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Description Core body temperature is lowered. |
Symptoms
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Causes Exposed to cool air or water without proper insulation. |
First Aid Passive Warming - remove wet clothing, replace with dry clothes and blankets, put in warm environment Active Surface Rewarming - Use heated blankets, a warm person, or warm water bottles and apply to the skin. If victim is alert, give liquids to protect from dehydration. No alcohol or caffeine. |
Wetsuits can protect from Hypothermia but can lead the diver to get too hot when out of the water.
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Description Core body temperature is elevated. |
Symptoms
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Causes Overheating can be due to wearing a wetsuit in the heat for too long before or after a dive. |
First Aid Cool the body slowly by covering with wet blankets, spraying with water. Administer fluids for rehydration |
All squeezes occur due to changing pressure, using Boyle's law.
As you descend the increased depth pressurizes air pockets reducing their volume. Every air pocket is affected by this law: lungs, sinuses, ears, stomach, and air within a BC, hood, mask, and drysuit.
The opposite can occur on ascent, a reverse block is when air pockets will expand.
Can rupture an ear drum. If rupture occurs water entering the middle ear can lead to vertigo.
Eustachian tube works like a one way valve allowing air to escape upon ascent.
That valve will be force shut if one descends a few feet w/o equalizing.
Equalize using the valsalva maneuver, hold your nose and push air through your eustachian tubes to equalize the pressure on the ear drum.
This must be done as descending, if the pressure builds too high the Valsalva maneuver may not work.
Muscles surrounding the eustachian tubes are used in yawning and swallowing.
Do not use earplugs, or the space between the ear plug and the ear drum will not be able to be equalized (outer ear squeeze).
Typically the sinus passages equalized automatically.
The opening between the nasal cavity and sinus can become blocked due to swelling or mucus, preventing natural equalization.
Without equalizing the mucus membrane is drawn inward away from the bone, causing irritation.
A reverse block is possible as gas generated during the dive expands on ascent.
An air pocket due to improper cavity filling may cause a reverse block on ascent.
Air in your lungs can compress significantly during free diving.
Equalized by exhaling slightly through your nose into the mask. If no equalization occurs blood vessels in the eyes may break creating "red eyes".
Do not use swimming goggles, the air can not be equalized within the goggles.
Dead Space - air that can not be equalized. The hood may lie tightly around the ear sealing it and preventing the aire in the outer ear to escape.
Tilt head back or pull your hood open to let air out of the hood.
Want a snug fitting wetsuit hood, or exhaled air will be captured in the hood.
A drysuit uses an air layer instead of a water layer to insulate the diver.
Differences in pressure or temperature in each ear causes disorientation.
Can be caused by rupture ear drum, allowing cool water into middle ear.
The world spins, if you equalize the symptoms may go away. Grab onto something stable, or yourself until symptoms pass.
Diving in cold water increases susceptibility.
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Description Rupture of the lung causes air to travel in the space (the mediastinum) between the two lungs and behind the sternum.
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Symptoms
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Causes Failure to exhale during ascent |
First Aid
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Description Rupture of the lung can leak into the lining surrounding the lungs (visceral pleura). This air between the chest wall and the lung compresses the lung and can partially or fully collapse the lung. |
Symptoms
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Causes Failure to exhale during ascent |
First Aid
Treatment
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Description Rupture of lung alveoli, allowing bubbles into the bloodstream which may block circulation to the brain or heart. |
Symptoms
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Causes Failure to exhale during ascent |
First Aid
Treatment Recompression Chamber |
Gas effects occur due to Dalton's and Henry's laws.
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Description High concentrations (above 2atm partial pressure O2) can attack the nervous system. |
Symptoms
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Causes Breathing high partial pressure of Oxygen, which can occur from breathing air at 10 atm ( 297 ft) . Physiological limit of diving is 297 ft. |
First Aid Return to the surface Fresh Air |
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Description Hemoglobin combines with CO about 200 times as readily as oxygen = Carboxyhemoglobin. This doesn't allow oxygen to combine with hemoglobin. |
Symptoms
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Causes Carbon monoxide from exhaust fumes of engines may get into the intake air when refilling tanks. |
First Aid Oxygen |
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Description The body's level of CO2 is used to regulate breathing rates. If CO2 levels are elevated the desire to breath more will occur. |
Symptoms
After-effects
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Causes Skip Breathing (Holding between breaths) Shallow Breathing (Can come from snorkeling) |
First Aid Fresh Air Breath Normally |
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Description Can occur at any depth. The body's level of CO2 is used to regulate breathing rates. If CO2 has been flush out of the system (due to hyperventilation), the subsequent build up of CO2 may not be enough to trigger the need for breathing even when all the O2 has been used. Leads to unconsciousness due to lack of oxygen. |
Symptoms
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Causes Hyperventilating, then holding ones breath under heavy exertion. |
First Aid Breath Normally |
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Description "Rapture of the Deep" Higher partial pressures of nitrogen are absorbed into body tissues which slows nerve impulses producing an intoxication effect. |
Symptoms
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Causes Symptoms may begin around 80 -130 ft. Every 50 ft afterwards is like having an additional Martini. Martini's Law: Every 33 ft equals 1 Martini. Deep Diving: limit depths to 130 ft. |
First Aid Ascend until effects are relieved. |
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Description Nitrogen released from body tissue during ascent can not be absorbed into the bloodstream and eliminated through respiration causing nitrogen bubbles. Bubbles can congregate at joints and other locations blocking circulation. |
Symptoms
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Causes Failure to follow dive tables or dive limits and spending too much time at particular depth which leads to absorbing too much Nitrogen which can not be released safely upon ascent. |
First Aid
Treatment Recompression Chamber |
Navy Maximum No Decompression Dive Times
| Depth | Maximum Bottom Time |
| 35 | 310 |
| 40 | 200 |
| 50 | 100 |
| 60 | 60 |
| 70 | 50 |
| 80 | 40 |
| 90 | 30 |
| 100 | 25 |
| 110 | 20 |
| 120 | 15 |
| 130 | 10 |
Menstration does not typically pose a problem with diving. If cramps are bothersome on land, those affects may be heightened during diving.
Scuba diving is dangerous during any stage of pregnancy.
Due to slightly higher body temperature, women are more prone to hypothermia.
