Objective: To establish a rabbit hypoglycemic model and evaluate the accuracy and timeliness of continuous subcutaneous glucose monitoring system (CGMS) in hypoglycemic monitoring.
Method: 16 white rabbits from New Zealand were randomly divided into 4 groups, 4 rabbits in each group. The control group received continuous intravenous injection of normal saline, and the experimental group received continuous intravenous injection of insulin. According to different doses, they are divided into insulin 0.1U/(kg·H) group (RI = 0.1U group) and insulin 0.2U/(kg·H) group. (RI = 0.2U group) and insulin 0.4U/(kg·H) group (RI = 0.4U group). During the test, CGMS was monitored for 240 minutes, blood was collected from the ear vein every 30 minutes, and blood glucose was monitored using a portable blood glucose meter (BG monitoring value).
Results: During the investigation period, a total of 1296 CGMS monitoring data were collected, and 136 BG monitoring data matching the time of CGMS were obtained. After insulin injection, BG and CGMS were significantly reduced. The reduction rates of BG and CGMS in the I = 0.1U group were 0.016 and 0.017 mmol/L/min, respectively. The reduction rates of BG and CGMS in the RI = 0.2U group were 0.04 and 0.027 mmol/L/min, respectively, with RI = 0.4, The U groups are 0.049 and 0.032 mmol/L/min, respectively. BG-CGMS divides the data into hypoglycemic and normoglycemic, depending on whether the BG monitoring value is less than 4.4 mmol/L. The average deviation of BG-CGMS in hypoglycemia is 0.55 mmol/L (upper and lower limits: -0.98 to 2.08 mmol/L), and the absolute difference rate (RAD) is 40.2%±45.2%, while BG- in normal blood sugar. The average deviation of CGMS was -0.19 mmol/L (upper/lower limit: -1.38 to 1.00 mmol/L), and the RAD was 5.8%±5.3%. Error grid analysis (EGA) shows that area A is 93.4%, area B is 0.7%, area D is 5.9%, and area D is distributed in areas with low BG and high CGMS.
Conclusion: The results of this study show that CGMS has a significant hysteresis when blood sugar drops faster. If blood sugar drops below 4.4 mmol/L, CGMS may overestimate blood sugar. This risk should be fully considered in the clinical application of CGMS.