ppt

1. ASPHYXIANTS
NAGASHREE S
3RD BAMS

2. CONTENTS
• Introduction
• Classification
• Properties
• Sources
• Mode of action
• Clinical features
• Management
• Autopsy findings
• ML importance
• References

3. These are the agents which cause asphyxia
Asphyxiants deprive the body of oxygen
Classification……
1. Simple Asphyxiants
2. Respiratory Asphyxiants
3. Systematic Asphyxiants
4. Volatile Asphyxiants

4. SIMPLE ASPHYXIANTS……..
These are the inert gases and when these gases are breathed
in high concentrations,act mechanically by displacing or
excluding oxygen
Ex;
Nitrogen
Butane
Ethane
Methane

5. RESPIRATORY ASPHYXIANTS
These agents,when inhaled cause destruction of the
respiratory tract or lung or both and cause
inflammatory changes
Ex;
Ammonia
Chlorine
Smoke
Formaldehyde

6. SYSTEMATIC ASPHYXIANTS
These agents cause systemic toxicity ex ;CO ,smoke
Volatile compounds ;these agents act as an anesthetic
agents
Ex, Aliphatic hydrocarbons

7. CARBON MONOXIDE……
Properties
• It is colourless
• Odouless ,tasteless
• Soluble in water
• Burns with blue
flame

8. SOURCES OF CARBON MONOXIDE
• Auto mobile exhaust
• Tobacco smoke
• Generates in gun
powder
Mines,and whenever there
is incomplete
Combustion of wood
,charcoal,kerosene,etc

9. MECHANISM OF ACTION
Carbon monoxide has 230 to 270 times greater affinity for
hemoglobin that that of oxygen thus it displaces oxygen from
its combination with Hb and forms relatively stable
compound known as carboxyhaemoglobin .Formation of
carboxy hemoglobin results in reduced arterial oxygen
content and causes tissue anoxia
• The resultant effect is decreased ability of blood to carry
oxygen and deliver to the tissues

10. Clinical features
Head ache
Confusion
Dizziness
Weakness
Palpitation
Visual distrubance
Parkinsonism

11. MANAGEMENT
• Remove patient from vitiated environment
• Mannitol for cerebral edema
• Convulsions treated with benzodiazepines
Oxygen administration.Hyperbaric oxygen is
considered to be beneficial

12. AUTOPSY FINDINGS
• Pinkish discoloration of
skin and mucosa
• Pinkish colour postmortem
lividity
• Features of asphyxia
• Pulmonary edema
• Froth at mouth and
nostrils

13. MEDICO LEGAL IMPORTANCE
• Accidental death
• Suicide-it is popular agent in western countries to
commit suicide. The victim usually uses motor vehicle
exhaust for the act of self -harm

14. CARBON DIOXIDE
Properties………
• Atmosphere contains about 0.4%
• Heavy,odorless ,colorless gas
• In solid form called as “dry snow”

15. SOURCES
• Combustion
• Respiration
• Mine explosions
• Man holes…..etc
Management…..
• Administer oxygen
• Supportive measures

16. CLINICAL FEATURES

17. AUTOPSY FINDINGS
• Cyanosis
• Congestion
• Dark fluid blood
• Venous engorgement
Medico legal importance….
Accidental deaths-worker working in
deep well,dampen pit…etc

18. HYDROGEN SULFIDE
Properties
• Colorless,heavy,inflammable gas
• Rotten egg like smell
• Hydrogen sulfide,carbon dioxide
And methane gases are formed in
sewers and called sewer gas.

19. MECHANISM OF ACTION
It acts as a cytochrome oxidase poison,blocking the electron
transport chain that catalyzes the reduction of molecular
oxygen to water
Fatal dose;1000-3000ppm
Sources….
Found in sewer,cesspool
Formed during decomposition of organic substances
containing sulphur…

20. CLINICAL FEARURES
• Breathlessness
• CNS depression
• Coma
• Death
• Delirium
• Giddiness
• Nausea
• Muscular weakness

21. MANAGEMENT
• Protect airway
• Oxygen administration
• Shift the patient from vitiated environment
• Supportive measures
AUTOPSY FINDINGS
• Signs of asphyxia
• Rotten egg like odor
• Blood and viscera –greenish-purple
Medico legal
importance
• Accidental
deaths
• Occupational
hazards

22. METHYL ISOCYANATE (MIC)
Properties
• Colorless liquid with pungent
sweetish smell below 27 degree
Celsius
• Becomes gas at 39 degree Celsius
• Highly volatile and inflammable
Mode of action
Causes carbamylation at
biochemical level

23. CLINICAL FEATURES
• Cough
• Dyspnea
• Coma
• Death
• Blurring of vision
• Convulsions

24. AUTOPSY FINDINGS….
• Signs of asphyxia
• Cerebral edema
• Pulmonary edema
• Visceral congestion
MANAGEMENT…….
• Oxygen administration
• Supportive measures
• Bronchodilators and steroids….
Medico legal importance
• Accidental deaths
• MLC was involved in
bhopal gas tragedy
occurred in 1984 causing
more than 2000 deaths…..

25. REFERENCES
• Mathew H,Lawson AAH.poisoning by toxic inhalants.ln
treatment of common acute poisoning,3rd ed,1975.
Churchill Livingstone,Edinburgh.56-68
• Klassen CD .Non metallic environment toxicants,air
pollutants,vapors and pesticides
• Long PI.Dermal changes associated with CO intoxication.
JAMA.1968;205;50-1
• Principles of Forensic medicine and toxicology by Rajesh
bardale…..

28. GUIDED BY
DR ADARSH SIR
DR SHIVANAND SIR