Cyanide Exposure & Treament

Cyanide Information

Cyanide and It’s Health Effects
Cyanide combines with and inhibits enzymes and iron in the body to bring the production of ATP, the major immediate energy source for living cells, to a halt. The organs most sensitive to energy deprivation (brain, heart) suffer first causing agitation, anxiety, confusion, lethargy, coma, convulsions, tachycardia, hypertension, hypotension, heart blocks, arrhythmias. Non specific findings may also occur including diaphoresis, weakness , nausea, vomiting, headache, metallic taste.

Treatment
Cyanide binds to Fe3+. Normal hemoglobin contains Fe2+. Hemoglobin with Fe3+ is called methemoglobin and cannot carry oxygen effectively. Usually this level within the red blood cells is below 1-2%. In a healthy person with a normal red blood count (i.e. not anemic) methemoglobin fractions of 20-30% can be tolerated.

Amyl nitrite and sodium nitrite raise the methemoglobin concentration in the blood causing they cyanide to move into the blood and out of the tissues. This makes the blood less efficient as described above, but does allow the other tissues to remain functional. The historically suggested dose of sodium nitrite for a healthy, nonanemic adult is 10ml of a 3% solution over several minutes. This may only cause up to 10% methemoglobinemia. Amyl nitrate works rapidly and is used as a temporizing measure until sodium nitrite can be given - sodium nitrite works over 30 minutes.

Sodium thiosulfate enhances the conversion of cyanide to thiocyanate. This also is slow acting but can assure conversion of cyanide to the inactive thiocyanate as it is released from the methemoglobin induced by sodium nitrite and/or amyl nitrate. The combination of sodium nitrite and sodium thiosulfate are synergystic - each agent alone probably only causes a 3-4 fold increase in the required lethal dose while the combination can increase it up to 13 times.

Side effects of treatment - hypotension, cyanosis

Immediate Response

1. Protect yourself. Prevention is worth a ton of cure.

2. Ventilate and oxygenate.

3. CPR if necessary - do not give mouth to mouth in a person with oral ingestion.

4. Amyl nitrate pearl in ventilation mask 30sec/min.

5. Sodium nitrite 10ml 3% solution (300mg) iv over several minutes (children, .33ml/kg up to 10ml).

6. Sodium thiosulfate 50ml of 24% solution iv over several minutes (children 1.65 ml/kg of 25% solution).

7. Additional full dose may be given to an adult with approval.

8. Remove all contaminated clothing and thoroughly decontaminate the victim with water

9. Transport for supportive care.