19-10 Change A
U.S. Navy Diving ManualVolume 5
Refer to Chapter 3 for more information on the signs and symptoms of the various
types of squeeze
Gastrointestinal Distention as a Result of Gas Expansion. Divers may occasion-
ally experience abdominal pain during ascent because of gas expansion in the
stomach or intestines. This condition is caused by gas being generated in the intes-
tines during a dive, or by swallowing air (aerophagia). These pockets of gas will
usually work their way out of the system through the mouth or anus. If not, disten-
tion will occur.
Treating Intestinal Gas Expansion. If the pain begins to pass the stage of mild
discomfort, ascent should be halted and the diver should descend slightly to
relieve the pain. The diver should then attempt to gently burp or release the gas
anally. Overzealous attempts to belch should be avoided as they may result in
swallowing more air. Abdominal pain following fast ascents shall be evaluated by
a Diving Medical Officer.
Preventing Intestinal Gas Expansion. To avoid intestinal gas expansion:
Do not dive with an upset stomach or bowel.
Avoid eating foods that are likely to produce intestinal gas.
Avoid a steep, head-down angle during descent to minimize the amount of air
Ear Barotrauma. Simple ear squeeze is discussed in paragraph 19-4.1. More
serious forms of ear barotrauma are rupture of the eardrum or round or oval
Eardrum Rupture. Ear squeeze may result in eardrum rupture. When rupture
occurs, this pain will diminish rapidly. If eardrum rupture is suspected, the dive
shall be aborted. Vertigo and/or nausea may occur if water enters the middle ear.
Suspected cases of eardrum rupture shall be referred to medical personnel. Antibi-
otics and pain medication taken orally may be required. Never administer
medications directly into the canal of a ruptured eardrum unless done in direct
consultation with an ear, nose, and throat medical specialist.
Inner Ear Barotrauma. The round window and oval window are membranes that
separate fluid in the inner ear from the middle ear. Inner ear barotrauma involves
the rupture of one of these membranes and may be associated with the diver who
had difficulty clearing his ears (vigorous Valsalva). However, a rupture may arise
for no apparent reason. Often symptoms of inner ear barotrauma will become
evident on the bottom or after the diver reaches the surface. Symptoms may
include vertigo, hearing loss, or tinnitus. Any hearing loss occurring within 72
hours of a hyperbaric exposure should be evaluated for inner ear barotrauma.