Anaesthesia and aspiration pneumonitis

Aspiration pneumonitis describes the inflammatory reaction of the lung parenchyma following contamination by stomach contents. It is an uncommon but potentially lethal complication of general anaesthesia. Protection of the airway from contamination has long been one of the fundamentals of safe anaesthetic practice. Aspiration pneumonitis was first recorded by John Snow in 1858 but not scientifically described until 1946 by Curtis Mendelson, an American obstetrician, who differentiated between the airway obstruction due to inhalation of solid material and aspiration of liquids which resulted in an intense inflammatory reaction of the lung tissue manifesting as bronchospasm, pulmonary oedema and hypoxia. He identified general anaesthesia as a major contributory factor due to the loss of protective airway reflexes and as a result of related animal studies suggested that the aspiration of acidic material resulted in severe pulmonary impairment.