NPO

Nil per os (Latin for 'nothing by mouth') — the pre-operative fasting status required before procedures under sedation or general anaesthesia. Modern guidelines from most anaesthetic societies permit clear liquids up to 2 hours pre-op, breast milk up to 4 hours, light meals up to 6 hours, and heavy/fatty meals up to 8 hours. Patients should follow the specific NPO instructions from their treating anaesthetist; ignoring NPO instructions is a common cause of procedure cancellation.