First presented at the 23rd Annual Undersea and Hyperbaric
Medical Society, Pacific Chapter meeting (Seattle, WA 1995) by
Edmond Kay, MD
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. Questions regarding "Techniques
of Equalization" should be addressed to me via my Guest Book.
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 which 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. Until recently I believed the effect to be caused by venous pooling and engorgement of Eustachian Tube tissues. Dr. Jolie Bookspan has eloquently pointed out that immersion reverses venous pooling, thus making redistribution of venous blood much less likely to be the cause of the problem. 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 to tubal patency are these tissues. A suboptimal position can compromise marginally patent Eustachian Tubes and 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 actually 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
sensation is heard, the listener can verify that the Eustachian
tube has actually 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)
which 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 which
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 sea water 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 raise 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 a contemporary Australian author and lecturer
who described a technique where pressurization such as that accomplished
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 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. In
a very few individuals allergies, acute or chronic infection or
nasal polyps may play a role. By far the most common reason 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. Learning
to listen for the crackle and pop of the Eustachian tube opening
(during swallowing) will help train the ears for advanced techniques.
Watch the tissues of the nose balloon out as inflation pressures
increase during pressurization maneuvers. Assess the adequacy
of inflation effort to help identify the causes of equalization
problems. Practice bobbing the "Adams Apple" to perfect
the Frenzel Maneuver and once middle ear barotrauma has occurred,
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.
Decongestants never help when cold or trauma symptoms are bad,
but at the very end of a cold, when just a little stuffiness remains,
the occasional use of an inhaled decongestants like Afrin (oxymetazalone)
spray will do no harm. Never use a spray more than three consecutive
days whether diving or not, and if symptoms are severe or prolonged,
medical evaluation is advisable.