EMS World

AUG 2011

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Page 65 of 71

DIVING EMERGENCIES Diving also causes “immersion diuresis,” which can lead to dehydration and associated issues, including syncope and arrhythmias.4 Dehydration is exacer- bated by other factors, including carrying equipment, exposure to sun, breathing dry, compressed air, airplane travel and taking diuretic medications. Hypothermia, hyperthermia and dehydration should be treated in accor- dance with your local protocols. Keep in mind that certain signs and symptoms of these conditions, such as nausea, are also associated with other diving injuries. BAROTRAUMA In much the same way you may feel ear pain during take-off or landing during a flight due to pressure changes, the changes in pressure when diving can cause injury to ears, sinuses and other air spaces. Although decompression illness and other emergencies are dramatic, ear injuries are much more common. Divers are trained to equalize the pressure in their ears to ensure that air enters the middle ear through the Eustachian tubes.5 Pressure may be felt quickly, and a 10- to 12-inch descent can be sufficient to cause discomfort and pain. Barotitis media (middle ear barotrauma) occurs when pressure in the middle ear is lower than the surrounding pressure (which may occur during descent), forcing the eardrum inward and causing pain and bleeding. A pressure differential can also cause the eardrum to tear or rupture, which results in pain and bleeding. Water entering the ear may cause vertigo, which is very dangerous when it occurs at depth.6 The membranes in the sinuses can also be damaged by pressure. Note that sinus barotrauma and related injuries can occur both during descent and ascent. When ascending, the mechanism of injury is reversed as air expands. An injury to the ears will manifest as a feeling of fullness, pressure or pain. There may also be hearing loss or complaints of a squeaking sound. Blood or other fluid discharge from the ear may be evident. A sinus injury can also cause fullness, pressure or pain (including pain in the upper teeth) with blood or other 62 AUGUST 2011 | EMSWORLD.com discharge from the nose. Divers with suspected barotrauma should not return to the water. They need to be assessed by a physician for proper treatment, which may include antibiotics, antihistamines and surgery. EFFECTS ON THE LUNGS The effects of the change in air volume and the other gas laws form the basis of decompression illness (DCI), which includes arterial gas embolism (AGE), and decompression sickness (DCS), commonly known as “the bends.” If a diver takes a breath of air and starts to ascend while holding his breath (or with air otherwise trapped in the lungs), the air expands as the ambient water pressure decreases, much like air expanding in a balloon. This can damage the alveoli and bronchial passages. “An injury to the ears will manifest itself as a feeling of fullness, pressure or pain.” Expanding air may rupture the lung and cause a pneumothorax. Mediastinal and subcutaneous emphysema can result from air that escapes from the lungs. AGE occurs when bubbles are forced into the bloodstream through alveoli, resulting in blockages when the bubbles reach smaller blood vessels. A cerebral arterial gas embolism (CAGE) results if the air embolizes in the brain. AGE will usually occur either during a dive or within 15 minutes after a diver surfaces.7 coughing and shortness of breath, bloody or frothy sputum, headaches and/or dizziness, visual disturbances (including partial or full blindness), numbness and/ or tingling, weakness or paralysis and loss of sensation in the body, and syncope. DCS: THE BENDS As a diver descends, the increased ambient pressure forces inspired nitrogen Symptoms include chest pain, into tissue.8 When a diver ascends the pressure is reduced and nitrogen is released from tissue into the blood- stream. If a diver ascends too quickly, has been down too long or otherwise has excessive amounts of nitrogen in his body, bubbles may form in the blood- stream or remain trapped in tissue.9 Since bubble formation can occur in any tissue, there are many forms of DCS. Pain may occur in the limbs or joints. Central nervous system DCS can cause paralysis and loss of sensation. Cerebral DCS may produce headaches, visual disturbances, paralysis, unconsciousness and altered mental status. “Skin bends,” or cutaneous DCS, present with itching, burning or mottling of the skin. The onset time of DCS varies within 24 hours of diving. In a recent report, half of all cases of DCS had symptom onset times of an hour and a half or less after a diver surfaced. Any symptoms that occur after 24 hours are probably unrelated to diving. In rare cases, divers exposed to altitude may exhibit initial symptom onset after 24 hours. The treatment for suspected cases of any DCI, including AGE and DCS, are essentially the same, with the ABCs as a priority. The importance of administering 100% oxygen cannot be overemphasized in suspected cases of DCI. In addition to providing respiratory support as it does in any emergency, oxygen promotes the elimination of inert gas bubbles in the tissues. Dive boats often have oxygen on hand, and someone may have begun administering oxygen prior to EMS’s arrival. DCI can be life-threatening, and any suspected DCI requires immediate transport to a medical facility where a complete diagnosis and treatment, such as hyperbaric chamber therapy, can be done. Note that changes in alti- tude can exacerbate a case of DCI, so if the patient needs to be transported by helicopter, it should be at the lowest safe altitude possible. The current recom- mendation is 1,000’ or lower. A physical exam, including a thorough neurological examination, should be performed and changes should be monitored care- fully. Never attempt “recompression” by placing a diver back into the water.

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