Acute respiratory distress syndrome (ARDS) Flashcards
Define ARDS
Syndrome of acute & persistent lung inflammation w/ increased vascular permeability
Characteristics of ARDS
5
Acute onset
Bilateral infiltrates consistent w/ pulmonary oedema
Hypoxaemia
No clinical evidence of increased left arterial pressure (pulmonary capillary wedge pressure)
ARDS is severe end of spectrum of acute lung injury
Aetiology of ARDS
2
Severe insults to the lungs & other organs leads to the release of inflammatory mediators
These lead to increased capillary permeability, pulmonary oedema, impaired gas exchange & reduced lung compliance
Causes of ARDS
8
Sepsis Aspiration Pneumonia Pancreatitis Trauma/burns Transfusion Transplantation (bone marrow & lung) Drug overdose/reaction
3 pathological stages of ARDS
Exudative
Proliferative
Fibrotic
Epidemiology of ARDS
incidence
Annual UK incidence 1/6000
Presenting symptoms of ARDS
5
Rapid deterioration of respiratory function Dyspnoea Respiratory distress Cough Symptoms of CAUSE
Signs of ARDS on physical examination
6
Cyanosis Tachypnoea Tachycardia Widespread inspiratory crepitations Hypoxia refractory to oxygen treatment Signs are usually bilateral but may be asymmetrical in early stages
Investigations for ARDS - CXR
Bilateral alveolar infiltrates & interstitial shadowing
Investigations for ARDS - bloods
8
(to figure out cause) FBC U&Es LFTs ESR/CRP Amylase ABG Blood culture Plasma BNP < 100 pg/ml could distinguish ARDS from heart failure
Investigations for ARDS - echocardiography
2
Check for severe aortic or mitral valve dysfunction
Low left ventricular ejection fractions = haemodynamic oedema rather than ARDS
Investigations for ARDS - pulmonary artery catheterisation
Check pulmonary capillary wedge pressure (PCWP)
Investigations for ARDS - bronchoscopy
If cause cannot be determined from history
