Diagnostic Criteria for Acute Respiratory Distress Syndrome

In this article, we will discuss about Diagnostic Criteria for Acute Respiratory Distress Syndrome. So, let’s get started.

Diagnostic Criteria

Acute respiratory distress syndrome is defined as an acute hypoxic respiratory failure characterized by extensive bilateral pulmonary infiltrates, rapid onset dyspnea, refractory hypoxemia, decreased lung compliance, and respiratory failure.

It is considered a medical emergency and carries a high mortality rate (40-60%).

Following are the diagnostic criteria  for ARDS:

1. Impaired oxygenation PaO2/FiO2 ratio <200 mmHg (mild (200-300 mmHg, moderate 100-200 mmHg, and severe <100 mmHg by Berlin definition)

2. Normal pulmonary capillary wedge pressure (PCWP) <18 mm with normal left atrial pressure.

3. Chest x-ray showing diffuse bilateral lung infiltrates.


Tension Pneumothorax

In this article, we will discuss about Tension Pneumothorax. So, let’s gets started

Tension Pneumothorax

In tension pneumothorax, the mean pleural pressure is positive which means that air in the pleural cavity is under tension which causes compression collapse of the lung. It develops due to persistent air leak (air entry) inside the pleural cavity by the communication which opens during inspiration and closes during expiration preventing the air to escape. In this way, with each successive breath, the intrapleural pressure increases which eventually causes the mediastinum to shift to the opposite side and increased intrapleural pressure also puts pressure on the surrounding blood vessels.

There is decreased venous return to the heart and along with decreased cardiac output causing hypotension (cardiac tamponade) and cyanosis.

Clinical Features

Dyspnea, cough and acute exacerbation of pneumothorax symptoms

Trachea and mediastinum shifts to the opposite side

Decreased or absent breath sounds, there may be amphoric breathing present at a localized place.

Hyperinflated chest with decreased or absent chest wall movement of the involved side

Tachypnea, tachycardia, hypotension, cyanosis, and paradoxical pulse.