Review Question - QID 214233

A 33-year-old man is brought to the emergency department by emergency medical services after being rescued from a fire at the smelting plant where he works. The patient is anxious, mildly confused, and cannot recall what happened. His temperature is 99.0°F (37.2°C), blood pressure is 135/88 mmHg, pulse is 124/min, respirations are 27/min, and oxygen saturation is 94% on room air. An initial lactate is 3 mmol/L (normal < 2.0 mmol/L). The patient is protecting his airway and has a Glasgow coma scale of 14. He is started on a non-rebreather at 15 L/min. Upon reassessment 30 minutes later, the patient appears more confused. A repeat lactate is drawn at that time and is 7.0 mmol/L. The patient is complaining of a headache and begins vomiting. Which of the following is the pathophysiology of the most likely diagnosis?