Aspiration pneumonia has the potential to cause oxygen desaturation if the amount of inhaled material is high and the inflammation is severe. Aspiration pneumonia refers to the mistaken inhalation of foreign objects, such as food, stomach acid, or volatile substances, the lungs are damaged by chemical irritation or caused by lung infections, and the lesions can lead to respiratory failure in severe cases. Some patients mistakenly inhale a large amount of material, blocking the airway, if you can not remove the foreign body in time, not only will be secondary to infection, but also impede gas exchange, resulting in a decrease in oxygen saturation. Some patients with aspiration pneumonia secondary to serious infections, or patients with impaired consciousness due to weakened cough reflex, inflammation is difficult to eradicate, causing serious lung infections, not only can lead to low oxygen saturation, but also acute respiratory distress syndrome, carbon dioxide retention, acidosis, etc.. Aspiration pneumonia has the potential to progress to oxygen desaturation and respiratory failure, so immediate medical attention should be sought when aspiration is suspected.