Why Can’t I Eat or Drink Before Surgery?

by | Apr 17, 2021

You have just been scheduled for surgery. Now, you have been told not to eat anything before surgery. You may have heard or had someone say that you need to be “NPO” for surgery. Nil Per Os (NPO) is a Latin term meaning “nothing by mouth.” 

When hunger strikes, you have likely wondered, “why can’t I eat or drink anything before surgery? Is it really that important?”

There are numerous reasons why it is dangerous to eat or drink before surgery. Before you become tempted to start snacking before your surgery, understand first that your decision could have extremely harmful consequences. Keep reading to learn more about why being NPO before surgery is so important.

Your Safety is Our Highest Concern

Patient safety is the main reason to have an empty stomach when having surgery or any other procedure involving anesthesia. You will receive specific instructions before any operation that requires anesthesia. It is imperative to follow those instructions. Anesthesia-related pulmonary aspiration (the entry of liquid or solid material from the stomach into the trachea and lungs) can result in adverse outcomes ranging from hypoxia to complete respiratory failure and death. The incidence of pulmonary aspiration during anesthesia is around one in every 2,000-3,000 surgeries.

There are certain risk factors that make a patient more likely to experience aspiration, even though it is important to note that the majority of patients undergoing anesthesia do not suffer from an aspiration event. These predisposing conditions include:

  • Gastrointestinal obstruction
  • Undergoing an emergency surgery
  • Having had a previous esophageal surgery
  • Lack of coordination of swallowing or respiration
  • Esophageal cancer
  • Hiatal hernia
  • Obesity

It is important for your anesthesia provider to be informed if you are experiencing any of these predisposing conditions. There are numerous strategies your anesthesia provider can take to significantly reduce your risks of pulmonary aspiration.

Avoiding Nausea and Vomiting After Surgery

Nausea and vomiting after surgery are the most common complications after surgery. Having an empty stomach before surgery is the best way to prevent nausea and vomiting after surgery. Additionally, if you still get nauseous and vomit, having an empty stomach reduces the risk of getting any stomach content in your lungs. When food, liquids or stomach contents gets into the lungs, it can cause damage to the lungs called aspiration pneumonia.

Reducing Your Risks for Aspiration Pneumonia

Aspiration Pneumonia can cause inflammation (swelling) or an infection of the lungs or large airways. A normal cough and gag reflex help prevent any water, food or saliva from “going down the wrong pipe” and entering the airway. Under general anesthesia or sedation, this normal cough and gag reflex is suppressed and does not prevent stomach contents, saliva or food from getting into the lungs. When foreign material gets into the airway, it can cause coughing, wheezing, shortness of breath and chest pain that can require hospitalization. In severe conditions, this can lead to long-term lung damage and even death. It is essential to follow specific instructions before any procedure to minimize any risk for any complications like aspiration pneumonia.

Common Guidelines and Recommendations

Guidelines and recommendations are carefully developed for patient safety. The following recommendations are general guidelines and are not to be replaced by any specific instructions provided by your surgeon or anesthesia provider about eating and drinking before any procedure. A patient that does not follow instructions could have their procedure canceled or postponed.

  • Adults are recommended not to eat any food or liquids eight hours before their scheduled arrival time for surgery. Eight hours is the time it takes a healthy individual to digest a regular sized meal. It may take longer to digest large, heavy meals with lots of fat. Certain medical conditions can delay stomach digestion like diabetes, obesity, acid reflux, and individuals with Hiatal Hernias may require more time to ensure the stomach is empty. Occasionally, it is acceptable to have clear liquids two hours before your arrival time. This includes water, sports drinks and black coffee with no cream or milk. Fruit smoothies or any juices with pulp are not clear liquids; these take longer than two hours to digest.
  • Infants and Children are recommended not to eat any food or liquids before their scheduled arrival time for surgery. Depending on the age of the child and specific procedure, guidelines can vary. It is essential to talk to your surgeon or the anesthesia provider for any particular eating and drinking guidelines.

If in Doubt, Ask Questions

Questions about certain circumstances? Rather than assuming it is okay to eat or drink something during a questionable time period, it is important to call your doctor’s office or anesthesia provider if you have any questions. Not following specific instructions can increase the risk of serious complications.

There are no silly questions when your safety is at stake!

Clear Liquids 2 hours Water, tea, black coffee, fruit juice without pulp, sports drink
Regular Meal 8 hours Meals that include any fat, or any meal over 8 0z.

If you are a patient looking for more information about what to expect from undergoing anesthesia care, you can learn more here