asphyxia

what is asphyxia

lack of pulsation, indicated through increased venous pressure

medicolegal issues with asphyxia

proving it happened

time

force

clinical stages of asphyxia

• effort to breath

• laboured respiration

• loss of consciousness

  • paired with convulsions, incontinence, vomiting

• death

classic signs of asphyxia

facial congestion and oedema

petechia haemorrhages

cyanosis

what is suffocation

obstruction of respiratory orifices

• o2 supply is reduced/ blocked

  or

• when the mouth or nose has been blocked

  • common with suicide

common ways suffocation occurs

agricultural/ industrial

death is often rapid

usually no signs

signs of suffocation via blockage of nose or mouth

• common in suicide

• injuries to inside of lips from being pushed against teeth is associated with homicide not suicide

• no positive findings on babies and old people (lack of teeth)

what is chocking

internal obstruction of upper airway

symptoms of chocking

rapid death

object present in the airway eg food, teeth, vomit/ blood

no positive findings of pressure

common in older people who develop problems with swallowing

aspiration of vomit- causes

anaesthetics, drugs and alcohol or illnesses

autopsy findings often inconsistent because of stomach regurgitation that often occurs at death p

pressure to the neck

via

• manual strangulation

• ligature strangulation

• hanging

signs of manual strangulation

finger nail marks

finger tip bruises

can have no marks if strangled by a headlock

signs of ligature strangulation

straight line horizontally around neck

signs of hanging

rise to the point of suspension

weight of the body often pulls to a point of suspension

rarely breaks the neck

often found touching the ground

effects of having the neck squeezed

quick effects:

trachea; larynx

jugular veins (reduced venous return)

carotid arteries (have to have been squeezed very hard)

baroreceptors in carotid bodies

baroreceptors

sensitive to pressure- so react to manual pressure

commonly used as defence for lack of intention to kill

traumatic asphyxia definition

inability of the chest to move

caused by…

• stadium disasters

• overturned vehicles

• industrial accidents

• postural asphyxia (linked to intoxication)

external signs of traumatic asphyxia

-              injuries from compressing agent

-              congestion; cyanosis; petechiae

drowning definition

fluid enters into the airways and replaces the air

• usually accidental and most common in males, children and those intoxicated

effect of drowning on the body

has an effect on osmosis in the body which means the blood becomes diluted and leads to cardiac arrest

survival percentages of drowning

salt water- 80%

freshwater - 50%

but is very dependent on initial resuscitation

morbidity of drowning

chronic brain damage

identification of drowning as a cause of death by post mortem

lungs containing water- not useful because of water logging

froth out of nose and mouth is good but is a transient factor which is destroyed by resuscitation and decomposition

overinflation of the lungs- useful but may also be because of asthma

main issues of asphyxia

cause of death and injury

proof

time

force