In carbon monoxide poisoning, which statement about pulse oximetry and treatment is true?

• A. Pulse oximetry may be falsely normal; treat with 100% oxygen and consider hyperbaric oxygen in severe cases
• B. Pulse oximetry is always accurate; treat with oxygen only if chest pain
• C. Hyperbaric oxygen is never indicated
• D. CO poisoning cannot occur without inhalation of smoke

Answer: (A)