Toxic Gases

Question 1

What is known as the silent killer?

Answer 1

Carbon monoxide

Question 2

Carbon monoxide poisoning treatment

Answer 2

Oxygen
Fluids IV
Steroids IV
Hyperbaric oxygen

Question 3

Hydrogen sulfide poisoning treatment

Answer 3

Antidote: sodium nitrite

100% oxygen
Fluids IV
Steroids IV 
Antibiotics if needed
Crystalloid and vasopressors for hypotension.

Question 4

Cyanide poisoning treatment

Answer 4

Antidote: hydroxocobalamin. Cyanide antidote kit: natrium thiosulfuricum, amyl nitrite, sodium nitrite

100% oxygen
Crystalloids and vasopressors for hypotension
Sodium bicarbonate

Decontamination, removal from site of exposure and oxygen supply are essential.

Question 5

What is the mechanism of toxicity of carbon monoxide?

Answer 5

It binds to hemoglobin with an affinity over 200 times that of oxygen and produces carboxyhemoglobin, which is ineffective in oxygen delivery to tissues. It also binds to myoglobin with affinity 60 times that of oxygen. It also binds to cytochrome oxidase with less affinity than oxygen, so it is possible that it requires significant intracellular hypoxia before binding. This interferes with aerobic metabolism and adenosine triphosphate synthesis. Cells respond by switching to anaerobic metabolism, causing anoxia, lactic acidosis and eventually cell death

Question 6

What are the symptoms of carbon monoxide poisoning?

Answer 6

Symptoms are similar to hypoxia

Question 7

Toxicity of CO in pregnancy?

Answer 7

CO can cross the placenta, and have more affinity for fetal hemoglobin than adult one, and may cause severe fetal adverse effects

Question 8

What is the mechanism of toxicity of hydrogen sulfide?

Answer 8

It is a mucous membrane and respiratory tract irritant, that may lead to pulmonary edema and even unconsciousness and death if inhaled. Eye contact may lead to painful dermatitis and burring eyes.

Question 9

When to suspect hydrogen sulfide poisoning?

Answer 9

• Rapid loss of consciousness (knocked down)
• Rotten egg odor
• Rescue from enclosed space such as sewer or manure pit
• Multiple victim with sudden death syndrome
• Collapse of a previously healthy worker at work site

Question 10

What is the mechanism of toxicity of cyanide?

Answer 10

It inhibits cytochrome c oxidase and by attaching to the iron within this protein, which prevents transport of electrons from cytochrome c to oxygen and thus the cell can no longer produce ATP.

Question 11

When should you suspect cyanide?

Answer 11

• Sudden collapse of laboratory or industrial worker
• Fire victim with coma
• Ingestion of artificial nail remover
• Ingestion of seeds or pits from prunus species
• Patient with altered mental status, academia and tachyphylaxis to nitroprusside