Acute respiratory failure.
PaO2 < 60 mmHg, PaCO2 > 55 mmHg due to insufficient alveolar ventilation (diminished carbon dioxide excretion): chronic bronchitis and emphysema (COPD), chest-wall deformities, respiratory muscle weakness (e.g. Guillain-Barre syndrome), depression of the respiratory centre.
PaO2 75-100 mmHg
HCO3- 21-28 mmHg
Saturation vs. oxygenation
Syndrome of severe dyspnoea, tachypnoea, cyanosis refractory to oxygen therapy, a reduction in lung compliance (stiff lungs), diffuse alveolar infiltrates on the chest X-ray
Causes: sepsis, shock, fat embolism, trauma, burns, acute pancreatitis, inhalation of smoke and toxic gases, amniotic fluid aspiration... usu. a part of MOF
Mortality: > 50% overall
Exsudate vs. transsudate – laboratory features