Accuracy of a Continuous Glucose Monitor in the Intensive Care Unit

Area of Science:

• Critical Care Medicine
• Endocrinology
• Medical Device Technology

Background:

• Continuous glucose monitoring (CGM) is standard for outpatient diabetes management but lacks approval for intensive care unit (ICU) use.
• Assessing CGM accuracy in ICUs is crucial for expanding its clinical application.

Purpose of the Study:

• To evaluate the accuracy of CGM glucose measurements in an ICU setting compared to standard methods.
• To identify device malfunctions, adverse events, and caregiver acceptance of CGM in the ICU.

Main Methods:

• Dexcom™ G7 CGM sensors were used in hyperglycemic ICU patients.
• CGM data were compared with simultaneous laboratory or point-of-care glucose measurements.
• Accuracy was assessed using Clarke Error Grid analysis and mean absolute relative difference (MARD).

Main Results:

• 99.7% of CGM readings fell within acceptable accuracy zones (Clarke Error Grid regions A or B).
• The overall MARD was 12.25%, indicating good agreement between CGM and standard measurements.
• No adverse events were linked to CGM use, and nurses reported no workflow concerns.

Conclusions:

• CGM glucose readings demonstrate reliability in specific critically ill patient populations within the ICU.
• CGM accuracy may be compromised in patients receiving high-dose vasopressors.
• Further research is warranted to explore CGM's role in enhancing ICU patient care.