1. Carbon monoxide (CO) Toxicology 2nd lab notes Dr. Ansam Jalal
Prepared by :
Shamil Naseh
Saya Amir

2. Introduction CO : silent killer gas
Colorless, odorless, tasteless, irritant gas
Cause incomplete combustion of any carbon containing material.

3. Sources of CO Smoke inhalation (industry, ciggarate, cars, drugs).
Automobile exhaust fumes.
Poor ventilated charcoal (eg: barbecue).
Kerosene, gasoline, diesel (eg:kerosene heaters due to incomplete combustion).
Cigarette smoking (smoking or inhalation).
Methylene chloride : paint remover (converted to Co in liver after inhalation.

4. Mechanism of toxicity
1-CO reduces oxy hemoglobin saturation and decrease blood carrying capacity so O₂ delivery to tissue is impaired.

5. Mechanism of toxicity
This step is reversible since increase O₂ is reversible in inviroment so sign and symptoms are reversible , when there is insufficient O₂ , CO toxicity occurs.
2- CO directly inhibit cytochrome oxidase and disrupt cellular function.
Cytochrome oxidase found in mitochondria of every cell responsible of electron transport chain in krebs cycle to deliver O₂ to tissues.

6. Mechanism of toxicity
3-CO binds to myoglobin ind impair myocardial contractility . Myoglobin is protien similar to hemoglobin found in muscle. (O₂ + Fe + protein) responsible for delivery of O₂ to muscle. In case of injury it will be found in blood which is diagnostic feature of tissue injury .

7. Sign & symptoms
Dizziness (since it is gas , CNS is first affected with respiration)
Headache , seizure , visual disturbances , impairment of cerebral function , heart & respiratory dysfunction , muscle weakness and muscle cramps.
Aggravation of pre existing disease.
Collapse and loss of consciousness is occurring in last step.

8. Treatment
Remove the patient from continued exposure and immediately institute O₂ therapy 100%.
Institute cardiac monitoring .
Avoid exertion to limit tisse O₂ demand.

9. Identification of CO poisoning
1- Dilution with water HbCO + water ---> pink Normal blood + water ---> faint yellow color 2- warm in waterbath HbCO warm ͢ brick red deposit Normal blood warm ͢ dark brown deposit 3-hoppe-seyler test HbCO (NaOH 10%)͢ bright red color Normal blood (NaOH 10%)͢ dirty green color

10. Identification of CO poisoning
4-kunkel test HbCO + 9 parts of water (few drops of 3% aqeous tannine)͢ pinkish white ppt. Normal blood + 9 parts of water (few drops of 3% aqeous tannine)͢ brownish white ppt.