NPO guidelines; or, A simple request of my fellow doctors, and some patients too.

NPO (Nil Per Os) means nothing by mouth.  It means that a patient cannot have anything to eat before surgery, or in my case, endoscopy.  There is a simple reason for this: If food or liquid is present in the stomach when anesthesia is given to a patient, that food or liquid can make its way from the stomach into the lungs with disastrous consequences.  This is called aspiration, and happens because anesthesia removes or lessens the gag and cough reflexes which usually protect against aspiration.

NPO no eating sign

There are well-established guidelines for NPO status.  Clear liquids can be had up to two hours before anesthesia.  Examples of clear liquids are juice, tea, black coffee, water, jello, Italian ices, etc.  Here are some examples of what are NOT considered clear liquids: juice with pulp, milk, alcohol, coffee with milk, broth with fat.   Solid food can be had up to eight hours before a procedure.  There are some guidelines that say a “light meal” that contains little or no fat can be had up to six hours before anesthesia, but let’s focus on the eight hour rule to keep everything easier to remember.  The important thing to remember is that solid food is a binary concept.  This means that the only acceptable answers to the question “Did you have anything to eat in the last eight hours?” is either “yes,” or “no.”  There is no category for “well, I had a small cookie, and a little piece of cheese”; that is a “yes” response.

Most people know that they cannot eat anything after midnight if they have a procedure scheduled the next day. However, what about when a procedure is not actually scheduled? Sometimes a little bit of common sense and a little foresight needs to be applied to avoid having a procedure delayed an entire day because of the NPO rules.  Here are two common situations that I encounter (without exaggeration) several times per week:

Me (at 4PM on a Friday): “Well, you have been vomiting blood and passing melena since last night, so we need to do an endoscopy ASAP.”

ER patient: “Let’s do it doc!”

Me: “What was the last thing you had to eat or drink?”

ER patient: “I stopped at Burger King on the way over here since I figured I was going to be waiting for a few hours.  But I only had some fries.”



And here is the other situation:

Other doctor at 1PM: “Hey, can you see this patient today? He came in late last night with trouble swallowing and weight loss.  He also had some chest pain, so they ‘cathed’ him this morning and it was negative.  I think he needs an endoscopy.”

Me: “Sure, I can get him on the schedule for this afternoon.”

Other doctor: “Great, I’d like to discharge him home today if everything checks out OK.  He doesn’t meet admission criteria and is on observation status.”

Me: “No problem, I’ll go see him now.  The endoscopy suite doesn’t close until 7PM, so we’ll get it done!”

Mr. Patient (sipping coffee with milk): “Hey doc! The other doctor told me you were coming to scope me! When can we get it over with? I want to go home tonight!”

Me (looking at the bedside table with an empty lunch tray, empty juice containers, empty butter packets, etc.): “D’oh!!!”

So doctors, if you are calling GI for a consult that may reasonably lead to a procedure, please keep the patient NPO until we evaluate them.  And patients, please don’t eat if you think you might have a procedure done that day.  If you are starving, then please just have clears.  I know it’s painful, but so is another night or entire weekend in the hospital waiting for a test to be done.

If you enjoyed this article, sign up for our free newsletter and never miss a post! 


Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures: An Updated Report by the American Society of Anesthesiologists Committee on Standards and Practice Parameters. Anesthesiology 2011;114:495-511.

Image via Brandon Grasley