Accuracy and Feasibility of Real-time Continuous Glucose Monitoring in Critically Ill Patients after Abdominal Surgery and Solid Organ Transplantation

Objectives: Glycemia management in critical care is posing a challenge in frequent measuring and adequate insulin dose adjustment. In recent years continuous glucose measurement is gaining accuracy and reliability in outpatient and inpatient setting. The aim of this study was to assess the feasibility and accuracy of real-time continuous glucose monitoring in ICU patients after major abdominal surgery.

Research design and methods: We included patients undergoing pancreatic surgery and solid organ transplantation (liver, pancreas, islets of Langerhans, kidney) requiring ICU stay after surgery. We used a Dexcom G6 sensor, placed in the infraclavicular region, for rtCGM. Arterial blood glucose measured by the amperometric principle (ABL 800, Radiometer, Copenhagen, Denmark) served as reference values and for calibration. Blood glucose was also routinely monitored by StatStrip bedside glucose meter. Sensor accuracy was assessed by mean absolute relative difference (MARD), bias, modified Bland-Altman plot and Surveillance Error Grid for paired samples of glucose values from CGM and ABL.

Results: We analyzed data from 61 patients and obtained 1546 paired glucose values from CGM and ABL. Active sensor use was 95.1%. MARD was 9.4%, relative bias 1,4%, 92.8% values fell in zone A, 6.1% in zone B and 1.2% in zone C of Surveillance Error Grid. Median time in range was 78%, with minimum (<1%) time spent in hypoglycemia. StatStrip glucose meter MARD compared to ABL was 5.8%.

Conclusions: Our study shows clinically applicable accuracy and reliability of Dexcom G6 CGM in postoperative ICU patients and a feasible alternative sensor placement site.