Carbon Monoxide Poisoning

• • Carbon monoxide is a gas with no color or odour. This means that it is often inhaled by accident.
  • It can be released by faulty boilers or combustion engines.
• CO poisoning pathophysiology:

  • Hemoglobin has an affinity for CO that is 210 times higher than it is for oxygen. This means that CO binding to hemoglobin is irreversible.
  • On an oxygen dissociation curve, this leads to a much earlier plateau.
• CO poisoning clinical features:

  • Headache (90% of cases)
  • Nausea and vomiting (50%)
  • Vertigo
  • Confusion
  • Subjective weakness
  • Severe toxicity - pink skin and mucosae, hyperpyrexia, arrhythmias, extrapyramidal features, coma and death.
• CO poisoning investigations:

  • VBG/ABG - pulse oximetry may be falsely raised.
  • Carboxyhemoglobin levels - will be >=3% in non-smokers and >=10% in smokers. Patient will be symptomatic at levels between 10-30%. Greater than 30% will indicate severe toxicity.
  • ECG - to look for cardiac ischemia.
• CO poisoning management:

  • Assess in ED
  • 100% high-flow oxygen via a non-rebreather mask, for a minimum of 6 hours. Target O2 sats are 100% - treat until symptoms are resolved.
  • Hyperbaric oxygen.