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Severe ARDS Mortality Reduction — FRCA Final MCQ

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ModerateIntensive Care MedicineSevere ARDS Mortality ReductionFRCA Final

A patient in ICU with ARDS is being ventilated with a FiO2 of 0.8 and PEEP of 14 cmH2O. An intra-arterial catheter samples show PaO2 8.0 kPa and PaCO2 6.0 kPa. pH is 7.28. What intervention has the strongest evidence for reducing mortality in ARDS with PaO2/FiO2 <100?

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Correct answer: E — Prone positioning for ≥16 hours per day

PaO2/FiO2 = (8 × 7.5)/0.8 = 75 mmHg → severe ARDS. The PROSEVA trial (2013) demonstrated that prone positioning for ≥16 hours/day in severe ARDS (P/F <150 with FiO2 ≥0.6) reduces 28-day and 90-day mortality (16% vs 33%, NNT ~6). This represents the strongest level 1 evidence for any adjunctive therapy in ARDS. It improves V/Q matching by recruiting dependent lung regions, reduces ventilator-induced lung injury, and improves right ventricular function.

Reference: Guérin C et al – 2013 – PROSEVA trial; ICS – 2024 – ARDS management guidelines