A 20-year-old fireman comes to the emergency room complaining of headache and dizziness after putting out a garage fire. He does not complain of shortness of breath, and the arterial blood gas shows a normal PO2. There is no cyanosis. Which of the following is the best first step in the management of this patient?
Assess for methemoglobinemia Obtain ECG Obtain carboxyhemoglobin level Obtain CT scan of head