11. ARDS Flashcards
What is acute respiratory distress syndrome (ARDS)
Lung damage and a release o f inflammatory mediators leading to increased capillary permeability and non-cardiogenic pulmonary oedema. Often accompanied by multi-organ failure.
What are the pulmonary causes of ARDS?
Pneumonia, gastric aspiration, inhalation, injury, vasculitis, contusion
What are the non-pulmonary causes of ARDS?
Sepsis, shock, heamorrhage, multiple transfusions, DIC, pancreatitis, acute liver failure, trauma, head injury
What are the clinical signs of ARDS?
Cyanosis, tachypnoea, tachycardia, peripheral vasodilation, bilateral fine inspiratory crackles.
What investigations should be undertaken in ARDS?
FBC U&E LFT Amylase Clotting CRP Blood cultures ABG CXR Pulmonary artery to measure pulmonary capillary wedge pressure
What is seen on a chest x-ray?
Bilateral infiltrates
What is the criteria for diagnosing ARDS?
Acute onset
CXR with bilateral infiltrates
PCWP- <19mmHg
Refractory hypoxaemia
What is the pulmonary treatment for ARDS?
CPAP with 40-60% ventilation
Most need mechanical ventilation (paO2<8.3kpa despite 60% oxygenation, paCO2>6kPa)
Low tidal volume, pressure limited approach with low or moderate PEEP improves outcome.
What is the circulatory treatment of ARDS?
Invasice heamodynamic monitoring with arterial line nd swan-ganz catheter.
Conservative fluid management
Use vasodialtors, ionotropes and blood transfusion
What is the support for SEPSIS and ARDS?
Identify organisms
If not borad spectrum antibiotics- amox, gent (+/- Metronidazole)
What other support can be given in ARDS?
Nutritional support (try to avoid TPN) with high fat, antioxidant supplements
Steroids to avoid short term fat embolisation. Controversial in long term ARDS
What is to be kept in mind when looking at an AP chest x-ray?
Cant see pulmonary effusions
Heart will look enlarged
Describe the pathological changes that occur in ARDS?
Protein rich oedema Fibrin Hyaline membranes Denuded basement membranes Epithelial proliferation Fibroblast proliferation Scarring (interstitium and airspaces)
