The evaluation of the ability of closed-loop glycemic control device to maintain the blood glucose concentration in intensive care unit patients

Objectives: Reduction in the variability of blood glucose concentration might be an important aspect of blood glucose management. A closed-loop glycemic control device (STG-22; NIKKISO, Tokyo, Japan) has been developed to maintain blood glucose levels within the target range through automatic infusion of insulin and glucose. We hypothesized that the STG-22 system could provide optimal blood glucose management without causing hypoglycemic events in patients admitted to intensive care units. In this study, we investigated the feasibility of glycemic control with the STG-22 system. Furthermore, we evaluated the variability in blood glucose concentration associated with the use of the STG-22 system. Design: Retrospective analysis. Setting: A five-bed medical/surgical intensive care unit in a university hospital. Patients: Two hundred eight patients admitted to the intensive care unit between August 2006 and July 2009. Interventions: None. Measurements and Main Results: We calculated the mean and sd of blood glucose concentrations in each patient during intensive insulin therapy (target range, 90-110 mg/dL) administered using STG-22. In addition, to evaluate the blood glucose control achieved using STG-22, the durations for which the blood glucose level was maintained at 70-110 mg/dL, 110-150 mg/dL, 150-180 mg/dL, and >180 mg/dL were calculated. The average operation time of STG-22 was 33.9 ± 42.4 hrs. The blood glucose level was maintained at 70-110 mg/dL for 49.5% of the study period; the corresponding values for 110-150 mg/dL, 150-180 mg/dL, and >180 mg/dL were 31.4%, 7.0%, and 6.9%, respectively. No hypoglycemic events occurred. The sd of blood glucose levels was 19.9 ± 10.9 mg/dL. After a level of 150 mg/dL was achieved, the sd of blood glucose was 12.6 ± 3.1 mg/dL. Conclusions: STG-22 can help maintain optimal blood glucose levels without causing hypoglycemia in patients admitted to the intensive care unit. In addition, the use of this device might help decrease the variability in blood glucose concentration. Further randomized clinical trials are required to elucidate whether the low glucose variability maintained using STG-22 can contribute to improving the outcomes of patients admitted to the intensive care unit.