Search

In the present era of near-continuous glucose monitoring (CGM) and automated therapeutic closed-loop systems, measures of accuracy and of quality of glucose control need to be standardized for licensing authorities and to enable comparisons across studies and devices. Adequately powered, good quality, randomized, controlled studies are needed to assess the impact of different CGM devices on the quality of glucose control, workload, and costs. The additional effects of continuing glucose control on the general floor after the ICU stay also need to be investigated. Current algorithms need to be adapted and validated for CGM, including effects on glucose variability and workload. Improved collaboration within the industry needs to be encouraged because no single company produces all the necessary components for an automated closed-loop system. Combining glucose measurement with measurement of other variables in 1 sensor may help make this approach more financially viable., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: JCP is a consultant for Edwards, Medtronic and Optiscan. JGC has consulted with Medtronic. RH has received speaker honoraria from Minimed Medtronic, Eli Lilly, BBraun, and Novo Nordisk, served on advisory panels for Eli Lilly, Novo Nordisk and Merck, received license fees from BBraun and Medtronic, and served as a consultant to BBraun. JIJ has received research funding and/or has been a consultant for Edwards Lifesciences, Medtronic Diabetes, GluMetrics, Glysure, Roche Diagnostics, Thermalin Diabetes, and Echo Therapeutics. JSK is a consultant for Edwards, Medtronic, Roche Diagnostics and Optiscan. CD is a consultant for Abbott, A. Menarini Diagnostics, Medtronic, Roche Diagnostics. LF has received speaking fees from Edwards Lifesciences., (© 2016 Diabetes Technology Society.)

Background: Using the standard venous reference for the evaluation of continuous glucose monitoring (CGM) systems could possibly negatively affect measured CGM accuracy since CGM are generally calibrated with capillary glucose and venous and capillary glucose concentrations differ. We therefore aimed to quantify the effect of using capillary versus venous glucose reference samples on estimated accuracy in capillary calibrated CGM., Methods: We evaluated 41 individuals with type 1 diabetes mellitus (T1DM) using the Dexcom G4 CGM system over 6 days. Patients calibrated their CGM devices with capillary glucose by means of the HemoCue system. During 2 visits, capillary and venous samples were simultaneously measured by HemoCue and compared to concomitantly obtained CGM readings. The mean absolute relative difference (MARD) was calculated using capillary and venous reference samples., Results: Venous glucose values were 0.83 mmol/L (15.0 mg/dl) lower than capillary values over all glycemic ranges, P < .0001. Below 4 mmol/l (72 mg/dl), the difference was 1.25 mmol/l (22.5 mg/dl), P = .0001, at 4-10 mmol/l (72-180 mg/dl), 0.67 mmol/l (12.0 mg/dl), P < .0001 and above 10 mmol/l (180 mg/dl), 0.95 mmol/l (17.1 mg/dl), P < .0001. MARD was 11.7% using capillary values as reference compared to 13.7% using venous samples, P = .037. Below 4 mmol/l (72 mg/dl) MARD was 16.6% and 31.8%, P = .048, at 4-10 mmol/l (72-180 mg/dl) 12.1% and 12.6%, P = .32, above 10 mmol/l (180 mg/dl) 8.7% and 9.2%, P = .82., Conclusion: Using capillary glucose concentrations as reference to evaluate the accuracy of CGM calibrated with capillary samples is associated with a lower MARD than using venous glucose as the reference. Capillary glucose concentrations were significantly higher than venous in all glycemic ranges., (© 2016 Diabetes Technology Society.)

Background: Hyperglycemia and hypoglycemia are associated with adverse clinical outcomes in intensive care patients. In product development studies at 4 ICUs, the safety and performance of an intravascular continuous glucose monitoring (IV-CGM) system was evaluated in 70 postsurgical patients., Methods: The GluCath System (GluMetrics, Inc) used a quenched chemical fluorescence mechanism to optically measure blood glucose when deployed via a radial artery catheter or directly into a peripheral vein. Periodic ultrasound assessed blood flow and thrombus formation. Patient glucose levels were managed according to the standard of care and existing protocols at each site. Reference blood samples were acquired hourly and compared against prospectively calibrated sensor results., Results: In all, 63 arterial sensors and 9 venous sensors were deployed in 70 patients. Arterial sensors did not interfere with invasive blood pressure monitoring, sampling or other aspects of patient care. A majority of venous sensors (66%) exhibited thrombus on ultrasound. In all, 89.4% (1383/1547) of arterial and 72.2% (182/252) of venous measurements met ISO15197:2003 criteria (within 20%), and 72.7% (1124/1547) of arterial and 56.3% (142/252) of venous measurements met CLSI POCT 12-A3 criteria (within 12.5%). The aggregate mean absolute relative difference (MARD) between the sensors and the reference was 9.6% for arterial and 14.2% for venous sensors., Conclusions: The GluCath System exhibited acceptable accuracy when deployed in a radial artery for up to 48 hours in ICU patients after elective cardiac surgery. Accuracy of venous deployment was substantially lower with significant rates of intravascular thrombus observed using ultrasound., (© 2015 Diabetes Technology Society.)

Hyperglycemia, hypoglycemia, and glycemic variability have been associated with increased morbidity, mortality, length of stay, and cost in a variety of critical care and non-critical care patient populations in the hospital. The results from prospective randomized clinical trials designed to determine the risks and benefits of intensive insulin therapy and tight glycemic control have been confusing; and at times conflicting. The limitations of point-of-care blood glucose (BG) monitoring in the hospital highlight the great clinical need for an automated real-time continuous glucose monitoring system (CGMS) that can accurately measure the concentration of glucose every few minutes. Automation and standardization of the glucose measurement process have the potential to significantly improve BG control, clinical outcome, safety and cost., (© 2015 Diabetes Technology Society.)

Background: Current methods of blood glucose (BG) monitoring and insulin delivery are labor intensive and commonly fail to achieve the desired level of BG control. There is great clinical need in the hospital for a user-friendly bedside device that can automatically monitor the concentration of BG safely, accurately, frequently, and reliably., Methods: A 100-patient observation study was conducted at 6 US hospitals to evaluate the first generation of the Intravenous Blood Glucose (IVBG) System (Edwards Lifesciences LLC & Dexcom Inc). Device safety, accuracy, and reliability were assessed. A research nurse sampled blood from a vascular catheter every 4 hours for ≤ 72 hours and BG concentration was measured using the YSI 2300 STAT Plus Analyzer (YSI Life Sciences). The IVBG measurements were compared to YSI measurements to calculate point accuracy., Results: The IVBG systems logged more than 5500 hours of operation in 100 critical care patients without causing infection or inflammation of a vein. A total of 44135 IVBG measurements were performed in 100 patients with 30231 measurements from the subset of 75 patients used for accuracy analysis. In all, 996 IVBG measurements were time-matched with reference YSI measurements. These pairs had a mean absolute difference (MAD) of 11.61 mg/dl, a mean absolute relative difference (MARD) of 8.23%, 93% met 15/20% accuracy defined by International Organization for Standardization 15197:2003 standard, and 93.2% were in zone A of the Clarke error grid. The IVBG sensors were exposed to more than 200 different medications with no observable effect on accuracy., Conclusions: The IVBG system is an automated and user-friendly glucose monitoring system that provides accurate and frequent BG measurements with great potential to improve the safety and efficacy of insulin therapy and BG control in the hospital, potentially leading to improved clinical outcomes., (© 2015 Diabetes Technology Society.)

Background: Continuous glucose monitoring (CGM) is a tool widely used in the treatment of patients with type 1 diabetes. The purpose of the current study was to evaluate whether accuracy and patient treatment satisfaction differ between the Enlite™ (Medtronic MiniMed, Inc., Northridge, CA) and Dexcom(®) (San Diego, CA) G4 PLATINUM CGM sensors., Subjects and Methods: Thirty-eight ambulatory patients with type 1 diabetes used the Dexcom G4 and Enlite sensors simultaneously for a minimum of 4 and maximum of 6 days. Patients measured capillary glucose levels with a HemoCue(®) (Ängelholm, Sweden) system six to 10 times a day. In addition, two inpatient studies were performed between Days 1-3 and 4-6., Results: The mean absolute relative difference (MARD) in blood glucose for the Dexcom G4 was significantly lower (13.9%) than for the Enlite sensor (17.8%) (P<0.0001). The corresponding MARDs for Days 1-3 were 15.0% versus 19.4% (P=0.0027) and 13.6% versus 15.9% (P=0.026) for Days 4-6. For glucose levels in the hypoglycemic range (<4.0 mmol/L), the MARD for the Dexcom G4 was 20.0% compared with 34.7% for the Enlite (P=0.0041). On a visual analog scale (VAS) (0-100), patients rated the Dexcom G4 more favorably than the Enlite in 12 out of the 13 user experience questions. For example, more patients rated their experience with the Dexcom G4 as positive (VAS, 79.7 vs. 46.6; P<0.0001) and preferred to use it in their daily lives (VAS, 79.1 vs. 42.1; P<0.0001)., Conclusions: The Dexcom G4 sensor was associated with greater overall accuracy than the Enlite sensor during initial (Days 1-3) and later (Days 4-6) use and for glucose levels in the hypoglycemic range. Patients reported a significantly more positive experience using the Dexcom G4 than the Enlite.

Patients managed in the intensive care units (ICUs) and general wards of the hospital experience a high incidence of hyperglycemia, hypoglycemia, and glycemic variability, despite significant hospital resources devoted to glucose control. Optimized glucose meters and monitoring systems are required to improve the safety and efficacy of insulin delivery and glucose control in the hospital. Safe insulin dosing requires timely and accurate glucose measurements, especially during dynamic changes in nutrition, insulin sensitivity, and physiological stress. In the current issue of Journal of Diabetes Science and Technology, Mitsios and coauthors describe the analytical accuracy of the new Accu-Check® Inform II blood glucose (BG) monitoring system commercialized by F. Hoffmann-La Roche Ltd. The point-of-care glucose meter achieved the desired degree of accuracy and precision, as defined by Clinical and Laboratory Standards Institute POCT12-A3 guidelines when evaluated using venous blood from 600 critically ill patients from multiple ICUs at two medical centers. Venous whole blood samples were used to obtain glucose meter results in duplicate. The remaining blood sample was centrifuged to obtain plasma for central hospital laboratory testing using the hexokinase method within 5 min of meter testing. A total of 98.8% of the 1200 Accu-Check Inform II meter's glucose values were within ± 12.5% (± 12 mg/dl) of the mean laboratory glucose value, and 99.8% were within ± 20% (± 20 mg/dl), thus meeting the Clinical and Laboratory Standards Institute criteria. Future studies are required to evaluate the clinical performance of the new BG monitoring system in the intended-use patient populations and critical care environments, using arterial, peripheral venous, central venous, and capillary blood samples., (© 2013 Diabetes Technology Society.)

The management reporting and assessment of glycemic control lacks standardization. The use of different methods to measure the blood glucose concentration and to report the performance of insulin treatment yields major disparities and complicates the interpretation and comparison of clinical trials. We convened a meeting of 16 experts plus invited observers from industry to discuss and where possible reach consensus on the most appropriate methods to measure and monitor blood glucose in critically ill patients and on how glycemic control should be assessed and reported. Where consensus could not be reached, recommendations on further research and data needed to reach consensus in the future were suggested. Recognizing their clear conflict of interest, industry observers played no role in developing the consensus or recommendations from the meeting. Consensus recommendations were agreed for the measurement and reporting of glycemic control in clinical trials and for the measurement of blood glucose in clinical practice. Recommendations covered the following areas: How should we measure and report glucose control when intermittent blood glucose measurements are used? What are the appropriate performance standards for intermittent blood glucose monitors in the ICU? Continuous or automated intermittent glucose monitoring - methods and technology: can we use the same measures for assessment of glucose control with continuous and intermittent monitoring? What is acceptable performance for continuous glucose monitoring systems? If implemented, these recommendations have the potential to minimize the discrepancies in the conduct and reporting of clinical trials and to improve glucose control in clinical practice. Furthermore, to be fit for use, glucose meters and continuous monitoring systems must match their performance to fit the needs of patients and clinicians in the intensive care setting.

Objective: This study shows the potential of continuous glucose monitoring (CGM) for the detection of hypoglycemia in hospitalized patients., Research Design and Methods: A Medtronic Diabetes (Northridge, CA) CGMS iPro continuous glucose recorder was inserted into the subcutaneous tissue of a hospitalized orthopedic surgery patient with type 1 diabetes the day after a moderate hypoglycemia event. The interstitial fluid glucose concentration was recorded every 5 min. Both the patient and the hospital staff were blinded to the CGM data. Bedside capillary blood glucose measurements were performed per hospital protocol., Results: The CGM recorded a repeat severe episode of hypoglycemia the next day. The hospital-defined threshold for hypoglycemia (70 mg/dL) was crossed 4.5 h prior to the patient being found unconscious by the nursing staff., Conclusion: Data from the CGMS iPro Recorder illustrate the potential benefit of using a real-time CGM in the hospital to detect hypoglycemia in a more timely fashion compared to infrequent point-of-care glucose meter measurements.

Automation and standardization of the glucose measurement process have the potential to greatly improve glycemic control, clinical outcome, and safety while reducing cost. The resources required to monitor glycemia in hospitalized patients have thus far limited the implementation of intensive glucose management to patients in critical care units. Numerous available and up-and-coming technologies are targeted for the hospital patient population. Advantages and limitations of these devices are discussed herewith in.

The automated insulin delivery systems show great promise to maintain the patient's BG concentration in the target range while eliminating the risk for hypoglycemia, especially when the clinical situation is changing rapidly in the operative room or ICU. We believe that using blood glucose value as the sixth vital sign and the implementation of continuous glucose monitoring systems (CGM or glucose sensors) in the hospital setting would significantly improve perioperative glycemic control. Insulin was not started until 9 am when his BG was 30.5 mmol/l. This emphasizes the importance of glucose control even in patients who are not diagnosed as having diabetes. [Extracted from the article]