Review: Acute Respiratory Distress Syndrome

Introduction: Acute respiratory distress syndrome (ARDS) is a severe inflammatory lung condition characterized by diffuse alveolar damage, leading to hypoxemia and respiratory failure. Since its initial description in 1967, the understanding and definition of ARDS have significantly evolved, integrating advances in basic science and clinical practice. A newly recommended global definition expands diagnostic criteria to enhance early recognition and management, especially in resource-limited settings. This review summarizes current insights into the epidemiology, pathophysiology, and evidence-based management of ARDS, highlighting key updates and future research priorities.

Key Recommendations:

1. New Global Definition of ARDS: Adoption of an expanded definition that includes patients receiving high-flow nasal oxygen (HFNO) support and allows diagnosis using pulse oximetry and thoracic ultrasonography. This makes ARDS identification feasible in diverse clinical environments, including those with limited resources.
2. Established Critical Care Interventions: Emphasis on early implementation of proven strategies such as low tidal volume ventilation (6 mL/kg predicted body weight) with plateau pressures ≤30 cm H₂O, prone positioning for patients with PaO₂/FiO₂ <150 mm Hg, and conservative fluid management after initial resuscitation. These interventions have consistently reduced mortality and are recommended as standard care.
3. Personalized Approaches and Phenotyping: Recognition of the heterogeneity in ARDS pathophysiology underscores the need for personalized treatment strategies. Identification of hyper-inflammatory and hypo-inflammatory phenotypes may guide targeted therapies and improve outcomes, although prospective validation is required.
4. Impact of COVID-19 on ARDS: Acknowledgment of the significant increase in ARDS incidence due to the COVID-19 pandemic. While COVID-19 ARDS shares similarities with traditional ARDS, notable differences in endothelial dysfunction and immune response highlight the necessity for tailored management approaches in these patients.
5. Pharmacologic Interventions: Updated guidelines provide conditional recommendations for the use of corticosteroids in ARDS, particularly in early moderate to severe cases. Ongoing research into pharmacologic agents such as statins, mesenchymal stromal cells, and other cell-based therapies shows potential but requires further clinical trials to establish efficacy.
6. Future Research Priorities: Identification of key areas for investigation, including the long-term sequelae of ARDS, optimization of non-invasive and invasive ventilation strategies, exploration of genetic and environmental risk factors, and development of rapid biomarker assays for real-time phenotyping and targeted therapy.

Conclusion: The evolving definition and understanding of ARDS aim to improve early detection and standardization of care across various clinical settings. Reinforcing established critical care interventions while advancing personalized and novel therapeutic approaches holds promise for reducing mortality and enhancing long-term patient outcomes. Continuous research into the pathophysiology and management of ARDS, enriched by insights from the COVID-19 pandemic, is essential to address ongoing challenges and improve patient care.

Reference: Wick KD, Ware LB, Matthay MA. Acute respiratory distress syndrome. BMJ. 2024;387:e076612. DOI: http://doi.org/10.1136/bmj-2023-076612