Acute Respiratory Distress Syndrome (ARDS), a condition that became familiar due to COVID-19, refers to a form of lung damage that can result from various causes, including illness, trauma, or complications following certain medical procedures. The condition was first identified during the Vietnam War in war injury patients and was called Da-Nang lung. “It is a life-threatening condition where the lungs are severely inflamed, making breathing very difficult. This condition causes fluid to accumulate in the lungs, leading to dangerously low blood oxygen levels, and high carbon dioxide levels in the blood, leading to Acute Respiratory Failure, shares Dr Yatin Mehta, Chairman, Critical Care, Medanta, Gurugram. ARDS is regarded as a medical emergency. Rapid identification is essential, with mortality rates in India ranging from 30-40%.
Risk factors for Acute Respiratory Distress Syndrome
Individuals with specific medical conditions and lifestyle habits face a higher risk of developing ARDS. Generally, older adults, smokers, and those who have preexistent lung diseases like chronic obstructive lung disease (COPD) are more susceptible. In rare instances, certain medical procedures involving large blood transfusions like cardiovascular surgery can trigger ARDS. Additionally, people with chronic liver disease, cirrhosis, or chronically suppressed immune systems are at an increased likelihood of developing ARDS. Basically, the lungs become stiff and water-laden, unable to transfer oxygen and carbon dioxide, which is their main function.
What Causes Acute Respiratory Distress Syndrome
ARDS is always caused by an illness or injury to the lungs, which could be divided into two broad categories, direct and indirect injuries. Conditions causing direct lung injury include:
- Pneumonia
- Inhalation of toxic substances
- Bruising of the lungs caused by chest trauma
- Near-drowning
- Fat embolism (when a globule of fat enters the pulmonary circulation like in major long bone fractures)
- Lung transplantation
- Viral infection of the lungs, including SARS-CoV-2 (COVID-19), bird or swine flu, etc.
- Aspiration of stomach contents into the lungs.
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Conditions causing indirect lung injury:
- Sepsis
- Severe trauma to the body
- Massive blood transfusion
- Pancreatitis
- Heart surgery or cardiopulmonary bypass (CPB)
- Drug overdose
Statistics also reveal that sepsis and pneumonia account for 40% to 60% of all ARDS cases.
Symptoms and Signs of ARDS
Patients find it increasingly difficult to breathe, breathe rapidly, and may turn blue with or without fever, sweating, or altered sensorium.
Management of ARDS
Treatment for ARDS typically focuses on increasing blood oxygen levels, providing breathing support, and addressing the underlying cause of the disease.
Oxygen and Ventilation: Most ARDS patients are placed on a mechanical ventilator, usually in the intensive care unit (ICU). The ventilator assists with breathing when the patient is unable to do so independently. Initially, oxygen administration can be tried by various devices.
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Prone Positioning: For ARDS in general, and particularly with COVID-19, placing patients on their belly (prone positioning), whether on or off a ventilator, can help utilize parts of the lungs that are less engaged when lying on their back.
Medications: Patients often receive diuretics to reduce fluid buildup in the lungs and pain medication to alleviate discomfort. Recently, a new drug (Aviptadil) is being used, which increases type II cells in the lung alveoli, producing surfactant that makes the lungs less stiff.
Treating the Underlying Cause: Alongside increasing blood oxygen levels, doctors must treat the medical condition that led to ARDS.
ECMO Therapy: In cases where ventilator treatment fails to sufficiently improve blood oxygen levels, despite advanced mechanical ventilation, doctors may employ Extracorporeal Membrane Oxygenation (ECMO) therapy. ECMO involves a machine that takes over the functions of the lungs and, if necessary, the heart. It drains blood from the heart, removes carbon dioxide, adds oxygen, and pumps it back to the patient. It is performed by an experienced team at a tertiary care hospital.
Final Word
Managing ARDS requires a comprehensive approach involving advanced respiratory support and careful critical care strategies. Customizing treatment for each patient and monitoring for complications are crucial for better outcomes. Our understanding of ARDS and its treatments continues to improve, offering hope for better survival rates and quality of life.