Does Anesthesia Type Affect Blood Sugar During Surgery?

What This Study Found

This article describes a new clinical trial called GlucoVITAL, not a completed study. Researchers want to find out whether the type of anesthesia used during major surgery affects blood sugar control. They believe that intravenous (IV) anesthesia may cause fewer blood sugar spikes and swings than inhaled gas anesthesia — especially in people who have diabetes or insulin resistance.

Why Does Anesthesia Type Matter for Blood Sugar?

Most people don't realize that surgery itself can push blood sugar higher — even if you haven't eaten. The stress of surgery triggers hormones that raise glucose levels. But the anesthetic drugs used to keep you asleep may also play a role.

Two main types of anesthesia are used during surgery:

• Total intravenous anesthesia (TIVA): All drugs are delivered through an IV line
• Inhaled (inhalation) anesthesia: Gases like sevoflurane are breathed in through a mask

Earlier research hinted that inhaled gases might worsen blood sugar control more than IV drugs. High blood sugar after surgery — called postoperative hyperglycemia — is linked to infections, organ problems, and longer hospital stays. For people already managing diabetes, these risks are even greater.

What Will the GlucoVITAL Trial Actually Do?

The trial will enroll 450 adults aged 50 and older who are scheduled for planned (elective) major noncardiac surgery. Participants will be randomly assigned to receive either TIVA or inhaled anesthesia. Researchers will then closely monitor their blood sugar:

• Before surgery
• Immediately after surgery
• The morning after surgery
• For up to 10 days after surgery using a continuous glucose monitor (CGM)

The CGM being used is the Dexcom G7 — the same type of device many people with diabetes use at home. This is notable because the trial will also test how well CGM readings match standard blood glucose lab tests in a hospital surgery setting.

What Outcomes Are Researchers Tracking?

Beyond blood sugar numbers, the team will track serious outcomes including:

• Days alive and out of hospital within 30 days of surgery
• Postoperative complications rated moderate or severe
• Heart injury within 24 hours of surgery
• Infections within 30 days
• Need for blood pressure support medications

Why This Matters for People With Diabetes

If the trial confirms that IV anesthesia leads to better blood sugar control, it could change how anesthesiologists make decisions for patients with diabetes or prediabetes having major surgery. That's a significant number of people — diabetes affects roughly 1 in 8 adults, and many will need surgery at some point in their lives.

It's important to note this is a protocol paper — the trial plan, not the results. Results are not yet available. But the research design is rigorous, and the findings, when they come, could be genuinely practice-changing.

If you use a CGM like the Dexcom G7 to track your glucose day-to-day, you're already using the same technology researchers are relying on in this trial. Staying informed about your glucose patterns — not just during surgery, but every day — is one of the most powerful things you can do to protect your health. Explore CGM supplies and diabetes monitoring tools at mdsdiabetes.com.

Citation: Janssen, Dias, Hiller (2025). Glucose variability and mode of anaesthesia in major noncardiac surgery (GlucoVITAL): study protocol for a randomised controlled trial. BJA open. PMID: 40511259. DOI: 10.1016/j.bjao.2025.100419