how to equalize

 

DAN (Divers Alert Network)

 

Your middle ears are dead airspaces, connected to the outside world only by the Eustachian tubes running to the back of your throat.

 

If you fail to increase the pressure in the middle ears to match the pressure in the outer and inner ears, the result is painful middle ear barotrauma, the most common pressure-related ear injury.

 

The key to safe equalization is opening the normally closed Eustachian tubes. Each has a type of valve at its lower end called an "Eustachian cushion," which prevents contaminants in its nose from migrating up to the middle ears. Opening the tubes to allow high-pressure air from your throat to enter your middle ears, which normally requires a conscious act. Swallowing it, we usually make it.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

You equalize your ears many times a day, without realizing it, by swallowing. Oxygen is constantly absorbed by the tissues of the middle ear, lowering the air pressure in these spaces. When you swallow, your soft palate muscles pull your eustachian tubes open, allowing air to pass from your throat to your middle ear and equalize the pressure. This is the "pop" or "click" you hear.

 

Diving, however, subjects this equalization system to much larger and faster pressure changes than it is designed to handle. You need help.

 

All methods of equalizing your ears are simply ways to open the lower ends of your Eustachian tubes so that air can enter.

 

Methods used:

 

Passive

It doesn't require any effort

It usually occurs during ascent.

 

Tubal Opening - Voluntary

Contract your throat and push your jaw forward

Contract the muscles in your soft palate and throat as you push your jaw forward and down as if you were starting to yawn. These muscles pull the Eustachian tubes open. This takes a lot of practice, but some divers can learn to control their muscles and keep their tubes open for continuous equalization.

 

Maneuver -Toynbee

Pinch your nose and swallow

Pinch your nostrils through the mask and then swallow. Swallowing opens your eustachian tubes, while the movement of your tongue, with your nose closed, compresses air against them.

 

Maneuver -Frenzel

Pinch your nose and make the letter "K" sound

Close your nostrils, and close the back of your throat as if straining to lift a weight. Then make the letter sound "K." This forces the back of your tongue upwards, compressing air against the openings of your eustachian tubes.

 

-Lowry Technique

Pinch your nose, blow and swallow

A combination of Valsalva and Toynbee: by closing your nostrils, blowing and swallowing at the same time.

 

Technique -Edmonds

Pinch your nose, blow and push your jaw forward

While tensing the soft palate (the soft tissue at the back of the roof of the mouth) and throat muscles and pushing the jaw forward and down, perform a Valsalva maneuver.

 

Maneuver -Valsalva

Pinch your nose and blow air through it

This is the method most divers learn: Pinch your nostrils (through your mask) and blow through your nose. The resulting overpressure in your throat usually forces your Eustachian tubes open.

 

But the Valsalva maneuver has three problems:

 

1. It doesn't activate the muscles that open the Eustachian tubes, so it may not work if the tubes are already blocked by a pressure difference.

 

2. It's very easy to blow hard enough to damage something.

 

3. Blowing into your stuffy nose increases your internal fluid pressure, including fluid pressure in your inner ear, which can rupture your "round windows." So don't blow too hard, and don't hold the pressure for more than five seconds.

 

Swallowing helps open the normally closed Eustachian tubes, reducing the pressure difference between the outer and inner ear. The safest methods of compensation use the neck muscles to open the tubes. Unfortunately, the Valsalva maneuver that most divers are taught does not activate these muscles, but the pressure of air from the throat into the Eustachian tubes.

 

This is fine as long as the diver always anticipates changes in outside pressure. However, if a diver does not break even early or often enough, the pressure differential can force the soft tissues together, closing off the ends of the tubes. Forcing air against these soft tissues only blocks them. Air does not reach the middle ears, which do not equalize, so the result ends up being barotrauma. Even worse, blowing too hard during a Valsalva maneuver can rupture the round and oval windows of the inner ear.