Irrespirable Gases Flashcards
Enumerate the irrespirable gases
- Carbon monoxide
- Carbon dioxide
- Hydrogen sulphide
- War gases
- Methyl isocyanate
Action of carbon monoxide
CO combines with Hb to COHb and cause anaemic hypoxia
Inhibits cytochrome A3 oxidase and cytochrome P450 and hinders intracellular respiration
Acute symptoms of CO poisoning
Headache
Dizziness
Nausea
Confusion
What is the result of CNS damage due to CO poisoning
Spastic paraplegia
Effect on liver due to CO poisoning
Enlarged and bleeding tendency
Effect on CNS due to CO poisoning
•spastic paralysis
•impairment of higher mental functions
•personality changes
•Parkinsonism
Effect on skin due to CO poisoning
Bullies lesions d/t skin hypoxia
How does a CO poisoning give a false impression of assault
Victim may move erratically in the room disturbing furniture and clothing
Diagnostic tests for CO poisoning
- Spectroscopy
- CT
- Kunkels test
- Hoppe-Seylers test
How is CO diagnosed
From 1. History , signs and symptoms
2. Lab findings
How is COHb analysed
By spectroscopy. Two absorption bands between Fraunhoffers lines D&E as in oxyhemoglobin
CT findings in CO poisoning
Symmetric low density areas in the region of globus pallidus, putamen and caudate nucleus
Kunkels test in CO poisoning
Diluted blood + few drops of tannic acid and shaken . Crimson red coagulum formed if COHb present
Hoppe-Seylers test in CO poisoning
Few drops of blood + NAOH
pink / red if COHb present otherwise greenish brown
Treatment of CO poisoning
- Remove patient to fresh air
- Patient blood COHb above 25% require hyperbaric Po2 of 2-3atm
- Blood transfusion
- Gastric lavage
- Cerebral edema - 20% mannitol solution 500ml IV
- Supportive measures
PM findings in CO poisoning
External
Cherry red colour hypostasis and mucous membranes
Fine froth at mouth and nostrils
Blisters on skin
Internal
Lungs and brain congested
Rhabdomyolysis
Heart shows petechial hemorrhage
Punctiform ring hemorrhage in white matter of brain
Circumstances of CO poisoning
Suicidal
Starting car in neutral in shed or exhaust tube connected to interior of car
Accidental
Exposure to exhaust gas - during burning of house , gas mines , closed space after explosion
Safety level of CO in air
0.1%
Enumerate the war gases
- Vesicants or blistering gases
- Asphyxiants or lung irritants
- Lachrymators or tear gases
- Sternutators or nasal irritants
- Paralysants
- Nerve gases
Name the vesicants
- Mustard gas
- Lewisite
Treatment of vesicants
- Wash affected part with soap and water
- Eye wash with sodium bicarbonate
- BAL
Asphyxiants or lung irritants
1.CO2
2. CO
3. Chlorine
4. Phosgene
5. Diphosgene
Green cross gases
Phosgene and diphosgene
Treatment of Asphyxiants
- Eye wash with saline
- Oxygen
- Antibiotics to prevent infection