ARDS

Question 1

Acute Respiratory Distress Syndrome

Answer 1

-A clinical syndrome of severe dyspnea of rapid onset, hypoxemia, and diffuse pulmonary infiltrates leading to respiratory failure.
-Cause: Lung injury – underlying medical and surgical disorders
Direct: toxic inhalation
Indirect: sepsis

Question 2

Direct Lung injury

Answer 2

• Pneumonia
• Aspiration of gastric contents
• Pulmonary contusion
• Near – drowning
• Toxic inhalation injury

Question 3

Indirect lung injury

Answer 3

• Sepsis
• Severe trauma
• Multiple bone fractures
• Flail chest,Head trauma Burns
• Multiple transfusions
• Drug over dose, Pancreatitis
• Postcardiopulmonary bypass

Question 4

Etiology

Answer 4

• Most cases (>80%) are caused by severe sepsis syndrome and/or bacterial pneumonia (̴40 – 50%), trauma, multiple transfusions, aspiration of gastric contents, and drug over dose.
• Trauma: pulmonary contusion, multiple bone fracture, and chest wall trauma/flail chest

Question 5

Exudative Phase

Answer 5

• Alveolar capillary endothelial cells and Type I pneumocytes (alveolar epithelial cells) are injured
• Edema fluid, rich in protein, accumulates in the interstitial and alveolar space.
• High concentrations of cytokines and lipid mediators
• Leukocytes (especially neutrophils) move into the pulmonary interstitium and alveoli
• Alveolar edema
• Intrapulmonary shunting and hypoxemia develop
• Microvascular occlusion

Question 6

Proliferative Phase

Answer 6

• Lasts from day 7 to day 21
• Period of recovery and liberation from mechanical ventilation
• Dyspnea, tachypnea, and hypoxemia
• Progressive lung injury and early changes of pulmonary fibrosis

Question 7

Fibrotic Phase

Answer 7

-Some patients recover from ARDS in 3 – 4 weeks, others enter a fibrotic phase

Question 8

Tx

Answer 8

• General principles of treatment:
• Aim at reduction in ARDS/ALI mortality
• Recognition and treatment of the underlying medical and surgical disorders
• Minimizing procedures and their complications
• Prophylaxis against venous thromboembolism, GI bleeding, aspiration, excessive sedation, and central venous catheter infection
• Prompt recognition of nosocomial infections
• Provision of adequate nutrition