Feasibility and Precision of Subcutaneous Continuous Glucose Monitoring in Patients Undergoing CABG Surgery

Objectives: To evaluate if subcutaneous continuous glucose monitoring (sCGM) is feasible in cardiac surgery and if reliable glucose values are reported under hypothermic extracorporeal circulation. Design: Feasibility trial. Setting: University hospital. Participants: Ten consecutive patients undergoing coronary artery bypass grafting. Interventions: Prior to surgery, during hypothermic extracorporeal bypass, and 48 hours postoperatively, arterial blood glucose samples were compared with sCGM every 30 minutes. Statistical analysis utilized Clarke's error grid and Bland-Altman plot. Measurements and Main Results: Three hundred fiftyone pairs of glucose measurements were recorded including 59 during hypothermic extracorporeal circulation. Agreement between these measurements was acceptable, with a regression line slope of 0.88 and an offset of 17.4 (p = 0.87). Error grid analysis indicated a safe margin of 99.1% within zone A (no clinical action needed) or zone B (values would not lead to inappropriate treatment). Only 0.9% were plotted in zone D (potentially dangerous failure). Measurements during hypothermic extracorporeal circulation were comparable. Correlation coefficient was 0.760. The offset regression line was more pronounced (50.9) with a flatter slope (0.640). Within the error grid all plot values were in zone A or B. Conclusions: sCGM compared with arterial blood gas glucose monitoring under hypothermic extracorporeal circulation appears to be feasible and reliable. (C) 2014 Elsevier Inc. All rights reserved.