If you’ve ever needed a surgical procedure, chances are you were given strict instructions about abstaining from eating and drinking for a particular period of time before your surgery. While fasting can be uncomfortable, this requirement keeps you safe and helps your procedure go smoothly.
The Primary Reason
“The main risk we are trying to mitigate is something called aspiration, which is when stomach contents travel up the esophagus and then down into the lung causing injury,” says Cam Norris, MD, an anesthesiologist at University of Utah Health. “When you go to sleep with anesthesia, you are unable to protect your airway with typical reflexes like coughing. If you have just eaten, there is a real risk of those stomach contents going down into the lungs and causing a severe lung problem. The risk is much lower if you don’t have any food or liquid in your stomach.”
Aspiration can be life-threatening, and can lead to other serious complications such as:
- Aspiration pneumonia: When contents of the stomach enter the lungs, it can lead to an infection.
- Hypoxia: This life-threatening condition occurs when there are low levels of oxygen in the body.
- Acute respiratory distress syndrome (ARDS): Inhaling food or drink into your airway and lungs can damage your respiratory system and make it difficult for the body to get enough oxygen.
Typical Fasting Guidelines
Be sure to follow the specific directions your doctor gives to you. The American Society of Anesthesiology adheres to the following guidelines:
“We actually encourage patients to keep drinking clear liquid until two hours before surgery because it helps with hydration,” Norris says. “Clear liquids include water, sports drinks, and even black coffee—just don’t put any cream or milk in it.”
A light meal is considered something like plain toast with a clear liquid. Heavier meals, especially ones that are fried or high in fat, take longer to digest and therefore require more fasting time.
Aspiration can happen with both solids and liquids, which is why it’s important to carefully follow your doctor’s guidelines for fasting from food and beverages. Not adhering to these fasting guidelines could mean delaying or rescheduling your procedure to keep you safe under anesthesia.
Special Considerations
Unfortunately, sometimes emergencies happen, and someone may find themselves needing a surgery they weren’t planning on having that day.
“When there’s an emergency, the need for the surgery outweighs the risk of possible aspiration, so we adjust our technique to reduce the risk of aspiration,” Norris says. “We use higher doses of medications to help us place the breathing tube in 30 to 60 seconds after the patient falls asleep, instead of the standard procedure, which is to wait a couple of minutes while we help the body breathe without a breathing tube as the standard doses of medications take full effect. It may not seem like that big of a difference, but it can be the difference between aspirating and not aspirating.”
Norris says another important factor to consider is if the patient is taking GLP-1 medications, such as Ozempic. Since those medications prolong the amount of time food is in the stomach, patients have a different set of guidelines they must follow:
- Do not take the medication for a week before surgery
- Only consume clear liquids for 24 hours before surgery
If you do arrive for your procedure and you haven’t quite hit the minimum fasting period, an ultrasound can check to see if anything is still in your stomach. This can help doctors make the safest decision if you’re in a gray area of being close to your recommended fasting period.
However, taking care to follow the fasting guidelines will ensure that your procedure happens on time while also keeping you safe from aspirating.