From the Guidelines
ARDS is a life-threatening condition that requires immediate attention and treatment with lung-protective mechanical ventilation strategies, and the use of corticosteroids, venovenous extracorporeal membrane oxygenation (VV-ECMO), and neuromuscular blockers may be beneficial in selected patients. Acute Respiratory Distress Syndrome (ARDS) is characterized by widespread inflammation and fluid accumulation in the lungs, leading to severe breathing difficulties. The etiology of ARDS is multifactorial, with common causes including pneumonia, sepsis, trauma, aspiration, pancreatitis, and COVID-19 1. Patients with ARDS present with rapid onset of severe shortness of breath, low blood oxygen levels despite oxygen therapy, rapid breathing, and respiratory distress, usually occurring within 1 week of a known clinical insult.
Symptoms and Diagnosis
The symptoms of ARDS include:
- Rapid onset of severe shortness of breath
- Low blood oxygen levels despite oxygen therapy
- Rapid breathing
- Respiratory distress Diagnosis is based on clinical presentation, arterial blood gas analysis showing hypoxemia (PaO2/FiO2 ratio ≤300 mmHg), and chest imaging revealing bilateral opacities not fully explained by effusions, collapse, or nodules.
Treatment and Management
Treatment focuses on supportive care with mechanical ventilation using lung-protective strategies, including:
- Low tidal volumes (4-8 mL/kg predicted body weight) 1
- Inspiratory pressures <30 cmH2O
- Appropriate positive end-expiratory pressure (PEEP) (typically 10-15 cmH2O) 1
- Prone positioning for 12-16 hours daily is recommended for moderate-to-severe ARDS Additional management includes:
- Conservative fluid strategy
- Neuromuscular blockade in severe cases (conditional recommendation, low certainty of evidence) 1
- Consideration of extracorporeal membrane oxygenation (ECMO) for refractory hypoxemia (conditional recommendation, low certainty of evidence) 1
- Corticosteroids may be beneficial, particularly in COVID-19 related ARDS (conditional recommendation, moderate certainty of evidence) 1
Outcome and Quality of Life
The mortality rate remains high (30-40%), with survivors often experiencing long-term physical, cognitive, and psychological impairments requiring comprehensive rehabilitation. The use of higher PEEP without lung recruitment maneuvers (LRMs) is suggested as opposed to lower PEEP in patients with moderate to severe ARDS (conditional recommendation, low to moderate certainty) 1. Prevention of complications like ventilator-associated pneumonia, deep vein thrombosis, and pressure ulcers is crucial to improve outcomes and quality of life.
From the Research
Definition and Etiology of ARDS
- Acute Respiratory Distress Syndrome (ARDS) is a condition characterized by inflammation and injury to the lungs, leading to impaired gas exchange and potentially life-threatening respiratory failure 2, 3, 4, 5, 6.
- The etiology of ARDS can be direct, such as pneumonia, or indirect, such as sepsis, trauma, or shock 3, 4, 5.
Symptoms of ARDS
- Symptoms of ARDS include shortness of breath, cough, chest pain, and fatigue 3, 4, 5.
- Patients with ARDS may also experience hypoxemia, hypercapnia, and respiratory acidosis 2, 3, 4, 5, 6.
Treatment and Management of ARDS
- The primary treatment for ARDS is mechanical ventilation, which helps to improve oxygenation and reduce the work of breathing 2, 3, 4, 5, 6.
- Lung-protective ventilation strategies, including low tidal volumes and low plateau pressures, are recommended to minimize ventilator-induced lung injury 2, 3, 4, 5, 6.
- Positive end-expiratory pressure (PEEP) is used to maintain lung recruitment and improve oxygenation, but the optimal level of PEEP is uncertain 2, 3, 4, 5, 6.
- Prone position ventilation, high-frequency oscillatory ventilation, and extracorporeal membrane oxygenation may be used as salvage therapies in severe cases of ARDS 3, 4, 5.
- Non-invasive ventilation may be used with caution in patients with ARDS, but it is not recommended as a primary treatment 4, 5.
Ventilatory Strategies in ARDS
- Low tidal volumes (4-8 ml/kg predicted body weight) and low plateau pressures (<30 cmH2O) are recommended to minimize lung injury 2, 3, 4, 5, 6.
- The use of recruitment maneuvers and optimization of PEEP may help to improve lung recruitment and oxygenation 2, 3, 4, 5.
- Airway pressure release ventilation and partial liquid ventilation are not recommended as primary treatments for ARDS 4, 5.
- High-frequency oscillatory ventilation may be used as a rescue therapy in patients with severe ARDS and refractory hypoxemia 5.