NPO (Nil Per Os)

Category: science

A medical instruction indicating that the animal must receive nothing by mouth, completely withholding food and liquids.

Derived from the Latin phrase meaning "nothing through the mouth," NPO status is standard protocol prior to general anesthesia. Fasting minimizes the stomach volume, reducing the risk of active vomiting and secondary fatal aspiration pneumonia during intubation and extubation cycles.

Common Examples

• The surgical checklist confirms the patient has been under NPO status since midnight to prepare for the exploratory laparotomy.
• NPO timelines drop significantly for pediatric or diabetic veterinary patients to prevent sudden dangerous drops in blood glucose levels.