Performance of a factory-calibrated, real-time continuous glucose monitoring system during elective abdominal surgery

We assessed the performance of the factory-calibrated, sixth-generation continuous glucose monitoring (CGM) system Dexcom G6 (R) (DexCom Inc., San Diego, California) during elective abdominal surgery. Twenty adults with (pre)diabetes undergoing abdominal surgery (>2 hours; 15 men, age 69 +/- 13 years, glycated haemoglobin 53 +/- 14 mmol/mol) wore the sensor from 1 week prior to surgery until hospital discharge. From induction of anaesthesia until 2 hours post-surgery, reference capillary glucose values were obtained every 20 minutes using the Accu-Chek (R) Inform II meter (Roche Diabetes Care, Mannheim, Germany). The primary endpoint was the mean absolute relative difference (ARD) between sensor and reference method during this period. In total, 1207 CGM/reference pairs were obtained. In the peri-operative period (523 pairs), mean +/- SD and median (interquartile range [IQR]) ARD were 12.7% +/- 8.7% and 9.9 (6.3;15.9)%, respectively, and 67.4% of sensor readings were within International Organization of Standardization 15197:2013 limits. CGM overestimated reference glucose by 1.1 +/- 0.8 mmol/L (95% limits of agreement -0.5;2.7 mmol/L). Clarke error grid zones A or B contained 99.2% of pairs (A: 78.8%; B: 20.4%). The median (IQR) peri-operative sensor availability was 98.6 (95.9;100.0)%. No clinically significant adverse events occurred. In conclusion, the Dexcom G6 device showed consistent and acceptable accuracy during elective abdominal surgery, opening new avenues for peri-operative glucose management.