A 28-year-old woman with severe primary pulmonary hypertension (mean pulmonary artery pressure 55 mmHg) is scheduled for laparoscopy. Which inhalational agent should be specifically avoided because it worsens her condition?
- A Sevoflurane
- B Isoflurane
- C Nitrous oxide ✓
- D Xenon
Correct answer: C. Nitrous oxide
Explanation
Nitrous oxide activates the sympathetic nervous system and causes pulmonary vasoconstriction, raising pulmonary vascular resistance, which is dangerous in established pulmonary hypertension. The halogenated ethers tend to blunt hypoxic pulmonary vasoconstriction slightly and relax pulmonary vessels, so they are relatively preferred. Xenon is cardiovascularly stable. The exam-relevant point is that N2O is contraindicated in pulmonary hypertension because of its sympathomimetic, pulmonary vasoconstrictor effect.
Reference: Morgan and Mikhail's Clinical Anesthesiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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