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GEMC- Electrical Misadventures- Resident Training

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This is a lecture by Joe Lex, MD from the Ghana Emergency Medicine Collaborative. To download the editable version (in PPT), to access additional learning modules, or to learn more about the project, …

This is a lecture by Joe Lex, MD from the Ghana Emergency Medicine Collaborative. To download the editable version (in PPT), to access additional learning modules, or to learn more about the project, see http://openmi.ch/em-gemc. Unless otherwise noted, this material is made available under the terms of the Creative Commons Attribution Share Alike-3.0 License: http://creativecommons.org/licenses/by-sa/3.0/.

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  • 1. Project: Ghana Emergency Medicine Collaborative Document Title: Electrical Misadventures Author(s): Joe Lex, MD, FACEP, FAAEM, (Temple University) 2013 License: Unless otherwise noted, this material is made available under the terms of the Creative Commons Attribution Share Alike-3.0 License: http://creativecommons.org/licenses/by-sa/3.0/ We have reviewed this material in accordance with U.S. Copyright Law and have tried to maximize your ability to use, share, and adapt it. These lectures have been modified in the process of making a publicly shareable version. The citation key on the following slide provides information about how you may share and adapt this material. Copyright holders of content included in this material should contact open.michigan@umich.edu with any questions, corrections, or clarification regarding the use of content. For more information about how to cite these materials visit http://open.umich.edu/privacy-and-terms-use. Any medical information in this material is intended to inform and educate and is not a tool for self-diagnosis or a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional. Please speak to your physician if you have questions about your medical condition. Viewer discretion is advised: Some medical content is graphic and may not be suitable for all viewers. 1
  • 2. Attribution Key for more information see: http://open.umich.edu/wiki/AttributionPolicy Use + Share + Adapt Make Your Own Assessment Creative Commons – Attribution License Creative Commons – Attribution Share Alike License Creative Commons – Attribution Noncommercial License Creative Commons – Attribution Noncommercial Share Alike License GNU – Free Documentation License Creative Commons – Zero Waiver Public Domain – Ineligible: Works that are ineligible for copyright protection in the U.S. (17 USC § 102(b)) *laws in your jurisdiction may differ Public Domain – Expired: Works that are no longer protected due to an expired copyright term. Public Domain – Government: Works that are produced by the U.S. Government. (17 USC § 105) Public Domain – Self Dedicated: Works that a copyright holder has dedicated to the public domain. Fair Use: Use of works that is determined to be Fair consistent with the U.S. Copyright Act. (17 USC § 107) *laws in your jurisdiction may differ Our determination DOES NOT mean that all uses of this 3rd-party content are Fair Uses and we DO NOT guarantee that your use of the content is Fair. To use this content you should do your own independent analysis to determine whether or not your use will be Fair. { Content the copyright holder, author, or law permits you to use, share and adapt. } { Content Open.Michigan believes can be used, shared, and adapted because it is ineligible for copyright. } { Content Open.Michigan has used under a Fair Use determination. } 2
  • 3. Joe Lex, MD, FACEP, FAAEM Department of Emergency Medicine Temple University School of Medicine Philadelphia, PA Electrical Misadventures
  • 4. Objectives Discuss controversies about… …microwave injuries …cord-biting injuries …lightning injuries …TASER® injuries Steve and Sara, Flickr
  • 5. Objectives • Explore some controversies in management of electrical injuries • Determine who really requires hospital admission • Discuss how pregnancy changes management
  • 6. Microwave Mk2010, Wikimedia Commons
  • 7. Microwave • More similar to electric burns than to conventional oven burns • Tend to be sharply demarcated • Can burn skin and muscle, but not hurt subcutaneous tissues • Biopsy  layered sparing
  • 8. Microwave Source: Dixon JJ, et al. Burns. 1997 May;23(3): 268-8. Source: Dixon JJ, et al. Burns. 1997 May;23(3): 268-8.
  • 9. Cord Biting Injury Fg2, Wikimedia Commons
  • 10. Cord Biting Injury Source Undetermined
  • 11. Cord Biting Injury • Chew through cord insulation • Most injuries unilateral: lateral commissure, tongue • Systemic problems uncommon • Labial artery injury not apparent immediately due to vascular spasm, thrombosis, eschar
  • 12. Cord Biting Injury • Severe bleeding from labial artery in up to 10% when eschar separates, usually 5 days – 2 weeks • Old recommendation: admit • Newer recommendation: reliable parents  outpatient adequate Garcia CT, et al. Ann Emerg Med. 1995 Nov;26(5):604-8.
  • 13. Lightning Injury National Oceanic and Atmospheric Association, Wikimedia Commons
  • 14. Lightning Injury • Annual US Deaths Reported: 60 • Annual US Injuries Reported: 400 • Odds of being struck by lightning in a given year: 1/400,000 • Odds of being struck in your lifetime: 1/5000
  • 15. Lightning Injury Source: New England Journal of Medicine
  • 16. Lightning Injury James Heilman, MD, Wikimedia Commons
  • 17. Lightning Injury • Typical industrial shock: 20 – 63 kilovolts • Lightning strike: 300 kilovolts • Industrial shocks rarely last longer than 500 milliseconds • Lightning strikes last only few milliseconds
  • 18. Lightning Injury • Unlike other multiple victim trauma, give priority to people who appear dead • Aggressively resuscitate; survival has been reported after prolonged respiratory arrest • Immobilize spine when mental status altered
  • 19. Lightning Injury • Hypotension is unexpected and should prompt investigation for hemorrhage • Treat ventricular tachycardia or fibrillation and asystole with standard ACLS protocols • Treat seizures with standard therapy
  • 20. Lightning Injury • Admit patients with minor injuries for cardiac and neurologic monitoring • Admit all pregnant patients for fetal monitoring
  • 21. Taser United States Military, Wikimedia Commons
  • 22. Taser • Series of damped sinusoidal electrical impulses designed to induce involuntary muscle contraction and incapacitation • High voltage (50 kilovolt) low amperage, low average energy
  • 23. Taser • Uses Electro-Muscular Disruption (EMD) technology to cause neuromuscular incapacitation (NMI) and strong muscle contractions through involuntary stimulation of both sensory and motor nerves
  • 24. Taser • Considered safe • Function appropriately on calm, healthy, individual in relaxed and controlled environment • 2001-2007: >245 deaths occurred after Taser use http://www.amnesty.org/en/library/info/AMR51/030/2006
  • 25. Taser http://en.wikipedia.org/wiki/Taser_safety_issues • 7 cases: ME said Taser was cause or contributing factor • 16 cases: ME said Taser was secondary or contributory factor • Dozens of cases: ME cited excited delirium (not in DSM-IV) • Several cases: fall caused by Taser implicated as cause
  • 26. Taser • ACEP now recognizes “excited delirium” as a diagnosis • Doubt other specialties will join us – they don’t see what we see • Should help exonerate some law- enforcement people accused for “deaths in custody”
  • 27. Taser • But no evidence taser on chest can cause R-on-T phenomenon, leading to Vfib and death • No evidence taser can cause malfunction of pacemaker or AICD • Should victims be monitored? No clear evidence Heart Rhythm Society. Abstract presented 5/11/07.
  • 28. Taser •Go to 1:25 •Series
  • 29. Electrical Shock Injury Magnus Manske, Wikimedia Commons
  • 30. Some Epidemiology • Severe nonlethal electrical injuries account for 3 to 5% of admissions to burn centers • About 17,000 victims of electrical injury treated each year in U.S. emergency departments
  • 31. Some Epidemiology Three distinct populations at risk • Toddlers: household electrical sockets and cords • Adolescents: risky behavior around electrical power lines • Electrical utility workers: annual death in US of ~1 per 10,000
  • 32. Some Epidemiology • Easy electric flow: conductors • Poor electric flow: insulators • Best conductors: tissues with high fluid and electrolyte content
  • 33. Some Epidemiology • High voltage  severe burns despite fraction of a second contact time • Household voltages (110v)  minimal burns, even after several seconds of contact time
  • 34. Some Epidemiology • Even in low-voltage electrocution deaths, electrical burns absent in > 40% of cases • Somebody “thrown” from electric source actually having tetany • AC current can also cause flexor tetany  unable to release
  • 35. Types of Burns • Flash burns: heat from nearby arc causes thermal burns • Electrothermal burns: current passage through body • Flame burns: clothing ignition • Arc burns: current arcs to victim –May be mix of flash, electrothermal and flame
  • 36. Flash Burns Ben Watts, Flickr
  • 37. Flash Burns Source Undetermined
  • 38. Electrothermal Burns Occupational Safety and Health Administration, Wikimedia Commons
  • 39. Electrothermal Burns Source Undetermined
  • 40. Electrical Arc • Spark of current through air between objects of differing electrical potential • Typically source to patient • Voltages are extreme • Temperatures can reach 2500°C (4532°F)
  • 41. Arc Burns Source Undetermined
  • 42. High vs. Low Voltage • Brief dose of high voltage electricity is not necessarily fatal • Low voltage just as likely to kill as high voltage RK Wright, et al. J. Forensic Sci. 1980; 25:514-521. Sonarpulse, Wikimedia Commons
  • 43. Specific Injuries: Cardiac • Low-voltage AC: VFib • High-voltage AC, DC: transient ventricular asystole • Cardiac arrhythmias in up to 30% of high-voltage victims –Sinus tach, PACs, PVCs, SVT, AFib, 1o or 2o AV block
  • 44. Specific Injuries: Cardiac All stops out resuscitation 1) many victims young, no prior cardiovascular disease 2) often not possible to predict outcome based on age and initial rhythm
  • 45. Specific Injuries: CNS • Neurologic impairment in ~50% with high-voltage injuries • Transient loss of conscious common • Others: agitation, coma, seizures, confusion, quadriplegia, aphasia hemiplegia, vision changes
  • 46. Specific Injuries: Spinal Cord • Immediate from vertebral fractures, usually found in workup • Delayed from electrical current itself: may present as ascending paralysis, complete or incomplete spinal cord syndromes, transverse myelitis
  • 47. Specific Injuries: Spinal Cord • If purely electrical, MRI results not closely correlated with prognosis – Rarely initial MRI will be normal in electrical trauma patients with permanent spinal cord injury – Majority of patients with spinal cord impairment following mechanical trauma who have a normal initial spinal MRI will have complete resolution of neurologic dysfunction
  • 48. Specific Injuries: Peripheral • Peripheral nerve injuries often involve hands • Paresthesias can be immediate and transient or delayed up to 2 years after injury • Contact with palm produces median or ulnar neuropathy more than radial nerve injury
  • 49. Specific Injuries: Eyes • Cataract formation described weeks to years after electrical injury to head, neck, upper chest • Also reported after electric arc or flash burns • High-voltage: retinal detachment, corneal burns, intraocular hemorrhage and thrombosis
  • 50. Specific Injuries: Shoulders • Posterior dislocations and scapular fractures both reported Source Undetermined
  • 51. Specific Injuries: Pregnancy Fatovich DM. J Emerg Med. 1993 Mar-Apr;11(2):175-7. • Case reports of pregnant women receiving apparently harmless contacts with electric current later suffering fetal damage or loss • In most cases, mechanism of fetal injury is uncertain
  • 52. Specific Injuries: Pregnancy Fatovich DM. J Emerg Med. 1993 Mar-Apr;11(2):175-7. 1) Monitor fetal heart rate and uterine activity for 4 hours if >20-24 weeks’ gestation 2) Monitor maternal cardiac and fetal heart rate and uterine activity for 24 hours if ECG changes, loss of consciousness, history of heart disease
  • 53. Specific Injuries: Pregnancy • Fetal ultrasonography also recommended immediately and at 2 weeks, but… • No proof that monitoring or treatment can influence fetal outcome in pregnant women following electric injury without mechanical trauma Einarson A, et al. Am J Obstet Gynecol. 1997 Mar;176(3):678-81
  • 54. Cardiac Monitoring James T at al. Cardiac abnormalities demonstrated post-mortem in four cases of accidental electrocution and their potential significance relative to non-fatal electrical injuries of the heart. American Heart Journal. 120: 143- 57, 1990. Robinson N et al. Electrical injury to the heart may cause long-term damage to conducting tissue: a hypothesis and review of the literature. Int J Cardiol. 53: 273-7, 1996.
  • 55. Cardiac Monitoring Alexander L. Electrical injuries of the nervous system. J Nerv Ment Dis 1941; 94: 622-632 Jensen PJ, et al. Electrical injury causing ventricular arrhythmias. Br Heart J 1987; 57: 279-283 Norquist C, et al. The risk of delayed dysrhythmias after electrical injuries. Acad Emerg Med. 6: 393, 1999
  • 56. Cardiac Monitoring • Common knowledge: All patients with electrical injury require 24 hours of cardiac monitoring Bionerd, Wikimedia Commons
  • 57. Cardiac Monitoring 9 articles Authors Voltage Number of patients Initial ECG Normal Initial ECG Abnormal Late Rhythm Problems Purdue and Hunt 1000 48 40 8 0 Wrobel < 1000 35 31 4 0 Moran and Munster 110 – 850 42 40 2 0 Kirschmair and Denstl 220 – 900 19 15 4 0 Fatovitch and Lee 240 20 18 2 0 Cunningham 240 70 59 11 0 Kreinke and Kienst > 220 31 29 2 0 Bailey, et. al. 120 & 240 120 119 1 0 Arrowsmith > 220 73 69 4 0
  • 58. Cardiac Monitoring • Not justified in asymptomatic patient • Not justified in patient with only cutaneous burn • Not justified in patient who has normal ECG after a 120v or 240v injury
  • 59. Felt current pass through body Current passed through heart Was held to source of electric current Held to source for >1 second Lost consciousness Voltage source >1000 volts Cardiac monitor for 24 hours No No No No
  • 60. Burn marks on skin Evaluate and treat burns Thrown from source Evaluate and treat trauma Pregnant BENIGN SHOCK Reassure and release No No No Evaluate fetal activity
  • 61. Indications for Heart Monitor 1. Loss of consciousness 2. Cardiac dysrhythmia 3. Abnormal ECG 4. Abnormal mental status or physical examination 5. Injury expected to cause hemodynamic instability or electrolyte problem Fish RM. J Emerg Med. 2000 Feb;18(2):181-7.
  • 62. Failure to Document Normals Conditions that can arise after initial presentation include • Cataracts • Vascular occlusion • Compartment syndrome • Brain and spinal cord dysfunction
  • 63. Summary • Electrical injuries involve multiple body systems • Entry and exit wounds fail to reflect true extent of underlying tissue damage • Electrical current may cause injuries distant from its apparent pathway through the victim
  • 64. Summary • Controversies exist regarding indications for admission and cardiac monitoring following low voltage injuries
  • 65. Thank you