Acute Respiratory Distress Syndrome

Acute Respiratory Distress Syndrome (ARDS) – Treatment Options

Introduction
Acute respiratory distress syndrome (ARDS) is a severe inflammatory lung condition characterized by diffuse alveolar damage, increased pulmonary vascular permeability, and non-cardiogenic pulmonary edema. It leads to refractory hypoxemia, decreased lung compliance, and bilateral infiltrates on chest imaging. ARDS is triggered by direct lung injury (pneumonia, aspiration, trauma) or indirect systemic insults (sepsis, pancreatitis, massive transfusion). Mortality remains high despite advances in critical care. Treatment is supportive, focusing on lung-protective ventilation, underlying cause management, and prevention of complications.

1. Immediate Stabilization

• Airway and breathing: Most patients require intubation and mechanical ventilation.

• Oxygen supplementation: High-flow oxygen initially; escalate to invasive ventilation if hypoxemia persists.

• Hemodynamic support: IV fluids for perfusion, but avoid fluid overload (restrictive strategy preferred). Vasopressors (norepinephrine) if septic shock is present.

2. Mechanical Ventilation (Cornerstone Therapy)

• Lung-protective ventilation (low tidal volume strategy):

  • 6 mL/kg predicted body weight tidal volume.

  • Plateau pressure ≤30 cm H₂O.

• PEEP (positive end-expiratory pressure):

  • Moderate to high levels to prevent alveolar collapse.

• Permissive hypercapnia: Accepting higher PaCO₂ to avoid barotrauma, unless contraindicated (raised ICP, severe acidosis).

• Prone positioning:

  • At least 16 hours/day in moderate-to-severe ARDS (PaO₂/FiO₂ <150).

  • Improves oxygenation and survival.

3. Rescue Therapies for Refractory Hypoxemia

• Neuromuscular blockade (cisatracurium): For early severe ARDS to improve synchrony.

• Inhaled vasodilators (nitric oxide, epoprostenol): Temporary bridge therapy.

• Extracorporeal membrane oxygenation (ECMO): Considered in specialized centers for severe, refractory cases (PaO₂/FiO₂ <80 despite optimal therapy).

4. Medical and Supportive Therapies

• Corticosteroids:

  • Dexamethasone or methylprednisolone may reduce inflammation and duration of ventilation in selected patients.

• Fluid management:

  • Conservative fluid strategy improves outcomes once shock is controlled.

• Nutrition:

  • Enteral nutrition preferred; avoid overfeeding.

• VTE prophylaxis: Low-molecular-weight heparin unless contraindicated.

• Stress ulcer prophylaxis: PPIs or H2 blockers in critically ill patients.

5. Treatment of Underlying Cause

• Sepsis: Early broad-spectrum antibiotics and source control.

• Aspiration: Supportive therapy ± antibiotics if secondary pneumonia develops.

• Trauma or transfusion-related ARDS: Address primary insult while applying ARDS supportive measures.

6. Monitoring and Long-Term Care

• ICU monitoring: Continuous hemodynamic, oxygenation, and ventilatory parameters.

• Prevention of ventilator-associated pneumonia (VAP): Head-of-bed elevation, oral hygiene, sedation minimization.

• Rehabilitation after recovery: Many survivors experience long-term pulmonary dysfunction, muscle weakness, and psychological effects requiring multidisciplinary rehabilitation.

7. Multidisciplinary Care

• Critical care specialists: For ventilation and ECMO decision-making.

• Respiratory therapists: For ventilator optimization and prone positioning.

• Infectious disease specialists: For sepsis or pneumonia management.

• Rehabilitation teams: For post-ICU physical, pulmonary, and psychological recovery.