Carbon Monoxide Poisoning


Poisons are chemical or physical agents that produce adverse responses in biological systems.

Poisoning on the other hand is the ingestion by, or exposure of a patient to excessive doses of a medicine or other substances that may cause harm.

Carbon monoxide poisoning results from inhalation of smoke, car or generator fumes caused by incomplete combustion in a confined space.

Carbon monoxide reversibly binds to
haemoglobin, myoglobin and mitochondria, inhibiting cellular respiration

Clinical features of carbon monoxide poisoning

  • Respiratory system: Dyspnoea
  • Tachypnoea
  • Headache
  • Emotional liability
  • Confusion
  • Impaired judgement
  • Clumsiness
  • Syncope
  • Nausea, vomiting and diarrhoea may occur
  • Ischaemic chest pain,
  • Arrhythmias,
  • Heart failure and hypotension may occur

In severe poisoning:

  • Coma and cerebral oedema may occur
  • Pulmonary oedema
  • Respiratory depression
  • Cherry-red colour of skin and mucus membranes (rarely cyanosis)


  • Full Blood Count and ESR
  • Serum Urea, Electrolytes and Creatinine
  • Liver function tests
  • Acid-base status.
  • Blood gases

Non-drug treatment

  • Remove from carbon monoxide exposure, move to fresh air

Drug treatment

  • Oxygen administration: face mask in conscious patients and endotracheal intubation in comatose patients after clearing the airways
  • Treat hypotension & arrhythmia
  • Mannitol (10-20% ; 250 ml intravenously over 30 minutes. May repeat every 8 hours)

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