Lightning Injuries in the Backcountry

1. Lightning Injuries in the Backcountry Remote Areas Emergency Medicine and Survival

2. Content • Lightning Fact and Figures • Lightning Myths • Epidemiology • Mechanism of Injury • Pathophysiology • Management • Prevention

3. Lightning Facts • There are 1,800 thunderstorms on the • earth at any moment • Equates to 16 million storms each year • An average of 25 million strokes of • lightning from the cloud to ground every • year in the U.S.

4. Lightning Facts • Lightning temps ~8,000 - 50,000° C • Leader stroke travels one-third the speed of light • Leader stroke est. 3-8 cm in diameter • Lasts .01 - .001 of a second • 10 to 200 million Volts • Up to 200,000 amps

5. Lightning Facts

6. Lightning Facts

7. Lightning Facts • Lightning can strike even if it is not raining • Can strike in front of or behind storm • Known to strike as far as 10-25 miles from the storm • “Bolts from the Blue” • “Out of the Clear Blue Sky” • Can strike in sunny conditions after storm

8. Lightning Myths

9. Lightning Myths • If it is not raining, there is no danger from lightning • Rubber soles of boots or rubber tires on a car will protect you from being struck by lightning • People struck by lightning carry an electrical charge and should not be touched

10. Lightning Myths • Lightning is always fatal • Lightning turns victims into “crispy critters” • Lightning never strikes the same place twice • Victims bodies remain in “suspended animation”

11. Lightning Myths • If caught in a lightning storm outside, it is better to seek shelter under an isolated or small group of trees than to remain out in the open. • Heat Lightning is harmless and poses no threat to anyone

12. Epidemiology

13. Epidemiology

14. Epidemiology • 84% M, 16% F • June, July, August • Wed/Sat/Sunday • 2-6 pm

15. Odds of Becoming a Victim Odds of being struck by lightning in a given year (reported deaths + injuries) 1/700,000 Odds of being struck by lightning in a given year (estimated total deaths + injuries) 1/400,000 Odds of being struck in your lifetime 1/5000 (Est. 80 years) Odds you will be affected by someone being struck 1/500 (Ten people affected for every one struck)

16. Mechanism of Injury • Factors determining Injury • Type of circuit • Resistance of tissues • Amperage and voltage • Current pathway • Duration • Environmental Factors • Size of contact point • Clothing

17. Mechanism of Injury Heat = current x resistance x time Very short duration of exposure …a “short circuit”…

18. Mechanism of Injury Duration of Exposure • Longer the contact duration, the greater the intensity and thus increased injury • The major difference between lightning (DC current) and high-voltage electrical injuries (AC current) • Electricity takes most direct route to exit to ground • Lightning – “flashover” effect • Hot Lightning – lasting up to 0.5 sec • acts like high voltage energy

19. Mechanism of Injury Tissue Resistance • Humidity affects skin moisture and thus resistance • Resistance drops significantly when surface is wet • Higher resistance can ignite clothes and cause thermal burns • Metal objects increase risk thermal burns

20. Mechanism of Injury • Tissue Resistance • Least: • Nerve, blood, muscle • Intermediate: • Dry skin • Most: • Tendon, fat, bone

21. Mechanism of Injury • Direct Strike - most common to the head and shoulders • Contact Injury - touching object in pathway • Side Flash - jumps from object to victim • Step Voltage – travels through the ground • Blunt Injury - fractures and muscle contractions

22. Direct Strike

23. Contact Flash

24. Step Voltage

25. Pathophysiology

26. Clinical Presentation • Brain, heart and skin most commonly affected • Immediate cardiopulmonary arrest is primary cause of death from lightning strike

27. Cardiopulmonary Arrest • Effects to the respiratory center • apnea • Effects to the conduction pathway in the heart • Asystole • V-fib • Spontaneous conversion to NSR may occur • MI rare • Autonomic instability

28. Cardiopulmonary Arrest • Apnea persists causing hypoxia • May outlast cardiac arrest • May cause secondary hypoxic arrest

29. Skin • Feathering burns… “Lichtenberg Figures” • Linear burns • Punctate burns • Thermal burns

30. Feathering Burns

31. Linear Burn

32. Punctate Burns

33. Thermal Burns

34. Skin 2º-3º burns Thermal Burns

35. Neurologic Injuries • LOC: • anterograde amnesia • CNS: • Infarction • Hematoma • Encephalopathy • Degeneration • Peripheral: • autonomic instability

36. Neurologic Injuries • Similar to after effects of electroconvulsive therapy • Pupillary dilatation may be secondary to autonomic injury • Intracranial bleeding, cerebral edema, seizures, anoxia

37. Keraunoparalysis • Intense vascular spasm in extremities • temporary loss of pulses • mottling • absence of sensation in an extremity • usually resolves spontaneously

38. Renal…rare Ophthalmic: cataracts less common entire axis injury noted Otologic: TM rupture Musculoskeletal: injury secondary to trauma Blunt Trauma Post-Traumatic Headaches Miscellaneous Trauma

39. Management

40. Managing Lightning Strike • Survey scene for safety • Activate EMS • -depending location in the backcountry • Move victim to safer location • Evaluate ABCs and treat accordingly • Use reverse triage principle • -CPR is very effective in these victims • ACLS with good ventilation

41. Managing Lightning Strike • Evaluate and treat for hypothermia and shock • Evaluate for blunt trauma and treat for fractures • Evaluate and treat for burns • Plan evacuation methods • ambulatory or litter • air evacuation • overnight shelter

42. Long-term Management • Survivors are an even greater tragedy! • ~ 70% Long-Term Medical Problems • ~ 30% Suffer Debilitating Problems • Elusive Data - 40-70% Under-Reported • Support group is recommended

43. Lightning Strike and Electric Shock Survivors International • info@lightning-strike.org • www.lightning-strike.org • 1-910-346-4708 • Jacksonville, NV

44. PREVENTION

45. STAY INDOORS! Lightning Safety

46. If you can see lightning or hear thunder, activate your safety plan. Resume activities only when lightning and thunder have not been observed for 30 minutes. If you can see it (lightning), flee it; if you can hear it (thunder), clear it. Lightning Safety

47. Lightning Safety • These are some key facts to remember about lightning safety: • No place in the out of doors or the wilderness is absolutely safe from lightning. • The safest location is inside a substantial building, away from all windows and doors. • The next best location is inside a hard top automobile with windows rolled up.

48. Lightning Safety • Indoor Lightning Safety • Avoid using telephone (remember the wires) • Avoid using water – sink, tub, etc. (plumbing) • Unplug appliances (remember the wires) • Inner rooms are the best

49. Lightning Safety • Vehicles: car, bus, etc. • close windows • keep hands on lap it’s not the rubber tires that make a vehicle safe; it’s the metal cage • Convertibles or canvas type (soft) tops offer no protection

50. Lightning Safety • If you remain outdoors • Stay away from rivers, lakes, or other bodies of water • Be aware of the potential for flooding in low-lying areas • NEVER stand under an isolated tree