Causes of ALI/ ARDS

Causes of Acute Lung Injury and Acute Respiratory Distress Symdrome are:

DIRECT Causes:

• Pneumonia
• Aspiration
• Inhalational injuries
• Blunt pulmonary trauma
• Near drowning

INDIRECT Causes:

• Sepsis
• Severe traumatic shock
• Large volume blood transfusion (>15 units)
• Pancreatitis
• Reperfusion after cardiopulmonary bypass

Although more than 60 conditions have been associated with ARDS, the most frequent cause is sepsis, followed by pneumonia and aspiration.

MCQ 15:

Most common cause of ARDS?

a – Sepsis

b – Trauma

c – Pneumonia

d – Aspiration

Ans: Sepsis

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MCQ 8:

Patient is having ARDS with a Peak Inspiratory Pressure of 65 cm H2O; develops a pneumothorax, what will you do?

a – Increase the Fractional concentration of O2

b – Switch over to Pressure Control Ventilation

c – Decrease the tidal volume

d – Decrease the respiratory rate

Ans: Switch over to Pressure control ventilation

Diagnostic Criteria for ALI and ARDS

1. Acute Onset

2. Presence of a predisposing condition.

3. Bilateral infiltrates on frontal chest x-ray, consistent with pulmonary edema.

4. PaO2 / FiO2 < 200 mm Hg for ARDS, < 300 mm Hg for ALI, regardless of the level of positive end-expiratory pressure (PEEP).

5. Pulmonary artery occlusion pressure =18 mm Hg or no clinical evidence of left atrial hypertension.

Bernard GR, Artigas A, Brigham KL, et al. The American–European Consensus Conference on ARDS: definitions, mechanisms, relevant outcomes, and clinical trial coordination. Am Rev Respir Crit Care Med 1994;149:818–824.