. Plan for an alternative air source for emergencies.
I hope you enjoyed this article about what is it called when a diver comes up too fast
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