Respiratory System MCAT Practice Question
A 62-year-old man with a history of esophageal cancer undergoes esophagectomy with bilateral vagal nerve injury during the procedure. Postoperatively, he is extubated and breathing spontaneously on room air with adequate oxygenation. However, the surgical team notices his breathing pattern is markedly irregular with prolonged inspiratory efforts and variable tidal volumes, despite normal arterial blood gas values and no evidence of pain or anxiety. Which of the following best explains these respiratory abnormalities?
Answer choices
- ALoss of chemoreceptor feedback from the carotid and aortic bodies due to vagal denervation
- BInterruption of the Hering-Breuer reflex pathway, eliminating vagal feedback from pulmonary stretch receptorsCorrect answer
- CAcute respiratory acidosis from hypoventilation due to loss of all autonomic respiratory drive
- DIncreased activity of expiratory neurons in the dorsal medullary respiratory group
- EParalysis of the external intercostal muscles from motor vagal fiber loss
- FInhibition of the apneustic center in the lower pons due to loss of vagal inhibitory inputs
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