Wilderness and Rescue Medicine 7th Edition Jeffrey Isaac, PA-C and David E. Johnson, MD

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Section V: Environmental Medicine

superficial, with more serious deep burns occur- ring in less than 5% of patients. Nervous system injury, including noncontact traumatic brain injury, is common, with many patients experi- encing loss of consciousness, amnesia, numbness, tingling, and weakness. Treatment of Lightning Injury Treat what you see. Lightning can induce cardiac arrest. If heart damage is minimal, the pulse often returns spontaneously. Lightning-induced respi- ratory arrest may not spontaneously resolve, even when the respiratory system is relatively intact. In these cases, the prompt initiation of cardio- pulmonary resuscitation (CPR) or positive pres- sure ventilation (PPV) can be lifesaving. Burns, shock, brain injury, and musculoskeletal trauma are all treated as you would with any other patient. It is interesting to note that about 25% of sur- vivors develop significant long-term physical or psychological problems, such as chronic pain or depression.

they are attached reduce the risk of damage by offering a low-resistance pathway to ground. Trees and rocks, by contrast, offer higher resistance to the flow of current and will become hot, burn, and may explode as the moisture in the wood or rock instantly vaporizes. In the field, the best tactic to avoid a lightning injury is to get away from the places most likely to be hit. Drop off the ridgeline or mountain top and into the forest. If continued travel takes you lower, keep moving. When travel is no longer possible or will not reduce your risk, stop and squat or sit as low as you can on your foam pad or backpack, which may help insulate you from ground cur- rent. Avoid being near the tallest trees or rock outcrops. A group should be well spread out, so that a strike will not incapacitate everybody at once. If you are onboard a larger boat, avoid hav- ing the whole crew clustered in the cockpit. Water is a good conductor, so do not swim or wade dur- ing a thunderstorm. If you are in a tent, sit up or squat to reduce the exposure of vital organs to ground current. The inside of a vehicle is a relatively safe place during a lightning storm. The insulating value of the tires offers protection only from ground current, but the metal shell tends to conduct the energy of a direct strike around the occupants and into the ground. The metal shrouds and stays sup- porting the mast of a sailing vessel may have the same effect, provided there is a good grounding system and you are not leaning on them. On a cliff, lightning current follows the cliff face, especially where it is wet. Wet climbing ropes may also become conductors. Hollows and caves may seem attractive as shelter, but current can jump across the opening and include you in the path. The same effect can occur between an object like an airplane wing or vehicle and the ground. No matter where you are during a lightning storm, always keep fundamental avoidance guidelines in mind.

General Principles

Lightning Injuries

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Assessment and Treatment: • Immediate BLS • Treat what you see: burns. – blunt and penetrating trauma

– cardio-pulmonary arrest – neurologic impairment – burns

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©2018WMA

Prevention of Lightning Injury The height and isolation of an object are the only two factors that predict the likelihood of a direct strike. The type of material has no influence of the probability of being struck. Metal, however, will do a much better job of conducting the current to ground than wood or plastic. As a result, side flash will be more common from a tree than from a metal tower. Lightning rods projecting above the top of a building increase the probability of a strike, but the heavy grounding cables to which