A 35-year-old woman and her two children develop headache, dizziness, and nausea while sleeping in a house with a faulty furnace during winter. The mother presents with BP 128/82, HR 102, RR 18, and confusion. Pulse oximetry is normal at 98% on room air. Carboxyhemoglobin level is elevated at 22%. She denies dyspnea. Which of the following best explains the mechanism of her poisoning?
- A)Oxidation of hemoglobin iron from Fe2+ to Fe3+
- B)Competitive inhibition of cytochrome oxidase by cyanide
- C)Increased affinity of hemoglobin for oxygen with impaired release to tissuesGABARITO
- D)Direct GABA-A receptor blockade
- E)Irreversible inhibition of acetylcholinesterase
Explicação
Carbon monoxide binds hemoglobin with very high affinity, reducing oxygen carrying capacity and shifting the oxygen dissociation curve to the left so that oxygen delivery to tissues is impaired. Standard pulse oximetry can appear normal, making the history esp... Ver explicação completa e trilha adaptativa →