NPO after midnight? No thanks!

This morning, Dr. Johnson posed an interesting question: do we really need to be NPO after midnight before a minor procedure? This is the standing dictum, but why? How many hours pre-procedure – 4, 6, 8? Does it change based on the type of procedure being performed?

In 2011, the American Society of Anesthesiologists put forth revised guidelines on pre-operative fasting to reduce the risk of aspiration. The summary is below, but here is the punch-line: your patient may not need to be NPO at midnight (but don’t use this to start a fight!).

Fasting Recommendations

Ingested Material Minimum fasting Period
Clear liquids 2 hours
Breast milk 4 hours
Infant formula 6 hours
Nonhuman milk 6 hours
Light meal 6 hours



Take a look at the full guidelines here (website) or here (pdf).