High Blood Sugar Levels After Surgery

How Diabetes and Blood Glucose Levels Can Affect Your Surgery Outcome

doctor talking to patient, surgeon talking to patient

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Having surgery can mean loads of added stress on the body, thanks to both the procedure itself and the anesthesia. The effects of this stress may result in elevated blood sugar (glucose) levels, and people with diabetes are especially likely to experience complications following a surgical procedure. But it's important to note that even those without diabetes may have increased glucose levels, too. Learn how surgery can affect your blood sugar, and how you can take appropriate steps to control your glucose before, during, and after surgery.

How Surgery Affects Blood Sugar

The physical and emotional stress of an operation and anesthesia, along with what can be significant changes in lifestyle, diet, and exercise before and after surgery, can all dramatically change an individual's glucose levels. Though all patients are at risk for high blood sugar levels after surgery due to stress, people with diabetes face even greater risks of complications after a procedure.

This is likely due to several factors. The physical trauma associated with surgery can result in an increase in the stress hormone cortisol, along with catecholamines (neurotransmitters released into the bloodstream when you're stressed), both of which may result in increased insulin resistance—a lack of sensitivity to normal levels of insulin, requiring more and more insulin to remove glucose from the bloodstream.

Additionally, high levels of insulin often seen in diabetes can make arteries and veins less flexible, restricting blood flow that leads to slower healing times and poor circulation to the heart and other organs.

How Uncontrolled Levels Impact Surgery and Recovery

Uncontrolled blood glucose can create complications for surgery patients, whether they have diabetes or not. Blood sugar that's even slightly elevated can lead to delayed healing and can increase your chances of getting a wound infection from less than two percent to over 10 percent. In general, the higher the blood sugar, the higher these risks.

Along with an increased chance of infection, additional risks include:

  • Slow or poor wound healing
  • Fluid and electrolyte imbalance
  • Kidney issues
  • Heart problems

This increase in complications risk is why you may find that even without diabetes you are having routine or even frequent glucose checks while recovering in the hospital after surgery.

Potential Complications and Solutions

There are several complications that may arise when undergoing surgery when you have diabetes.

Glucose Fluctuations

If you have diabetes, make sure your doctor has your blood sugar checked before meals and at bedtime while you're in the hospital. Checking your glucose during surgery is reasonable if the surgery is a lengthy one or if your glucose levels have been unpredictable.

Even those with diabetes who normally have well-controlled glucose levels thanks to diet and exercise can experience high levels of blood glucose during the hours and days following surgery. If your glucose is fluctuating widely between checks, you may even need to have it checked during the night if you're having symptoms of low or high blood glucose.

If you are having same-day surgery, have your blood glucose level checked before you leave the facility. If you have diabetes, you may want to test more frequently once you're home until you're completely healed.

Medication Interactions

Be sure to let your surgeon know which medications you're currently taking or have recently taken, as metformin, a common medication used to balance blood sugar, may increase the risk of lactic acidosis (a buildup of lactic acid in the blood) if not stopped for 48 hours prior to and 48 hours following surgery.

Other medications called SGLT2 inhibitors (gliflozins) may increase the risk of blood sugar issues during surgery, so be sure to provide your doctor with your complete list of current prescriptions, over-the-counter medications, and supplements.

Insulin Effects

If you take insulin, talk to your surgeon as well about what dose you should take the night before and/or the morning of your surgery. Both hyperglycemia (having too much glucose in the blood) and hypoglycemia (having too little glucose in the blood) can be dangerous for surgery.

Post-Surgery Management Tips

Your diabetes needs to be well controlled after your surgery as well to prevent complications such as wound infections, slow healing, and increased scarring. If your track record of taking care of yourself, dosing your medications as prescribed, and routinely checking your glucose level is poor, be sure to seek help from your healthcare team to put an effective treatment plan in place.

If you're experiencing symptoms post-surgery such as vomiting, lack of appetite, stress, pain, or if you've been prescribed medications that may increase your blood sugar, be prepared that you may need to extend your hospital stay so that your healthcare providers can adequately monitor your blood sugar.

Keep in mind that the following are essential to a quick and healthy recovery:

  • Eating appropriate foods after surgery (whole grains, fruits, vegetables, and lean protein)
  • Frequently checking your glucose levels
  • Taking your insulin or other diabetes medications as prescribed

Exercise is also an important part of recovery for people with or without diabetes and will help control glucose levels. Your surgeon will be the best judge of what type of physical activity is possible after surgery and how quickly you can attempt more strenuous exercise during your recovery. 

Simply checking your glucose levels more frequently than usual is one change in your daily routine that may have the single largest impact on how well and how quickly you heal after surgery.

A Word From Verywell

Surgery becomes more complicated when you have diabetes, for a number of different factors. It is worth the time and effort to work to control your glucose levels—both before and after surgery—to maintain good health and wellbeing. Doing so can help your body heal faster and avoid infection—a sure bonus during the post-operative period.

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