A left-sided double-lumen endobronchial tube is preferred over a right-sided tube for lung isolation because:
- A The left main bronchus is wider
- B The right upper lobe bronchus origin is variable and easily obstructed ✓
- C The left main bronchus is shorter
- D Right-sided tubes cause more bronchospasm
Correct answer: B. The right upper lobe bronchus origin is variable and easily obstructed
Explanation
Left-sided double-lumen tubes are preferred because the right upper lobe bronchus arises laterally and variably from the right main bronchus, making right-sided tubes prone to obstructing it and causing right upper lobe collapse. The left main bronchus is longer (about 5 cm), allowing safer placement with a margin of safety. The right main bronchus is actually wider and shorter, which is why right-sided tubes are more difficult to position correctly.
Reference: Miller's Anesthesia, 9th ed.
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Written and medically reviewed by the StethoPrep medical team.