Toxicology 15: Carbon Monoxide Poisoning Portal
Carbon monoxide poisoning is often missed because the patient may complain only of a headache and may not be aware of any risk. Consider carbon monoxide poisoning in almost every case of headache, decreased LOC, and coma.
Oxygen saturation monitors do not distinguish between COHgb and OxyHgb. Although, pulse CO-oximeters are now available, which give both a carbon monoxide level and an oxygen reading. Also, cyanosis may not appear because COHgb is bright red. Blood gas machine readings will also be misleading because the PaO2 may be normal. Obtain CO blood levels from your lab as soon as this diagnosis becomes a possibility.
Management
Administer 100% oxygen by non-rebreather mask if the patient is able to cooperate.
Intubate and ventilate with 100% oxygen if the patient is comatose.
Establish IVs and determine the COHgb level. If the patient is seizing, terminate the seizure activity. (Vol III—NEU1 Status Epilepticus)
Obtain a chest x-ray and an ECG.
With the patient breathing 100% oxygen, the half-life of COHgb is about 1 hour. If hyperbaric oxygen treatment is not used, continue the 100% oxygen until the COHgb level is less than 3% and the patient is asymptomatic.
Because severe delayed neurologic changes may occur even after the patient has returned to normal, hyperbaric oxygen is recommended for cases that have manifested severe neurologic or cardiac symptoms such as:
History of loss of consciousness
Depressed LOC on arrival
History of seizure or focal neurological deficit
Ischemic chest pain
New dysrhythmia
Hypotension
Pregnancy
Consider hyperbaric oxygenation if the patient is younger than 2 years, if the COHgb level is greater than 25%, has a hemoglobin level less than 10 g/dL, or was exposed for greater than 2 hours. Consider hyperbaric oxygen treatment for all patients with COHgb levels greater than 40%.
Consult your hyperbaric treatment center if there is any question about the need to treat with hyperbaric oxygen.