Electrical Injuries CHRIS PONDER PGY 3

No Disclosures

Objectives  Epidemiology  Physics  Classification of Injury  Mechanisms of Injury  Electrical Weapons  Management

Epidemiology  Electrical burns account for 3-4% of all burns  > 3000 admissions to burn units annually  Burns in Children are accidental  < 6 are electoral cords or outlets  Oral burns are common  > 6 are power lines while climbing  Burns in Adults are work related  2 nd leading cause of occupational deaths  >90% male victims

Definitions  Current (I)  Volume of Electrons travelling between two points every second  Voltage (V)  The force that drives the electrons across the potential difference  High Voltage is > 1000V  Low Voltage is < 1000V  Resistance (R)  The hindrance to the flow of electrons

Current Alternating Current  Direction changes cyclically  Found in households, businesses, industries  Household current is 60hz Direct Current  Direction of the current remains constant  Batteries, Railroads, Cars, Lightning

Physics  Ohm’s Law  Voltage (V) = Current (I) x Resistance (R)  V = I x R  Joule’s Law of Heating  Heat (P) = Current (I) x Voltage (V) x Time of contact (t)  P = I x V x t  P = I² x R x t

Resistance  P = I² x R x t  Heat and Resistance are proportional Greatest to least resistance 1. Bone 2. Fat 3. Tendon 4. Skin 5. Muscle 6. Blood Vessels 7. Nerves

High or Low Voltage

Mechanisms of Injury 1. Direct effect on tissues 1. Arrhythmias 2. Apnea 2. Blunt mechanical injuries 1. Muscle contraction 2. Falls 3. Conversion of electrical to thermal energy 4. Electroporation 1. Disruption of cell membrane 2. Loss of ion gradient

Respiratory  Inhibition of CNS Respiratory Drive  Paralysis of Respiratory Muscles  Cardiorespiratory arrest from V.Fib or Asystole

Cardiovascular  Arrhythmias  V. Fib most common from AC  Asystole most common from DC or high-voltage AC  Conduction Abnormalities  Sinus Bradycardia  High degree AV blocks  Myocardial Injury  From electro-thermal conversion and electroporation  Ck-MB is often elevated, Troponin not well studied in this setting  Vascular Injuries include coagulation and aneurysm formation

Neurological  Loss of Consciousness  Autonomic Dysfunction  Respiratory Depression  Memory Loss  Sensorineural Hearing Loss

Skin 1. Electro-thermal burns 2. Arc burns 3. Flame burns

Electro-thermal burns

Arc Burns

Flame Burns

Musculoskeletal  Joint dislocation  Muscular Thermal Injury  Rhabdomyolysis  Compartment Syndrome

Electrical Weapons

 NO evidence of dangerous lab abnormalities, physiologic changes, immediate or delayed cardiac ischemia or arrhythmia for exposures 15 seconds or less  No need for diagnostic testing in otherwise asymptomatic alert patients  Fatal arrhythmia has been reported in some cases  Concurrent intoxication with cocaine, PCP, Meth can increase risk  Preexisting cardiovascular disease may increase risk  Injuries may occur after falling from being stunned

Management  Cardiopulmonary Resuscitation  Most victims are young and have good outcomes  Prolonged CPR regardless of initial rhythm  In mass casualty events triage protocols should be reversed  Cardiac Assessment  Evaluation with ECG AT LEAST for every High Voltage injury  Hemodynamic monitoring as high incidence of arrhythmia  CK-MB is poor and Troponin has not been studied

Management  Fluid Resuscitation  Burn percentage is severely underestimated  Parkland formula can not be used  Maintain UOP > 1cc/kg/hr for adults  Abdominal Compartment Syndrome  Gastrointestinal Injuries  Rare, however case reports of perforations  Vascular injuries

Disposition  High voltage injuries  Disposition based on injuries  If asymptomatic STILL hours of cardiac monitor  Low voltage injuries  Disposition based on injuries  If asymptomatic no tests required and can be discharged

Sources  Chalkias A, Iacovidou N, Xanthos T. Continuous chest compression pediatric cardiopulmonary resuscitation after witnessed electrocution. Am J Emerg Med. 2014;32:(6)686.e1-2. [pubmed]pubmed  Marques EG, Júnior GA, Neto BF, et al. Visceral injury in electrical shock trauma: proposed guideline for the management of abdominal electrocution and literature review. Int J Burns Trauma. 2014;4:(1)1-6. [pubmed]pubmed  Schwarz ES, Barra M, Liao MM. Successful resuscitation of a patient in asystole after a TASER injury using a hypothermia protocol. Am J Emerg Med. 2009;27:(4)515.e1-2. [pubmed]pubmed  Spies C, Trohman RG. Narrative review: Electrocution and life-threatening electrical injuries. Ann Intern Med. 2006;145:(7) [pubmed]pubmed  Rechtin C, Jones JS. Best evidence topic reports. Bet 2: Cardiac monitoring in adults after taser discharge. Emerg Med J. 2009;26:(9) [pubmed] Roberts S,pubmed  Meltzer JA. An evidence-based approach to electrical injuries in children. Pediatr Emerg Med Pract. 2013;10:(9)1-16; quiz [pubmed]pubmed