Updated October 2025
Critical Care Evidence
ARDS Management: Prone Positioning, ECMO, and Adjunctive Therapies
Early, protocolized lung-protective ventilation remains the cornerstone of ARDS care. For refractory hypoxemia, early prolonged prone positioning improves survival in moderate–severe ARDS, while VV-ECMO is indicated for selected patients failing optimized conventional therapy. Adjunctive strategies should be targeted, time-limited, and safety-monitored with attention to patient selection and response.
Clinical question
In adult ARDS, what is the evidence-based role of prone positioning, venovenous ECMO, and adjunctive therapies, and how should these be operationalized at the bedside?
ARDSProne PositioningECMOCritical CareMechanical VentilationAdjunctive Therapies
Key points
Initiate lung-protective ventilation immediately
Low tidal volumes (4–6 mL/kg PBW) and plateau pressure ≤30 cmH2O form the base; optimize PEEP and FiO2 before escalation.
Escalate to prone positioning for moderate–severe ARDS
Start early and maintain long sessions (≥16 h); monitor for PaO2/FiO2 improvement and PaCO2 response, which may predict outcomes [4], [5].
Select ECMO for refractory cases
In experienced centers, early VV-ECMO in severe ARDS with life-threatening hypoxemia/hypercapnia despite optimization can improve outcomes [1].
Consider prone positioning during ECMO selectively
Physiologic benefits are common; randomized evidence in ECMO patients is evolving—early use may reduce mortality in observational data; neutral for weaning time in RCT primary outcome [2], [3].
Use adjunctive therapies judiciously
Adjuncts (neuromuscular blockade, conservative fluids, recruitment strategies) are variably applied and should be time-limited, response-guided, and safety-monitored [6].
Evidence highlights
≥16 h/day when PaO2/FiO2 ≤150 on FiO2 ≥0.6 and PEEP ≥10
Prone early, prolonged
Severe hypoxemia/hypercapnia despite optimized care; consider RESCUE steps within 6–12 h
ECMO referral trigger
ECMO strategy ↓90-day mortality vs conventional (HR ~0.76; per-protocol) [1]
ECMO benefit signal
May improve physiology; mixed outcome data, early use possibly ↓mortality [2], [3]
Prone on ECMO
Stepwise Management of Moderate–Severe ARDS
Prioritize low tidal volume ventilation; escalate through prone positioning and ECMO using objective thresholds and safety checks.
1
1) Establish the foundation: lung-protective ventilation
Set VT 4–6 mL/kg PBW, plateau ≤30 cmH2O, driving pressure as low as feasible. Use PEEP-FiO2 tables or individualized PEEP; target PaO2 55–80 mmHg or SpO2 88–95%, permissive hypercapnia if pH ≥7.20. Ensure conservative fluid strategy and early, frequent reassessment.
2
2) Prone positioning: early and prolonged
Indication: PaO2/FiO2 ≤150 on FiO2 ≥0.6 and PEEP ≥10. Deliver sessions ≥16 h/day with a trained team. Expect improved oxygenation and mechanics; a PaCO2 decrease may indicate better outcomes [4], [5]. Monitor for pressure injury and airway obstruction [7], [8].
3
3) Rescue therapies if hypoxemia persists
Trial neuromuscular blockade for severe dyssynchrony and refractory hypoxemia; consider inhaled pulmonary vasodilators as bridge. Avoid injurious recruitment maneuvers; individualize based on compliance and hemodynamics. Reassess within 2–6 h.
4
4) ECMO referral and initiation
Criteria include persistent PaO2/FiO2 <80–100 for >6 h despite optimization and proning, or severe hypercapnia with pH <7.20. In EOLIA, an ECMO strategy reduced treatment failure with a trend toward lower 60–90 day mortality; crossover complicates intention-to-treat effects, but per-protocol and Bayesian analyses suggest benefit [1]. Initiate in centers with expertise; manage anticoagulation carefully [9], [10], [11].
5
5) Prone during ECMO: selective use
Proning on VV-ECMO often improves oxygenation and mechanics; RCT data showed no reduction in ECMO weaning time as primary outcome, though physiologic benefits were present [2]. Observational data suggest early proning on ECMO may reduce mortality; late or any-time proning showed neutral overall survival [3], [12]. Apply when lung rest is limited by refractory hypoxemia or dorsal collapse.
Operational Checklists and Safety
Use structured protocols to standardize care, reduce complications, and detect response.
Prone Positioning Protocol
Indication: PaO2/FiO2 ≤150 on FiO2 ≥0.6 and PEEP ≥10 after optimization.
Session length ≥16 h; daily reassessment for continued need.
Team roles assigned; secure airway and lines; eye and skin protection.
Outcome targets: ↑PaO2/FiO2 ≥20–30% or ↓PaCO2 within first session [4], [5].
Complications: pressure injury, tube obstruction; mitigate with cushions and suctioning [7].
ECMO Candidacy Snapshot
Severe hypoxemia/hypercapnia despite proning and rescue adjuncts.
Reversible lung injury and acceptable comorbidity/frailty profile.
Center capability: 24/7 ECMO team, anticoagulation protocols, imaging/surgical backup.
Discuss goals of care; monitor for bleeding, limb ischemia, infection [1], [9], [10], [11].
Adjunctive Therapies
Neuromuscular blockade: short course for severe dyssynchrony or refractory hypoxemia.
Inhaled NO/prostacyclin: bridge while arranging proning or ECMO; stop if no response.
Conservative fluid strategy; avoid excessive diuresis if shock present.
Recruitment maneuvers: avoid high-pressure, prolonged holds; tailor to compliance.
Practice variability is high; standardize within unit pathways [6].
Response Windows
Prone: reassess gas exchange and mechanics in 1–4 h; continue daily if benefit persists.
Rescue adjuncts: stop within 12–24 h if no objective improvement.
ECMO: evaluate within 6–12 h of failing optimized/prone strategy; earlier if crashing.
Daily weaning trials as oxygenation/mechanics improve, including on ECMO [2].
Safety and Monitoring
Plateau ≤30 cmH2O; driving pressure as low as feasible.
Monitor skin, eyes, airway; frequent suctioning when prone.
Anticoagulation targets per ECMO circuit; surveillance for hemolysis/bleeding.
Vent synchrony assessment; minimize sedation while maintaining safety.
References
Source material
Primary literature that informs this article.
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Prone Position for Acute Respiratory Distress Syndrome. A ...
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Extracorporeal membrane oxygenation (ECMO) in adults ...
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Venovenous extracorporeal membrane oxygenation ...
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Extracorporeal membrane oxygenation (ECMO) ...
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To prone or not to prone ARDS patients on ECMO - PMC
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Effectiveness of prone position in acute respiratory distress ...
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Effectiveness of ECMO for burn-related acute respiratory ...
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