What is the treatment for Acute Respiratory Distress Syndrome (ARDS)?

Treatment of Acute Respiratory Distress Syndrome (ARDS)

All patients with ARDS require lung-protective mechanical ventilation with low tidal volumes (4-8 mL/kg predicted body weight) and plateau pressures ≤30 cmH₂O, and patients with severe ARDS (PaO₂/FiO₂ <100 mmHg) must be placed in prone position for >12 hours daily. 1, 2

Initial Ventilatory Management

Lung-Protective Ventilation (All ARDS Patients)

• Set tidal volume at 4-8 mL/kg predicted body weight (not actual body weight) and maintain plateau pressure ≤30 cmH₂O 1. This is the only ventilation strategy proven to reduce mortality, decreasing death rates from 39.8% to 31.0% 3.

• Target SpO₂ no higher than 96% to avoid oxygen toxicity 2, 4.

• For moderate or severe ARDS (PaO₂/FiO₂ <200 mmHg), use higher PEEP strategies 1, 2. The evidence supports this as a conditional recommendation with moderate confidence 1.

• Avoid high-frequency oscillatory ventilation in moderate or severe ARDS—this is a strong recommendation against its routine use 1.

Pre-Intubation Considerations

• High-flow nasal cannula (HFNC) at 30-40 L/min with FiO₂ 50-60% may be considered for mild ARDS only 2, 4.

• Proceed to early intubation in a controlled setting if deterioration occurs within 1 hour or if FiO₂ >70% and flow >50 L/min for >1 hour 2, 4.

• HFNC is contraindicated with hypercapnia, hemodynamic instability, multi-organ failure, or altered mental status 4.

Severity-Based Treatment Algorithm

Severe ARDS (PaO₂/FiO₂ <100 mmHg)

Prone Positioning (Mandatory)

• Implement prone positioning for >12 hours daily (ideally 12-16 hours) 1, 2, 5. This intervention has demonstrated significant mortality reduction and is a strong recommendation 2, 4.

• Apply deep sedation and analgesia during prone positioning 4.

Neuromuscular Blockade

• Consider cisatracurium infusion for 48 hours in early severe ARDS to improve ventilator synchrony and reduce oxygen consumption 2, 5, 4.

• Particularly beneficial when ventilator-patient dyssynchrony persists despite sedation 4.

Corticosteroids

• Administer systemic corticosteroids (conditional recommendation, moderate certainty of evidence) 2, 5. This has shown mortality benefit, particularly in COVID-19 ARDS 2.

Moderate ARDS (PaO₂/FiO₂ 100-200 mmHg)

• Use higher PEEP without prolonged lung recruitment maneuvers 2, 5.

• Avoid prolonged lung recruitment maneuvers (strong recommendation, moderate certainty) 1, 2, 5.

• Consider prone positioning if approaching severe criteria or failing to improve 2.

Mild ARDS (PaO₂/FiO₂ 200-300 mmHg)

• Lung-protective ventilation remains mandatory 1, 4.

• HFNC or non-invasive ventilation may be attempted with close monitoring, but failure rates are high 4.

Fluid Management Strategy

Implement conservative fluid management to minimize pulmonary edema while maintaining adequate organ perfusion 2, 5, 4. Fluid overload worsens oxygenation, promotes right ventricular failure, and increases mortality 4.

• Monitor fluid balance carefully and avoid excessive fluid administration 2, 4.

• Ensure adequate intravascular volume initially but transition to restrictive strategy once hemodynamically stable 5.

Rescue Therapies for Refractory Hypoxemia

Inhaled Pulmonary Vasodilators

• Consider a trial of inhaled nitric oxide or other pulmonary vasodilators as rescue therapy for severe hypoxemia despite optimized ventilation 2, 4.

• Discontinue if no rapid improvement in oxygenation 2, 4. Inhaled nitric oxide is ineffective in ARDS for improving mortality and is not routinely recommended 6, 7.

Extracorporeal Membrane Oxygenation (VV-ECMO)

• Consider VV-ECMO in selected patients with severe ARDS (PaO₂/FiO₂ <100 mmHg) who fail conventional management, particularly those with reversible disease 1, 2, 4.

• VV-ECMO should only be implemented at centers with ECMO expertise 4.

• Blood is pumped from the femoral vein and returns to the right atrium through the internal jugular vein after membrane oxygenation 4.

• Additional evidence is necessary to make a definitive recommendation for or against ECMO use 1.

Monitoring Requirements

• Continuously monitor oxygen saturation, respiratory mechanics, and hemodynamics 2, 5, 4.

• Use echocardiography to assess right ventricular function and detect acute cor pulmonale in severe cases 2, 5, 4.

• Assess for ventilator-patient dyssynchrony 4.

• Closely monitor patients receiving non-invasive ventilation or HFNC for worsening respiratory status 4.

Weaning from Mechanical Ventilation

• Perform daily spontaneous breathing trials once the patient's condition improves, as this consistently reduces duration of mechanical ventilation 4.

• Use non-invasive ventilation after extubation for patients at high risk for extubation failure to reduce ICU length of stay and mortality 4.

Common Pitfalls to Avoid

• Do not use traditional tidal volumes (10-15 mL/kg)—this causes stretch-induced lung injury and increases mortality 3.

• Do not delay prone positioning in severe ARDS 5. This is one of the most underutilized evidence-based interventions 1, 5.

• Do not use high-frequency oscillatory ventilation routinely 1.

• Do not administer excessive fluids that worsen pulmonary edema 5, 4.

• Be vigilant for barotrauma when using higher PEEP strategies (PEEP >10 cmH₂O), particularly in COVID-19 patients 2.

• Do not continue inhaled nitric oxide if there is no rapid improvement in oxygenation 2, 4.