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COPD exacerbation with hypercapnic respiratory failure — ABIM Board MCQ

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HardPulmonary/Critical CareCOPD exacerbation with hypercapnic respiratory failureABIM Board

A 52-year-old man with BMI 48 kg/m2 has daytime sleepiness, awake PaCO2 49 mm Hg, serum bicarbonate 31 mEq/L, and no alternative cause of hypoventilation. Polysomnography shows obstructive sleep apnea with an apnea-hypopnea index of 58 events/hour. He is clinically stable and has not used positive-airway-pressure therapy. Which initial nocturnal treatment is preferred?

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Correct answer: A — Begin CPAP therapy with objective adherence and gas-exchange follow-up

The best answer is “Begin CPAP therapy with objective adherence and gas-exchange follow-up”. Stable ambulatory obesity hypoventilation syndrome accompanied by severe obstructive sleep apnea is initially treated with CPAP rather than NIV. CPAP addresses the dominant obstructive physiology and often improves awake hypercapnia; adherence and physiologic response must be reassessed, with NIV reserved for inadequate response or phenotypes without severe OSA. Oxygen alone can worsen untreated hypoventilation.

Reference: ATS Clinical Practice Guideline: Evaluation and Management of Obesity Hypoventilation Syndrome: https://member.thoracic.org/statements/guideline-implementation-tools/eval-and-mgmt-of-ohs.php