How do carboxyhemoglobin levels in the blood correspond to the clinical presentation of smoke inhalation injury?

Updated: Oct 15, 2021
  • Author: Keith A Lafferty, MD; Chief Editor: Joe Alcock, MD, MS  more...
  • Print
Answer

Carboxyhemoglobin levels in the blood and the corresponding clinical manifestations are as follows [1] :

  • 0-10% - Usually no symptoms

  • 10-20% - Mild headache, atypical dyspnea

  • 20-30% - Throbbing headache, impaired concentration

  • 30-40% - Severe headache, impaired thinking

  • 40-50% - Confusion, lethargy, syncope

  • 50-60% - Respiratory failure, seizures

  • Greater than 70% - Coma, death

Blood carboxyhemoglobin levels may underestimate the degree of CO intoxication because of oxygen administered to the patient before arrival to the hospital. Smokers may have baseline levels up to 5-10% and may experience more significant CO poisoning for the same level of exposure as nonsmokers. Finally, correlation between carboxyhemoglobin levels and eventual neurologic outcome is poor.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!