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Acute exacerbation of COPD with acidotic hypercapnic ventilatory failure — MRCEM SBA MCQ

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EasyRespiratory emergenciesAcute exacerbation of COPD with acidotic hypercapnic ventilatory failureMRCEM SBA

A 68-year-old man with established COPD presents with two days of increased breathlessness and sputum production. He receives controlled oxygen, air-driven nebulised bronchodilators and oral prednisolone. His initial arterial blood gas shows pH 7.30 and PaCO₂ 8.2 kPa. After 70 minutes of treatment, he remains breathless; SpO₂ is 90% on controlled oxygen, and repeat arterial blood gas shows pH 7.28 and PaCO₂ 8.6 kPa. He is alert, cooperative and haemodynamically stable. What is the most appropriate next respiratory support plan?

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

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Correct answer: D — Start bilevel non-invasive ventilation and repeat arterial blood gases in a monitored unit.

The repeat blood gas shows **worsening respiratory acidosis with rising PaCO₂** despite more than an hour of initial treatment for a COPD exacerbation. His SpO₂ of 90% is within the recommended 88–92% range, but satisfactory oxygen saturation does not establish adequate ventilation. NICE recommends non-invasive ventilation (NIV) for persistent acidotic hypercapnic ventilatory failure that is not improving after one hour of optimal medical therapy. It should be delivered by experienced staff in a dedicated setting, with blood-gas reassessment and a plan for deterioration. ([nice.org.uk](https://www.nice.org.uk/guidance/qs10/resources/chronic-obstructive-pulmonary-disease-in-adults-pdf-2098478592709)) **A** delays ventilatory support despite worsening acidosis; continued observation would be more appropriate if the blood gases were improving. **B** addresses oxygenation rather than the demonstrated ventilatory failure, and his saturation is already in the target range. **C** may provide oxygen support but is not the recommended treatment for persistent hypercapnic ventilatory failure in this case. **D** supports ventilation while he remains alert and able to cooperate. **E** is an escalation to consider if invasive ventilation becomes necessary, for example if he deteriorates or cannot be managed with NIV; the current findings support an NIV trial first. ([nice.org.uk](https://www.nice.org.uk/guidance/qs10/resources/chronic-obstructive-pulmonary-disease-in-adults-2098478592709))

Reference: NICE NG115: Chronic obstructive pulmonary disease in over 16s — recommendations (Updated 26 July 2019) — https://www.nice.org.uk/guidance/ng115/chapter/Recommendations NICE QS10: Chronic obstructive pulmonary disease in adults — quality statements 6 and 7 (Updated 19 September 2023) — https://www.nice.org.uk/guidance/qs10/resources/chronic-obstructive-pulmonary-disease-in-adults-pdf-2098478592709