Continuous peri-operative glucose monitoring in noncardiac surgery: A systematic review.

Background: Glucose management is an important component of peri-operative care. The usefulness of continuous glucose monitoring (CGM) in noncardiac surgery is uncertain.

Objective: To systematically assess the glycaemic profile and clinical outcome of patients equipped with a CGM device during the peri-operative period in noncardiac surgery.

Design: Systematic review.

Data sources: Electronic databases were systematically searched up to July 2024.

Eligibility criteria: Any studies performed in the peri-operative setting using a CGM device were included. Closed-loop systems also administering insulin were excluded. Analyses were stratified according to diabetes mellitus status and covered intra-operative and postoperative data. Outcomes included glycaemic profile (normal range 3.9 to 10.0 mmol l -1 ), complications, adverse events, and device dysfunction.

Results: Twenty-six studies (1016 patients) were included. Twenty-four studies were not randomised, and six used a control arm for comparison. In bariatric surgery, diabetes mellitus patients had a mean ± SD glucose of 5.6 ± 0.5 mmol l -1 , with 15.4 ± 8.6% time below range, 75.3 ± 5.5% in range and 9.6 ± 6.7% above range. During major surgery, diabetes mellitus patients showed a mean glucose of 9.6 ± 1.1 mmol l -1 , with 9.5 ± 9.1% of time below range, 56.3 ± 13.5% in range and 30.6 ± 13.9% above range. In comparison, nondiabetes mellitus patients had a mean glucose of 6.4 ± 0.6 mmol l -1 , with 6.7 ± 8.4% time below range, 84.6 ± 15.5% in range and 11.2 ± 4.9% above range. Peri-operative complications were reported in only one comparative study and were similar in CGM and control groups. Device-related adverse events were rare and underreported. In 9.21% of cases, the devices experienced dysfunctions such as accidental removal and issues with sensors or readers.

Conclusion: Due to the limited number of controlled studies, the impact of CGM on postoperative glycaemic control and complications compared with point-of-care testing remains unknown. Variability in postoperative glycaemic profiles and a device dysfunction rate of 1 in 10 suggest CGM should be investigated in a targeted surgical group.