ARDS

Question 1

definition?

Answer 1

syndrome of acute respiratory failure characterized by hypoxemia and bilateral pulmonary infiltrates not due to heart failure or fluid overload

Question 2

etiology? both systemic and pulmonary?

Answer 2

systemic: acute pancreatitis, shock, sepsis

pulmonary: pneumonia, aspiration, inhalation injury, drowning, fat emboli, amniotic fluid emboli

Question 3

clinical features?

Answer 3

dyspnea, tachypnea, tachycardia, cyanosis, bilateral diffuse inspiratory crackles

Question 4

diagnostic criteria?

Answer 4

ARDS is a diagnosis of exclusion and consider other causes of its not acute or there is no predisposing trigger

1. acute onset: within one week of a known predisposing trigger
2. bilateral opacities on imaging similar to pulmonary edema of CHF
3. hypoxemia: PO2/FiO2 equal or <300 mmHg
4. EXCLUDE CHF and other causes of fluid overload. Pulmonary capillary wedge pressure <18 in ARDS. >18 in CHF

Question 5

investigations?

Answer 5

1. chest xray is sufficient for diagnosis but cannot differentiate between ARDS and CHF
2. ABG to show respiratory alkalosis
3. CBC and blood cultures: leukocytosis and sepsis/ pneumonia
4. lipase for pancreatitis
5. BNP for HF
6. pulmonary artery catheter to measure PCWP. <18 is diagnostic

Question 6

management?

Answer 6

oxygenation with mechanical ventilation
early prone positioning
lung protective ventilation to prevent further damage
treat underlying cause
diuretics (furosemide)
fluid management
optimize nutrition enteral (feeding tube)