Carbon monoxide poisoning

Question 1

Characteristics and pharmacodynamics of CO?

Answer 1

Colorless, odorless, no irritation. Lighter than air

• 2-300x higher affinity to Hb than O₂, CO₂.
  
  • It diplaces O₂ from Hb (reversible)
• In high dose, may block citrate cycle

Question 2

Acute clinicale features?

Answer 2

< 50% concentration in the blood:

• Headache, dizziness
• Nausea
• Blurred vision
• Weakness, collapse
• Skin is white and clammy

> 50% concentration in the blood:

• Hyperventilation
• Tachycardia
• Seizures, coma

> 60% concentration in the blood:

• Respiratory failure, death
• If survival: brain edema, irreversible cortical damage

CO doesn’t affect the O₂ tension, thus chemoreceptor stimulation only in severe cases (>50-60% concentration)

Question 3

Chronic clinical features?

Answer 3

• Strong headach
• Sleeping pill resistant insomnia
• Ataxia
• Parkinson-like symptoms
• Memory disturbances

Question 4

Therapy?

Answer 4

• 100% O₂ (carbogen: 95% O₂, 5% CO₂) is harmful in acidosis
• Brain edema –> GC, mannitol
• Acidosis –> alkali therapy