Middle ear barotrauma is the most frequent diving injury I see in my medical
practice. It occurs much more commonly in the novice diver as a direct result of
improper middle ear equalization technique. The following information is
intended for the diving instructor, diving safety officer and any individual
charged with the responsibility of managing novice divers. This information
should also be of value for the advanced or commercial diver interested in rapid
descent. The topic includes a discussion of nine different techniques of
equalization, and offers tips on assessing the effectiveness of middle ear
pressurization.
At the end of this topic, the reader should be able to:
The Eustachian tube was first identified by Bartolomeo Eustachio (Latin: Eustachius), an Italian anatomist who died in the 1500's. In the United States the Eustachian tube is usually pronounced "yoo-sta-shan", but some pronounce it "yoo-sta-ke-an" in honor of the anatomist as it more closely approximates the original Latin pronunciation of the name. The tube is approximately 1.5" long and is located in the back of the nasopharynx at approximately nostril level. The tube is normally closed and has a highly variable patency. This means that some individuals will virtually never have problems with middle ear equalization while diving. Others with narrow or partially obstructed Eustachian Tubes may have trouble equalizing their middle ears in airplanes or elevators. These later individuals can dive safely, but for them middle ear pressurization requires meticulous attention to detail and much practice.
Thanks to the comments of Francisco Javier Orellana Ramos, a Diving Medical Officer from Spain, I am reminded that there are several factors that influence tubal patency and tolerance to pressure changes. The Eustachian Tube angle and the shape of the tube can affect ones ability to pressurize the middle ear. Individuals with a relatively large volume of air in the mastoid sinuses will be less tolerant to pressure changes as the actual volume change in the middle ear will be greater for a given amount of descent. Allergies, trauma, infection and Thyroid disorders are other possible causes of disruption in normal tubal function.
For individuals who have difficulty pressurizing ears,
the position in the water column is extremely important. It is well known that
the head-down position during descent can make middle ear equalization more
difficult. Less well understood is the reason for this effect. There are soft
tissues in the nasopharynx which surround the membranous Eustachian Tube, and no
doubt gravity plays a role in there normal functioning. The most likely
candidate for positional obstruction is this soft tissue. A sub-optimal position
can compromise marginally patent Eustachian Tube. For this reason it is
advisable for students to begin descent slowly, and always in the head up
position. Divers with prior ear problems, timid divers and those who are not
sure whether middle ears will equalize should also assume this position. Half of
the Eustachian Tube is surrounded by bone but the other half is open to the
pressure changes of the respiratory system (ambient pressure). This membranous
later half is partially surrounded by a "C" shaped cartilage and
during swallowing, muscles of the soft palate pull on the Eustachian Tube. This
traction opens the tube while closing the nasopharynx. The act of swallowing
often causes a clicking or crackling sound to be heard and this sound is the
noise made when the moist tissues of the Eustachian Tube pop open. You can hear
this sound for yourself in a fellow diver or student by applying a stethoscope
in the area around the ear. If the student swallows and the crackling sound is
heard, the listener can verify that the Eustachian tube has opened. This
technique was first described by Joseph Toynbee in the 1800's, and will be
described later.
Ear Fear is a term I have coined to describe the
apprehension associated with middle ear equalization. It tends to occur in
individuals who have had prior middle ear trauma, a frequent childhood history
of middle ear infections or those who just get queasy when they feel new bodily
sensations. To some, this sensation of pressure in the middle ears and the
crackling in one's head associated with the popping open of a Eustachian tube is
uncomfortable. These are the individuals who do not like to "pop"
their ears and many have been told all their life that this is "bad to
do". For these individuals, middle ear pressurization effort is anxiety
provoking and efforts tend to be very cautious and tentative. For many of these
novice divers, middle ear trauma occurs at the first dive. Students can become
confused about the actual pressure needed to achieve middle ear equalization
when well meaning friends remind them not to blow too hard. This advice is
certainly prudent when a student is under water and experiencing middle ear
squeeze. Unfortunately, for the squeamish individual, and especially if a
marginally patent Eustachian tube is present, this limits the ability of some to
pressurize adequately at anytime during the dive. Pressurization of the middle
ear can and should be vigorous on the surface, when no negative pressure
gradient is present across the middle ear. This means that it is possible (and
desirable) for an individual to pre-pressurize the middle ear and to inflate the
Eustachian tube prior to descent. Pressurization of the middle ear provides a
pillow of air behind the tympanic membrane, protecting the "ear drum"
(TM) from barotrauma." As descent occurs, more air can easily enter an
inflated Eustachian tube and pass into the middle ear, if pressurization begins
early in the dive. If the Eustachian tube is allowed to collapse at any time
during descent due to squeeze, the pressure to re-inflate it becomes greater.
For this reason, I always recommend that individuals practice pressurization of
their middle ears prior to diving in order to test their Eustachian tubes for
patency, and to perform middle ear pressurization before beginning actual
descent to cushion the ears against trauma..
Before teaching pressurization techniques, it is
useful to learn a technique for assessing the adequacy of pressurization. A
technique I use in my office is to "watch the nose inflate" (Watch the
Schnazolla). Inflation can be observed if one pinches the nasal passages (nares)
closed, with pinching fingers held low on the nose. With fingers occluding the
nares, observe the fleshy portion of the nose immediately above the fingers. A
good, strong pressurization effort will cause the tissues above the occluding
fingertips to balloon outward. This nasal inflation is an indication of the
inflation effort (nasopharyngeal pressure) that has been applied to the
Eustachian tubes. This can be practiced in the mirror in order to optimize
technique. Merely pressurizing the nose is not quite the same as inflating the
middle ear, but if the diver reports no evidence of a popping or crackling
sensation the instructor may check the pressure of the nose to evaluate
inflation effort. Practicing on yourself allows some comparisons of effort (and
pressure) to be made.
Among the simplest and most basic techniques in
diving are the yawn, swallow, jaw thrust and the head tilt. These techniques of
equalizing middle ears are useful for individuals who have widely patent
Eustachian tubes and never have problems with equalization. These methods hardly
ever work alone without the addition of pressurization in an individual with
marginally patent tubes. I do not recommend these techniques for the novice
diver as they offer little margin for error. The first dive in a swimming pool
is often the cause of significant barotrauma due to a combination of poor
technique, student distraction and other factors such as buoyancy control.
Pressurization techniques (see below) should ALWAYS be used first, until
a student is comfortable with a preferred technique that reliably prevents
middle ear squeeze.
Antonio Valsalva lived in the 1700's and was the
first to record a technique for pressurization of the middle ears. With the
nostrils pinched closed, pressure is increased in the chest. An attempt is made
to blow out the closed nostrils and cheek muscles are kept tight and retracted,
not puffed out. With this technique, gradients of 6-10' of seawater can be
achieved. This technique does have some disadvantages however as prolonged
effort can cause venous engorgement of the tissues around the Eustachian tubes.
It also causes a decrease in venous return to the heart and can lower blood
pressure if the effort is prolonged. It does seem to be the easiest and most
intuitive of the techniques and usually is what a student will perform on their
own with no other training.
Herman Frenzel was a Luftwaffe commander who taught
this technique to dive bomber pilots during WW2. The pressure changes in
commercial aviation are usually much more gentle and occur more slowly than in
diving. A dive-bomber pilot will experience pressure changes more rapidly
however, much the same as in diving. The technique developed for flying is to
close off the vocal cords, as though you are about to lift a heavy weight. The
nostrils are pinched closed and an effort is made to make a "K" or
guttural "guh" sound. By doing this you raise the back 1/3 of the
tongue and the "Adams Apple" will elevate. For this reason I call the
technique the "throat piston". A diver is actually making a piston out
of the back of the tongue, pushing it upward. This maneuver compresses air in
the back of the throat and the pressurization effort can be seen in the fleshy
tissues of the nose. A student may practice the technique by watching the nose
inflate and by watching the "Adams Apple" move up and down. Bobbing
the "Adams Apple" is good practice for dive-bomber pilots and scuba
divers alike. This technique is actually my preferred pressurization maneuver as
it can be done anytime during the respiratory cycle and it does not inhibit
venous return to the heart. The effort is usually brief and can be repeated may
times quickly.
Joseph Toynbee lived in the 1800's and as you
recall, he first identified the crackling sound present in ones head with the
anatomical opening of the Eustachian tube during swallowing. His technique is to
pinch nostrils shut while swallowing. The muscles in the back of the throat pull
open the Eustachian tube and allow air to equalize if a gradient is present.
Swallowing can be difficult for the novice diver, especially while breathing dry
air. This technique is not recommended for rapid descent, as there is no margin
for error if the Eustachian tube does not equalize on first effort. If a middle
ear squeeze is already occurring, it will be more difficult for the Eustachian
tube to be pulled open.
In the 1950's, the French Navy developed a technique
for middle ear equalization called "Voluntary Tubal Opening". This
technique is difficult to teach and in my hands, only approximately 30% of those
taught can perform it reliably. Muscles of the soft palate are contracted while
upper throat muscles are employed to pull the Eustachian tube open. This
technique is similar to the events that happen in the back of your throat at the
end of a yawn. It is also similar to wiggling your ears, and some people seem to
be born with the talent, but many cannot master the technique reliably. For
commercial divers and dive tenders in Hyperbaric chambers (people who spend many
hours in decompression), there is an excellent opportunity to practice the
technique while undergoing gradual and predictable pressure changes.
Noel Roydhouse is a Sports Medicine Physician from New Zealand. He has written an excellent book on the subject, referenced at the end of this article. Some of the most interesting tidbits of information in this section come from his book and I highly recommend it for the reader who just cannot get enough information about the ears. His technique is similar to the Voluntary Tubal Opening except that Dr. Roydhouse has provided an additional clue for contracting the muscles in their proper order in the back of the throat. The instructions are to contract the palate lifters (the levator palatini) and to contract the palate tensor muscles, (tensor palatini). This raises up and tilts forward the uvula. The uvula is the small, fleshy protuberance hanging down from the soft palate in the back of your throat and it can be seen in the mirror. If an individual watches the soft palate and trains the uvula to rise up and tilt forward, half of the technique is mastered. The second part is to tense the muscles of the tongue in such a way as to cause the crackling sensation of Eustachian tube opening to occur. Often a jaw thrust can help make this maneuver more effective, and if the technique for "blowing smoke rings" was ever mastered, this is another good training maneuver which teaches you to recognize the muscles necessary to pull open the Eustachian tube.
Carl Edmonds is an Australian author and lecturer who
described a technique where pressurization by either the Valsalva or the Frenzel
maneuver can be combined with jaw thrust or head tilt to more effectively open
the Eustachian tube. His book (see below) is a must for anyone interested in
Diving Medicine.
Another combination technique has been described,
whereby a pressurization maneuver is combined with a swallow. Coordination and
practice is required to pinch nostrils, build up pressure and swallow at the
same time but the technique is very effective once it is mastered. Carl Edmonds
knows how this technique came about and as soon as he tells me the story I'll
update this section. While I have not had that much luck teaching the technique,
one of the most respected ENT Physicians in diving medicine, Dr. Alan Decklebaum
of San Francisco (now retired) prefers it.
This combination technique is effective for some,
and involves pinching nostrils with a moderate pressure in the back of the
throat. Generation of pressure is again by either Valsalva or Frenzel Technique.
Instead of swallowing as in the Toynbee Maneuver, the head is suddenly
"twitched" sideways. Tension in the throat muscles helps to make this
a more effective maneuver.
Most new divers have trouble with technique, not
anatomy or illness. In a very few individuals allergies, acute or chronic
infection or nasal polyps may play a role. By far the most common reason for
middle ear barotrauma however is inadequate pressurization of the middle ears
due to a lack of basic understanding of the mechanisms involved. "Ear
Fear" must always be considered as a possible complicating factor and an
instructor must be sensitive to the issues surrounding the reluctance of a diver
to fully and aggressively pressurize the middle ears. Occasionally a
"dragooned diver" will be quite reluctant to learn the techniques of
equalization as this may provide a legitimate reason to drop out of the diving.
Other phobias may be present such as the fear of water, or confinement fear
(claustrophobia). Problems with nasal anatomy such as a deviated nasal septum,
intranasal polyps, or obstructed sinuses must be addressed by a medical
practitioner and occasionally these will require surgery. Recent advances in
endoscopic surgery offer vast improvements over older techniques. There is much
that a professional diving safety officer or a good friend can do to help an
individual learn safe middle ear equalization practices, but don't forget to
look for the obvious. A person with cold symptoms should not dive until the cold
has cleared and the Eustachian tube clearly pops with a swallow.
* Eustachian tube awareness should be taught to all divers.
* New divers should always use pressurization to prevent middle ear barotrauma.
* Watch the tissues of the nose balloon out as inflation pressure increases during pressurization maneuvers. Assessing the adequacy of inflation effort will help to identify the causes of equalization problems.
* Listen for the crackle and pop of the Eustachian Tube opening (during swallowing) as this will help train your ears for advanced techniques.
* Practice bobbing your "Adams Apple" to perfect the Frenzel Maneuver, and teach others this technique.
* If middle ear barotrauma does occurs, discontinue diving immediately. If symptoms are mild, they should subside within 1-2 weeks. When equalization ability is back to normal, no abnormal sounds or crackles are present in the middle ears and hearing is normal, a diver can return safely to the water. If there is any question, a medical opinion should be obtained.
* Decongestants never help when cold or trauma symptoms are present, but at the very end of a cold, when just a little minor stuffiness remains, the occasional use of an inhaled decongestant like Afrin (oxymetazalone) spray will do no harm and may help.
* Never use a nasal decongestant spray more than three consecutive days whether diving or not, and if symptoms are severe or prolonged, medical evaluation is advisable.
1) "Underwater Ear And Nose Care", Noel Roydhouse: Best, 1993
2) "Diving And Subaquatic Medicine", Carl Edmonds: (Third Edition) Butterworth 1992
3) "Diving Physiology in Plain English", Jolie Bookspan, Ph.D
4) Divers Alert Network
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