What is the recommended management protocol for a patient with Acute Respiratory Distress Syndrome (ARDS)?

ARDS Management Protocol

Implement lung-protective ventilation immediately with tidal volumes of 4-8 mL/kg predicted body weight (target 6 mL/kg) and plateau pressure ≤30 cmH2O for all patients with ARDS, and add prone positioning for at least 12-16 hours daily in severe ARDS (PaO2/FiO2 <150 mmHg). 1

Core Ventilation Strategy: Lung-Protective Ventilation (MANDATORY)

All ARDS patients require lung-protective ventilation—this is a strong recommendation with moderate certainty of evidence. 1

• Set tidal volume at 6 mL/kg predicted body weight (acceptable range 4-8 mL/kg PBW) 1, 2
• Calculate predicted body weight: Males = 50 + 0.91 × [height (cm) - 152.4] kg; Females = 45.5 + 0.91 × [height (cm) - 152.4] kg 2
• Maintain plateau pressure <30 cmH2O at all times 1, 2
• Accept permissive hypercapnia (pH >7.20) as a consequence of lung protection—do not prioritize normocapnia over these ventilator targets 2
• Use volume-preset, assist-control mode for better control of tidal volume 3
• Increase respiratory rate as tidal volume is reduced to maintain minute ventilation and prevent acute hypercapnia 3

PEEP Strategy: Titrate to ARDS Severity

For moderate-to-severe ARDS (PaO2/FiO2 <200 mmHg), use higher PEEP (typically >10 cmH2O); for mild ARDS (PaO2/FiO2 200-300 mmHg), lower PEEP may be appropriate. 1, 2

• Higher PEEP is a conditional recommendation with low-to-moderate certainty of evidence 1
• The 2024 American Thoracic Society guideline specifically recommends higher PEEP without lung recruitment maneuvers 1
• Monitor for barotrauma when using PEEP >10 cmH2O 2
• In patients with cirrhosis or hemodynamic instability, use lower PEEP (<10 cmH2O) for mild ARDS to avoid impairing venous return 2

Prone Positioning: Essential for Severe ARDS

For severe ARDS with PaO2/FiO2 <150 mmHg, implement prone positioning for at least 12-16 hours daily—this is a strong recommendation with moderate certainty of evidence. 1, 2

• Prone positioning reduces mortality in severe ARDS (relative risk 0.74) 2
• Duration matters: trials with >12 hours/day proning showed mortality benefit, while shorter durations did not 2
• Do not delay prone positioning in severe ARDS—early implementation improves outcomes 2

Corticosteroids: Now Recommended

Administer systemic corticosteroids to mechanically ventilated patients with ARDS—this is a conditional recommendation with moderate certainty of evidence from the 2024 American Thoracic Society guideline. 1, 2

This represents a significant update from the 2017 guideline, which did not address corticosteroids. The 2024 guideline is the most recent high-quality evidence supporting this intervention. 1

Neuromuscular Blockade: Early Use in Severe ARDS

For early severe ARDS with PaO2/FiO2 <150 mmHg, use neuromuscular blocking agents for up to 48 hours—this is a conditional recommendation with low certainty of evidence. 1, 2

• Administer as intermittent boluses rather than continuous infusion when possible 2
• Use continuous infusion only for persistent ventilator dyssynchrony, need for deep sedation, prone positioning, or persistently high plateau pressures 2
• The 2019 British Thoracic Society guideline suggested cisatracurium specifically for 48 hours in patients with PF ratios ≤20 kPa 4

Recruitment Maneuvers: AVOID Prolonged Use

Do not use prolonged lung recruitment maneuvers in patients with moderate to severe ARDS—this is a strong recommendation with moderate certainty of evidence from the 2024 guideline. 1

This represents a critical update from the 2017 guideline, which conditionally recommended recruitment maneuvers. 1 The newer evidence shows harm from prolonged recruitment maneuvers, though brief recruitment may still have a role in selected patients. 1

• Hemodynamic monitoring is mandatory if recruitment maneuvers are attempted, as transient hypotension occurs frequently 5
• Do not perform recruitment maneuvers in patients with hemodynamic instability, active hypovolemia, or recent pneumothorax 5

Fluid Management: Conservative Strategy

Use a conservative fluid strategy in established ARDS without tissue hypoperfusion. 2, 4

• Conservative fluid management improves ventilator-free days without increasing non-pulmonary organ failures 2

Rescue Therapies for Refractory Hypoxemia

For severe refractory ARDS despite optimized ventilation, proning, and other interventions, consider VV-ECMO in carefully selected patients at experienced centers—this is a conditional recommendation with low certainty of evidence. 1, 2

• ECMO should only be considered in carefully selected patients due to resource-intensive nature 2
• The 2019 British Thoracic Society guideline suggested ECMO as an adjunct to protective mechanical ventilation for patients with very severe ARDS 4

Interventions to AVOID

Do not use high-frequency oscillatory ventilation—this is a strong recommendation against with high certainty of evidence. 1, 6

• Do not routinely use pulmonary artery catheters for ARDS management 2
• Do not use β-2 agonists for ARDS treatment without bronchospasm 2
• Do not use inhaled nitric oxide routinely—it is ineffective in ARDS and not indicated 7, 4

Oxygenation Targets

Target SpO2 of 88-95% to avoid hyperoxia while maintaining adequate oxygenation. 2, 6

• Start supplemental oxygen if SpO2 <92%, and definitely if <90% 2
• Maintain SpO2 no higher than 96% in acute hypoxemic respiratory failure 2

Sedation and Weaning

• Minimize continuous or intermittent sedation, targeting specific titration endpoints 2
• Evaluate for weaning when adequate oxygenation can be maintained on 40% oxygen and PEEP of 8 cmH2O 3
• Use spontaneous breathing trials in patients ready for weaning 2, 3
• Pressure support levels between 5-20 cmH2O (above 5 cmH2O PEEP) are used for weaning and titrated to keep respiratory rate <35 breaths/min 3

Critical Pitfalls to Avoid

• Do not use tidal volumes >8 mL/kg PBW even if plateau pressures are acceptable—both parameters must be optimized simultaneously 2
• Do not prioritize normocapnia over lung-protective ventilation—accept permissive hypercapnia as necessary 2
• Do not delay prone positioning in severe ARDS—early implementation improves outcomes 2
• Do not use recruitment maneuvers routinely or for prolonged periods—the 2024 guideline strongly recommends against this due to associated harm 1
• Do not apply higher PEEP indiscriminately—tailor to ARDS severity and hemodynamic tolerance 2
• When dyspnea results in double-triggered breaths, tidal volume can be titrated to 7-8 mL/kg, provided plateau pressure remains ≤30 cmH2O 3
• In severe acidosis (pH <7.15), tidal volume can be increased, but every effort should be made to maintain plateau pressure and tidal volume goals by buffering severe acidosis and treating patient-ventilator asynchrony with sedation 3