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Decompression illness refers to the conditions Decompression
sickness ( DCS ) and / or Arterial gas embolism( AGE )
and all of their clinical presentations and manifestations.
Decompression
sickness (DCS) is the most common condition that divers are familiar
with. It results from gas coming out of solution in the bodily
fluids and tissues when a diver ascends too quickly. This occurs
because the decreasing pressure that results when moving from the
deep to shallower levels lowers the solubility of gas in liquid -
resulting in the gas turning into bubbles.
Joint pain is the most
common complaint in DCS, especially in the elbow, shoulder, hip and
knee which if severe enough can make the patient bend over in pain ,
hence the term " bends " or the diver got "
bent" . The gas bubbles can cause blockage of blood vessels
causing ischemia ( lack of oxygen ) and infarction (damage) of
tissues beyond the obstruction.
Other symptoms are the mottled appearance of the skin and even edema
or swelling in the involved area. More severe cases
may involve the brain, the spinal cord, or the cardiopulmonary
system. Neurologic manifestations may include sensory deficits,
hemiplegia, paraplegia, paresthesias, and peripheral neuropathies.
These mean that patients may feel a range of symptoms like itchiness,
numbness, weakness to outright paralysis. Balance and coordination
may also be affected. Possible cardiopulmonary effects include massive pulmonary gas
emboli or myocardial infarction( heart attack ).
The expansion of gas in the lungs may lead to alveolar
rupture, also known as "Pulmonary Overinflation Syndrome,"
which may, in turn, result in arterial gas embolism (AGE). Which can
present as breathing difficulties to convulsions to unconsciousness.
Decompression sickness is treated
with recompression in a chamber to 60 FSW or deeper, associated with
hyperbaric oxygen breathing. In the US, this therapy is usually
guided by a Navy Treatment Table. These tables are very effective,
especially when recompression is begun promptly.
The
Bubble and The Pressure
On the
earth's surface, the human body is exposed to an ambient pressure
which is the result of the combined partial pressures of all the
gases in the earth's atmosphere. At sea level, the force of this
pressure is described as 1 atmosphere absolute (ATA). When diving,
as the diver goes deeper the pressure increases forcing more gas to
dissolve in the bodily fluids and tissues. Upon ascent, the
atmospheric pressure decreases so there will be less pressure
forcing the gas into solution. Rapid ascent may lead the gas to form
bubbles causing decompression sickness (DCS) or alveolar rupture ("Pulmonary
Overinflation Syndrome" ) with resultant bubbles in the
arterial circulation (arterial gas embolism-AGE )
The
Treatment
Because of recreational
scuba diving's increasing popularity, it has become the most common type of hyperbaric
exposure. This then lead to the emergence of an increase interest in
diving medicine as a specialty. For divers being afflicted with
decompression illness or the bends, Hyperbaric oxygen (HBOT) therapy
has become the treatment of choice. HBOT, aside from treating
decompression sickness, however, is also being recognized as
the definitive therapy for a growing number of disorders, including
AGE, Carbon monoxide poisoning, clostridial infections,
crush injuries, diabetic leg ulcers, skin graft failures, refractory
osteomyelitis, thermal burns, necrotizing soft tissue infections,
and osteoradionecrosis.
It is
incumbent on divers, dive professionals and resort staff to be
familiar with the symptoms of decompression Illness ( DCI ) as well
as the procedures necessary to obtain immediate and
appropriate medical management for the victims. Recognizing the
presence of DCI; access to a reliable hyperbaric facility compliant
with international standards which is manned by appropriately
trained personnel and a diving physician is important because the
hyperbaric chamber is now widely recognized as effective in
reversing the sometimes-deadly changes that take place with
decompression illness.
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