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Barotrauma (Ear and Lung)


Baro= pressure
Trauma= damage

Barotrauma is damage to tissues or organs caused by pressure. It occurs in diving when a rigid air-filled compartment within the body is subject to changes in pressure and the compartment cannot conform or contort itself to accommodate the change in pressure. Common rigid compartments in the body that may be injured are the sinus cavities of the face or the middle ear. Damage may be done to other air-filled compartments that are not as rigid if the compartment is subject to a rapid or large internal increase in pressure. The lungs are an example of an organ that may be damaged in this way.<.p>

Consider an air-filled beach ball or an empty, sealed tin can. The walls of the beach ball are easily stretched or compressed without causing damage. The walls of the tin can are much more rigid and do not stretch or compress. Atmospheric pressure (the pressure that surrounds you) below the water’s surface is higher than it is at sea level due to the dense weight of water. The deeper you go, the greater the atmospheric pressure. If you were to transport the ball and tin can from sea level to the ocean floor, the further you descended the higher the pressure would be on the walls of either object. In order to counteract the increase in external pressure, pressure within the object would also have to increase. One way to increase internal pressure is to decrease volume by compressing the walls of the object. The beach ball can collapse and not become damaged because its walls are flexible. At a depth of 100 meters, the ball would be much smaller (lower volume with a higher internal pressure) than at the surface. The rigid tin can would have a more difficult time responding to the increase in external pressure. As the tin can descended the external pressure on its rigid walls would increase, and eventually the walls would collapse or the can would “implode” on itself. If a small hole was made in the tin can, water would rush in, pressures would be equalized, and the walls of the can would not collapse. The middle ear is an air-filled, bone-walled cavity much like the tin can. On descent, without pressure equalization, the walls of the middle ear may collapse, the eardrum may break inwards, or blood vessels within the ear may burst to fill the middle ear with blood. Each of these events would result in equal pressure on the inside and outside of the compartment. To avoid such damage during descent you must facilitate air movement into the middle ear via pressure equalization techniques though the eustachian tube (see below).

As you ascend to the surface, atmospheric pressure drops and the eardrum bulges out. To equalize pressure inside the middle ear compartment air must move out of the middle ear through the eustachian tube.

Air-filled cavities that may be injured by barotrauma during a dive are:

  1. The middle ear
  2. The lungs
  3. The sinus cavities of the face
  4. A segment of intestine
  5. A tooth with a cavity in the center

Ear barotrauma

Trauma to the middle ear can occur on ascent or descent. The middle ear would be an entirely closed space were it not for a very thin tube that connects the middle ear to the back of the nasal passages (and thus the outside atmosphere). This channel, called the eustachian tube, must be kept open for there to be adequate drainage of air and fluids into and from the middle ear. Many children get frequent ear infections because the tube may not be very well developed until the age of about two or three. Fluids stagnate in the middle ear of these kids and infection may ensue. Divers must have an open eustachian tube for air to freely pass into the middle ear on descent or out of the middle ear on ascent. If the tube is clogged damage will occur to the walls of the middle ear or to the eardrum. Divers are taught equalizing techniques to move air into the middle ear on descent. These involve swallowing, the valsalva maneuver (holding your nose and closing the glottis while blowing), moving your jaws back and forth, or the Toynbee maneuver. Please refer to your dive instructor for further instruction. On ascent, techniques are used to move air out of the middle ear. If the diver does not attempt equalization techniques then barotrauma will occur.

Factors that interfere with a diver’s ability to move air into or out of the middle ear (eustachian tube dysfunction or blockage) include:

  1. Allergies
  2. Upper respiratory tract infections (e.g., a cold)
  3. Nasal polyps or tumors of the nasal passages
  4. Smoking
  5. Use of oral isotretinoin (Accutane™) an acne medication

Signs and symptoms of middle ear barotraumas:

  1. Bleeding from the nasal passages (blood vessels have burst on descent)
  2. Ear pain
  3. Decreased hearing
  4. Temporary vertigo (dizziness) and/or nausea (if the eardrum has burst)

Other damage to the ear

Pain may be experienced in the external ear canal or the eardrum may rupture if wax or earplugs obstruct the external canal. When closed to the outside world the external ear canal has become the closed space subject to the pressure changes of ascent and descent.

The inner ear may be damaged if excessive force is used to equalize middle ear pressures using standard techniques. This is a rare occurrence and typically happens only when there is obstruction of the eustachian tube that predisposes an individual to attempt excessively forceful equalization maneuvers.

Lung barotrauma

Barotrauma of the lungs is not as common as other pressure-related traumas that may affect any of the body’s other air-filled cavities. The lungs are very effective at pressure equalization during normal breathing without special maneuvers. With a few exceptions, lung barotrauma during descent, called chest squeeze, may be experienced by divers holding their breath, by divers on very deep dives or by divers who descend too rapidly. If barotrauma does occur on descent it is characterized by bleeding into the lungs and subsequent difficulty breathing and/or shortness of breath. If severe, it can lead to hypoxia (low oxygen), confusion, stupor, and death.

Lung burst describes the trauma that may affect the lungs during ascent. On ascent, atmospheric pressure decreases and volume within the lung increases. As long as air is released via normal breathing, pressures are equalized and the lungs are not damaged. Under certain conditions, air may be trapped within the small breathing units (alveoli) of the lung despite normal respiration. If an alveoli traps air that cannot be released during normal breathing the alveoli may burst on ascent.If an alveolus bursts, air can escape into the space that surrounds the lung (the pleural cavity). If multiple alveoli burst, then a larger volume of air escapes. Breathing continues and the hole(s) in the lung now act as vents for air escaping into the pleural cavity. Pressure in the pleural cavity then rises with each breath. Soon the air may make its way into the surrounding tissues causing subcutaneous emphysema (visible air bubbles trapped under the skin) or mediastinal emphysema (air trapped along tissues within the chest). Worse yet, the air may make its way into the circulatory system via arteries that have ruptured when the alveoli burst. If this occurs dangerous gas bubbles may travel throughout the circulatory system and become lodged and block the blood supply to any end organ, e.g., kidneys, brain, heart, intestine, etc. Widespread damage and catastrophic events may ensue.  Another dangerous sequel to lung burst may occur if the volume and pressure of escaped air into the pleural space becomes so great that the heart cannot pump blood to the body and the lungs can no longer fill with air. The extent of damaged alveoli directly correlates with the severity of emphysema or heart and lung compromise.

Lung burst may occur if a diver:

If lung burst is suspected by chest pain, shortness of breath, or signs of organ damage (namely the brain-altered mental status, confusion, etc.) then immediate medical attention must be sought. The following guidelines should also be followed:

  1. Inform a dive physician.
  2. Keep the diver calm, immobile, and lying flat. Some authorities recommend that you put the diver on his or her hands and knees with the left shoulder lower than the right for the first 10 minutes after resurfacing and then lay the diver flat. This may drive bubbles away from the brain.
  3. the diver is unconscious, place the diver left side down with the head elevated to 15°.
  4. Administer 100 percent oxygen (if available).
  5. Start IV fluid (if available).
  6. Get to a dive center or emergency room as soon as possible.