The purpose of this research study is to test the accuracy of the Dexcom continuous glucose monitoring device during the cardiothoracic surgical procedure and recovery period in the Cardiac Intensive Care Unit. Readings from the device will be compared with the standard of care blood glucose levels that are obtained during your surgery and postoperatively.

The proposed study would examine 100 adult patients specifically undergoing cardiac surgical procedures with the explicit goal of comparing continuous glucose monitoring accuracy to point-of-care testing, particularly in the setting of physiologic perturbations due to vasopressors, acidosis, and hypothermia. With a large sample size and few stipulations on the included patients, this well-powered study would give broadly applicable guidance regarding continuous glucose monitoring use in this population. The study would establish a pathway to further research regarding optimizing continuous glucose monitoring accuracy, providing earlier detection of out-of-range glucose values, improving the precision of insulin titration, and ultimately improving glucose control in the cardiac surgical population, which may improve patient outcomes, including mortality. This would be the first study to describe intraoperative use of the newest Dexcom continuous glucose monitoring device, the G7, which has the shortest available warmup time and may be the most accurate continuous glucose monitoring device on the market.

Inclusion Criteria:

• 18 years of age or older
• Undergoing cardiac surgery with cardiopulmonary bypass at Atrium Health Wake Forest Baptist Medical Center

Exclusion criteria:

• Under 18 years of age
• Pregnant women
• Patients with a contraindication to device placement on the posterior arm, including rash, missing extremity, or existing line or device