If you are scheduled for surgery, you have probably been told, “Do not eat or drink after a certain time.” This rule can feel frustrating, especially if you are hungry or nervous. But there are very important reasons for it.
At Iowa Specialty Orthopedics, our goal is to keep you as safe as possible before, during, and after surgery. Fasting before surgery is one of the most important steps you can take to protect your health and help your procedure go smoothly.
The Main Reason: Protecting Your Lungs
The main reason you cannot eat before surgery is to prevent a serious problem called aspiration.
What Is Aspiration?
Aspiration happens when food, liquid, or stomach acid travels up from the stomach and accidentally enters the lungs. This can cause:
- Breathing problems
- Lung injury
- Infection, such as aspiration pneumonia
- In severe cases, life-threatening complications
When you are awake, your body protects you with natural reflexes like coughing and swallowing. These reflexes help keep food out of your airway.
How Anesthesia Affects Your Body
During surgery, anesthesia is used to keep you comfortable and pain-free. However, anesthesia also:
- Relaxes your muscles
- Slows digestion
- Temporarily shuts down protective reflexes
This means you cannot cough or swallow if something comes up from your stomach. If your stomach is full, food or liquid can move into your lungs without you knowing it.
Fasting helps make sure your stomach is empty, which greatly reduces this risk.
Why Vomiting Is Also a Concern
Anesthesia can sometimes cause nausea or vomiting. If vomiting happens while you are asleep and your airway is not protected, stomach contents can enter the lungs.
Not eating before surgery helps:
- Lower the chance of vomiting
- Reduce nausea after surgery
- Create a safer environment during anesthesia
What Is NPO and Why Does It Matter?
You may hear your care team use the term NPO, which is from the Latin "nil per os" and means “nothing by mouth.” This includes food, drinks, gum, and candy.
NPO instructions are carefully timed to:
- Keep your airway safe
- Reduce surgical risks
- Prevent delays or cancellations
If fasting rules are not followed, your surgery may need to be postponed or rescheduled for safety reasons.
Typical Fasting Guidelines Before Surgery
Always follow the specific instructions given by your surgical team. In general, anesthesia guidelines include:
- 8 hours before surgery:
Stop eating heavy, fatty, or fried foods - 6 hours before surgery:
Stop eating light meals (such as toast) or drinking milk - 2 hours before surgery:
Stop drinking clear liquids
What Are Clear Liquids?
Clear liquids may include:
- Water
- Sports drinks
- Black coffee or tea (no milk or cream)
- Apple juice (no pulp)
In many cases, drinking clear liquids up to two hours before surgery is encouraged to help with hydration, but only if your doctor approves.
Special Situations to Know About
Medications
Some medications should be taken the morning of surgery with a small sip of water, while others should be stopped ahead of time. Always review your medication list with your provider.
Emergency Surgery
In emergencies, surgery cannot always wait. In these cases, anesthesia teams use special techniques to reduce aspiration risk as much as possible. Even so, planned fasting remains the safest approach whenever surgery is scheduled in advance.
What If You Accidentally Eat or Drink?
Be honest with your surgical team. This is very important.
If you eat or drink too close to surgery:
- Your team may delay or reschedule the procedure
- This decision is made to protect your safety
In some situations, tools like ultrasound may be used to check if your stomach is empty, but prevention is always best.
We’re Here to Help You Prepare Safely
At Iowa Specialty Orthopedics, your safety is our top priority. Our experienced orthopedic surgeons, anesthesia providers, and care teams take the time to explain each step of your surgical preparation so you feel informed and confident.
If you are preparing for surgery or want to learn more about what to expect, contact Iowa Specialty Orthopedics today. We are here to guide you every step of the way and help you have the safest, smoothest surgical experience possible.
To learn more about what to do before surgery, visit our surgery preparation page or request an appointment to speak with our orthopedic care team.
