Electrical Death. National Forensic Service Gwangju Institute. Forensic Medicine Division. Na, Joo Young

Transcription

1 Electrical Death National Forensic Service Gwangju Institute Forensic Medicine Division Na, Joo Young

2 He directeth it under the whole heaven, and his lightening unto the ends of the earth. After it a voice roareth: he thundereth with the voice of his excellency; and he will not stay them when his voice is heard. Got thundereth marvellously with his voice; great things doeth he, which we cannot comprehend. Job 37:3-5 그 소리를 천하에 펼치시며 번갯불을 땅 끝까지 이르게 하 시고, 그 후에 음성을 발하시며 그의 위엄 찬 소리로 천중 을 치시며 그 음성이 들리 때에 번개를 멈추게 아니하시느 니라. 하나님은 놀라운 음성을 내시며 우리가 헤아릴 수 없 는 큰 일을 행하시느니라. 욥기 37:3-5

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4 Introduction Basic, general description of electricity Electrocution Low voltage High voltage Lightning Case

5 Definition Electricity Movement of electrons through a circuit Resistance: Object s ability to avoid becoming part of an electrical circuit Voltage: Potential difference between two points within an electrical circuit Low voltage 1000 V High voltage > 1000 V Current: number of electrons flowing within an electrical circuit

6 General descriptions Manmade electricity Alternating current (AC): alternates its direction within a circuit at regularly occurring intervals Hertz (cycles per second): frequency at which change occurs Most household and industrial electricity Direct current (DC): one direction within a circuit Battery-operated electrical devices Cardiac defibrillators, certain welding machines Natural forms of DC: static electricity, lightning Generally, DC is considered less dangerous than AC. But, death can still result from DC.

7 Electrocution Only death? vs More generalized definition, Any situation where a person becomes incorporated into an electrical circuit Fatal electrocution Electric shock burns In order for an electrocution to occur, Source of electricity: sufficient force to overcome the resistance of the body Relatively low-resistance pathway to ground

8 Fatal electrocution Whether or not an electrocution result in death Amount of current passing through the body Effects of that current on the anatomic structures through which the current travels: heart Location of the entry and exit d/t tend to take the shortest pathway between the point of entry and ground Seconds Possibly, no external or internal physical evidence of electrocution

9 Symptoms Overall effects of an electrocution: proportional to the amount of current amp tingle sensation 0.02 amp can muscular paralysis 0.04 amp loss of consciousness can occur 0.1 amp fatal arrhythmia (VF) can occur 0.2 amp ventricular standstill can occur (common household fuse, around 20 amps: to prevent fires, not electrocutions)

10 Internal organs and tissues Vey low resistances because of their high water content, with some as low as 500 ohms With 220 V household current, Dry thick skin (palm) 100,000 ohms Dry thin skin 30,000 ohms Wet palm skin 1000 ohms Wet thin skin 100 ohms amps amps 0.22 amps - heart standstill 2.2 amps - - heart standstill

11 Mechanism of death in electrocution May remain conscious for several seconds Shout out Move away from Even unplug or turn off the source of the electrocution

12 Mechanism of death in electrocution Electrically-induced cardiac arrhythmia Muscular paralysis (including the diaphragm) asphyxial mechanism Head (primary site of the electrical current) CNS respiratory center paralysis High voltage electrocution severe electrothermal injuries Secondary injuries to die

13 Scene investigation

14 Scene investigation Safety!! To discover How the electrical circuit was completed from the source, through the victim, and to the ground Cloth: areas of melting, other thermal damages

15 Autopsy findings

16 Low voltage A significant number of low-voltage electrocution victims have no or very subtle electrical injuries.

17 Low voltage Electrical burn If enough energy is transferred onto the skin for a long enough period of time, Typically at the site of entry But, can also at the site of grounding (exit site) From quite subtle To rather obvious

18 From quit subtle White blisters Dark pinpoint sites of burnt or melted keratin Small white blisters at entry site in low voltage Multiple crater-like area of melted keratin

19 To rather obvious Larger blister / Red-yellow abrasion-like injuries Target-like appearance injuries Concentric zone of white tissue, red tissue, and possibly even brown or charred tissue Peripheral zone of blanched skin

20 High voltage All high-voltage electrocutions result in the presence of electrical injuries. May jump from source Distance of jump: increased with voltage 100,000 V: jump about 35 cm

21 High voltage Characterized by charred tissue, surrounded by and area of blanching and a peripheral rim of red skin

22 High voltage In some cases, dark pinpoint spark injuries

23 Other features Metallization Small traces of metal from the electrified source transferred to the skin (or clothing) Potassium ferrocyanide: applying to the skin black/purple discoloration, indicating that metal has been deposited on the skin Can demonstrated by chemical testing or visualised by scanning electron microscopy. Electrical petechiae Pinpoint hemorrhages in some electrocutions Both low- and high voltage On the eyelids, conjunctivae, pleural surfaces, epicardium

24 Other features Microscopically Consistent with thermal damage Nuclear streaming Thinned, elongated, and aligned in parallel with adjacent nuclei Metal staining: iron, copper

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27 lightning

28 Lightning Very high-voltage direct current electricity Around 100 lightning strike deaths per year in the USA Kill the persons by Direct strike side flash Strikes another object and the jump to the victim Conduction through another object

29 Lightning Cardiac arrest and/or electrothermal injuries Force of a lightning Rip the clothing off of a victim Metal objects on or in the clothing, or on the body (jewelry) can shown evidence of arc marks Charring or even melting

30 Lightning Spectrum of injuries Various From virtually non to near total obliteration from massive electrothermal forces Severe charring and deep burns are relatively uncommon. Injuries can mimic other electrical injuries. Relatively superficial injuries (some of which are discolored yellow) are not infrequent.

31 Lightning Arborescent pattern of the skin: Representing a fern or tree-like pattern of pink skin discoloration Frequently transient (< 24 h if survival) May represent intravascular hemolysis within the subcutaneous capillary/venous blood vessels

32 Case review

33 31세 남성 변사자는 OO 회사 생산과 작업근로자인 자로, 20OO년 6월 20일 10:50경 경 기도 김포시 OO공장 내에서 래미콘 생산 시설인 뱃쳐블랜트 1호기 내 콘베어 벨트 중간 스크린 상부 보수작업을 하던 중 용접봉이 변사자의 상체부위에 붙 은 채 어 하는 소리를 내자 동료가 발견하고 생산과장에게 알려 전기를 차단 하고 후송하였으나 사망한 것임. 작업 동료의 말에 의하면, 공장 전체에는 마이너스 전류가 흐르고 있고, 용접 봉은 플러스 전류로서 작업 중 용접기 홀더를 변사자에게 건네준 후 잠시 후 용접봉이 변사자의 상체부위(구체적인 부위는 기억나지 않음)에 붙은 채 어 하는 소리를 냈다고 함.

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39 사인(Cause of Death, COD) : 감전사 사망의 종류(Manner of Death, MOD) : 사고사

40 Screaming, swearing, or shouting followed by collapse Early or partial development of rigor mortis