EMS World

AUG 2011

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DIVING EMERGENCIES Resources The Divers Alert Network (DAN) is available to answer dive emergency questions and off er assistance during diving emergencies. DAN can also direct you to the nearest emergency care facility with staff trained in diving medicine. Call 919/684-9111 or visit www.DAN.org. Breathing Dangers NITROGEN NARCOSIS Inert gases under pressure have an intoxicating effect. Nitrogen under pres- sure can cause nitrogen narcosis, which impairs the ability to think and reason. Divers can usually stop nitrogen narcosis by ascending until symptoms resolve. The danger of nitrogen narcosis lies in impaired judgment, causing divers to lose track of time, remaining air and depth limits and resulting in agitation, panic or confusion. This can lead to various problems, including drowning when they run out of air, or increasing the chances for serious injury or illness by ascending too rapidly.10 OXYGEN TOXICITY Divers run little risk of oxygen toxicity when they stay within recreational depth limits of 130’ and use regular dive air, but it becomes a concern when they use mixed gases like enriched air nitrox.11 There are two types of oxygen toxicity. The first is central nervous system (CNS) oxygen toxicity. Signs and symptoms of CNS oxygen toxicity include convulsion, visual disturbance, tingling, twitching, muscle spasms (especially along the lips and mouth), irritability, dizziness and/or dyspnea. CNS toxicity is the more dangerous form of oxygen toxicity due to the risk of having convulsions under water. The second type is pulmonary toxicity, which can affect the lungs or other parts of the body. Symptoms include chest pain and discomfort, coughing and fl uid in the lungs. CARBON MONOXIDE POISONING Carbon monoxide poisoning can occur when the air in a scuba tank has been contaminated by fumes from an improperly maintained air compressor. Carbon monoxide poisoning often produces no symptoms before the diver loses consciousness, although there may be symptoms including headache, dizzi- ness, nausea or altered mental status. There may also be excessive red or blue coloring of the lips, nail beds or skin. Patients with suspected carbon monoxide poisoning should be given oxygen. Questions to Ask As in any other emergency, fact-gath- ering is important. Divers are trained to dive in a way that reduces the chance of DCI or other injury, but they may still expe- rience problems even if they follow all the rules. In addition to medical history and other information you normally gather, there is information particular to diving that treating physicians will find useful. Questions that need to be asked include: • “How long did it take the diver to ascend to the surface, and did he stop along the way?” A slower, controlled ascent coupled with one or more stops helps the body off-gas before bubbles form and also helps prevent barotraumas from air expansion. • “How deep and long was the tinnitus, nausea, dive?” There are recommendations on how long a diver may remain at various depths in order to minimize the risk of bubble formation. • “How long was it before the diver showed signs or symptoms?” DCI (including different forms of DCS) will present at various times based on severity and the type of DCI. • “What type of breathing gas was the diver using?” The gas mixture can help determine what illness or injury occurred. Divers are normally trained to dive with a buddy, who may be able to provide information. Don’t interfere with the equipment the diver was using other than to close the valves on the tank and note the number of turns it took to close the valve.12 There may be regional differences regarding what actions should be taken, including whether you should close the valves on a tank, so follow local procedures and defer to the judgment of law enforcement or other investigators on scene. As mentioned, many cases of DCI and other emergencies will present quickly, but others will have delayed signs and symptoms. For example, air travel after diving can cause or exacer- bate DCS. Though recommendations vary, based on different factors, a general rule is that divers should not fly within 24 hours after their last dive. If questions you ask a patient reveal recent air travel or diving activities that lead you to suspect a diving injury or illness, it should be treated accordingly. Case Studies Patient 1: You are called to the hotel room of a 30-year-old male with no medical history, who began experiencing some minor pain in his shoulders and tingling in his arms 20 minutes earlier. The pain has increased “from 2 to about a 4” on a 1–10 scale. He tells you he has been diving the last few days “pretty deep and for good, long dives,” but says he thought he was close to, but did not exceed, the maximum recommended guidelines. He completed multiple dives over the last few days; his last dive was completed 8 hours ago. You place him on oxygen, and your exam during transport does not reveal any neurological defi cits. Even though he did not exceed any recommended guidelines, it does not mean he is 100% safe from having DCI, especially since he did many deep dives over a few days. Treatment in a hyperbaric chamber often resolves all symptoms. Patient 2: A call comes in from a local pier where a boat is arriving with a 50-year-old male diver who is having trouble breathing. The boat is docking when you arrive, and you see a diver on the deck wearing a blood-spattered oxygen mask. His wife, who was diving with him, says they were fairly deep and had begun ascending to end the dive when she noticed her husband had not ascended and was many feet below her, staring into the water. She banged on her tank to attract his attention and headed toward him, but, before she could reach him, he looked at his air gauge and headed “like a rocket” to the surface. Immediately after surfacing he EMSWORLD.com | AUGUST 2011 63

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