Term
| Carbon Dioxide Retention (Hypercapnia). Hypercapnia |
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Definition
An abnormally high
level of carbon dioxide in the blood and body tissues hypercapnia is generally the result
of a buildup of carbon dioxide in the breathing supply |
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Term
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Definition
A condition where breathing stops and both hypoxia and
hypercapnia occur |
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Term
| Involuntary Hyperventilation |
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Definition
The term applied to breathing
more than is necessary to keep the body’s carbon dioxide tensions at proper level. |
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Term
| Oxygen Deficiency (Hypoxia) |
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Definition
An abnormal deiciency of oxygen in
the arterial blood |
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Term
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Definition
The part of the respira-
tory system that has no alveoli, and in which little or no exchange of gas between
air and blood takes place. |
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Term
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Definition
The ratio of the amount
of carbon dioxide produced to the amount of oxygen consumed during cellular
processes per unit time |
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Term
| Respiratory Minute Volume |
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Definition
| The total amount of air moved in or out of the lungs in a minute |
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Term
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Definition
Volume of air moved in or out of the lungs during
a single normal respiratory cycle. |
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Term
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Definition
The volume of air that can be expelled from the
lungs after a full inspiration. |
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Term
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Definition
One complete breath consisting of an
inspiration and exhalation, including any pause between the movements. |
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Term
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Definition
Term divers apply to
an episode of acute hypercapnia that develops when a diver works at a level greater
than his UBA can support |
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Term
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Definition
Damage to body tissues from the mechanical effects of pressure,
results when pressure differentials between body cavities and the hydrostatic pres-
sure surrounding the body, or between the body and the diving equipment, are not
equalized properly (Middle ear squeeze most common) |
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Term
| Gastrointestinal Distention |
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Definition
Divers may occasionally experience abdominal
pain during ascent because of gas expansion in the stomach or intestines. |
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Term
| Pulmonary overinlation syndromes |
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Definition
Group of barotrauma-related diseases
caused by the expansion of gas trapped in the lung during ascent (reverse squeeze)
or overpressurization of the lung with subsequent overexpansion and rupture of
the alveolar air sacs. |
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Term
| Arterial Gas Embolism (AGE) |
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Definition
Sometimes simply called gas embolism, is an obstruction of blood low caused by gas bubbles (emboli)
entering the arterial circulation |
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Term
Mediastinal emphysema, also called
pneumomediastinum |
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Definition
When gas is forced through torn lung tissue into the
loose mediastinal tissues in the middle of the chest surrounding the heart, the
trachea, and the major blood vessels |
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Term
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Definition
| Occurs when that gas subsequently migrates into the subcutaneous tissues of the neck . Mediastinal emphysema is a pre-requisite |
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Term
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Definition
Air trapped in the pleural space between the
lung and the chest wall |
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Term
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Definition
state of euphoria and exhilaration that
occurs when a diver breathes a gas mixture with a nitrogen partial pressure greater
than 4 ata. |
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Term
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Definition
Exposure to a partial pressure of oxygen above that encountered
in normal daily living may be toxic to the body. |
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Term
| Pulmonary Oxygen Toxicity |
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Definition
sometimes called low
pressure oxygen poisoning, can occur whenever the oxygen partial pressure
exceeds 0.5 ata. A 12 hour exposure to a partial pressure of 1 ata will produce mild
symptoms and measurable decreases in lung function. |
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Term
| Central Nervous System (CNS) |
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Definition
Sometimes called high pressure oxygen poisoning, can occur
whenever the oxygen partial pressure exceeds 1.3 ata in a wet diver or 2.4 ata in a
dry diver. |
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Term
| Decompression Sickness (DCS) |
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Definition
A diver’s blood and tissues absorb additional
nitrogen (or helium) from the lungs when at depth. If a diver ascends too fast this
excess gas will separate from solution and form bubbles. These bubbles produce
mechanical and biochemical effects that lead to a condition known as |
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Term
| Excessive Heat Loss (Hypothermia) |
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Definition
Lowering of the core
temperature of the body. |
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Term
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Definition
The eardrum does not have to rupture for caloric vertigo to occur.
Caloric vertigo can occur simply as the result of having water enter the external ear
canal on one side but not the other. The usual cause is a tight itting wet suit hood
that allows cold water access to one ear, but not the other. It can also occur when
one external canal is obstructed by wax |
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Term
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Definition
Sudden exposure of the face to cold water or immersion of the whole
body in cold water may cause an immediate slowing of the heart rate (bradycardia)
and intense constriction of the peripheral blood vessels. Sometimes abnormal heart
rhythms accompany the bradycardia. This response is known as |
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Term
| Excessive Heat Gain (Hyperthermia) |
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Definition
Raising of the core
temperature of the body |
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Term
| High Pressure Nervous Syndrome (HPNS) |
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Definition
A derangement of central nervous system function that occurs during
deep helium-oxygen dives, particularly saturation dives. The cause is unknown. |
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Term
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Definition
Most divers will experience pain in the joints during
compression on deep dives |
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Term
| Immersion Pulmonary Edema |
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Definition
Immersion in water can cause luid to leak out of
the circulation system and accumulate irst in the interstitial tissues of the lungs
then in the alveoli themselves. This condition is called |
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Term
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Definition
External pressure on the carotid artery from a tight itting
neck dam, wet suit, or dry suit can activate receptors in the arterial wall, causing
a decrease in heart rate with possible loss of consciousness. |
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Term
| Middle Ear Oxygen Absorption Syndrome. |
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Definition
The negative pressure that may develop in the middle ear
following a long oxygen dive |
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Term
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Definition
Different from trauma that occurs at the surface because it may be complicated by the loss of the diver’s gas supply
and by the diver’s decompression obligation. |
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Term
| Otitis Externa (swimmer’s ear) |
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Definition
Infection of the ear canal caused
by repeated immersion. |
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Term
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Definition
| Abnormally low blood sugar (glucose) level. |
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Term
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Definition
| A force acting upon a particular area of matter |
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Term
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Definition
33 feet of sea water
or 14.7 psi, |
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Term
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Definition
Constant at sea level; minor fluctuations caused by the weather are usually
ignored. Also acts on all things in all directions. |
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Term
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Definition
The water on the surface pushes down on the water
below and so on down to the bottom where, at the greatest depths of the ocean
(approximately 36,000 fsw), the pressure is more than 8 tons per square inch
(1,100 ata). The pressure due to the weight of a water column is referred to as |
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Term
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Definition
| The force that makes objects loat |
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Term
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Definition
The buoyancy of a
submerged body can be established by subtracting the weight of the submerged
body from the weight of the displaced liquid. If the total displacement (the weight
of the displaced liquid) is greater than the weight of the submerged body, the
buoyancy is positive and the body will loat or be buoyed upward. If the weight
of the body is equal to that of the displaced liquid, the buoyancy is neutral and the
body will remain suspended in the liquid. If the weight of the submerged body is
greater than that of the displaced liquid, the buoyancy is negative and the body
will sink. |
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Term
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Definition
A diver with full lungs displaces a greater volume of water and, therefore, is
more buoyant than with delated lungs |
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Term
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Definition
| The most common gas used in diving |
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Term
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Definition
basic explanation of the behavior of gases under all
variations of temperature and pressure is known as |
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Term
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Definition
Boyle’s law states that at constant temperature, the absolute pressure
and the volume of gas are inversely proportional. As pressure increases the gas
volume is reduced; as the pressure is reduced the gas volume increases. |
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Term
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Definition
C = × P V
Where:
C = a constant
P = absolute pressure
V = volume |
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Term
| Charles’/Gay-Lussac’s Law |
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Definition
Law states that at a constant pressure, the volume of a gas is directly proportional
to the change in the absolute temperature. If the pressure is kept constant and
the absolute temperature is doubled, the volume will double. If the temperature
decreases, volume decreases. If volume instead of pressure is kept constant (i.e.,
heating in a rigid container), then the absolute pressure will change in proportion
to the absolute temperature. |
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Term
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Definition
Gas laws that when combined
predict the behavior of a given quantity of gas when any of the factors change. |
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Term
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Definition
The total pressure exerted by a mixture of
gases is equal to the sum of the pressures of each of the different gases making up
the mixture, with each gas acting as if it alone was present and occupied the total
volume.” |
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Term
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Definition
| The process of intermingling or mixing of gas molecules |
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Term
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Definition
The amount of any given gas that will dissolve
in a liquid at a given temperature is directly proportional to the partial pressure of
that gas.” |
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Term
| What are the five objectives in the diving record keeping and reporting system |
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Definition
1)Establish a comprehensive operational record for each diving command.
2)Gather data for safety and trend analysis.
3)Provide data for a personal record
4)Report information about diving mishaps and casualties.
5)Report information about equipment deficiencies to the responsible technical agencies. |
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