A 50-year-old woman was pulled from the window of a burning building and found to be in cardiac arrest with pulseless electrical activity. Standard advanced cardiac life-support was started, and infusion of intra-osseous hydroxocobalamin (OHCob) was administered at the time of intubation because of the concern for cyanide (CN) gas exposure during smoke inhalation. Return of spontaneous circulation occurred before arrival at the hospital.Upon presentation to the ED, the patient's vital signs were: initial blood pressure (BP), 92/47 mm Hg; heart rate (HR), 112 beats/min; respiratory rate (RR), 31 breaths/min; and temperature (T), 99.7°F.Following intubation, the patient's oxygen saturation (SaO 2 ) on pulse oximetry (POX) was 93%, and her fraction of inspired oxygen (FiO 2 ) was 100%.On physical examination, the patient's face was covered with soot. The lung sounds were equal and clear to auscultation bilaterally. The neurological examination was significant for a Glasgow Coma Scale of 3, without administered sedation, and there were no signs of dermal burns. Initial arterial blood gas (ABG) results were: pH, 7.06; carbon dioxide partial pressure (PCO 2 ), 58 mm Hg; partial pressure of oxygen (PO 2 ), 152 mm Hg; bicarbonate (HCO 3 ), 17 mm Hg; SaO 2 , 98% (after intubation); FiO 2 , 100%; carboxyhemoglobin (COHb), 30%; and lactate, 14 mmol/L.