What is it about ?
Diving is a popular hobby that is enjoying more and more followers. But it remains associated with certain risks. Barotrauma, decompression sickness and drowning caused by unconsciousness underwater are the main accidents to which divers can be exposed.
Water is much heavier than air. The pressure to which your body is subjected is therefore greater underwater and increases with depth. Compact tissues, such as muscles, resist the change in pressure well. It is quite different for the cavities of our body which are filled with air, such as the lungs, middle ear, sinuses, etc. Indeed, this air compresses during the descent, then decompresses during the ascent. As it slowly descends and rises in the water, a healthy body can adapt to it, but too rapid a change in pressure can cause problems.
The most common causes of diving accidents are not of a medical nature. Hardware failures are rare, too. No less than 80% of diving accidents are the result of human error and / or non-compliance with safety procedures.
The main danger associated with diving is damage to the middle ear caused by pressure.
How to recognize them?
Barotrauma
A barotrauma is an injury caused by pressure. It can occur both following an excessively rapid increase in pressure during the descent as well as following a too rapid decrease in pressure during the ascent. The characteristic lesions are damage to the middle ear and pneumothorax.
- Middle ear damage
During the descent, the air in the middle ear is compressed. This bulges the eardrum inward. Normally, the diver can actively correct this change by balancing the pressure, for example by swallowing or trying to blow through the pinched nose (Valsalva maneuver). If the pressure equalization fails, the eardrum will stretch further and eventually tear. In this case, the diver experiences ear pain and, at an advanced stage, dizziness and nausea. He may also feel disoriented. The same type of problem can occur during ascent, if the pressure drops too quickly. In this case, the diver mainly suffers from the sinuses of the nose.
- Pneumothorax
Here, the pressure causes a leak in the pleura. The air then settles between the pleura and pushes back the lung tissue.
This problem occurs when the diver does not exhale sufficiently during the ascent, which causes air to accumulate in the lungs (“air trapping”) and considerably increases the pressure. As a result, the lung tissue stretches and eventually tears. Pneumothorax affects more divers who suffer from lung conditions such as infection, asthma or emphysema. The diver feels the first manifestations directly, including shortness of breath, coughing and a feeling of tightness in the chest. In severe cases, the diver may lose consciousness.
- Other tissues, such as the intestines, can also contain air and are therefore prone to pressure changes. Serious lesions are rather rare.
Decompression sickness
Decompression sickness is the development of gas bubbles in the blood. The diver’s compressed air contains a mixture of oxygen and nitrogen. However, nitrogen can form gas bubbles when it rises too quickly. The bubbles prevent blood from passing to the tissues, which therefore no longer receive enough oxygen.
The less severe form, type 1, is characterized mainly by pain in the joints and possibly a mild rash. In the severe form, type 2, the central nervous system is affected and neurological symptoms appear, such as loss of feeling and even paralysis and loss of consciousness. Treatment consists of administering pure oxygen under high pressure. This treatment should be started quickly.
What can you do ?
To dive, you must be in good physical condition and be well informed of the possible risks, safety measures and medical contraindications. The diver must systematically confirm that he has understood the information provided and the health factors listed and that, if one of the risk factors concerns him, he must consult a doctor.
It is strongly recommended not to dive alone. The diver must be well trained and be able to correctly estimate the rate of descent and ascent. This is why it is always better to dive in a club.
The following medical conditions involve a risk and are in principle contraindications to diving:
- neurological conditions: epilepsy, other sudden disturbances in the level of consciousness;
- psychiatric disorders: panic disorder (panic is one of the leading causes of serious diving accidents), claustrophobia or agoraphobia, serious psychological problems (altered sense of reality, suicidal tendencies, severe depression, paranoia, …), use antipsychotics, alcohol abuse or illicit drug use;
- respiratory system disorders: exertional asthma, upper respiratory tract infections, decreased respiratory function, conditions predisposing to pneumothorax and / or gas embolism;
- Cardiovascular disorders: heart rhythm disturbances, heart failure, recent heart attack, uncontrolled high blood pressure, coronary heart disease;
- muscle and bone disorders that severely interfere with normal movement;
- diabetes: the use of insulin, in particular, constitutes a significant risk;
- blood diseases: people who take anticoagulants and / or who have an increased tendency to bleed;
- ear problems: difficulty balancing the pressure in the middle ear (for example with otitis media), sinus problems, inner ear problems.
If you still want to go diving while suffering from any of these conditions, you should first seek the advice of a specialist.
What can your doctor do?
The doctor will discuss with you if you have any risk factors for diving. If necessary, he will refer you to a doctor specializing in diving and hyperbaric medicine. This type of doctor is the only one who can perform the medical assessment of a professional diver.
If you are the victim of a diving accident, the doctor will start treatment as soon as possible. The objective is to remove excess nitrogen and ensure the return of a normal oxygen concentration. The best way to do this is to administer pure oxygen under pressure, through an airtight mask. If this device is not available, compressed air can also be used. Once this treatment is in place, the diver must be taken to a center equipped with a hyperbaric chamber. This is a special room, where the pressure corresponds to that exerted at a depth of 18 meters. The diver receives there pure oxygen via a mask. The sooner treatment can be started, the better the recovery and the lower the risk of complications and permanent damage.
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