What is Acute Respiratory Distress Syndrome (ARDS)?

From the Guidelines

The management of Acute Respiratory Distress Syndrome (ARDS) should prioritize lung-protective ventilation strategies, including the use of low tidal volumes and higher positive end-expiratory pressure (PEEP) without lung recruitment maneuvers, as recommended by the most recent guidelines 1.

Key Recommendations

• The use of corticosteroids is suggested for patients with ARDS, with a conditional recommendation and moderate certainty of evidence 1.
• Venovenous extracorporeal membrane oxygenation may be considered in selected patients with severe ARDS, although the certainty of evidence is low 1.
• Neuromuscular blockers, such as cisatracurium, may be used in patients with early severe ARDS, with a conditional recommendation and low certainty of evidence 1.
• Prone positioning for at least 16 hours daily is recommended for patients with moderate-to-severe ARDS (PaO2/FiO2 < 150) to improve oxygenation.

Pathophysiology and Clinical Considerations

The pathophysiology of ARDS involves diffuse alveolar damage, increased capillary permeability, and surfactant dysfunction, leading to non-cardiogenic pulmonary edema, decreased lung compliance, and severe hypoxemia 1. Early recognition and addressing the underlying cause (sepsis, pneumonia, trauma, etc.) are essential for improving outcomes in patients with ARDS.

Ventilatory Strategies

• Low tidal volumes (4-6 mL/kg predicted body weight) and limiting plateau pressures to less than 30 cmH2O are crucial for minimizing ventilator-induced lung injury (VILI) 1.
• Higher PEEP without lung recruitment maneuvers may be beneficial in patients with moderate to severe ARDS, as suggested by the latest guidelines 1.

Adjuvant Therapies

• Conservative fluid management should be implemented to reduce pulmonary edema while maintaining adequate organ perfusion.
• Extracorporeal membrane oxygenation (ECMO) serves as rescue therapy for refractory hypoxemia in patients with severe ARDS.

From the Research

Definition and Management of ARDS

• Acute respiratory distress syndrome (ARDS) is a leading cause of morbidity and mortality in critically ill patients, despite advancements in the field 2.
• The goal of mechanically ventilating patients with ARDS is to ensure adequate oxygenation and minimal ventilator-associated lung injury 3.

Mechanical Ventilatory Strategies

• Lung-protective mechanical ventilation strategies, including low tidal volumes, low plateau pressures, and low FiO2, are vital components of ARDS management 2, 3.
• Positive end-expiratory pressure (PEEP) should be optimized to maintain or improve lung recruitment, and prone ventilation can be used to decrease morbidity and mortality 2, 4.
• Driving pressure is a key parameter to optimize tidal volume, and the optimal level of PEEP may be titrated by the inflection point obtained from static pressure-volume curve 3.

Adjunctive Therapies

• Adjunctive therapies, such as recruitment maneuvers, inhaled pulmonary vasodilators, neuromuscular blockers, and glucocorticoids, may improve oxygenation but do not clearly reduce mortality 4.
• Extracorporeal membrane oxygenation (ECMO) can be used as a salvage therapy in select patients with refractory hypoxemia, and may improve gas exchange and modestly improve survival 4, 5.

Current Practices and Preferences

• A survey of academic medical centers in the United States found that most intensivists would consider ECMO in patients who fail optimal mechanical ventilation strategies, but few favored its use as a first-line modality 5.
• The majority of respondents reported limited knowledge of ECMO and desired specific ECMO education during training 5.