Page 66 - Journal of Special Operations Medicine - Summer 2016

Inner Ear Barotrauma After Underwater Pool Competency
Training Without the Use of Compressed Air

Case and Review

Sean McIntire, MD; Lee Boujie, SO-IDC

ABSTRACT

Inner ear barotrauma can occur when the gas-filled underwater swim to a maximum depth of 13 feet. No
chambers of the ear have difficulty equalizing pressure compressed air breathing apparatus was used. Upon ex-
with the outside environment after changes in ambient iting the pool, he had difficulty standing and was nause-
pressure. This can transpire even with small pressure ated. He denied chest pain or shortness of breath. The
changes. Hypobaric or hyperbaric environments can patient was brought back to the battalion aid station
place significant stress on the structures of the middle (BAS) where his vital signs were as follows: tempera-
and inner ear. If methods to equalize pressure between ture, 98.1°F; blood pressure, 124/78mmHg; heart rate,
the middle ear and other connected gas-filled spaces 73 beats per minute; respirations, 16 breaths per min-
(i.e., Valsalva maneuver) are unsuccessful, middle ear ute; and blood oxygen saturation, 96% on room air. He
overpressurization can occur. This force can be trans- did not require supplemental oxygen. Ear examination
mitted to the fluid-filled inner ear, making it susceptible showed no evidence of tympanic membrane rupture bi-
to injury. Damage specifically to the structures of the laterally. The right-side tympanic membrane exhibited
vestibulocochlear system can lead to symptoms of ver- good flexibility with Valsalva maneuver, whereas the left
tigo, hearing loss, and tinnitus. This article discusses the did not. Head, ear, nose, and throat examinations were
case of a 23-year-old male Marine who presented with otherwise unremarkable. A full neurologic examination
symptoms of nausea and gait instability after perform- was performed concurrently. The patient was alert and
ing underwater pool competency exercises to a maxi- oriented to person, place, and time. He was able to per-
mum depth of 13 feet, without breathing compressed form serial 7s (i.e., counting back from 100 by 7) and
air. Diagnosis and management of inner ear barotrauma had appropriate short-term recall. Cranial nerves (CN)
are reviewed, as is differentiation from inner ear decom- II–XII were intact. Strength was 5 out of 5 in all muscle
pression sickness. groups of the bilateral upper and lower extremities. Sen-
sation was intact to light touch except for a patch (7
Keywords: inner ear; barotrauma, inner ear; decompression inches × 3 inches) of decreased sensation over the left
sickness; inner ear; vertigo; tinnitus; hearing loss antecubital forearm. Coordination testing was remark-
able for difficulty with heel to shin movement and insta-
bility with Romberg testing. Upon further questioning,
the patient endorsed difficulty equalizing ear pressure
Introduction
while at depth in the pool during knot-tying exercises
Inner ear barotrauma is a well-known diving-related in- the day before. This resulted in transient vertigo-like
jury that occurs when middle ear pressure fails to equal- symptoms that resolved shortly after that day. The Ma-
ize with the ambient environment. Overpressurization rine also endorsed congestion throughout the week, for
is transmitted to the fluid-filled inner ear, damaging the which he was using over-the-counter pseudoephedrine
vestibulocochlear system. This can happen any time a for symptomatic relief. There was no significant con-
change in ambient pressure occurs. In the hyperbaric tributory past medical or surgical history.
undersea/underwater environment, this injury can be
encountered simply by diving a few feet under the sur- Ear Anatomy
face, with or without breathing compressed air. Anatomically, the ear is divided in to three parts: ex-
ternal, middle, and inner (Figure 1). The external ear
Case Presentation extends from the auricle (external ear structure) to the
A 23-year-old male Marine presented to the Corpsman tympanic membrane (ear drum). It includes the struc-
on site during a pool underwater competency train- tures of the external ear and external auditory canal. Its
ing evolution, with dizziness after completing a 25m principle function is to collect and funnel sound to the

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