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Adult Respiratory Distress Syndrome
(ARDS)
Clinical Features
- develops over 24-48 hours after insult
- rapid, shallow breathing
- severe hypoxaemia
- stiff lungs
- scattered crepitations
- usually no cough / chest pain / haemoptysis
- PaO2 low but PaCO2 normal unless very severe
Investigation
- CXR
- diffuse pulmonary shadowing
- Echo / Catheterisation
- normal pulmonary artery pressure
Pathology
- increased capillary permeability → alveolar interstitial oedema
- reduced lung compliance
- leakage of fluid into alveolar spaces
- right to left shunting of blood
- hyaline membrane formation
Causes
Direct Insults
- lung contusion
- near drowning
- aspiration of gastric acid
- inhalation of smoke / corrosive chemicals
- radiation pneumonitis
Systemic Insults
- multiple trauma with shock
- septic shock
- severe acute pancreatitis
- major head injuries
- fat / air / amniotic fluid emboli
- major blood transfusion reaction / massive blood transfusion
- DIC
- Cardiopulmonary bypass
- Eclampsia
- Severe allergic reactions
- Drug overdose / sensitivity
Treatment
- ITU
- treat underlying cause
- ventilation (PEEP)
- fluid balance
- may need CVP + Swann-Ganz catheter
- not diuretics (no effect as is NOT heart failure)
- prevent renal failure
Prognosis
- if complicated mortality ~90%
Complications
- renal failure
- interstitial fibrosis
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