Control of respiration · Physiology

In a patient with chronic obstructive pulmonary disease (COPD) and long-standing hypercapnia, why is it potentially dangerous to administer high-flow supplemental oxygen?

  1. High oxygen levels can cause oxygen toxicity and damage within the alveoli
  2. It may trigger a massive surge in arterial PCO2 acting through the Bohr effect
  3. Respiratory drive may depend on hypoxic drive due to blunted CO2 sensitivity
  4. A high PO2 directly inhibits the diaphragm's own ability to contract normally
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Correct answer: Respiratory drive may depend on hypoxic drive due to blunted CO2 sensitivity

In chronic hypercapnia, central chemoreceptors become desensitized to CO2. The respiratory drive then shifts to the peripheral chemoreceptors (hypoxic drive); providing too much oxygen can remove this stimulus, leading to respiratory depression.

Difficulty: Medium Question 29 of 40

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