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Frequently Asked Questions -
Diving Hazards
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The increased pressure
experienced by a diver underwater has the potential to cause injury to
body parts and systems which contain air, if the increase in pressure
is not properly managed. Examples of these body parts and systems are
the middle ear, lungs and the sinus cavities. When diving deeply into
the water, the internal pressure of the body's air spaces (or
"cavities") must be maintained in balance with (or equalized to) the
surrounding water pressure at all times during each immersion. While we
are diving deeper into the water, the quantity (volume) of air in the
cavities must increase in order to equal and counter-effect the
increased pressure the water exerts upon us at that depth.
Conversely, when swimming to the surface after completing a dive, the
body must release the now expanding air from these body cavities in
order to match the decrease in the surrounding water pressure as we
move upward into more shallow water. In this adaptive manner, when done
correctly, we are able to maintain the body's all important internal
and external pressure balance. Situations where the body cannot adjust
smoothly to changes in the surrounding pressure may lead to damage of
the tissues in and around the air cavities affected. In diving, one of
the most fragile parts of our body, the ear's tympanic membrane, is the
most commonly injured, due to tissue damage which may result from the
inadequate internal and external pressure equalization of the middle
ear. Improper or insufficient equalizing of the pressures affecting the
ear cavity may initially cause pain. If the ascent or descent is
continued without attaining the proper pressure balance, the eardrum
may be damaged (barotrauma). When a pressure imbalance causes injury to
the sinus cavities, one may initially experience pain in and around the
sinus area, sometimes accompanied by nosebleed and severe headache.
These conditions are best prevented by the pursuit of approved
training, attention to that which is learned, and slow, easy ascent and
descent rates in practice.
The most potentially dangerous injury caused by inadequate pressure
equalization is referred to as "Lung Over Expansion" injury. This
condition develops when air trapped anywhere in the lungs cannot find a
free path to escape or to safely expand as the pressure affecting the
lungs lessens, which causes the gas volume to increase (Boyle's Law).
This may occur if a diver suddenly runs out of air, and in a state of
panic, swims quickly to the surface while holding their breath. The
rapidly expanding air in the lungs can be quite suddenly and
explosively released into nearby blood vessels, or might forcefully
enter the tissues of the lungs or chest cavity. A dangerous amount of
this expanding air can potentially enter circulatory system blood
vessels from the lungs in the form of bubbles, which then exhibit the
potential for causing a blockage (embolus) in the arterial or venous
blood supply systems in various parts of the body. In the case that a
bubble of expanded air escapes from the lungs and blocks the blood
circulation to the brain, it can precipitate quite serious symptoms.
Fast response and professional attention are imperative to safe
resolution of this potentially life threatening injury, known as
"Arterial Gas Embolism".
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Last Updated ( Jan 12, 2007 at 04:20 PM )
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