STARS Open Water Diver Manual

Index

Orientation
Transform into a Fish on Your Holidays
Certificate of Fitness for Diving
Certification Card (C-Card)
 
Dive Equipment
Mask
Snorkel
Fins
Gloves/Boots
Diving suits
Weights
Tank
Regulator
Backup Scuba
BC
Gauge
Other Equipment 1
Other Equipment 2
Other Equipment 3
Equipment Setup
Equipment Maintenance
 
Underwater Environment
Topography and Artificial Structures 1
Topography and Artificial Structures 2
Ocean Conditions 1
Ocean Conditions 2
Poisonous Sea Life 1
Poisonous Sea Life 2
Aggressive Sea Life
 
Underwater Physiology
Light and Color
Sound
Drag/Buoyancy
Heat Absorption
Air Composition
Breathing and Circulation Mechanism
Diver Breathing /Air Consumption
Pressure
Pressure and Gas Volume
Lung Over-expansion Injury
Air Embolism
Gas Poisoning
Hyperventilation
Skip Breathing
Decompression Sickness (DCS)
The Human Body’s Air Spaces
Squeeze and Equalization
Specific Squeeze Types
Reverse Block and Equalization
Specific Body Air Cavities and Reverse Block
 
Plan and Rules
Diving Site Selection
Leader and Member
Buddy System
Equipment
Health Maintenance
Refresher Course
Cancellation and Modification
Emergency Plan
Communication
Air Consumption Ratio
Dive Table
Change of the internal nitrogen quantity
Comparison of the internal nitrogen quantity
Constitution of the Dive Table
No-decompression Dive Limit
Residual Group
Surfacing Time
Nitrogen Disappearance Time
Surface Interval Time
No-decompression Dive Limit for the second diving
Residual Nitrogen Time
Residual Group for the second diving
Decompression Stop
Safety Stop
Time Until Safe To Fly
Other attention
Work Sheet
Making a Dive Plan
Multi-Level Diving
Manners
 
Diving Skills
Donning Snorkel Set
Snorkel Clear
Fin Work
Donning the Weight Belt
Head First
Equipment Setup
Entry
Descent
Regulator Clear
Mask Clear
Regulator Recovery
Buoyancy Control
BC Donning and Removal
Weight Belt Donning and Removal
Equipment Release
Dealing with Emergencies 1
Dealing with Emergencies 2
Dealing with Emergencies 3

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Specific Squeeze Types


■Middle Ear

When the ear, normally adjusted to surface pressures, is exposed to increased pressure during diving, the middle ear’s eardrum can feel painfully disturbed. In this case, we use the Valsalva maneuver to equalize pressure. The Valsalva maneuver is performed by forcibly exhaling at the same time you are pinching your nose while keeping your lips tightly closed.

The action forces air into the middle air via the Eustachian tube. However, you should take care not to overdo the maneuver to avoid auditory damage form over-pressurization.

Swallowing and a yawning motion are some of the gentler methods that can work as well.



In order to prevent squeeze, you should equalize frequently and in advance of any pain developing. If you find it difficult to equalize, slowly ascending to a shallower depth should resolve the issue. As well, equalization is easier if you descend feet first from the surface. If discomfort or pain is ignored and you continue to descend, there is a risk of a perforated eardrum, which allows water to enter the middle and inner ear regions. Water’s chilling effect on the cochlea causes excessive dizziness and malaise. In the case of this happening, grab hold of a rock or anchor-line to stabilize yourself, and once the water is warmed and balance somewhat restored, make an emergency assent.



■Sinus

Sinuses are joined to the nasal cavity via small orifices called ostia. These remain open and so pressure equalizes under normal conditions. However, these become blocked relatively easily by colds and allergic inflammation, causing sinusitis. For divers, this can present a problem with pain due to unequal ear pressure equalization. Most commonly, the sinus cavities in the forehead area become painful. In the worst case scenario, the pressure causes capillaries to break, causing bleeding in the sinus areas that pools in the throat area.

If you have a cold with blocked sinuses, don’t dive.


■Lungs

Even though at 40m depth lungs compress to 1/5 their normal size, pliable lungs can suffer squeeze. This is due to the unique phenomenon called “Blood Shift”, where the blood gathers in the areas of the body due to pressure.


■Teeth

Dental care, such as fillings, can create spaces in teeth in which nerves get pulled due to squeeze. This can be corrected by visiting your dentist.


■Mask

If you feel mask squeeze, you can equalize by blowing air out from your nostrils into the mask. This is called “Mask Blow”. If you neglect to complete a necessary mask blow, the pulling can cause blood vessels in your eyes to rupture. In the worst case, this pooled blood can cause bruising in the eyes or around the face.



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