What is the recommended treatment approach for a patient with acute respiratory distress syndrome (ARDS)?

Management of Acute Respiratory Distress Syndrome (ARDS)

All patients with ARDS must receive lung-protective mechanical ventilation with tidal volumes of 4-8 mL/kg predicted body weight and plateau pressures ≤30 cmH₂O, and patients with severe ARDS (PaO₂/FiO₂ <150 mmHg) require prone positioning for at least 12-16 hours daily. 1, 2

Core Ventilation Strategy: Mandatory for All ARDS Patients

Implement lung-protective ventilation immediately upon ARDS diagnosis:

• Set tidal volume at 6 mL/kg predicted body weight (acceptable range 4-8 mL/kg PBW), calculated as: males = 50 + 0.91 × [height (cm) - 152.4] kg; females = 45.5 + 0.91 × [height (cm) - 152.4] kg 1, 2
• Maintain plateau pressure <30 cmH₂O by measuring with an end-inspiratory pause of 0.3-0.5 seconds 1, 2
• Accept permissive hypercapnia with pH >7.20 as a consequence of lung protection—do not increase tidal volume to normalize CO₂ 2, 3
• This strategy reduces mortality with moderate confidence in effect estimates and is the only intervention proven to improve survival across all ARDS severities 1

PEEP Titration: Based on Disease Severity

Adjust PEEP according to ARDS severity classification:

• For moderate-to-severe ARDS (PaO₂/FiO₂ <200 mmHg): Use higher PEEP, typically 10-15 cmH₂O 1, 2, 4
• For mild ARDS (PaO₂/FiO₂ 200-300 mmHg): Lower PEEP may be appropriate, typically 5-10 cmH₂O 2
• Monitor for barotrauma when PEEP exceeds 10 cmH₂O 2
• In patients with hemodynamic instability or cirrhosis, use lower PEEP (<10 cmH₂O) to avoid impairing venous return 2

The recommendation for higher PEEP in moderate-to-severe ARDS is conditional with moderate confidence, meaning clinical judgment regarding hemodynamic tolerance is required 1.

Prone Positioning: Non-Negotiable for Severe ARDS

For severe ARDS with PaO₂/FiO₂ <150 mmHg:

• Implement prone positioning for at least 12-16 hours daily 1, 2
• This is a strong recommendation with moderate confidence in effect estimates, showing mortality reduction (RR 0.74) 1, 2
• Duration is critical: trials demonstrating mortality benefit used >12 hours/day, while shorter durations showed no benefit 2
• Do not delay implementation—early prone positioning improves outcomes 2

This intervention should be considered mandatory for severe ARDS, not optional 1.

Neuromuscular Blockade: Early Use in Severe ARDS

For early severe ARDS with PaO₂/FiO₂ <150 mmHg:

• Administer neuromuscular blocking agents for up to 48 hours 2
• Use intermittent boluses rather than continuous infusion when possible 2
• Reserve continuous infusion for persistent ventilator dyssynchrony, need for deep sedation, prone positioning, or persistently high plateau pressures 2

This prevents expiratory efforts that cause derecruitment and helps maintain lung protection 5.

Corticosteroids: Recommended for ARDS

Administer systemic corticosteroids to mechanically ventilated patients with ARDS 2. This is a conditional recommendation with moderate certainty of evidence, representing the most recent high-quality guidance from the American Thoracic Society 2. While the evidence is not as strong as for lung-protective ventilation or prone positioning, the balance of benefits versus harms favors corticosteroid use.

Fluid Management: Conservative Strategy

Use a conservative fluid strategy in established ARDS without tissue hypoperfusion 2. Conservative fluid management improves ventilator-free days without increasing non-pulmonary organ failures 2, 6. This means targeting neutral to negative fluid balance once hemodynamic stability is achieved.

Oxygenation Targets: Avoid Hyperoxia

Target SpO₂ of 88-95% to avoid hyperoxia while maintaining adequate oxygenation 2, 4:

• Start supplemental oxygen if SpO₂ <92%, and definitely if <90% 2
• Maintain SpO₂ no higher than 96% in acute hypoxemic respiratory failure 2
• Do not prioritize normoxia over lung-protective ventilation 2

Recruitment Maneuvers: Use Cautiously

For moderate or severe ARDS, recruitment maneuvers are conditionally recommended with low confidence in effect estimates 1. This means they may be considered but should not be routine or prolonged, as they are associated with potential harm 2, 7.

Rescue Therapies for Refractory Hypoxemia

When optimized ventilation, proning, and neuromuscular blockade fail:

• Consider veno-venous ECMO in carefully selected patients at experienced centers 2, 6
• ECMO should only be used in severe refractory ARDS due to its resource-intensive nature and modest survival benefit 2, 6
• Additional evidence is necessary to make a definitive recommendation for or against ECMO 1

Interventions to Avoid: Strong Recommendations Against

Do not use high-frequency oscillatory ventilation—this is strongly recommended against with high confidence in effect estimates 1, 2. This mode may worsen hemodynamics and increase mortality 5.

Do not routinely use:

• Pulmonary artery catheters for ARDS management 2
• β-2 agonists for ARDS treatment without bronchospasm 2

Common Pitfalls and How to Avoid Them

Critical errors that worsen outcomes:

1. Using tidal volumes >8 mL/kg PBW even if plateau pressures are acceptable—both parameters must be optimized simultaneously 2, 8
2. Prioritizing normocapnia over lung protection—accept permissive hypercapnia as necessary 2, 3
3. Delaying prone positioning in severe ARDS—early implementation is essential 2
4. Applying higher PEEP indiscriminately—tailor to ARDS severity and hemodynamic tolerance 2
5. Underrecognizing ARDS—evidence-based interventions are frequently underused, contributing to preventable mortality 1

Monitoring and Weaning

As patients improve:

• Minimize continuous or intermittent sedation, targeting specific titration endpoints 2
• Use spontaneous breathing trials in patients ready for weaning 2
• Implement a weaning protocol for patients who can tolerate weaning 2, 8

The heterogeneity of ARDS means that while these guidelines provide the framework, attention to individual patient response—particularly hemodynamic tolerance and oxygenation—guides fine-tuning of therapy 1, 6, 7.