Tuesday, July 19, 2011

Decompression Sickness & Scuba Diving

Decompression Sickness (DCS), as it is commonly know, is caused by a build up of nitrogen bubbles in the body. When we breathe underwater, approximately 79 of the air (depending on gas blend) we’re breathing is nitrogen. As we descend deeper in water, the pressure around our bodies increases, causing nitrogen to be absorbed into our body tissues.

Decompression Sickness is the term uses to describe the illness and effects that result from a reduction in the ambient pressure surrounding the human body.



As long as the diver remains at pressure, the gas presents no problem. If the pressure is reduced too quickly, however, the nitrogen comes out of solution and forms bubbles in the tissues and bloodstream. This commonly occurs as a result of violating or approaching too closely the diving table limits, but it can also occur even when accepted guidelines have been followed. ( Like in the video above)

Bubbles forming in or near joints are the presumed cause of the joint pain of a classical “bend.” When high levels of bubbles occur, complex reactions can take place in the body, usually in the spinal cord or brain. Numbness, paralysis and disorders of higher cerebral function may result. If great amounts of decompression are missed and large numbers of bubbles enter the venous bloodstream, congestive symptoms in the lung and circulatory shock can then occur.

The diagnosis of DCS is made on the basis of signs and/or symptoms after a dive or altitude exposure.

There are two types of DCS

Type 1: Type 1 DCS is the least serious form of DCS. It usually involves pain in the body and is usually not an immediate life threat. It is important to understand that type 1 DCS can be warning signs of type 2 DCS.

  • Cutaneous Decompression Sickness
    This occurs when nitrogen bubbles come out of solution in skin capillaries. Resulting in red rashes, often near the chest and shoulders.
  • Joint and Limb Pain Decompression Sickness
    This type is recognized by aching and or pain in the joints. The pain can be in one place or it can move around the joint.

Type 2: Type 2 DSC is more serious and be life threatening. Usually effecting the nervous system.

  • Neurological Decompression Sickness
    When nitrogen bubbles affect the nervous system they can cause problems throughout the body. This type of Decompression Sickness normally shows as tingling, numbness, respiratory problems, and unconsciousness. Symptoms can spread quickly and if left untreated can lead to paralysis or even death.
  • Pulmonary Decompression Sickness
    This is a rare form of Decompression Sickness that occurs when bubbles form in lung capillaries. Fortunately, the majority of the time bubbles dissolve naturally through the lungs. However, it is possible for them to interrupt blood flow to the lungs which can lead to serious and life-threatening respiratory and heart problems.
  • Cerebral Decompression Sickness
    It is possible for bubbles that make their way into the arterial blood stream to move to the brain and to cause an arterial gas embolism. This is extremely dangerous and can be identified by symptoms such as blurred vision, headaches, confusion, and unconsciousness.

Symptoms of DCS

  • Extreme Fatigue
  • Joint and Limb Pain
  • Tingling
  • Numbness
  • Red Rash on Skin
  • Respiratory Problems
  • Heart Problems
  • Dizziness
  • Blurred Vision
  • Headaches
  • Confusion
  • Unconsciousness
  • Ringing of the Ears
  • Vertigo
  • Stomach Sickness

Signs of DCS

  • Skin may show a blotchy rash
  • Paralysis, muscle weakness
  • Difficulty urinating
  • Confusion, personality changes, bizarre behavior
  • Amnesia, tremors
  • Staggering
  • Coughing up bloody, frothy sputum
  • Collapse or unconsciousness

** Symptoms and signs usually appear within 15 minutes to 12 hours after surfacing; but in severe cases, symptoms may appear before surfacing or immediately afterwards. Delayed occurrence of symptoms is rare, but it does occur, especially if air travel follows diving.

Preventing Decompression Illness:

You can help minimize the risk of DSC by using a Dive Planner or a diver computer properly. You also need to follow other dive safety practices that you should have learned in your scuba diving training.

There are many things you should be aware of when diving:

-Never dive to the limits: always have a margin before you hit your dive/table limit

- Fat: Nitrogen dissolves easily into fat tissue. People with a larger ration of fat to body weight may absorb more nitrogen when diving.

- Age: As you get older your circulatory system becomes less efficient, affecting nitrogen elimination.

-Alcohol: Any type of alcohol before or right after a dive can accelerate and alert your circulation.

-Cold Water: Diving in cold water can cause your extremities to receive less circulation as they cool, this effects nitrogen elimination.

-Hot shower/bath: Hot showers and baths after a dive cause skill capillaries to dilate, which will draw blood away from other areas. These areas will then eliminate nitrogen more slowly.

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