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PART 6: OPERATIONAL ENVIRONMENTS
Chapter 20: Dive Medicine
Dive Medicine: Barotrauma to Ears
CPT Jeffrey Morgan, MC, USAIntroduction: The volume of a gas changes inversely to air pressure-gas expands as pressure drops and
compresses as pressure rises. An enclosed, gas-filled cavity in the body is susceptible to injury from the
expansion or compression of the gas if it is not able to equalize to the outside pressure. The middle ear is the
most frequently injured body part. There are three types of ear barotraumas: external ear barotrauma (pinna
to tympanic membrane). middle ear barotrauma (tympanic membrane to cochlea) and inner ear barotrauma
(round or oval window rupture, perilymph fistula). NOTES: All tables in this chapter refer to the Treatment
Tables in the United States Navy Dive Manual and are included at the end of this chapter. All references to
paragraphs within the Treatment Tables refer to paragraphs in the Navy Dive Manual, Revision 4.
Subjective: Symptoms
External ear barotrauma: Diving with ear plugs, tight fitting diving hood, cerumen impaction or some other
object in the external ear canal (EAC) creates a confined space between the object and tympanic membrane
(TM). This space is compressed with increasing depth, creating a vacuum, tugging the sensitive TM and
creating pain. Divers feel pain during descent, typically at shallow depths.
Middle ear barotrauma: Pain, usually on descent (squeeze) but may be on ascent (reverse squeeze);
caused by the eustachian tube (ET) failing to equalize pressure. ET dysfunction is often secondary to upper
respiratory infection or allergies. If a diver continues deeper despite the pain, blood may fill the middle ear
cavity and cause temporary conductive hearing loss and give a feeling of fullness in the ear. Continued
pressure may result in TM rupture. If the TM ruptures, the pain will stop but nausea and vomiting may ensue
as cold water enters the middle ear and causes vertigo. The dive should be immediately aborted after a TM
rupture. Alternatively, a prolonged vacuum in the middle ear will be relieved with a serous effusion seeping
from lining tissues. Symptoms of a serous effusion are mild pain, popping sensations in the ear and temporary
conductive hearing loss.
Inner ear barotrauma: Often associated with, and usually secondary to middle ear barotrauma. Following
a forceful Valsalva, the diver may have roaring tinnitus and sensorineural hearing loss. If the vestibular
symptoms are present for less than one minute, the vertigo is considered transient. Vertigo underwater is a
life-threatening situation and the injured diver needs immediate assistance to the surface. If the vertigo lasts
for more than one minute, the vertigo is considered persistent.
Objective: Signs
Using Basic Tools: 512 Hz Tuning fork
Using Advanced Tools: Otoscope with insufflation bulb
Sudden loss of balance, nausea and vomiting, tinnitus, and hearing loss are seen in all 3 conditions.
External ear barotrauma: Inflammation of the TM unrelieved by Valsalva, edema or blood in the EAC,
very tender in EAC and on tragus, severe cases have TM irritation and/or rupture, cerumen impaction is
sometimes seen.
Middle ear barotrauma: TM redness, hemorrhage or rupture; blood behind TM; middle ear barotrauma
graded on Teed Classification (listed below) serous effusions are typically amber-colored fluid and sometimes
have bubbles behind the TM.
Inner ear barotrauma: Nausea, vomiting, ataxia, vertigo, tinnitus, sensorineural hearing loss (high frequency
loss more common than low), positive fistula test. TM rupture due to middle ear barotrauma may also be
seen.
Fistula test: Pressurize inner ear using insufflation bulb on otoscope, and evaluate for vertigo to test for
round window or oval window rupture. The insufflation bulb can also be used to test for an intact TM.