REMY AYOB - TOP CYCLIST NOW 2018 BECAUSE DECOMPRESSION SICKNESS

                                                  REMY AYOB

TOP  CYCLIST IN THE WORLD 2018 – VIA DECOMPRESSION SICKNESS

Remy Ayob, 25, from Sungai Lui Ulu Langat, Selangor, who had biked across 20 countries from Malaysia since March last year and final United Kingdom on 24 February 2018.  

Talking about Decompression Illness (DCI) describes a range of symptoms arising from decompression of the body. DCI can be caused by two different mechanisms, which result in overlapping sets of symptoms. The two mechanisms are:

• Decompression sickness (DCS), which results from metabolically inert gas dissolved in body tissue under pressure precipitating out of solution and forming bubbles during decompression. It typically afflicts underwater divers on poorly managed ascent from depth or aviators flying in inadequately pressurised aircraft.
• Arterial gas embolism (AGE), which is gas bubbles in the bloodstream. In the context of DCI these may form either as a result of bubble nucleation and growth by dissolved gas into the blood on depressurisation, which is a subset of DCS above, or by gas entering the blood mechanically as a result of pulmonary barotrauma. Pulmonary barotrauma is a rupturing of lung tissue by expansion of breathing gas held in the lungs during depressurisation. This may typically be caused by an underwater diver ascending while holding the breath after breathing at ambient pressure, ambient pressure escape from a submerged submarine without adequate exhalation during the ascent, or the explosive decompression of an aircraft cabin or other pressurised environment.

In any situation which could cause decompression sickness, there is also potentially a risk of arterial gas embolism, and as many of the symptoms are common to both conditions, it may be difficult to distinguish between the two in the field, and first aid treatment is the same for both mechanisms.

Signs and symptoms

Below is a summary comparison of the signs and symptoms of DCI arising from its two components: Decompression Sickness and Arterial Gas Embolism. Many signs and symptoms are common to both maladies, and it may be difficult to diagnose the actual problem. The dive history can be useful to distinguish which is more probable, but it is possible for both components to manifest at the same time following some dive profiles.

A more detailed account of the signs and symptoms of Decompression Sickness can be found.

Decompression sickness	Arterial Gas Embolism
Signs
Skin rash	Bloody froth from mouth or nose
Paralysis, muscle weakness	Paralysis or weakness
Difficulty in urinating	Convulsions
Confusion, personality changes, bizarre behaviour	Unconsciousness
Loss of memory, tremors	No breathing
Staggering	Death
Collapse or unconsciousness
Symptoms
Fatigue	Dizziness
Skin itch	Blurring of Vision
Pain in joints or muscles	Areas of decreased sensation
Dizziness, vertigo, ringing in the ears	Chest pain
Numbness, tingling and paralysis	Disorientation
Shortness of breath

Safe versus dangerous diving

Over the past 20 years diving has become extremely popular, both at home and abroad.

But diving is not without its dangers. It's vital to attend a recognised diving school for training, and subsequently make sure that you keep your skills up to date.

Diving must be planned and carried out in a responsible manner, making sure that first aid equipment and relevant telephone numbers are at hand should an accident take place.

Finally, it's important to know the signs of decompression sickness and to be able to give first aid to an affected diver.

What is decompression sickness?

Decompression sickness, also called the bends, is caused by nitrogen bubbles forming in the bloodstream and tissues of the body.

The bubbles occur if you move from deep water towards the surface (where the surrounding pressure is lower) in too short a space of time.

Symptoms occur soon after the dive has finished and, in the most serious cases, it can lead to unconsciousness or death.

If you suspect decompression sickness: stop the dive, initiate first aid, and summon assistance from a specialist in divers' medicine. Treatment is 100 per cent oxygen on site and during transportation, followed by treatment in a decompression chamber.

What are the symptoms?

The symptoms of decompression sickness vary because the nitrogen bubbles can form in different parts of the body.

The diver may complain of headache or vertigo, unusual tiredness or fatigue. He or she may have a rash, pain in one or more joints, tingling in the arms or legs, muscular weakness or paralysis. Less often, breathing difficulties, shock, unconsciousness or death may be seen.

The symptoms generally appear in a relatively short period after completing the dive. Almost 50 per cent of divers develop symptoms within the first hour after the dive, 90 per cent within six hours and 98 per cent within the first 24 hours.

In practice this means symptoms that appear more than 24 hours after the dive are probably not decompression sickness.

An exception is if the diver has travelled in an aircraft or has been travelling in the mountains. Under these circumstances, low pressure can still trigger decompression sickness more than 24 hours after the last dive. As a result, it's wise not to fly within 24 hours of a deep dive.

What if you or a friend have symptoms?

• Stop the dive and keep calm.
• If the diver is unconscious, give first aid.
• Summon the emergency services immediately.
• Breathe pure oxygen if possible.
• Avoid over-exertion.
• Drink plenty of liquid.
• Any unusual condition after a dive could be decompression sickness. So if in doubt, get medical help.

Why does it happen?

Nitrogen makes up 70 per cent of the air we breathe (in the air around us and in our diving bottles). During a dive, large amounts of nitrogen are taken into the body's tissues. This is because the diver is breathing air at a higher pressure than if they were at the surface. The quantities of dissolved nitrogen depend on the depth and duration of the dive. The deeper and longer the dive, the more nitrogen is taken up by the body. This does not present a problem as long, as the diver remains under pressure.As the diver begins to ascend to the surface, the surrounding pressure falls, and nitrogen is released from the body via the lungs when the diver breathes out.If the rate of ascent exceeds that at which nitrogen can be released, it forms bubbles in the blood and tissues (similar to opening a bottle of fizzy drink too quickly).To minimise the risk of bubbles forming and divers developing decompression sickness, various tables have been drawn up that show the relationship between a given depth of water and the time a diver can stay down.

In addition, divers are advised to make a safety stop every 5 metres, and not to ascend at a pace of more than 10 metres a minute. If the dive has been deep or of long duration, it may be necessary to stop one or more times on the way up, making so-called decompression stops.But following the advice of the tables is no guarantee of avoiding decompression sickness. This is because the risk of developing decompression sickness is not only determined by the depth and length of the dive, but also by any safety or decompression stops. Factors such as cold, current, exertion and lack of fluid also play a part.Personal characteristics such as age, sex, percentage of body fat and physical condition must also be considered. Women are more at risk of decompression sickness than men. Similarly, the risk becomes greater the older the diver and also depends on the level of physical fitness.

How is it diagnosed?

In most cases, the diving history (ie information on the number of dives, diving depth, dive time, rate of ascent and decompressions) – as well as information on contributory factors such as cold, current, work and the diver's physical condition – will give some indication as to whether it could be decompression sickness.After a thorough examination, which includes investigating balance, coordination, sense of touch, reflexes and muscular strength, the doctor can build up a complete picture to evaluate whether decompression sickness is likely.The doctor will also decide if the diver requires treatment in a decompression chamber (also called a hyperbaric or recompression chamber).

What measures can be taken to avoid decompression sickness?

• Dive within the limits set out in the diving tables.
• Keep your rate of ascent to a maximum 10 metres a minute.
• Don't plan any dives that need a decompression stop in the water.
• Make a three-minute safety stop at a depth of 5 metres.
• Don't dive more than three times in one day.
• If you plan more than one dive in one day, start by making the deepest dive first.
• If you are diving for several days in a row, have a dive-free day after two to three days.
• Don't do any hard work before or after diving.
• Drink lots of liquid (ideally oral rehydration solutions) before diving. Lack of fluid due to heat or excess alcohol is dangerous.
• Make sure you are in good physical condition and well rested. Have regular medical checkups.
• Make sure there is an interval of at least 24 hours between diving and travel by air or climbing up mountains. If you have had decompression treatment, the recommended interval before the next dive is at least 48 hours.

Recovery after decompression sickness

Mild forms of decompression sickness can resolve themselves without treatment or by breathing 100 per cent oxygen at the site of the accident.

But if there's any suspicion of decompression sickness, the diver must be examined by a doctor. This is because, although it might not seem serious at the time, the condition may deteriorate.

If the diver receives treatment at an early stage, the chances of avoiding permanent injury are good. The longer that treatment is delayed, the greater the risk of serious consequences.

You should take a rest from diving after treatment for decompression sickness. The length of this rest depends on the severity of the decompression sickness and the effects of treatment, and they should be discussed with a specialist in divers' medicine.

How is decompression sickness treated?

There's no medicine that's used as a matter of routine in treating decompression sickness.

At the diving station and during transport

• 100 per cent oxygen by mask, at a rate of 10 to 15 litres a minute.
• Give the diver plenty of fluid to drink.
• Give first aid if the diver is unconscious.
• Prevent the diver from exerting himself or getting cold.

In hospital and specialised centres

• A decompression chamber is a steel tank that can be pressurised. There are decompression chambers in various places in the UK - some of these are situated at naval centres. The pressure in a decompression chamber can be increased by closing the doors and pumping air in.
• During treatment for decompression sickness, pressure is increased to correspond to the pressure found 18m under water. In some cases, the pressure in the chamber is set at 50 metres.
• The diver breathes pure oxygen through a mask, which improves exhalation of nitrogen. At depths in excess of 18 metres, and also after adequate intervals, the mask can be removed in the chamber. Pressure in the chamber is reduced gradually until the diver reaches surface pressure again.
• Treatment typically lasts between five and six hours.
• Throughout treatment a specially trained helper stays with the diver in the chamber. The diver's condition is closely monitored by further examination of coordination and balance, sense of touch, etc.
• If necessary, the diver's medical specialist can join the diver in the chamber, but otherwise takes charge of the treatment outside the chamber in co-operation with the specially trained helper.
• After treatment, the diver will be kept for 24 hours for observation in case his condition deteriorates.
• In most instances one course of treatment is adequate, but occasionally several treatments may be needed.
• After treatment for decompression sickness, a diver should take a rest from diving. The length of this rest should be discussed with a specialist in divers' medicine.

Further information

The now outsourced charity DDRC Healthcare Diving mergency Hotline is +44 (0)7831 151523 (24 hrs in emergency, will advise and pass to the nearest acute treatment unit if necessary. An alternative number is 01752 20999.