skip to main content

Oxygen-induced hypercapnia — SCE Respiratory MCQ

Instant feedback + full explanation. One question, done properly.

ModerateCOPDOxygen-induced hypercapniaSCE Respiratory

A 71-year-old man with COPD is admitted with infective exacerbation. On 15 L/min oxygen his SpO2 is 99%; ABG shows pH 7.24, PaCO2 11.0 kPa, PaO2 22.5 kPa and HCO3- 34 mmol/L. He is confused but protecting his airway. What is the most appropriate immediate management?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Reduce oxygen to a controlled target saturation and start NIV

He has oxygen-induced worsening hypercapnic respiratory failure and should receive controlled oxygen targeting 88-92% plus NIV because he is acidotic. Continuing high-flow oxygen will worsen CO2 retention. CPAP lacks ventilatory pressure support, while bicarbonate and doxapram do not correct the primary ventilatory problem.

Reference: BTS Oxygen Guideline 2017; BTS/ICS Acute Hypercapnic Respiratory Failure Guideline