Use of Flash Glucose Monitoring during the Perioperative Period of Cardiac Surgery in a Patient with Type 1 Diabetes Mellitus

: FreeStyle Libre (flash glucose monitoring) is useful to control the blood sugar levels of outpatients with diabetes. We used FreeStyle Libre for a patient with type 1 diabetes mellitus during the perioperative period of cardiac surgery except during and just after surgery. We adjusted the insulin amount according to the glucose level of the device before surgery and prevented prolonged hypoglycemia. After surgery, we could also adjust the blood sugar levels using the device until discharge. All data were within zones A and B of the Clarke error grid analysis when referred to as arterial blood sugar levels in the intensive care unit. In the general ward after surgery, 95% of the data referred to as venous blood sugar levels were within zones A and B. FreeStyle Libre was useful for adjusting the amount of insulin for a patient with type 1 diabetes mellitus during the perioperative period of cardiac surgery in the ward and also might be useful for decreasing the frequency of arterial blood collection in the intensive care unit.