Why Can’t I Eat Before Surgery?

DON’T FORGET YOUR PREOPERATIVE FASTING INSTRUCTIONS.

Strange as it may seem, not a week goes by at Grand River Hospital where someone forgets their preoperative eating and fasting instructions. Patients show up for their surgery only to be told that their operation or procedure is surely delayed or often even cancelled.  Everyone is unhappy, especially the patient.

Everyone is told to not eat any solid food after midnight. Most folks remember that part. You are also instructed that you may drink CLEAR liquids up to two hours before your scheduled procedure time. This is the more complicated part it seems. Clear liquids are liquids that you can see through clearly. For example, water, energy drinks, tea, black coffee, apple or cranberry juice. NOT included in the clear liquid list are; coffee with creamer, milk, milkshakes, juices with pulp or breakfast sandwiches. These rules are not arbitrary. The basic reason for avoiding all liquids other than clear liquids is that your stomach does not have to process clear liquids in any way. What comes in moves out rapidly. All other oral intake must be processed in the stomach for a period causing that liquid to remain in the stomach for a longer period. When you are sedated or anesthetized for your procedure, the muscles that keep your stomach contents from refluxing into your throat and possibly your lungs relax and greatly increasing your risk of a severe or even fatal lung infection.

Most medications can be taken with some type of clear liquid and should be taken in the morning with sips of water if that is your usual routine. If you need to take morning medicines with food, then you should take them after your procedure.

We see an ever-increasing number of patients who are taking GLP-1 medications for prediabetes, non-insulin dependent diabetes or weight management. These drugs include but are not limited to: Liraglutide (Victoza), semaglutide (Ozempic or Wegovy), and tirzepatide (Mounjaro or Zepbound). If you are taking any of these medications, there are special preoperative fasting considerations. Since all these medications work in part by lengthening the time for the stomach to empty, extra time is necessary to induce sedation or anesthesia safely. The current guidelines (as of November 2024) are these:  If you take an oral form of these medicines, you should withhold it for at least 24 hours prior to your procedure. That could be one or two days. If you take an injectable weekly type, you should hold it for one full week prior to your procedure.

As always, if you have any questions or concerns about the information presented above, contact your primary care provider, your surgeon or the anesthesia department at Grand River Hospital.