Table 2.

Rescue therapies for ARDS

	Proposed mechanism	Clinical settings for use	Potential risks	Key studies
ECMO	Allow ultraprotective ventilation; rescue oxygenation	Severe and persistent hypoxaemia; severe and persistent acidosis; refractory elevated inspiratory plateau pressure; first 7 days of mechanical ventilation with reversible cause	Bleeding, vascular access complications, thrombocytopenia, stroke; only available at referral centres	Peek et al,167 Combes et al168
Higher PEEP strategies	Recruit collapsed alveolar units, thereby improving compliance and oxygenation	Refractory hypoxaemia	Decreased preload leading to hypotension; barotrauma	Mercat et al,106 Meade et al,107 Brower et al108
Recruitment manoeuvre	Recruit collapsed alveolar units, thereby improving compliance and oxygenation	Refractory hypoxaemia, particularly in patients who seem PEEP responsive	Decreased preload leading to hypotension; barotrauma	Brower et al,108 Cavalcanti et al109
Inhaled pulmonary vasodilators	Improve V/Q matching, reduce pulmonary vascular pressures	Refractory hypoxaemia	Associated with acute kidney injury; development of tachyphylaxis	Gebistorf et al150
Corticosteroids	Decrease inflammation	Refractory hypoxaemia	Immunosuppression, critical illness myopathy or neuropathy; increased duration of viral shedding in influenza or SARS-CoV-1; conflicting data on benefits; late administration associated with harm	Lewis et al,157 Villar et al,169 Steinberg et al,170 Bernard et al171
CRRT	Additional fluid removal and acid clearance; theoretical cytokine clearance	Refractory acidosis in setting of plateau pressure limitation	Risks of vascular access, bleeding	..

Not recommended: high-frequency oscillatory ventilation.172, 173 ARDS=acute respiratory distress syndrome. CRRT=continuous renal replacement therapy. ECMO=extracorporeal membrane oxygenation. PEEP=positive-end expiratory pressure. V/Q=ventilation–perfusion.