Neuromuscular blockade in severe ARDS — FFICM MCQ

Correct answer: C — Use a time-limited neuromuscular blocker infusion with deep sedation

The correct answer is C, use a time-limited neuromuscular blocker infusion with deep sedation. In severe ARDS with persistent double-triggering, rising plateau pressures and hypoxaemia despite optimised analgesia and sedation, patient effort is driving injurious high tidal volumes and dyssynchrony, defeating lung-protective ventilation. UK guidance from the Intensive Care Society and Faculty of Intensive Care Medicine supports a 48 hour infusion of a neuromuscular blocking agent such as cisatracurium in patients with severe ARDS (PF ratio thresholds around 20 to 27 kPa) to abolish spontaneous effort, restore synchrony, and permit strict adherence to low tidal volume, pressure-limited ventilation. This is deliberately time-limited to reduce the risk of ICU-acquired weakness, and is used alongside deep sedation rather than as a substitute for it. Why the other options are wrong: B, allow spontaneous high tidal volumes: uncontrolled large tidal volumes and transpulmonary pressure swings from vigorous effort worsen patient self-inflicted lung injury and raise plateau pressure further, the opposite of lung protection. C, extubate to NIV: severe ARDS with PaO2 7.4 kPa on FiO2 0.85 and PEEP 14 represents refractory hypoxaemia unsuitable for NIV, which cannot deliver the PEEP or FiO2 needed and risks delayed intubation and aspiration. D, stop analgesia to assess drive: withdrawing analgesia in a paralysable, dyssynchronous, hypoxaemic patient will increase respiratory drive, worsen double-triggering and raise injurious tidal volumes and plateau pressures. E, suxamethonium infusion for 48 hours: suxamethonium is a depolarising agent licensed only for rapid single-dose intubation, not prolonged infusion, and causes hyperkalaemia, tachyphylaxis and prolonged block risk, so it is never used this way in ICU. Key point: In severe ARDS with refractory dyssynchrony and injurious tidal volumes despite adequate sedation and analgesia, a short, time-limited neuromuscular blockade infusion (typically cisatracurium for up to 48 hours) is the guideline-supported adjunct to enforce lung-protective ventilation.

Reference: Intensive Care Society, Guidelines on the management of acute respiratory distress syndrome (2019), ics.ac.uk/resource/ards-guideline.html