Scuba Diving | What Are The Bends And How Do You Prevent Them?
What are the bends in scuba diving? What are some of the common signs of decompression sickness? What happens to divers if they come up too fast? How to prevent and treat the bends...
When learning to scuba dive, there are a few things that everyone worries about.
Whether it be finding the right diving equipment, going a safe dive spot in the UK, or just getting the right diving qualifications to dive, there are many different things to consider when getting in the water. The big thing most people worry about however, are the dreaded bends and whether they will happen to them.
The bends, or decompression sickness, is widely known both inside diving culture and in general culture more widely, yet what it actually means eludes most people. Also known as Caisson disease, it is a condition that does not occur in freediving, but can happen when a diver is using a breathing regulator. The symptoms can effect just about any body area including joints, lung, heart, skin and brain.
Whether you're starting to dive and wondering what the bends actually are, wanting to dive deeper and need information on how to avoid the bends, or just want to know how to treat them if they do happen, look no further - All of the information you could ever want on the dreaded bends is right here!
Definition Of The Bends
The bends are the process of dissolved gases (mainly nitrogen) that come out of solution in bubbles because of decompression in scuba divers or high altitude or aerospace events. They can affect any body area including joints, lung, heart, skin and brain.
The popular description for the bends or decompression sickness was classified through it symptoms by F.C. Golding in 1960 as:
- "Type I ('simple')" for symptoms involving only the skin, musculoskeletal system, or lymphatic system"
- "Type II ('serious')" for symptoms where other organs (such as the central nervous system) are involved."
Exposure to the bends when diving can be managed through proper decompression prevention and are becoming a lot less common than they have been in the past, however they can still be very serious when contracted.
Computers and tablets are used by divers, to control ascent speed and avoid DCS (decompression sickness.)
What Causes The Bends?
The bends occurs in the body after scuba diving because of gases in the body releasing as bubbles on depressurisation. When we are living on dry land at sea level, the air around us has a pressure of 14.7 PSI (pounds per square inch), or one atmosphere. That is a "normal pressure" for our bodies.
Water is heavy compared to air, it does not take much water to exert a lot of pressure. One-inch by one-inch column of water 33 feet high exerts another 14.7 pounds per square inch than the same column of air.
If you hold your breath and dive down 33 feet, your lungs contract in size by a factor of two because there is twice as much pressure around the air in your lungs, making them contract. When you rise back up, the air expands again and your lungs return to normal size.
When you breathe from a scuba tank however, the air coming out of the tank has to have the same pressure as the pressure that the water is exerting. Therefore, when scuba diving, the air in your lungs at a 33-foot depth has twice the pressure of air on land and the pressure continues to double as the depth gets deeper.
"If a diver stays under a low depth of water for a certain period of time, some amount of nitrogen from the air will dissolve inside them"
Imagine a carbonated drink, Carbonation in liquid is made through high-pressure gases in the air coming in contact with water and dissolving. When you release the pressure in a bottle of carbonated liquid, the dissolved gas quickly rises as bubbles.
If a diver stays under a low depth of water for a certain period of time when diving, some amount of nitrogen from the air will dissolve inside them, much like the gas in carbonated drinks. If they swim to the surface quickly, the dissolves gasses inside their body will react in much the same way as those inside a carbonated drink and come to surface in bubbles.
This occurrence in a human body is called decompression sickness and can cause many problems, at very worst it can be fatal to a diver.
What Are The Symptoms Of The Bends?
The symptoms of the bends can range from mild to excruciating and require different levels of treatment, depending on the individual. If an individual shows any of these symptoms when diving, provide them with an oxygen mask as soon as possible and call for a medical professional.
Muscoskeletar -Localized deep pain and pain in the joints. Sometimes a dull ache, can be excruciating.
Skin- Itching around the face, neck, and upper body. Sometimes skin can look marbled or swollen.
Fatigue - A feeling of extreme tiredness.
The Chokes -Dry cough, chest pain, trouble beathing and shortness of breath.
The Staggers - Loss of balance and hearing, dizziness, vertigo, nausea and vomiting.
How To Prevent The Bends
To prevent decompression sickness, divers limit their ascent rate and carry out a decompression schedule as necessary, to stop the release of bubbles that cause damage to the body.
To safely ascend from a deep scuba diving session, divers must remain at each particular depth until sufficient gas has been eliminated from the body, each of these is called a decompression stop.
"If you have access to oxygen, a mask should be applied to the diver as soon as possible."
Decompression stops are carefully measured by divers both before and during a diving session, through decompression tables, decompression software and dive computers. These are commonly based upon a mathematical model of the body's uptake and release of inert gas as pressure changes.
Breathing mixtures containing much less inert gas during the decompression phase of the dive can help to shorten decompression time on ascent.
How To Treat The Bends
A doctor should always be called for in the case of the bends, however there are a few things you can do yourself to treat the symptoms of the bends, until medical help arrives.
Dry the diver and warm with blankets if their body temperature shows sings of dropping. Administer fluids to fight off dehydration, but do not give aspirin as it may mask symptoms. If you have access to oxygen, a mask should be applied to the diver as soon as possible.
Call both the emergency services and the Divers Alert Network to locate the nearest hyperbaric chamber (100% oxygen delivered in a high-pressure chamber) and to get specialist advice.
The diver will need to lie in a horizontal position when transported and in the case of air transport, the cabin must stay below 1,000 feet, or pressurized to sea level pressure. Use high-flow oxygen throughout transportation and up to the point where a hyperbaric chamber is available.
The duration of treatment depends on the symptoms, the diver's history and the type of recompression therapy on hand.