Emergency Oxygen Flow Rate — MFDS Part 1 MCQ

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ModeratePharmacologyEmergency Oxygen Flow RateMFDS Part 1

A 64-year-old patient develops persistent central crushing chest pain during dental treatment. They are pale and clammy, and their oxygen saturation is 82% on air. They have no known COPD or other risk factors for hypercapnic respiratory failure. While a colleague calls 999, what is the most appropriate initial oxygen therapy?

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Correct answer: A — 15 litres per minute via a non-rebreathing reservoir mask

The correct answer is A. This patient has suspected acute coronary syndrome with severe hypoxaemia: SpO2 is below 85% and there is no identified risk of hypercapnic respiratory failure. Initial oxygen should therefore be delivered at 15 litres/min through a non-rebreathing reservoir mask, then titrated to an SpO2 of 94–98% when reliable monitoring is available. Low-flow nasal cannulae or a simple face mask may be used for less severe hypoxaemia but are inadequate as the initial intervention at an SpO2 of 82%. A 28% Venturi mask is principally used for controlled oxygen delivery when hypercapnic respiratory failure is a concern. Oxygen is not routinely indicated for normoxic chest pain, but option B is inappropriate because this patient is markedly hypoxaemic.

Reference: Sheffield Health and Social Care NHS Foundation Trust. Prescribing and Administration of Emergency Oxygen in Adults in Hospital, Appendix C: Guidelines and flowchart for oxygen use. 2023. https://www.sheffieldpartnership.nhs.uk/sites/default/files/2023-02/Prescribing%20and%20Administration%20of%20Emergency%20Oxygen%20in%20Adults%20in%20Hospital%20%28MD%20016%20V4%20Feb%202023%29%20%20%281%29.pdf