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Hypercapnic respiratory failure — ABIM Board MCQ

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HardPulmonary/Critical CareHypercapnic respiratory failureABIM Board

A 72-year-old with COPD exacerbation is drowsy after uncontrolled high-flow oxygen. SpO2 is 99%, pH 7.24 and PaCO2 78 mm Hg. After bronchodilators, which respiratory strategy is most appropriate?

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Correct answer: D — Titrate oxygen to 88–92% and begin bilevel noninvasive ventilation with close reassessment

The best answer is “Titrate oxygen to 88–92% and begin bilevel noninvasive ventilation with close reassessment”. This is acute hypercapnic respiratory failure with respiratory acidosis. Controlled oxygen reduces oxygen-associated worsening of hypercapnia, and bilevel ventilation improves alveolar ventilation while work of breathing is treated. Deteriorating consciousness or failure of a closely monitored trial requires intubation, but neither persistent hyperoxia nor CPAP alone addresses the current physiology.

Reference: GOLD Pocket Guide 2026: https://goldcopd.org/wp-content/uploads/2025/11/GOLD-Pocket-Guide-2026-v1.1-20Nov2025_WMV.pdf