1. Project: Ghana Emergency Medicine Collaborative Document Title: Electrical and Lightening Injuries Author(s): Rashmi Kothari, M.D. 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. Rashmi U. Kothari MD Associate Professor KCMS/MSU BotMultichillT, Wikimedia CommonsWikimedia Commons Maksim, Wikimedia CommonaWikimedia Commona 3

4.  Electrical Injuries  Low Voltage  High Voltage  Lightening Injuries  Pathophysiology  Complications  Management 4

5.  Electrical burns:  1000 deaths annually  4-6.5% of all burn admissions  Almost all involve litigation (negligence, product liability, workmen’s compensation)  Lightening Injuries:  50-300 deaths annually  4-5 X as many lightening strikes  2 nd leading cause of weather related deaths 5

6.  Voltage: electrical pressure in a circuit  Resistance: tissues resistance to flow of electrons  Current: amount of energy in a circuit  Current = Voltage/Resistance 6

7. Current Strength (I)= Voltage/Resistance Thermal Power (J)=(I) 2 X Resistance X duration Severity =(Voltage) 2 X duration Resistance 7

8.  Current (Amperage)  Type of current  Resistance  Duration of contact  Voltage  Pathway of current 8

9. Physical EffectMilliamperes (mA) Tingling1-4 Let go current Children4 Women7 Men9 Freezing to circuit10-20 Thoracic muscle tetany20-50 Ventricular fibrillation60-120 *at 50-60 Hz (frequency of household AC current) 9

10.  Which is more dangerous?  AC 3X more dangerous than DC  How do their mechanisms of injuries differ?  AC causes tetany  DC throws you away 10

11.  Source:  Power lines  Household current  Clinical Presentation  3X more dangerous than DC  Continuous tetany  V-fib  Contact wounds 11

12.  Source:  Power generating stations  Long distance transmission lines  Submarine cable connections  Portable generators  Clinical Presentation  Single contraction  Associated blunt trauma  Arrhythmias cardiac phase dependent  Entrance/Exit wounds 12

13.  Amount tissue resists flow of electrons  resistance the greater potential to convert electric energy to heat energy  Tissue resistance changes with charring 13

14. Resistance of Body Tissues Least Nerves Blood Mucous membranes Intermediate Dry skin Most Tendon Fat Bone 14

15. TissueResistance (W/cm 2 ) Calloused hands1-2 million Soles of feet100-200K Other skin10-40K Sweaty skin2500 Bathtub1200-1500 Mucous Membranes100 15

16. Injury=Voltage 2 x Duration Resistance Dry hands vs. Wet hands 2,000,000 W/cm 2  1,200 W/cm 2 16

17.  Child puts key in socket  110V AC current  Dry skin (10-40K W/cm 2 )  current = 2.75-11 mA  Child in tub, key in socket  110V AC current  Wet skin (1,200-1,500 W/cm 2 )  current =73-92 mA Injury=(V) 2 X t R Chris Phan, FlickrFlickr 17

18. Physical EffectMilliamperes (mA) Tingling1-4 Let go current Children4 Women7 Men9 Freezing to circuit10-20 Thoracic muscle tentany20-50 Ventricular fibrillation60-120 *at 50-60 Hz (frequency of household AC current) 2.75-11 73-92 18

19.  duration destruction  AC increases duration due to grip strength 19

20.  Difference in electrical potential between two points  Low Voltage <500-1000 V  24 V=Long distance communication lines  65 V Telephone lines  110-220 V Household current  High Voltage >500-1000 V  Transformers, Power lines 20

21.  Determines tissue at risk  Thorax: V-fib, myocardial damage  Head: resp. arrest, seizure, paralysis  Eye: cataracts Anetode, Wikimedia CommonsWikimedia Commons 21

22.  Current (Amperage)  Type of current  Resistance  Duration of contact  Voltage  Pathway of current 22

23.  Usually minor:  Tingling  Local contact burns  Exception:  Lower resistance (moisture)  Ocular involvement  Oral injuries  Appliance capacitor (microwave, monitor, TV)  Pregnancy Source Undetermined 23

24.  Child bites electrical cord  Arc burn  Electricity jumps from high to low potential region  High temperatures  Delayed bleeding  Cosmetic & Dental deformity Source Undetermined 24

25.  Evaluate for any burns  Cardiaorespiratory complaints  ECG/monitor  Isoenzymes  Consider ocular involvement  Ophthalmology referral  Short ED observation  Discharge home 25

26.  Devastating burns  Electrical injuries  Blunt trauma  Renal complications Xy01, Wikimedia CommonsWikimedia Commons Source Undetermined 26

27.  Direct contact  Electrothermal heating  Indirect contact  Arc  Flame  Flash 27

28.  Heating of tissue secondary to current  Low voltage injuries with local burns  High voltage  Damage anywhere along current path  Prolonged exposure due to inability to release 7mike5000, Wikimedia CommonsWikimedia Commons Source Undetermined 28

29.  Spark between unconnected objects  Most destructive indirect burn  Temperatures of 2,500° C  Oral cord burns  Lightening strikes Achgro, Wikimedia CommonsWikimedia Commons Source: Brown Medical School 29

30.  Occur when external objects catch on fire and cause the burn.  Most commonly, clothes 30

31.  Current flashes over the body, rather than going through the tissues  Seen primarily in lightening injuries. Source Undetermined 31

32.  Head  Cardiac  Skin  Extremities  Neurological 7mike5000, Wikimedia Commons Wikimedia Commons 32

33.  Common point of contact  Burns  Blunt trauma  Cataracts  Days, weeks, months  Complete eye exam  Outpatient Ophthalmology Batholith, Wikimedia Commons Wikimedia Commons EyeMD, Wikimedia Commons Wikimedia Commons Source Undetermined 33

34.  Arrhythmias  V-Fib or Asystole  Sinus Tach/ A-fib/BBB  ECG changes  ST elevation  Prolonged QT  AMI  Rare  Elevation of CPK & CPK MB% 34

35.  Common contact sites  Head/hands/heels  Internal flow of current  Deep muscle injury  Can’t estimate damage from surface burn Guyprocter, Wikimedia Commons Wikimedia Commons Magnus Manske, Wikimedia Commons Wikimedia Commons 35

36.  Damage distant to skin burns  Arterial injury  High flow  delayed injury  Venous injury  Slow flow  acute thrombosis & edema  Severe muscle necrosis  Fasciotomy  Rhabdomyolysis  Kissing burns Source Undetermined 36

37.  Transient loss of consciousness  Concussive type symptoms  Difficulty concentrating  Dizziness  Flat affect  Spinal Injuries  Fractures/ligamentous injuries Source Undetermined 37

38.  Immediate  Weakness/parasthesias within hours  Lower extremity >upper extremity  Good prognosis  Delayed  Days to years  Ascending paralysis/ALS/Transverse myelitis  Motor>sensory  Poor prognosis 38

39.  Current impulse  High voltage/Short duration  Very minimal skin damage  Flash over Maksim, Wikimedia CommonsWikimedia Commons 39

40.  Direct strike  Orifice entry  Contact  Side flash, “splash”  Ground current or step voltage  Blunt trauma Ambika Kilaparthi, FlickrFlickr 40

41.  Enters eyes, ears, mouth  High incidence of:  cataracts/uveitis/detached retina/optic atrophy  ruptured TM/hearing loss, tinnitus, vertigo 41

42. object  person  ground 42

43. Source Undetermined 43

44.  Thrown 2° to massive contraction of current passing through body  Air superheats then quickly cools  explosive force 44

45.  Cardiovascular  Cardiac arrest 2° electrical shock or vascular spasm  Respiratory arrest > Cardiac arrest  Skin  <5% deep burns  Linear lesions  Punctate lesions  Feathering  Thermal 45

46. Source Undetermined 46

47.  Extremities  Transient vasospasm  Cold, blue, mottled, pulseless  Resolves within hours 47

48.  Common  LOC, confusion, antegrade amnesia  Paresthesias  Less common  ICH, seizure, paraplegia  Delayed muscle atrophy 48

49.  Keraunoparalysis  2/3 of patients  Extremities mottled, cold, blue  Legs>arms  Transient (clears w/in hours)  Vascular spasm & sympathetic instability 49

50.  Evaluate for other injuries  Other burns  Ocular involvement  Admission  Pain or poor oral intake  Poor compliance or follow-up  Discharge home  Educate parents regarding bleeding  Burns follow-up  Dental referral  ±Plastics referral  ±Ophthalmology referral 50

51.  ABC  Fluids & foley  Urine output 0.5-1.0 cc/kg/hr  Heme in urine 1-1.5 cc/kg/hr  Cardiac monitor/ECG  Trauma Evaluation  Labs  CBC & CMP  Serum Myoglobin, U/A 51

52.  Trans-abdominal current  Hepatic, lipase, PT/PTT  Altered MS  CT head  Cardio-respiratory complaints  Troponin, CPK with Isoenzymes  Poor correlation: CPK MB, Angio, echo, thallium studies with AMI 52

53.  Status post arrest  Concomitant severe injuries  Loss of consciousness  Suspicion of conductive injury  Abnormal ECG or dysrhythmia  History of CAD  Significant CAD risk factors  Chest pain 53

54.  Inhospital  Trauma  Burns/Plastics  Outpatient  Ophthalmology  Neurology 54