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ARDS Prone Positioning — FRCA Final MCQ

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ModerateIntensive Care MedicineARDS Prone PositioningFRCA Final

A 52-year-old man is within 24 hours of developing ARDS and has received optimised lung-protective ventilation. His settings are FiO2 0.70, PEEP 14 cmH2O, tidal volume 6 mL/kg predicted body weight, respiratory rate 28 min−1 and plateau pressure 29 cmH2O. His PaO2 is 8.0 kPa, giving a PaO2/FiO2 ratio of approximately 86 mmHg. There is no contraindication to turning him. Which adjunctive intervention has the strongest direct randomised evidence for reducing mortality in this severity of ARDS?

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

Reveal the answer and explanation

Correct answer: A — Prone positioning for at least 16 hours per session

Explanation lettering: B = shown as A · A = shown as B · D = shown as C · E = shown as D · C = shown as E

B is correct. This patient has early, severe ARDS despite optimised lung-protective ventilation and meets the PROSEVA physiological criteria. PROSEVA used prone sessions lasting at least 16 hours and reduced 28-day mortality from 32.8% to 16.0%, an absolute reduction of 16.8% and an NNT of approximately 6. Proning improves ventilation homogeneity and reduces regional overdistension, cyclic atelectasis and ventilator-induced lung injury. Inhaled nitric oxide may transiently improve oxygenation but has no established mortality benefit. High-frequency oscillatory ventilation is not recommended because trials found no benefit and possible harm. VV-ECMO is a rescue strategy for selected refractory cases, usually after proning. Recruitment manoeuvres with incremental PEEP do not have comparable mortality evidence and may cause haemodynamic compromise or barotrauma.

Reference: Griffiths MJD et al. Guidelines on the management of acute respiratory distress syndrome, section: Prone positioning. BMJ Open Respiratory Research. 2019;6:e000420. https://bmjopenrespres.bmj.com/content/6/1/e000420