Jane flew to a resort in Mexico for a vacation. She chose the resort partly because it offered scuba diving lessons and she had been wanting to learn to dive. After a couple of days of basic instruction in a pool, she and the other beginners were taken a little way offshore for an open water training dive. Jane had trouble clearing her ears on descent and was falling behind the class, so one of the instructors helped her catch up by pulling her deeper under water. Jane fought her way to the surface and back to the boat, where she told the captain she was having trouble hearing and had severe pain in both ears. Back at the resort she was treated with nasal decongestant and steroid sprays along with oxycodone for pain. She recovered and was able to fly home at the end of the week, vowing to try rafting next year.
After the first amphibians crawled up onto a beach, the ears of land-based animals had to evolve to function in air rather than water. Fortunately for people who love the water, the human ear has retained the ability to do both. But the ear is a delicate organ and, for many of us, is not efficient at adapting to rapid pressure changes that occur in scuba or free diving. In fact, the most common medical problems of divers involve the ears and occur because the pressure on our ears increases as we go deeper.
Although no one know for sure, it is estimated that there are about four million registered scuba divers with an estimated two hundred thousand new divers trained annually. With that many people in the water, medical complications of the ear may be expected to occur.
Equalizing Pressure in the Middle Ear
Have another look at figure 1.1 in chapter 1. Notice how the eardrum is an airtight seal between the outer world and the middle ear. As pressure in the outer world increases, it will painfully stretch the eardrum inward or even rupture it unless the pressure inside the middle ear is increased to match the outside pressure.
Chapter 1 describes the Eustachian tube, how it is closed at rest but opens when we swallow, yawn, or increase nasal pressure. This normally occurs many times each day and may be accompanied by a clicking or popping sound. The problem with diving is that the pressure change is greater and occurs faster than on land. Surprisingly, equalizing pressure is harder from 0 to 10 feet than it is from 40 to 50 feet. That is why it is so important not to let the pressure get ahead of you. Equalize before you feel discomfort and continue to do so every few feet all the way down.
Methods
Swallow
As noted above, the most natural method of opening the Eustachian tube is to swallow. This is easier on land, so that is where you should begin your practice. Swallow a sip of water and listen for a click or crackling sound. If you’re not sure, pinch your nose when you swallow the water. Hint: if you are going to take scuba lessons or learn to free dive, practice equalizing your ears on land, in front of a mirror, until you can always click open your Eustachian tubes. Try it in the pool with your head barely under water.
Table 27.1
The Effects of Pressure on the Ear at Shallow Depths
|
Depth |
Effect |
|
1 foot |
Slight feeling of ear pressure |
|
4 feet |
Significant eardrum stretch, pain, difficulty equalizing |
|
8 feet |
Tissue damage, Eustachian tubes lock—inability to equalize |
|
10 feet |
Severe pain, likely ruptured eardrum, vertigo, permanent hearing loss |
Pseudo-Valsalva Maneuver
The pseudo-Valsalva maneuver consists of pinching the nostrils and blowing air pressure against them through your nose. Many unsuccessful divers think they are increasing nasal pressure when they are actually increasing pressure in the lungs by bearing down. You fall into this category if your face turns red when you try it. The important thing is to get the pressure to the right place.
The best way to accomplish this is to “make balloons.” While learning this technique, look in a mirror, pinch your nostrils at their lowest edge, and blow gently until you can see the nostrils balloon out. Try it again with your mouth open. When you see your nostrils balloon out, the pressure is in the right place and you can add more pressure until your Eustachian tubes gently click open.
Toynbee Maneuver
This technique consists of pinching the nostrils and swallowing (see above).
Lowry Maneuver
The Lowry maneuver combines the Valsalva and the Toynbee. With the nostrils pinched and a little water in your mouth, make balloons and swallow at the same time. The Lowry maneuver is the most difficult to learn, but can be the most effective for many people.
If you are still unable to clear your ears, it might be best to find another sport. Or, you can see an ear specialist. Steroid and twelve-hour decongestant sprays are safe if used as prescribed and sometimes a severely deviated septum can be corrected to improve nasal air-flow and equalization.
Barotrauma
Most ear disorders associated with diving are caused by pressure. Called barotrauma and sometimes “squeeze,” pressure can affect the outer, middle, or inner ear. Fortunately, most of these problems can be avoided but rarely, complications may be severe or life threatening.
Middle Ear Barotrauma
Middle ear barotrauma is the single most common medical condition of divers. As described above, it occurs when the pressure outside the eardrum is greater than the pressure inside. It is avoided by learning to equalize pressure, not diving when you have a cold or allergy symptoms (sneezing, runny nose), and discontinuing the dive if you are not able to equalize at a depth of 4 feet. If you feel pain at any time, stop and ascend just a few feet and clear your ears. Pain is your warning, do not proceed. If you are having trouble, descend on a dive line or anchor line, hand over hand to control your rate of descent. Go feet first.
The complications of middle ear barotrauma include bleeding into the eardrum or the middle ear, filling of the middle ear space with mucous that can last for weeks, and perforation of the eardrum. If your drum perforates, water will run in through your ear and down your throat as well as cause severe vertigo. You may not be able to tell up from down. Your eyes will be closed because of the vertigo and you may end up swimming downward. Practice taking a deep breath and remaining motionless to allow your buoyancy to carry you slowly to the surface.
Your physician will advise you after an examination, but mild middle ear barotrauma is generally treated by not diving for a period of up to a few months. Most perforations will close without surgery, but the ear must be kept meticulously dry to avoid infection. If the eardrum does not heal in three months, surgical repair may be needed (see chapter 17). Another complication of middle ear barotrauma is inner ear barotrauma.
Inner Ear Barotrauma
Inner ear barotrauma is usually caused by middle ear barotrauma. Pressure on the eardrum is transmitted to the membranes and fluids of the inner ear and may cause membrane rupture. Most membrane ruptures inside the cochlea resolve with bed rest and oral steroids. However one type, perilymph fistula, may require other treatment.
Perilymph Fistula
A sudden pressure wave transmitted to the cochlear fluids may result in rupture at the round or oval window (see chapter 1). This may cause leakage of inner ear fluid (fistula) into the middle ear resulting in nerve deafness, tinnitus, and severe vertigo. It is treated with bed rest and often resolves spontaneously. However, in cases of severe to profound deafness or persistent vertigo, early surgery is recommended to repair the membrane. If necessary, this thirty-minute operation is done through the ear canal under local or general anesthesia as an outpatient.
Decompression Sickness
Decompression sickness (DCS) can also affect the inner ear. Also called the bends, DCS results from ascending to the surface too quickly. Nitrogen, which has been absorbed in tissue due to the high pressures at depth, will go back into the bloodstream and form bubbles when the pressure is reduced too quickly. The nitrogen bubbles can obstruct tiny capillaries anywhere in the body, especially the joints and nervous system. As opposed to barotrauma, which occurs during descent, DCS occurs during or after ascent with no history of difficulty clearing the ears. In sport diving, the depth and bottom time are regulated to prevent DCS. Nonetheless, a five-minute stop at 15 feet is recommended due to the remote possibility of the bends. Working divers, who go deeper and stay longer, may require decompression stops during ascent to allow the bubbles to dissolve.