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Asphyxiation

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Asphyxiation types:
* suffocation
* strangulation
* chemical asphyxiation
Definition of Asphyxiation:
* decreased oxygenated blood to the brain
* mechanical obstruction of blood vessels to brain
* airways closed
Types of Suffocation:
* entrapment/environmental
* smothering
* choking
* mechanical asphyxia
* suffocating gases
What leads to entrapment and environmental suffocation?
* inadequate oxygen in environment
* certain industries such as sewer and subway systems
Will you be able to know the cause of death with autopsy alone in an environmental suffocation?
* no
* need to know circumstances of scene investigation and interviews
Definition of Smothering:
* mechanical obstruction or occlusion of the external airway
What can be declared homicidal, suicidal or accidental mechanical obstruction of external airways?
* smothering
What is an example of accidental smothering?
* child co-sleeping with an adult
Definition of Choking:
*obstruction of nasal passages
* obstruction of internal airways
Example of natural choking:
* epiglottitis
Example of Homicidal choking:
* movement of gag
Example of Accidental choking:
* inhalation of food or other foreign object
Definition of Mechanical asphyxia:
* pressure on outside of body prevents respiration
What type of mechanical asphyxia are there?
* traumatic asphyxia
* positional asphyxia
* riot crush asphyxia
Defintion for traumatic asphyxia:
* heavy weight compresses the chest or upper abdomen
What is present during a traumatic asphyxia?
* compression
* petechia
What can lead to traumatic asphyxia?
* burking
* overlaying
Definition of positional asphyxia:
* associated with drugs and alcohol
* usually accidental
* trapped in position which impairs breathing
What are clinical signs of positional asphyxia?
* congestion
* cyanosis
* petechiae
Gases displace oxygen from the atmosphere are called?
* suffocating gases
What are examples of suffocating gases?
* carbon dioxide
* methane
What causes unconsciousness in seconds and eat in minutes?
* reduction of atmospheric oxygen in less than 25%
Are there specific autopsy findings in suffocating gases incidents?
* no
Types of strangulation:
* hanging
* ligature strangulation
* manual strangulation
What is used for ligature strangulation?
* tie and rope
What is used for manual strangulation?
* hands and arms
What defines hanging?
* compression of the neck by noose or other object by weight of the body
Hanging may be what type of suspension?
* complete - feet of the ground
* incomplete - feet partially on the ground
What amount of pressure is needed for hanging - carotids?
* 11 lbs
What amount of pressure is needed for hanging - jugular veins?
* 4.4 lbs
What amount of pressure is needed for hanging - vertebral arteries?
* 66.1 lbs
What amount of pressure is needed for hanging - trachea?
* 33 lbs
Will you find petechia under complete suspension?
* no
Definition of hanging?
* ligature proceeds upward with a point of suspension
* protrusion and drying of tongue
What can be seen in a hanging victim?
* ligature mark - possibly
* petechia - possibly
* tardieu spots
Can you possible fracture neck structures in a hanging incident?
* yes
Risk of fractures in a hanging victim increase with what?
* age
Judicial hangings:
* fx of C2
* injury to spinal cord
* fx hyoid bone, thyroid cartilage
* laceration of vertebral artery
How fast does one lose consciousness in a judicial hanging?
* immediately
Ligature strangulation is usually the result of __?
* homicides
What is an example of ligature strangulation that is accidental?
* tie caught in shredder
Ligature marks:
* highly variable
* usually horizontal
* dry and parchment like
What type of injury comes with ligature strangulation?
* minimal internal injury
* hemorrhage in strap muscles
Fractures of hyoid bone and thyroid cartilage in ligature strangulation are ____?
* uncommon
Pseudo ligature marks are seen in ___?
* infants
* elderly
Manual strangulation is the result of ___?
* compression of the neck by hand, forearm or limb
In manual strangulation there is an occlusion of the ___ arteries?
* carotid
Vasovagal reaction:
* good strong hold -> loss on consciousness within 10 seconds -> need to hold for death to occur, if let go early, person will recover
What is seen in manual strangulation?
* cyanosis
* petechiae
* congestion
* pulmonary edema
Can you determine which had was used for manual strangulation?
* no
Definition of chemical asphyxiation:
* prevents utilization of oxygen at a cellular level
What chemicals can lead to asphyxiation?
* carbon monoxide
* hydrogen cyanide
* hydrogen sulfide
Definition of carbon monoxide:
* colorless
* odorless
* tasteless
* competes with oxygen for binding sites on oxygen carrying proteins
What a medical signs of carbon monoxide asphyxiation?
* cherry red discoloration of tissue
* necrosis of globes pallidus, cerebral cortex, hipocampus
Definition of hydrogen cyanide:
* produces cellular hypoxia by competing with the ferric iron atom of intracellular cytochrome oxidase
* smells of almonds
* burns gastric mucosa
* pink discoloration of tissue
Where is hydrogen cyanide used?
* suicides
* gas chambers
How fast does one die with hydrogen cyanide poisoning?
* no instantaneous
Hydrogen sulfide:
* produced by fermentation of organic matter
Where is hydrogen sulfide found?
* sewers and cess pools
Low doses of hydrogen sulfide smell like ___?
* rotten eggs
High doses of hydrogen sulfide paralyze ___?
* olfactory nerves
How fast does death occur in hydrogen sulfide poisoning?
* high doses - fast
Auto-erotica asphyxia?
* hanging
* anoxia increases sexual arousal
* ligature often padded and self rescue device present
Crucifixion:
* nailed to cross with wrists and feet
What causes death in crucifixion?
* shock
* dehydration
* asphyxiation
* exhalation difficult