Respiratory distress syndrome, adult

Respiratory Distress Syndrome, Adult

Respiratory Distress Syndrome (RDS) in adults, also known as Acute Respiratory Distress Syndrome (ARDS), is a severe lung condition that occurs when fluid builds up in the alveoli, the tiny air sacs in the lungs. This fluid prevents the lungs from filling with enough air, which means less oxygen reaches the bloodstream. ARDS can lead to organ failure and is often life-threatening.

Pathophysiology

ARDS is characterized by rapid onset of widespread inflammation in the lungs. The condition is often triggered by an injury to the lung, which can be direct, such as pneumonia or inhalation of harmful substances, or indirect, such as sepsis or severe trauma. The inflammatory response leads to increased permeability of the alveolar-capillary barrier, resulting in pulmonary edema, decreased lung compliance, and impaired gas exchange.

Causes

Common causes of ARDS include:

• Sepsis
• Pneumonia
• Aspiration of gastric contents
• Severe trauma
• Inhalation of toxic substances
• Pancreatitis
• Blood transfusions (transfusion-related acute lung injury)

Symptoms

Symptoms of ARDS typically develop within a few hours to a few days after the initial injury or infection. They include:

• Severe shortness of breath
• Labored and unusually rapid breathing
• Low blood pressure
• Confusion and extreme tiredness

Diagnosis

The diagnosis of ARDS is based on:

• A history of a known risk factor for the condition
• Acute onset of symptoms
• Bilateral opacities on chest imaging
• Absence of left atrial hypertension (to rule out cardiogenic pulmonary edema)
• PaO2/FiO2 ratio of less than 300 mmHg

Treatment

Treatment of ARDS focuses on improving oxygenation and supporting the patient while the underlying cause is treated. Key components include:

• Mechanical ventilation with low tidal volumes
• Positive end-expiratory pressure (PEEP)
• Prone positioning
• Conservative fluid management
• Treatment of the underlying cause

Prognosis

The prognosis of ARDS varies depending on the severity of the condition, the patient's age, and the presence of other medical conditions. Mortality rates range from 30% to 50%. Survivors may experience long-term effects such as reduced lung function, muscle weakness, and psychological issues.

Also see

• Acute lung injury
• Pulmonary edema
• Mechanical ventilation
• Sepsis
• Pneumonia