Deep-Six Underwater Systems, Inc.
"Add Depth to Your Life"

Table of Contents

1 Pressure and Gases
2 The Face Mask
3 The Snorkel
4 The Fins
5 Weight Systems
6 The Knife
7 The Wetsuit
8 Pressure and Water
9 The Ear and Pressure
10 The Sinus and Pressure
11 The Stomach/Intestine and Pressure
12 The Lung and Pressure
13 Barotrauma caused by External Air Spaces
14 The Buoyancy Compesation Device (BCD)
15 The Scuba Cylinder
16 The Scuba Cylinder Valve
17 The Regulator
18 Density and the Diver
19 The 4 Gas Laws
20 Hand Signals
21 Carbon Monoxide Poisoning
22 Hyperventilation
23 Nitrogen Narcosis
24 Diver's Flags
25 Sound Underwater
26 Color Underwater
27 Decompression Sickness
28 Breathing Oxygen
29 Deep Diving
30 Thermoclines
31 Thunderstorms
32 Underwater Life
33 Open Water Dives
34 The Final Examination
35 The Environment
36 Advanced Course

13 - Barotrauma caused by External Air Spaces

     According to Boyle's law, flexible gas spaces will compress as pressure is applied to them externally. Put a face mask on and go down in the water. The pressure of the water will try to make the face mask smaller. Because it is rather rigid other things will happen first. The pressure inside the body is also greater than the pressure inside the mask. So, the face is "pushed" into the mask. Possible results: The eyes bulge, the nose bleeds, blood vessels break under the skin and in the whites of the eyes, the vision narrows, and there may be swelling. Depending on the difference in the pressure results in the variety of results. The diver may not notice the squeeze or damage because there is not that much pain connected with it. To avoid it simply gently exhale through the nose as you descend. This will keep the pressure differential to a minimum so no facial damage can occur. As the divers comes up the expanding air in the mask will simply bubble out without notice. When it happens some divers have left the water looking like they were involved in a serious domestic encounter. Usually the appearance of a face mask squeeze barotrauma is worse than it really is. It usually does not require treatment and will go away in about a week.

     If you were to wear goggles in scuba diving serious barotrauma to the eyes may result. There is no provision for adding air to the inside of the goggles as descent is made because the nose is not in it. Goodbye eyeballs!

     Dry suits contain air. That air will compress as the diver descends. The suit will feel like a total body blood pressure cuff as the outside pressure increases. The skin may be pushed into the natural folds in the suit. Blood vessels may burst in the skin causing lines of blood blisters and bruises. As with any other air space that is connected to the body, air must be added to the dry suit when going down to prevent the squeeze. And, most importantly, the air must be removed as the diver ascends to avoid an out-of-control ascent because of the expanding air in the suit. Dry suits require an extra measure of training that is way beyond the training needed for a wet suit!   

Copyright Information about this text, DIVING WITH DEEP-SIX is as follows: Copyright 1996 - 2007 by George D. Campbell, III; President. All Rights Reserved. This file may be posted on Electronic Bulletin Boards for download, but may not be modified, printed for distribution, or used for any commercial purpose without the author's written permission. is using this material with the permission of Deep Six. The full version is available at:
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