Smoke Inhalation With Progressive Upper Airway Edema
A 45-year-old man is brought to the emergency department after being rescued from a house fire. He has facial burns, singed nasal hairs, soot in the oropharynx, hoarseness, and inspiratory stridor. He is alert but anxious. Respiratory rate 28/min, heart rate 118/min, blood pressure 140/85 mm Hg, SpO2 94% on a nonrebreather mask at 15 L/min. Arterial blood gas on the nonrebreather: pH 7.35, PaCO2 42 mm Hg, PaO2 90 mm Hg, HCO3 22 mEq/L. Carboxyhemoglobin is 18%. Chest radiograph is normal. There is no evidence of trauma. He weighs 95 kg. The team is preparing for possible intubation and asks about timing, equipment, and how to manage the carbon monoxide exposure.
1. Should this patient be intubated now? Justify your answer using the airway findings and trajectory.
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Yes, he should be intubated now rather than observed. Stridor at rest, hoarseness, oropharyngeal soot, facial burns, and singed nasal hairs indicate thermal and chemical injury with progressive upper airway edema. The airway can narrow rapidly over minutes to hours, and waiting for worsening stridor or a deteriorating blood gas may make intubation much more difficult or impossible. The currently normal chest radiograph does not exclude airway injury. The ABG is not reassuring enough to delay: a PaCO2 of 42 mm Hg in a tachypneic patient with stridor is a warning that reserve is limited. The safest judgement is early intubation while the airway is still navigable, with a plan for a difficult airway.
2. Outline the airway equipment and drug plan, including tube size and neuromuscular blocker choice.
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Prepare for a difficult airway: video laryngoscopy, a range of endotracheal tubes including 7.0 and 7.5 mm internal diameter, suction, bag-mask ventilation, oral and nasal airways, a bougie, capnography, and immediate surgical airway backup. Preoxygenate with 100% oxygen for 3–5 minutes. Use rapid-sequence intubation with ketamine 1–2 mg/kg or etomidate for induction, and rocuronium 1.2 mg/kg for paralysis. Avoid succinylcholine because burn injury beyond the first 24–48 hours can cause dangerous hyperkalemia. Choose a smaller tube than predicted because of edema; a 7.0–7.5 mm tube is reasonable for this 95-kg man. Confirm placement with waveform capnography and secure the tube carefully, anticipating further airway swelling.
3. How do you manage the carboxyhemoglobin, and when would hyperbaric oxygen be considered?
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Give 100% oxygen continuously through a tightly fitting nonrebreather mask or, once intubated, via the ventilator until carboxyhemoglobin is below 5–10% and symptoms have resolved. The half-life of carboxyhemoglobin is roughly 4 hours on room air but about 1 hour on 100% oxygen. Hyperbaric oxygen is considered for carboxyhemoglobin above 25%, neurological symptoms such as syncope or altered mental status, pregnancy, cardiac ischemia, or persistent severe symptoms. This patient's level is 18% without reported neurological symptoms, so hyperbaric therapy is not mandatory, but he needs serial neurological assessment. In smoke inhalation, also consider cyanide toxicity, especially with unexplained lactic acidosis, and monitor for airway edema, bronchospasm, and delayed pulmonary injury.