Carbon Monoxide Poisoning

Avidly binds to hemoglobin, which results in reduced oxygen-carrying capacity and altered delivery of oxygen to cells

At low carbon monoxide levels (carboxyhemoglobin [COHb] 10–20%)

• Headache

• Dizziness

• Abdominal pain

• Nausea

With somewhat higher levels (COHb 20–50%)

• Confusion

• Dyspnea

• Syncope

With high levels (COHb > 50–60%)

• Hypotension

• Coma

• Seizures

Permanent neurologic or neuropsychiatric deficits may develop in survivors of acute severe poisoning

Suspect in the setting of severe headache or acutely altered mental status, especially if multiple victims

Diagnosis depends on

• Specific measurement of the arterial or venous COHb saturation

• However, the level may have declined if high-flow oxygen therapy has already been given

• COHb levels do not always correlate well with clinical findings

Routine arterial blood gas testing and pulse oximetry are not useful because they may give falsely normal PaO₂ or oxygen saturation levels

Remove victim from exposure

Administer 100% oxygen by tight-fitting high-flow reservoir face mask or endotracheal tube

Hyperbaric oxygen (HBO)

• Can provide 100% oxygen in higher than atmospheric pressures, further shortening the half-life

• May also reduce incidence of subtle neuropsychiatric sequelae

Indications for HBO treatment after acute carbon monoxide exposure

• Loss of consciousness

• Metabolic acidosis

• COHb > 25%

• Age > 50 yr

• Cerebellar findings on neurologic examination