Experience with the continuous glucose monitoring system in a medical intensive care unit.

Strict glycemic control improves clinical outcomes in critically ill patients. However, practical tools for frequent monitoring of blood glucose (BG) levels in the intensive care unit (ICU) are limited. The Continuous Glucose Monitoring System (CGMS, Medtronic MiniMed, Northridge, CA) is currently approved for detecting glycemic excursions in outpatients with diabetes mellitus. The use of this device has never been carefully examined in the inpatient setting. This preliminary study was designed to investigate the accuracy of the CGMS in critically ill patients admitted to a medical ICU (MICU). Subjects at risk for hyperglycemia were recruited from among all patients admitted to our MICU. CGMS sensors were implanted for up to 72 h. Study subjects wore between one and five consecutive sensors. Four or more standard capillary BG readings were recorded per 24 h. All paired meter-sensor (M-S) readings were used both for CGMS calibration and for data analysis. Twenty-two MICU patients wore 41 CGMS sensors, yielding 546 M-S BG pairs. Overall, the Pearson correlation coefficient ( r ) was 0.88, with a mean M-S difference of 3.3 +/- 26.7 mg/dL (0.6 +/- 17.4%) and a mean absolute M-S difference of 19.7 +/- 18.3 mg/dL (12.8 +/- 11.9%). Clarke Error Grid analysis categorized 98.7% of the M-S pairs within "clinically acceptable" zones A and B. The CGMS is promising for potential use in critically ill patients. If validated in larger studies, the device could serve as a useful research tool for investigating the role of hyperglycemia (and strict glycemic control) in ICU patients. If further developed as a "real-time" glucose sensor, CGMS technology could ultimately prove clinically useful in the ICU, by decreasing nursing workload and/or by providing alarm signals for impending glycemic excursions.

Implementation of a safe and effective insulin infusion protocol in a medical intensive care unit.

OBJECTIVE: In a recent randomized controlled trial, lowering blood glucose levels to 80-110 mg/dl improved clinical outcomes in critically ill patients. In that study, the insulin infusion protocol (IIP) used to normalize blood glucose levels provided valuable guidelines for adjusting insulin therapy. In our hands, however, ongoing expert supervision was required to effectively manage the insulin infusions. This work describes our early experience with a safe, effective, nurse-implemented IIP that provides detailed insulin dosing instructions and requires minimal physician input. RESEARCH DESIGN AND METHODS: We collected data from 52 medical intensive care unit (MICU) patients who were placed on the IIP. Blood glucose levels were the primary outcome measurement. Relevant clinical variables and insulin requirements were also recorded. MICU nurses were surveyed regarding their experience with the IIP. RESULTS: To date, our IIP has been employed 69 times in 52 patients admitted to an MICU. Using the IIP, the median time to reach target blood glucose levels (100-139 mg/dl) was 9 h. Once blood glucose levels fell below 140 mg/dl, 52% of 5,808 subsequent hourly blood glucose values fell within our narrow target range; 66% within a "clinically desirable" range of 80-139 mg/dl; and 93% within a "clinically acceptable" range of 80-199 mg/dl. Only 20 (0.3%) blood glucose values were <60 mg/dl, none of which resulted in clinically significant adverse events. In general, the IIP was readily accepted by our MICU nursing staff, most of whom rated the protocol as both clinically effective and easy to use. CONCLUSIONS: Our nurse-implemented IIP is safe and effective in improving glycemic control in critically ill patients.