The bends in scuba diving: Symptoms and Signs of The Bends (Decompression Sickness): Treatment

18.07.202312.06.2023 by alexxlab

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Scuba Diving: Decompression Illness & Other Dive-Related Injuries

Arterial Gas Embolism

Gas entering the arterial blood through ruptured pulmonary vessels can distribute bubbles into the body tissues, including the heart and brain, where they can disrupt circulation or damage vessel walls. The clinical presentation of arterial gas embolism (AGE) ranges from minimal neurologic findings to dramatic symptoms requiring urgent and aggressive treatment.

In general, suspect AGE in any scuba diver who surfaces unconscious or loses consciousness within 10 minutes after surfacing. Initiate basic life support, including administration of the highest fraction of oxygen. Because relapses can and do occur, divers suffering AGE should be rapidly evacuated to a hyperbaric oxygen treatment facility even if they appear to have recovered fully.

Decompression Sickness (“The Bends”)

Breathing air under pressure causes excess inert gas (usually nitrogen) to dissolve in and saturate body tissues. The amount of gas dissolved is proportional to, and increases with, the total depth and time a diver is below the surface. As the diver ascends, the excess dissolved gas must be cleared through respiration. Depending on the amount of gas dissolved and the rate of ascent, some gas can supersaturate tissues, where it separates from solution to form bubbles, interfering with blood flow and tissue oxygenation.

Other Conditions Related to Diving

Drowning

Any incapacitation while underwater can result in drowning (see Sec. 4, Ch. 12, Injury & Trauma).

Hazardous Marine Life

Oceans and waterways are filled with marine animals, most of which are generally harmless unless threatened. Most injuries among divers are the result of chance encounters or defensive maneuvers of marine life. Wounds from marine life have many common characteristics, including bacterial contamination, foreign bodies, bleeding, and occasionally venom. See Sec. 4, Ch. 7, Zoonotic Exposures: Bites, Stings, Scratches & Other Hazards, for prevention and injury management recommendations.

Immersion (Induced) Pulmonary Edema

The normal hemodynamic effects of water immersion account for a shift of fluid from peripheral to central circulation that can result in higher pressures within the pulmonary capillary bed, forcing excess fluid into the lungs. Cold water can cause peripheral vasoconstriction and augment this central fluid shift. Symptoms and signs of immersion (induced) pulmonary edema (IPE) generally begin on descent or at depth and include chest pain, dyspnea, wheezing, and productive cough with frothy, sometimes pink-tinged sputum. Although not entirely well understood, age, overhydration, overexertion, negative inspiratory pressure, and left ventricular hypertrophy are believed to increase IPE risk in otherwise healthy divers. Anyone experiencing acute pulmonary edema while diving requires a work-up to rule out myocardial ischemia, evaluation of left ventricular function, hypertrophy, and valvular integrity.

Nitrogen Narcosis

At increasing depths, generally >100 ft (≈30 m), the partial pressure of nitrogen within the breathing gas increases, causing narcosis in all recreational divers. Nitrogen narcosis can be life threatening when it impairs a diver’s ability to make appropriate and proper decisions while under water. This narcosis quickly clears on ascent and is not seen on the surface after a dive, which helps differentiate this condition from AGE.

Oxygen Toxicity

At increasing partial pressures of oxygen, levels in the blood become high enough to cause seizures. This condition is not seen when diving on compressed air within recreational depth limits.

Diving & Air Travel

Flying after Diving

The risk of developing decompression sickness increases when divers go to increased altitude too soon after a dive. Commercial aircraft cabins are generally pressurized to the equivalent of 6,000–8,000 ft (≈1,830–2,440 m) above sea level. Instruct asymptomatic divers to wait before flying at an altitude or cabin pressure >2,000 ft (610 m) for

≥12 hours after surfacing from a single no-decompression dive;

≥18 hours after multiple dives or multiple days of diving; or

24–48 hours after a dive that required decompression stops.

These recommended preflight surface intervals reduce, but do not eliminate, risk for DCS. Longer surface intervals further reduce this risk.

Diving after Flying

There are no guidelines for diving after flying. Divers should wait a sufficient period to acclimate mentally and physically to their new location to focus solely on the dive.

Preventing Diving Disorders

Recreational divers should dive conservatively and well within the no-decompression limits of their dive tables or computers. When multiple dives are planned, strict guidelines, known as surface intervals, are prescribed to allow adequate time for dissolved inert gas to drop to acceptable levels before the next dive. Tables derived from man-tested algorithms have traditionally been used by divers to manually calculate dive times and surface intervals. Dive computers possess the reliability and computing power to use the same algorithms and compute individual guidance based on real-time depth and time inputs. Dive computers have largely replaced the use of tables for the manual process of dive planning.

Risk factors for DCI are primarily dive depth, dive time, and rates of ascent. Additional factors, such as altitude exposure soon after a dive, difficult diving conditions (e.g., colder water, currents, decreased visibility, wave action), dives to depths >60 ft (18 m), multiple consecutive days of diving or repetitive dives, overhead situations (e.g., diving in underwater caves or wrecks), strenuous exercise, and certain physiologic variables (e.g., dehydration), also increase risk. Caution divers to stay well hydrated and rested and dive within the limits of their training. Diving is a skill that requires training and certification and should be done with a well-trained, attentive companion (dive buddy).

Treatment of Diving Disorders

Definitive treatment of DCI begins with early recognition of symptoms, followed by recompression with hyperbaric oxygen. Be suspicious of any unusual symptoms occurring soon after a dive, especially neurological symptoms, and evaluate these properly. Provide a high concentration (100%) of supplemental oxygen; surface-level oxygen given for first aid might relieve the signs and symptoms of DCI and should be administered as soon as possible.

Because of either incidental causes, immersion, or DCI itself, which can cause capillary leakage, divers often are dehydrated. In most cases, treatment includes administering isotonic glucose-free intravenous fluids. Oral rehydration fluids also can be helpful, provided they can be administered safely (i.e., if the diver is conscious and can maintain their airway).

The definitive treatment of DCI is recompression and oxygen administration in a hyperbaric chamber. Stable or remitting symptoms of mild DCI (e.g., constitutional symptoms, some cutaneous sensory changes, limb pain, or rash) in divers reporting from remote locations without a hyperbaric facility might not require recompression. Medical management decisions made with the assistance of a qualified dive medicine physician also should account for the prevailing circumstances, logistics and hazards of evacuation, and the implications of failing to recompress. Serial neurologic exams are essential to the decision-making process.

Divers Alert Network (DAN) maintains 24-hour emergency consultation and evacuation assistance at +1-919-684-9111 (collect calls accepted). DAN can help with the medical management of injured divers by deciding if recompression is needed, providing the location of the closest recompression facility, and arranging patient transport. Divers and health care providers also can contact DAN for routine, nonemergency consultation by telephone at 919-684-2948, extension 6222, or by accessing the DAN.

Travelers who plan to scuba dive might want to ascertain whether recompression facilities are available at their destination before embarking on their trip.

The following authors contributed to the previous version of this chapter: Daniel A. Nord, Gregory A. Raczniak, James M. Chimiak

Brubakk AO, Neuman TS, Bennett PB, Elliott DH. Bennett and Elliott’s physiology and medicine of diving, 5th edition. London: Saunders; 2003.

Chapter 6: Pulmonary and Venous Disorders. In: J. Chimiak, editor. The heart & diving. Durham (NC): Divers Alert Network. Available from: https://dan.org/wp-content/uploads/2020/07/the-heart-and-diving-dan-dive-medical-reference.pdf.

Dear G, Pollock NW. DAN America dive and travel medical guide, 5th edition. Durham, NC: Divers Alert Network; 2009.

Divers Alert Network. Flying after diving. 2003. Available from: https://dan.org/research-reports/research-studies/flying-after-diving.

Mitchell SJ, Doolette DJ, Wachholz, CJ, Vann RD, editors. Management of mild or marginal decompression illness in remote locations. Sydney, Australia: Undersea and Hyperbaric Medical Society; 2004.

Moon RE. Treatment of decompression illness. In: Bove AA, Davis JC, editors. Bove and Davis’ diving medicine, 4th edition. Philadelphia: WB Saunders; 2004. pp. 195–223.

Neuman TS, Thom SR. Physiology and medicine of hyperbaric oxygen therapy. Philadelphia, PA: Saunders; 2008.

US Navy. The Navy diving manual revision 7. USA: Carlisle Military Library; 2018.

Scuba Diving | What Are The Bends And How Do You Pre…

Diving

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…

by Lou Boyd

loukayboyd

lauraloubeeboyd

8th June 2016

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.

Scuba Diving For Beginners | Everything You Need To Know

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 also called ‘Decompression Sickness’ and occur because of the release of gases in the body Photo: iStock

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 can happen to a diver of any experience level Photo: iStock

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 bends can attack any part of the human body Photo: iStock

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

A decompression schedule must be created for the ascent of a dive, to avoid the bends Photo: iStock

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

If a diver shows symptoms of the bends, provide them with an oxygen mask as soon as is possible Photo: iStock

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.

TEST. Diving equipment EPRON

30.04.2022

Test your knowledge of diving equipment and how to care for it. Course OWD

/19

9 votes, 4.9 average 49

Created by April 30, 2022

TEST. Diving equipment

Test passed with 80% correct answers

1 / 19

1. Part of the regulator with the mouthpiece is called:

1. Compensator

2. Second stage

3. Inflator

4. First stage

2 / 19

2. First stage regulator… .

1. …reduces pressure from the cylinder to ambient

2. …reduces pressure from the cylinder to intermediate

3. …increases pressure for easier breathing

4. …adjusts depth

3 / 19

3. Most important controller feature:

1. adjustable second stage

2. ability to provide ease of breathing

3. modern design and configuration

4. ease of maintenance and use

4 / 19

majority equipment items include:

1. rinse thoroughly with fresh water after each dive

2. rinse and dry in the sun

3. grease with silicone and soak in water

5 / 19

5. Gauge shows …

90 002 1. … speed and direction movements

2. …dive time

3. …amount of air in the cylinder

4. …depth

6 / 19

check the air quality in the tank

2. check that there are no signs of corrosion on the inner surface of the cylinder

3. check that all markings and dates of pressure tests are present

4. check that there are no signs of corrosion on the outer surface of the cylinder

7 / 19

7. Connection type ____ implies the presence of a threaded hole on the valve, where the regulator is screwed

1. DIN

2. all correct

3. YOKE

8 / 19

8. What is the most effective method to prevent water from entering the cylinder?

1. Do not immerse the cylinder in water and do not flush the valve

2. Never allow the air pressure in the cylinder to drop to zero.

3. Do not pour water through the regulator

4. Do not open the valve without the first stage

9 / 19

9. When rinsing the regulator with water you need:

1. all answers are correct

2. tightly close the opening on the first stage with a protective cap

3. do not press the forced air supply button

4. make the water jet weak

10 / 19

10. Which of the following is not a design feature of the unit buoyancy aids?

1. Large diameter air inlet and bleed hose

2. Pockets, D-rings and knife holder

3. Inflator

11 / 19

cylinder in four stages

1. correct

2. incorrect

12 / 19

tests (pressure tests)

4. date of manufacture and inspection of the cylinder

13 / 19

13. Diving cylinders must be visually inspected:

1. every seven years

2. once a year

3. every five years

4 once every half a year

14 / 19

14. What type of fins are used with boats?

1. Slotted

2. Closed heel

3. Ribbed

4. Open heel

15 / 19

15. Buoyancy compensator ( BCD) is needed in order to …

1. all answers are correct

2. … to control buoyancy under water and ensure positive buoyancy on the surface

3. … to attach an air cylinder, a flashlight, a knife, a reel to it …

4. … to protect the diver’s body from the cold and make an emergency ascent

16 / 19

16. What are the additional maintenance procedures for the buoyancy compensator?

1. Store deflated and prevent water from entering the chamber

2. Flush inside with fresh water and keep pumped

3. Flush with fresh water and store disassembled

17 / 19

17. What design features of the blade make the fins work more efficiently?

1. material from which the fins are made

2. color and shape of the fins

3. length of the fins

0006

18 / 19

18. What are the main features of an easy-to-breathe snorkel?

1. Large diameter and smooth curves

2. Wave baffle and bellows included

3. Valve included

4. Very long length

19 / 19

19. A breathing snorkel is needed to…

1. conserve air while resting or swimming on the surface

2. breathe freely if the surface of the water is rough

3. swim to the boat if the air in the cylinder will end at the moment of being at a great distance from it

4. All answers are correct

Your score is

Please rate this quiz

A look from under the water

While alluring silence hung on the swimming fields of the country, and everyone is preparing for the stages of the Russian Cup, the correspondent of the All-Russian Swimming Federation Konstantin Vekhanen decided to get in touch with the neighbors of the water world – divers, and draw parallels between these sports.

The day before, the special correspondent had a chance to meet with the young talent of the country, the champion of Russia in diving, the bronze medalist of the II CMAS World Games, the winner of the Russian Cup, 17-year-old Dmitry Lobchenko, who with pleasure told about himself, his first gold medal and compared the types of swimming. Dmitry helped us to learn about the life of young talents in underwater sports, the level of training, disciplines and rules, as well as to understand the role of swimming with fins in the life of an athlete.

– Dima, please tell us how your sports career started? In general, why is swimming, also scuba diving?

“Well, it all started, probably, as it usually happens for many people. My mother took me to the pool, because in Kropotkin there was nowhere else to go. And since my aunt was already working as a diving coach, no one thought for a long time, and I was sent to her group.

– That is, in the Lobchenko family in little Dmitry they immediately saw an athlete?

“Well, not really. Now my mother says that at that time she wanted me to swim just for myself, for health, and already at the age of 10-12 I began to train more diligently, and it became clear that this would turn into something worthwhile. Just one of my first competitions, in which I took third place at the age of 11, and became a kind of impetus for swimming seriously.”

– Did you enjoy scuba diving at first?

“At first it was not very good, it was hard. But little by little, everything fell into place, regular training, competitions, everything is as it should be. Got involved.”

– Then tell us what scuba diving is, because many people don’t know much about this sport.

“Scuba diving is quite a young sport compared to ordinary swimming. It differs in that scuba diving uses snorkels, fins and, at some distances, breathing apparatus. I say right away that there are no technical devices that would give an advantage or something else. All divers swim with their muscular strength.

We have a large number of disciplines for different distances, just like ordinary swimmers. There are eight hundred meters, four hundred, one and a half thousand, in general, enough. On some, you have to use this self-contained breathing apparatus.

– Do you have any favorite races?

“Of course there is. I prefer long distances, I like 1500 meters the most, but I also swim 800 meters with the same pleasure.

– What is the main difference between scuba diving and ordinary diving?

“Well, for me it’s different sports, although it’s clear that we all swim. Many swimmers believe that if they join us, they will all win. But it’s not like that. Firstly, it is also very heavy physical activity, training. Secondly, you need to choose a flipper for yourself.

– What does it mean to pick up a flipper? Are there any subtleties in the choice?

“Of course. This is a very complicated process, because first you need to decide on the manufacturer, then choose the material for the plate, whether it’s carbon or plain glass. Next, swim and see how it behaves in the water, how hard it is, because in a hard flipper you will not swim far.

– Have you ever thought about switching from one species to another?

“No, I didn’t think about it. I really love fins, this is speed, this is a different kind of swimming, and I hope that someday our sport will be included in the Olympic program, and we will take the first team place.”

– “Not as an athlete, but as a spectator, do you watch what happens in swimming?

“Actually, this is my favorite sport in the Olympic program. I follow all the competitions if I have time, and especially Danila Izotov, as he competes for our Krasnodar Territory. He is a two-time Olympic medalist, and he is only 22. By the way, he sometimes trains in our pool.

– Let’s talk about you now. Your first adult success – the gold medal of the Russian Cup at a distance of 1500 meters. I’m right?

“That’s right, how quick-witted you are (laughs). In the 800m, I took silver at the Russian Cup, and I took my first gold in the 1500m, all in the same place in Balakovo. Of course, not without the work of my coach Evgeny Ivanovich Grigoriev, who invested a lot of strength and patience in me. I am very glad that he is my coach, thanks to him for everything.”

– Must be very demanding?

“Well, of course, the honored coach of Russia, who brought up world champions, multiple world champions, of course, strict discipline, you need to follow all his instructions, requirements, work and work again, in general.”

– You are 17 years old, you are the champion of Russia. What did you experience when you won that first gold at the senior level?

“Of course, I was very happy, but I don’t consider it an absolute victory, because my teammate won the World Championship with a better time than me. That’s when he is in shape, and I beat his record, then it will be a victory.

– Did you feel the attention from the public after the victory?

“To be honest, I don’t know. I think that you should not concentrate on this, first of all you swim to defeat yourself.

– I would like to know the secret of Dmitry Lobchenko’s victories. Maybe there are unique methods of preparation?

“Well, of course, I won’t tell the whole training session, this information is usually not distributed. It all starts with a warm-up, it takes half the time of the total workout. In training, we “sprint” a lot, it is given to me without much pleasure – I just don’t have time to accelerate. Whether it’s a series of “hundreds”, where you swim a lot at the same pace. In the same way, I don’t have much sympathy for swimming 300 meters. It’s inconvenient. And not 200, and not 400 meters. At the end of the training, you must definitely swim 400 meters “on the board”, although Evgeny Ivanovich sometimes says: “No boards, took the tubes and swam the crawl!”.

– Your day starts…

“My day starts with training, then school with delicious chops, studying for exams, then another training session. In my free time, I often want to stay at home, relax, watch a movie, because fatigue affects, well, or I can read a magazine with headphones under Eminem. This year I am finishing the eleventh grade and after that I am going to enter the Institute of Physical Education. I want to be as close to professional sports as possible.”

– This summer, at the end of July, the European Championship will take place in Italy, in which you will take part. Are you setting any goals for yourself?

“As always, there are many goals… Last year I qualified for only one distance, but now I want to try two. And of course, the 4 x 2000 meter marathon relay. This year it has been simplified: two men and two women are selected, so it will be twice as difficult.”

– And the last question: What do you dream about? Maybe there is a cherished dream?

“I want to win the World Championship, set a record so that it stands for a long, long time. And of course, I really hope that in the near future we will be included in the Olympic program, and then the national team of our country will show everyone what it is worth in this sport.