CGM During Surgery: What the Latest Research Shows

What Was Studied and Why It Matters

For people with diabetes facing surgery, keeping blood sugar stable is critically important. Poor glucose control during and after an operation significantly raises the risk of serious complications — including infections, slower wound healing, and longer hospital stays. Traditionally, surgical teams have relied on finger-stick checks to monitor blood sugar, but these only give a snapshot in time. Researchers wanted to know: could continuous glucose monitors (CGMs) — the same wearable sensors many diabetes patients use at home — do a better job during surgery and recovery?

This 2025 systematic review, published in Diabetes, Obesity & Metabolism, pulled together 40 studies covering nearly 2,400 patients to answer exactly that question.

What the Research Found

The results were cautiously encouraging. Across all the studies reviewed, CGM sensors performed comparably to traditional finger-stick blood glucose testing — and in many cases, they showed a trend toward better control of high blood sugar (hyperglycemia) with fewer episodes of dangerous low blood sugar (hypoglycemia).

Key findings include:

• Accuracy held up reasonably well: Sensors showed a median error rate (called MARD) of around 14%, and roughly 99% of readings fell within clinically safe accuracy zones — meaning care teams could generally trust what the sensor was telling them.
• Real-time alerts made a difference: Unlike a finger-stick that requires a nurse to draw blood and wait for a result, CGM provided continuous trends and instant alerts when glucose was heading too high or too low.
• Usage was widespread: Sensors were used in the operating room itself (45% of studies) and in intensive care units after surgery (nearly 58% of studies).
• Technical problems occurred: About half the studies reported interference issues — things like body temperature changes, fluid buildup under the skin, electrical equipment used during surgery, and heart-lung bypass machines could temporarily throw off sensor readings. Importantly, accuracy typically recovered once surgery was complete.

What This Means for Real Patients

If you or a loved one with diabetes is scheduled for surgery — particularly heart or abdominal procedures — this research suggests CGM could become a valuable part of your surgical care team's toolkit. Rather than relying on periodic finger-stick checks alone, a CGM gives doctors and nurses a continuous picture of what your blood sugar is doing, making it easier to react quickly to dangerous swings.

That said, CGM is not yet standard practice in operating rooms, and your surgical team will likely still use traditional monitoring as a backup, especially given the known technical limitations during certain procedures.

For everyday management at home before and after surgery, having reliable CGM supplies matters just as much. MDS Diabetes offers a wide range of CGM sensors, transmitters, and related diabetes supplies to help patients stay prepared at every stage of their care.

Bottom Line

CGM sensors can track blood sugar safely and accurately during surgery and ICU recovery, and may reduce dangerous glucose swings compared to finger-stick checks alone. Technical challenges during surgery are real but usually temporary. Larger, high-quality clinical trials are still needed before CGM becomes the surgical standard of care — but the evidence so far is promising for patients with diabetes facing operations.