Bodies from Fire and Asphyxia Flashcards

1
Q

What is the incipient phase of fire dynamics?

A

Fuel supply heated and ready to burn

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2
Q

What happens in the emergent smouldering phase of fire dynamics?

A

Inefficient combustion-smoke

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3
Q

What happens in growth flaming phase of fire dynamics?

A

Efficient burning

Intensity doubles for each 10 degrees rise in temperature

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4
Q

What happens in the oxygen regulated smouldering phase of fire dynamics?

A

Free burning depletes available oxygen
Glowing combustion
Superheated gases and smoke

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5
Q

What are the 4 phases of fire dynamics?

A
  1. Incipient
  2. Emergent smouldering
  3. Growth flaming
  4. Oxygen-related smouldering
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6
Q

What is the term for when a fire produces radiant heat and hot gases which brings nearby combustible objects to ignition temperature, then to ignite?

A

Flashover

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7
Q

`What temperatures can flashovers produce?

A

500-600

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8
Q

What is the term for if the fires oxygen supply is depleted, flames die out, residual heat, gases and smouldering remains so reintroduction of oxygen to fire causes explosive ignition?

A

Backdraft

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9
Q

Name three primary identifiers for victims in fire?

A

Fingerprinty comparison
Dental comparison
DNA- need comparison sample

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10
Q

Name three secondary identigiers for victims of fire?

A

Medical records
Radiological records
Medical devices and implants

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11
Q

Name some tertiary identifiers for victims of fire?

A

Circumstances, personal items, blood group and type

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12
Q

If victim was alive during fire what might be found on autopsy?

A

Soot creases around eyes
Soot around nostrils, mouth, airways
tehrmal injury to laryngeak mucosa
congestion of lungs

(CO and cyanide levels)

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13
Q

What czuses laryngeal injury?

A

Dry air bigger than 150 degrees. More common with steam inhalation (x4000 heat capacity of dry air)

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14
Q

What causes cardiac arrest with thermal airway injury?

A

Reflex vagal inhibition

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15
Q

What can cause tracheobronchial necrosis?

A

Thermal airway injury

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16
Q

What are normal levels of CO?

A

less than 1ppm- present in smokers and city dwellers

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17
Q

If CO bigger than 50% whast happens?

A

Fatalities- can be low as 30 in severe natural disease/children/elderly

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18
Q

What colour is carboxyhaemoglobin lividity?

A

Cherry red

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19
Q

Where will a 1-3 nm superheated soot particle reach?

A

Alveoli. Seen on histology.

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20
Q

What does cellulose, polyurethanes and acrylonitrile release?

A

Nitrogen dioxide

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21
Q

What does PVC release?

A

Hydrogen chloride

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22
Q

What does burning wool, silk, nylons and polyurethanes release?

A

Hydrogen cyanide

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23
Q

What does burning wool, cotton, paper, plasters, wood, nylon and polyester resin release?

A

Aldehydes

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24
Q

What does burning petrol, plastics and polystyrene release?

A

Benzene

25
Q

What does burning melamine and nylon release?

A

Ammonia

26
Q

Give an example of a radiany burn?

A

Sunburn- no direct contact

27
Q

Describe a flash burn?

A

Uniform burning of exposed areas

28
Q

What type of burn causes damage in less thsan one second for temperatures above 70?

A

Contact burn

29
Q

What causes a scald?

A

Hot liquid or vapour

30
Q

Wht degree of burns are superficial?

A

First - heals without scarring

31
Q

What degree of burns are full thickness?

A

Third- epidermis, dermis and subcut tissue

32
Q

Ard third degree burns sore?

A

Painless, dry and white and leathery with black/brown eschar

33
Q

What type of burns do scalds gibe?

A

First or second. Well demarcated.

34
Q

What colour does hair go after mild fire?

A

Ginger

35
Q

In fire what mimics an extradural haematoma?

A

Heat haematoma. Blood extruded from venous sinuses. Altered blood colour and texture.

36
Q

For electrical injuries where are burns seen?

A

At entry and exit points

37
Q

What burn is described with:

collapsed blister
surrounding zone of erythema
peripheral zone of pallor
metallisation of skin

A

Firm/direct contact electircal burn

38
Q

How far can 100 000v leap?

A

35 cm

39
Q

What melts epidermal keratin which then cools to form a hard brown noduel?

A

Arcing of electricity

40
Q

What produceds crocodile skin?

A

High voltage producing multiple sparks from loose contact

41
Q

What are litchtenberg figures from?

A

Lightening

42
Q

What do acid burns cause?

A

Coagulative necrosis- denaturation of proteins and enzymes

43
Q

What penetrates deeper acid or alkali?

A

Alkali- cement, drain cleaner, ammonium hydroxide cleaner

44
Q

What causes liquefactive necrosis?

A

Alkali- grey/white mucoid burns

45
Q

Define asphyxia?

A

Interference with oxygenation

46
Q

Give an example of impaired peripheral utilisation of oxygen?

A

Cyanide poisoning

47
Q

Severe hypoxia levels?

A

Less than 40mmHg

48
Q

Can you diagnose hypoxia PM?

A

No because blood gas levels change within minutes of death

49
Q

What does arterial occlusion to brain cause?

A

Cerebral hypoxia

50
Q

What does venous occlusion to brain cause?

A

Circulatory stagnation

51
Q

What are 5 stages of asphyxiation?

A
  1. Struggle
  2. Quiescence
  3. Convulsions
  4. Apnoea
  5. Anoxia and death
52
Q

What happens to heart in asphyxia?

A

Engorgement of right heart chambers

53
Q

Where is congestion and oedema seen?

A

Upstream of obstruction

54
Q

What is cyanosis obscured by?

A

Development of hypostasis

55
Q

When can inhalation asphyxia occur surprisingly?

A

Vomitus- occurs agonally, PM

56
Q

What is circmoral and circumnasal pallor seen in?

A

Asphyxia

57
Q

Where are petechial haemorrhages seen in asphyxia?

A

Eyelids, tarsal plates, lips and gums, behind ears, heart, lungs

58
Q

Other than asphyxia what else can you see petechial haemorrhages in?

A

Coughing
Vomiting
Crush/entrapment
Cardiopulmonary resuscitation

59
Q

Pressure on baroreceptors leads to increase in sinus BP, decreased HR, vascular dilatation and decreased BP

A

Vagal inhibition