In this section ou will find information on:

What is Decompression Illness?
Safe Diving Recommendations
How is DCI Diagnosis Performed?
Emergency Treatment at the Site of Accident

Decompression Sickness can occur after breathing compressed air in depths as shallow as 9 meters and during normal and safe dive profiles. When too much nitrogen has been dissolved into the tissues; bubbles can form and will continue to increase in size as more nitrogen is diffused into them.

What is Decompression Illness?

Decompression Illness is a term which includes arterial gas embolism and decompression sickness. These two diseases are described separately below because their presumed causes are different.

DCS – Decompression Sickness
AGE – Arterial Gas Embolism

DCS – Decompression Sickness

Decompression Sickness (DCS) results from the formation of bubbles in the blood or body tissues, and is caused by inadequate elimination of dissolved gas after a dive or other exposure to a high pressure.

Decompression sickness may also occur with exposure to atmospheric pressure (altitude exposure), as in an altitude chamber or sudden loss of cabin pressure in an aircraft. In certain individuals, decompression sickness may occur from no-decompression dives, or decompression dives even when decompression procedures are followed meticulously. Various conditions in the diver or in their surroundings may cause absorption of an excessive amount of inert gas or may inhibit the elimination of the dissolved gas during normal controlled decompression. Any decompression sickness that occurs must be treated in a recompression chamber.

AGE – Arterial Gas Embolism

Arterial Gas Embolism (AGE) is caused by entry of gas bubbles into the arterial circulation which then causes a blood vessel obstruction known as emboli. These emboli are frequently the result of pulmonary barotraumas caused by the over expansion of the lungs when breath is held in the lungs during ascent. The gas might have been retained in the lungs by choice (voluntary breath holding) or by accident (obstructed portion of the lungs that has been damaged from some previous disease or accident) Could also occur if a diver reacts with panic to a difficult situation may breath hold without realizing it.

If there is enough gas and if it expands sufficiently, the pressure will force gas through the alveolar walls into surrounding tissues and into the bloodstream. If the gas enters the arterial circulation, it will be dispersed to all organs of the body. The organs that are especially susceptible to arterial gas embolism and that are responsible for the life threatening symptoms are the central nervous system (CNS)
and the brain. In all cases of arterial gas embolism, associated pneumothorax is possible and should not be overlooked.

AGE may develop within minutes of surfacing; causing severe symptoms that must be diagnosed and treated quickly and correctly because the supply of blood to the central nervous system is almost always involved. Unless treated promptly and properly be recompression, AGE is likely to result in death or permanent brain damage.

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Safe Diving Recommendations

If you observe the following recommendations, the chances of getting decompression sickness or the bends can be reduced. This does not guarantee however, that you are 100% RISK-FREE. Most often an aggregate of mild symptoms marks the beginning of the Decompression Syndrome. If detected early the outcome chance of having a speedy and 100% satisfactory recovery dramatically increases.

DO: Drink plenty of water (prevents dehydration) and dive conservatively within table/computer limits; ascend slowly- no faster than 30fpm. Limit to three (3) dives within twelve hour period, make safety stops after every dive, plan your dives and make sure that you dive your plan.

NOTE: As a physiological reaction to pressure, for every dive you do, your body will get rid of approximately 500 to 700ml of water. So when adding all the other dehydrating factors on a diving day, you should be drinking about one litre of water after every dive to stay properly hydrated and safe.

DON’T: Over exercise, take hot showers or baths after diving; drink alcohol, coffee and sodas immediately before/or after, avoid getting too cold during and after diving; greasy foods; do not fly immediately after a dive.

The Signs

(1) Blotchy skin rash
(2) Weakness
(3) Staggering
(4) Coughing Spasms
(5) Shortness of Breath
(6) Altered Mental Status

The Symptoms

(A) Pain
(B) Extreme
(C) Headache
(D) Nausea
(E) Itching
(F) Skin Rash
(G) Restlessness
(H) Numbness
(I) Dizziness
(J) Personality Changes
(K) Paralysis
(L) Reflex Changes
(M) Bladder Problems
(N) Fatigue

Note: A Sign is something that can be seen on a patient whereas a symptom is something the patient will report and that can not be noticed by the examining personel.

How do we know if a Diver has Decompression Sickness?

An examination must be performed by a fully trained Diving Physician (specialised doctor).

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How is the Diagnosis Performed?

A Diagnosis is made by evaluation/performing the following:

1. Patients Diving History ( Dive Profile/s over the last month leading up to the accident)
2. Patients Medical History,
3. Mitigating factors such as;
a. Dehydration
b. Fatigue
c. Alcohol or Drug Consumption
d. Physical Fitness

4. The Doctor or Dive Medic Technician performs a comprehensive neurological exam on the patient.

The patient is questioned with regards to general description of symptoms, past medical history, allergies, medications, drug use, smoking and alcohol intake, fatigue and sickness.

The patient is examined on a general appearance and vital signs taken.

The respiratory system is assessed and the Glasgow Coma Scale is used to assess the patient’s respionsiveness.

The final step is a thorough neurological examination of the central nervous system is performed. Mental state, cranial nerves, sensation and muscle strength and tone is all examined according to international standards.

If you are interested in how this is done, please feel free to contact the Phuket Chamber on the West coast or the Samui Chamber on the East coast of Thailand at any time where the staff will be more than happy to show you.

A proper neurological exam together with the patients diving and medical history are the only way to detect decompression sickness.

What else can be Checked in the Diagnosis of DCS?

X rays are taken of divers whom we suspect might have had some kind of pulmonary barotraumas. It is critical to exclude the possibility of lung over-expansion injury before recompression is started.

Emergency Treatment at the Site of the Accident

(A) Check airway, breathing and circulation (ABCs).
(B) Administer 100% Oxygen.
(C) Place diver in recovery position.
(D) Treat for shock.
(E) Transport to the nearest Multi-place Hyperbaric facility ASAP.

Some good sources of information:

DAN – Divers Alert Network’s website
DDRC – Diving Diseases Research Center