Barotrauma is tissue injury caused by a pressure-related change in body compartment gas volume; it affects air-containing areas, including lungs, ears, sinuses, GI tract, air spaces in tooth fillings, and space contained by the diving face mask. Symptoms may include ear pain, vertigo, hearing loss, sinus pain, epistaxis, and abdominal pain. Dyspnea and loss of consciousness are life threatening and may result from alveolar rupture and pneumothorax. Diagnosis is clinical but sometimes requires imaging tests. Treatment generally is supportive but may include decongestants and analgesics for ear and sinus barotrauma or O2 and chest tube placement for pneumothorax. If arterial gas embolism accompanies lung barotrauma, recompression and O2 therapy (in a hyperbaric chamber) are needed. Proper diving safety techniques and prophylactic use of decongestants may reduce incidence of barotrauma.
Risk of barotrauma (often called squeeze by divers) is greatest from the surface to 10 m (33 ft). Risk is increased by any condition that can interfere with equilibration of pressure (eg, sinus congestion, eustachian tube blockage, structural anomaly, infection) in the air-containing spaces of the body. Ear barotrauma constitutes about two thirds of all diving injuries. In divers who inspire even a single breath of air or other gas at depth and do not let it escape freely during ascent, or when ascent is rapid, the expanding gas may overinflate the lungs. Lung overinflation occurs mostly in divers breathing compressed air but can occur even in swimming pools when compressed air is inspired at the bottom of the pool (eg, when scuba gear is used there) and, rarely, from an inverted bucket.
Manifestations depend on the affected area; all occur almost immediately when pressure changes. Some nonfatal disorders, if they occur at depth, may be disabling or disorienting and thus lead to drowning. Secondary infection is sometimes a late complication.
Diagnosis is primarily clinical; imaging tests can sometimes confirm barotrauma. Sometimes patients are evaluated for other problems or organ dysfunction.
Most barotrauma injuries resolve spontaneously and require only symptomatic treatment and outpatient follow-up; however, some injuries are life-threatening. Potentially life-threatening barotrauma emergencies are those involving alveolar or GI rupture, particularly in patients who present with any of the following:
Initial stabilizing treatment includes high-flow 100% O2 and, if respiratory failure appears imminent, endotracheal intubation see Tracheal Intubation. Positive pressure ventilation may cause or exacerbate pneumothorax.
Patients with suspected pneumothorax who are hemodynamically unstable or have signs of tension pneumothorax require immediate chest decompression (see Treatment) with a large-bore (eg, 14-gauge) needle placed into the 2nd intercostal space in the midclavicular line, followed by tube thoracostomy see Procedure. Patients with neurologic symptoms or other evidence of arterial gas embolism are transported to a recompression chamber (see Recompression Therapy) for treatment as soon as transportation can be arranged.
When stable, patients are treated for the specific type of barotrauma sustained.
Patients treated for severe or recurrent diving-related injuries should not return to diving until they have consulted with a diving medicine specialist.
Prevention of other diving injuries is discussed elsewhere (see Diving Precautions and Prevention of Diving Injuries).
During very deep breath-hold diving, compression of the lungs during descent may rarely lead to a decrease in volume below residual volume, causing mucosal edema, vascular engorgement, and hemorrhage, which manifest clinically as dyspnea and hemoptysis on ascent.
Overexpansion and alveolar rupture can occur when breath-holding occurs or when breathing compressed air during ascent particularly rapid ascent. The result can be pneumothorax (causing dyspnea, chest pain, and unilateral decrease in breath sounds) or pneumomediastinum (causing sensation of fullness in the chest, neck pain, pleuritic chest pain that may radiate to the shoulders, dyspnea, coughing, hoarseness, and dysphagia). Pneumomediastinum may cause crepitation in the neck, due to associated subcutaneous emphysema, and a crackling sound may rarely be heard over the heart during systole (Hamman sign). Tension pneumothorax, although rare with barotrauma, can cause hypotension, distended neck veins, hyperresonance to percussion, and, as a late finding, tracheal deviation. Alveolar rupture can allow air into the pulmonary venous circulation with subsequent arterial gas embolism (see Arterial Gas Embolism).
Patients require a neurologic examination for signs of brain dysfunction due to arterial gas embolism. Chest x-ray is done to look for signs of pneumothorax or pneumomediastinum (radiolucent band along the cardiac border). If chest x-ray is negative but there is strong clinical suspicion, then chest CT, which may be more sensitive than plain film x-rays, may be diagnostic.
Suspected tension pneumothorax is treated with needle decompression followed by tube thoracostomy (see Tube Thoracostomy). If a smaller (eg, 10 to 20%) pneumothorax is present and there is no sign of hemodynamic or respiratory instability, the pneumothorax may resolve when high-flow 100% O2 is given for 24 to 48 h. If this treatment is ineffective or if a larger pneumothorax is present, tube thoracostomy (using a pigtail catheter or small chest tube) is done.
No specific treatment is required for pneumomediastinum; symptoms usually resolve spontaneously within hours to days. After a few hours of observation, most patients can be treated as outpatients; high-flow 100% O2 is recommended to hasten resorption of extra-alveolar gas in these patients. Rarely, mediastinotomy is required to relieve tension pneumomediastinum.
Prevention of pulmonary barotrauma is usually the top priority. Proper ascent timing and techniques are essential. Patients with pulmonary blebs, Marfan syndrome, or COPD are at very high risk of pneumothorax and should not dive or work in areas of compressed air. Patients with asthma may be at risk of pulmonary barotrauma, although many people with asthma can dive safely after they are evaluated and treated appropriately.
Breathing improperly from a regulator or using ear and sinus pressure-equalization techniques may cause divers to swallow small amounts of air during a dive. This air expands during ascent, causing abdominal fullness, cramps, pain, belching, and flatulence; these symptoms are self-limited. GI rupture rarely occurs, manifesting with severe abdominal pain and tenderness with rebound and guarding.
If signs of GI rupture are present, immediate upright chest x-ray or CT is done to detect free air. Milder symptoms require no testing.
Patients with GI rupture require aggressive fluid resuscitation, broad-spectrum antibiotic therapy, and immediate surgical consultation for possible exploratory laparotomy.
Ear and Sinus Barotrauma
Diving can affect the external, middle, and inner ear. Typically, divers experience ear fullness and pain during descent; if pressure is not quickly equilibrated, middle ear hemorrhage or tympanic membrane rupture may occur. Inflow of cold water to the -middle ear may result in vertigo, nausea, and disorientation while submerged. On examination of the ear canal, the tympanic membrane may show congestion, hemotympanum, perforation, or lack of mobility during air insufflation with a pneumatic otoscope; conductive hearing loss is usually present.
Inner ear barotrauma often involves rupture of the round or oval window, which causes tinnitus, sensorineural hearing loss, vertigo, nausea, and vomiting. The resulting labyrinthine fistula and perilymph leakage can permanently damage the inner ear.
Sinus barotrauma most often affects the frontal sinuses, followed by the ethmoid and maxillary sinuses. Divers experience mild pressure to severe pain, with a feeling of congestion in the involved sinus compartments during ascent or descent and sometimes epistaxis. Pain can be severe, sometimes accompanied by facial tenderness on palpation. Rarely, the sinus may rupture and cause pneumocephalus with facial or oral pain, nausea, vertigo, or headache. Rupture of a maxillary sinus can cause retro-orbital air with diplopia due to oculomotor dysfunction. Physical examination may detect tenderness in the sinuses or nasal hemorrhage.
Patients with symptoms of inner ear trauma should be examined for signs of vestibular dysfunction and referred for formal audiometry and vestibular testing (see Testing).
Imaging (eg, plain x-rays, CT) is not necessary for diagnosis of uncomplicated sinus barotrauma, but CT is useful if sinus rupture is suspected.
Most ear and sinus barotrauma injuries resolve spontaneously and require only symptomatic treatment and outpatient follow-up.
Drug treatment for sinus and middle ear barotrauma is identical. Decongestants (usually oxymetazoline 0.05%, 2 sprays each nostril bid for 3 to 5 days or pseudoephedrine 60 to 120 mg po bid to qid up to a maximum of 240 mg/day for 3 to 5 days) can help open occluded chambers. Severe cases can be treated with nasal corticosteroids. Doing the Valsalva maneuver immediately after nasal spray therapy may help distribute the decongestant into the occluded chamber. Pain can be controlled with NSAIDs or opioids. If bleeding or evidence of effusion is present, antibiotics are given (eg, amoxicillin 500 mg po q 12 h for 10 days, trimethoprim/sulfamethoxazole 1 double-strength tablet po bid for 10 days). For middle ear barotrauma, some physicians also advocate a short course of oral corticosteroids (eg, prednisone 60 mg po once/day for 6 days, then tapered over 7 to 10 days).
Referral to an otorhinolaryngologist is indicated for severe or persistent symptoms. Surgery (eg, tympanotomy for direct repair of a ruptured round or oval window, myringotomy to drain fluid from the middle ear, sinus decompression) may be necessary for serious inner or middle ear or sinus injuries.
Ear barotrauma may be avoided by frequently swallowing or exhaling against pinched nostrils to open the eustachian tubes and equalize pressure between the middle ear and the environment. Pressure behind ear plugs cannot be equalized, so they should not be used for diving. Prophylaxis with pseudoephedrine 60 to 120 mg po bid or qid up to a maximum of 240 mg/day, beginning 12 to 24 h before a dive, can reduce the incidence of ear and sinus barotrauma. Diving should not be done if congestion does not resolve or if a URI or uncontrolled allergic rhinitis is present.
Other Types of Barotrauma
Dental barotrauma can occur during descent or ascent, when pressure in the air spaces at the roots of infected teeth or adjacent to fillings changes rapidly and causes pain or tooth damage. The affected tooth may be tender when percussed with a tongue blade.
Mask barotrauma occurs when the pressure in the space behind the face mask is not equalized during descent. The resulting relative vacuum can lead to local pain, conjunctival hemorrhage, and ecchymosis of the skin enclosed by the mask. Retro-orbital hemorrhage is possible but rare. If retro-orbital hemorrhage is suspected, complete eye examination (including visual acuity, extraocular movements, and intraocular pressure measurement) and head CT are done. Mask barotrauma may be avoided when pressures are equalized within the face mask by exhaling from the nose into the mask.
Eye barotrauma occurs when small air bubbles are trapped behind hard contact lenses. The air bubbles can damage the eye and cause soreness, decreased visual acuity, and halos around lights. A screening ophthalmic examination should be done to rule out other causes. Pressure behind goggles cannot be equalized, so they should not be used for diving.
Last full review/revision April 2013 by Alfred A. Bove, MD, PhD
Content last modified May 2013