Acute respiratory distress syndrome

Question 1

Acute respiratory distress syndrome

Answer 1

Rapid breathing difficulties caused by diseases such as pneumonia, sepsis
• Sepsis is the most common cause

Question 2

inflammation mech in ARDS

Answer 2

1. Cytokines enter alveoli in response to
   - Systemic infection
   - Alveolar macrophages
2. Cytokines caused capillary endothelial cells surrounding alveoli to
   - secrete inflammatory molecules
3. Stimulates neutrophils to cause INFLAMMATION

Question 3

Impacts of inflammation in ards

Answer 3

INFLAMMATION causes
1. endothelium of blood vessels becomes leaky and allows fluid to enter interstitium - (pulmonary oedema)
2. Pneumocytes die
- Type 2 - less surfactant produces
- inc surface tension
- alveolar collapse
3. Hyaline membrance              
  ( characteristic !)  
- dead cells and protein rich fluid accumulate in interstitial space
- gas exchange more difficult
4. Fibrosis

Question 4

V/Q mismatch in ARDS

Answer 4

1. Problems in ventilation
• Oedema/alveolar collapse
2. Perfusion is fine
3. V/Q mismatch
4. Hypoxemia -> Cynosis

Question 5

ARDS symptoms

Answer 5

1. Severe and life threatening
2. Begins with shortness of breath
3. Worsens to respiratory failure
4. Edema -> Crackling sound

Question 6

Diagnosis of ARDS

Answer 6

1. Acute < 1 week onset
2. X-ray/CT - white out due to massive oedema
3. pf ratio - partial pressure in arterial blood vs inspired air
4. Respiratory distress is not caused by oedema caused by heart failure
   - pulmonary blood pressure is normal unlike in heart failure

Question 7

Treatment

Answer 7

1. Mechanical ventilation/Positive pressure to prevent alveoli collapse
2. Still high mortality rate

Question 8

Clinical characteristic of ards

Answer 8

1. Bilateral fine inspiratory crackles
2. Progressive hypoxemia
3. Oedema with normal pulmonary blood pressure
4. Progressive hypoxemia