An injury that involves pressure changes, barotraumas can affect the lungs, the sinuses and most commonly, the ears. These are injuries that result from pressure changes between the air inside and outside of the body. When barotrauma affects the ear, it commonly manifests as discomfort which may range from a mild ache to horrendous pain and deafness. A barotrauma can be a temporary annoyance or it may be a medical emergency.
Definition & Facts
Barotrauma refers to conditions in which injury or symptoms arise from a difference between air pressure within the body and air pressure outside of the body (ambient air pressure). Most often these conditions occur in the ear, although they can happen in the sinuses or lungs as well. Barotraumas of the ear can affect the inner ear, middle ear, and outer ear. Barotraumas of the lungs are a leading cause of death among scuba drivers.
The basic mechanism at play is that air within the body changes in volume – either expanding or contracting - as a result of changes to ambient air pressure. For example, when a person goes diving, the air pressure increases dramatically the further the diver descends, causing any air contained within the cavities or pockets of the ear to decrease their volume. This results in a 'squeeze' in which swelling of the tissues in the ear occur.
The only way to combat this is to equalize the pressure in the ear, which is the primary function of the Eustachian tubes. The Eustachian tubes connect the middle ear to the chambers around the back of the throat (pharynx) and nose. It is normally closed but opens when swallowing, yawning, or blowing against a closed mouth and nose. If it is open, then pressurized air can enter the middle ear thus equalizing the space in the ear with outside air.
Symptoms & Complaints
Scuba divers may acquire bloodshot or even black eyes due to the differential air pressure caused by the diving mask. Fever, otitis (ear infection), or persistent pain may indicate a more serious condition. Permanent hearing loss or vertigo (dizziness) can result from a severe barotrauma.
Barotrauma of the lungs presents in pneumothorax and can cause the lungs to rupture and hemorrhage. Shortness of breath and symptoms of shock may ensue. Cardiac arrest can follow pulmonary barotrauma associated with mechanical ventilation. This is a medical emergency requiring immediate attention.
Barotraumas often occur when driving up or down a mountain road or in an airplane, especially during descent. Parachute divers can also notice the problem. Some people experience ear pain in an elevator in a high-rise building. When scuba diving, barotraumas are a particular risk when the diver ascends. Scuba divers have to be especially careful about pressure gradients in shallow depths, as the rate of differences in pressure is greater in shallower waters.
Being too close to a bomb's explosion or gunfire can trigger a barotrauma. High-order explosives produce over-pressurization blast waves that cause injury to gas-filled structures. 'Blast lung' is a condition seen among those who have been injured by high-order explosives.
Pulmonary barotrauma can also occur as a complication of acute respiratory distress syndrome. Pulmonary barotrauma is also a complication of mechanical ventilation or respiratory support while under medical care. As with severe barotraumas related to diving, the alveoli which are the air sacs of the lungs, can rupture among patients who are on mechanical ventilation. These ruptures can cause gas to escape into the chest cavity.
Diagnosis & Tests
Usually, pain from mild barotraumas will subside without any medical intervention, but if it lasts longer than 2-3 hours, professional advice should be sought. The doctor will examine a barotrauma of the ear with a lighted magnifying tool called an otoscope to look for infection, blood, or other fluid buildup. Sometimes it is necessary to check the eardrum by putting a light puff of air in to make certain the membrane has not been pushed out of proper position. Audiometry is required for any sort of severe barotrauma of the ear.
Survivors of bomb blasts will need to have chest X-rays performed. Anyone with breathing problems (dyspnea), cough, or hypotension following exposure to a high-order explosive should be tested for 'blast lung'.
Treatment & Therapy
Treatment depends on the type of barotrauma a patient has experienced. Most barotraumas from flying on an airplane are mild and fade away without medical intervention. When mild symptoms don’t respond to self-care, a consultation with a doctor is advised. In some cases, barotrauma causes a ruptured eardrum. A perforated membrane can take up to two months to heal properly on its own.
Antibiotics may be necessary if there is infection from a barotrauma affecting the ear, and corticosteroids can help reduce inflammation. Surgery may be necessary to prevent permanent damage to the ears; a tympanoplasty is a type of surgery that repairs and reconstructs the eardrum. Ear tubes called tympanostomy tubes or grommets—may be needed to clear up chronic ear infections or to prevent new ones. This treatment is most often prescribed for children.
In the case of pulmonary barotraumas, pure 100% oxygen may be used to eliminate gas that has built up in surrounding areas. Breathing 100% oxygen may also be used to treat mild cases of pneumothorax where the lung is less than 25% collapsed. Treating severe pneumothorax, however, involves inserting a tube into the space filled with air and pumping the air out of the pleural cavity.
Prevention & Prophylaxis
Divers should remember to not hold their breath excessively while diving. Holding their breath can extend the lungs and put them at risk of rupturing. When ascending, it is important for divers to do so slowly. This is important to keep in mind when an emergency ascent is required. Even if air supply is running low, a diver must balance the need for air with the need to not ascend too quickly and risk life-threatening pulmonary barotraumas.
Often it is helpful to take antihistamines or decongestants the night before and the morning prior to scuba diving, flying or engaging in any other activity that has caused a problem in the past. Of course, one should always check with their doctor before using a new medication.