[Show abstract][Hide abstract] ABSTRACT: The Space GlucoseControl system (SGC) is a nurse-driven, computer-assisted device for glycemic control combining infusion pumps with the enhanced Model Predictive Control algorithm (B. Braun, Melsungen, Germany). We aimed to investigate the performance of the SGC in medical critically ill patients.
[Show abstract][Hide abstract] ABSTRACT: Background: Glycaemic management in the hospital is based on glucose point-of-care testing (POCT) which lacks continuous information particularly in detecting hypoglycaemic events. The aim of this study was to analyse and compare the capability to detect hypoglycaemic events (<70 mg/dl) with either standard glucose POCT or continuous glucose monitoring (CGM) in hospitalized type 2 diabetes patients on basal-bolus insulin therapy. Methods: A total of 59 patients with type 2 diabetes (age: 68.9±9.5 yr, DM duration 14.3±10.3 yr, A1C: 8.5±3%, BMI: 29.9±6 kg·m-2, length of stay 8±4.5 days (mean±SD)) were treated with basal-bolus insulin therapy. Glucose POCT was performed at least 4 times per day (premeal, before bedtime), CGM was performed with the iPro2 system (MiniMed Medtronic) which was calibrated with the blood glucose measurements retrospectively. Results: 8,578 hours were recorded with 1,480 paired blood glucose-sensor readings. After adjusting the offset of sensor data 35 hypoglycaemic events (<70 mg/dl) were detected with glucose POCT compared to 134 detected by CGM. The majority of hypoglycaemic events that were detected with CGM occurred during the night (see Fig. 1). Sensitivity to detect hypoglycaemic events with the CGM was 42 %. Conclusion: Although the sensitivity of the CGM sensor signal system was low the data indicate a high number of hypoglycaemic events (<70 mg/dl) are not detected with standard glucose POCT in particular during the night. Better performing CGM sensors are needed for detecting hypoglycaemic events in clinical routine. Acknowledgement: The study is supported by the European Commission, Project REACTION (FP7-248590).
[Show abstract][Hide abstract] ABSTRACT: Standardized insulin order sets for subcutaneous basal-bolus insulin therapy are recommended by clinical guidelines for the inpatient management of diabetes. The algorithm based GlucoTab system electronically assists health care personnel by supporting clinical workflow and providing insulin-dose suggestions. To develop a toolbox for improving clinical decision-support algorithms. The toolbox has three main components. 1) Data preparation: Data from several heterogeneous sources is extracted, cleaned and stored in a uniform data format. 2) Simulation: The effects of algorithm modifications are estimated by simulating treatment workflows based on real data from clinical trials. 3) Analysis: Algorithm performance is measured, analyzed and simulated by using data from three clinical trials with a total of 166 patients. Use of the toolbox led to algorithm improvements as well as the detection of potential individualized subgroup-specific algorithms. These results are a first step towards individualized algorithm modifications for specific patient subgroups.
Studies in health technology and informatics 01/2014; 198:248.
[Show abstract][Hide abstract] ABSTRACT: To evaluate glycemic control and usability of a workflow-integrated algorithm for basal-bolus insulin therapy in a proof-of-concept study to develop a decision support system in hospitalized patients with type 2 diabetes.
In this ward-controlled study, 74 type 2 diabetes patients (24 female, age 68 ± 11 years, HbA1c 8.7 ± 2.4%, BMI 30 ± 7) were assigned to either algorithm-based treatment with a basal-bolus insulin therapy or to standard glycemic management. Algorithm performance was assessed by continuous glucose monitoring and staff's adherence to algorithm-calculated insulin dose.
Average blood glucose levels (mmol/l) in the algorithm group were significantly reduced from 11.3 ± 3.6 (baseline) to 8.2 ± 1.8 (last 24h) over a period of 7.5 ± 4.6 days (p < 0.001). The algorithm group had a significantly higher percentage of glucose levels in the ranges from 5.6-7.8 mmol/l (target range) and 3.9-10.0 mmol/l compared to the standard group (33% vs. 23% and 73% vs. 53%, both p < 0.001). Physicians' adherence to the algorithm-calculated total daily insulin dose was 95% and nurses' adherence to inject the algorithm-calculated basal and bolus insulin doses was high (98% and 93%). In the algorithm group significantly more glucose values <3.9 mmol/l were detected in the afternoon relative to other times (p < 0.05), a finding mainly related to pronounced morning glucose excursions and requirements for corrective bolus insulin at lunch.
The workflow-integrated algorithm for basal-bolus therapy was effective in establishing glycemic control and was well accepted by medical staff. Our findings support the implementation of the algorithm in an electronic decision support system.
Diabetes Obesity and Metabolism 08/2013; · 5.18 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Successful control of hyperglycemia has been shown to improve outcomes for diabetes patients in a clinical setting. We assessed the quality of physician-based glycemic management in two general wards, considering the most recent recommendations for glycemic control for noncritically ill patients (<140 mg/dl for premeal glucose). METHODS: Quality of glycemic management of 50 patients in two wards (endocrinology, cardiology) was assessed retrospectively by analyzing blood glucose (BG) levels, the glycemic management effort, and the online questionnaire. RESULTS: Glycemic control was clearly above the recommended target (mean BG levels: endocrinology: 175 ± 62 mg/dl; cardiology: 186 ± 68 mg/dl). When comparing the first half with the second half of the hospital stay, we found no difference in glycemic control (endocrinology: 168 ± 32 vs 164 ± 42 mg/dl, P = .67; cardiology: 174 ± 36 mg/dl vs 170 ± 42 mg/dl, P =.51) and in insulin dose (endocrinology: 15 ± 14 IU vs 15 ± 13 IU per day, P = .87; cardiology: 27 ± 17 IU vs 27 ± 18 IU per day, P = .92), despite frequent BG measurements (endocrinology: 2.7 per day; cardiology: 3.2 per day). A lack of clearly defined BG targets was indicated in the questionnaire. CONCLUSION: The recommended BG target range was not achieved in both wards. Analysis of routine glycemic management demonstrated considerable glycemic management effort, but also a lack of translation into adequate insulin therapy. Implementation of corrective measures, such as structured treatment protocols, is essential.
Journal of diabetes science and technology 03/2013; 7(2):402-409.
[Show abstract][Hide abstract] ABSTRACT: Purpose
To evaluate the effects of audit and feedback on service delivery and patient functioning in Austrian Geriatric Acute Care Units.
Quality initiative based on a standardised documentation form (core and optional data set) and a web-based performance feedback with peer comparison in 18 Geriatric Acute Care Units, representing 40% of all Austrian units. Main outcome measures were compliance with desired practice of geriatric care (comprehensive geriatric assessment [CGA], therapeutic consequences), discharge characteristics and mortality.
Overall 22,279 patient records were documented between 2008 and 2010. Active involvement in the web-based feedback system was indicated by a high frequency of data queries per year, 1401, 3148 and 2883 for 2008, 2009 and 2010, respectively. The mean completion rate for CGA tests increased from 73% in 2008 to 78% in 2010 (P < 0.05). For centres with completion of core and optional data (n = 8), the average number of documented therapeutic interventions increased from 4.4 to 5.0 (P < 0.05). Those aspects of CGA focusing on activities of daily living, mobility and cognition prompted the greatest degree of corresponding therapeutic interventions (> 90%). A lower intervention rate was induced by the nutritional assessment (< 20%). Mortality and discharge characteristics such as level of care and percentage of patients living at home after discharge did not change over the time.
Following implementation of a web-based performance feedback with peer comparison in Austrian Geriatric Acute Care Units, an improvement in health care professionals’ compliance with desired practice of geriatric care, but not in patients’ discharge characteristics, was observed.
European geriatric medicine 01/2013; · 0.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We aimed to investigate the performance of the Space GlucoseControl system (SGC) (B. Braun, Melsungen, Germany) in medical critically ill patients. The SGC is a nurse-driven, computer-assisted device for glycemic control combining infusion pumps with the enhanced Model Predictive Control algorithm.
The trial was designed as a single-center, open clinical investigation in a nine-bed medical intensive care unit in a tertiary center in Graz, Austria. Efficacy was assessed by percentage of time within the target range (4.4-8.3 mmol/L; primary end point), mean blood glucose, and sampling interval. Safety was assessed by the number of hypoglycemic episodes (≤2.2 mmol/L).
Twenty mechanically ventilated patients (age, 63±16 years; body mass index, 31.0±10.7 kg/m(2); Acute Physiology and Chronic Health Evaluation II score, 25.4±6.3; 14 males; six with diabetes) were included for a period of 7.0±3.6 days. Time within target range was 83.4±8.9% (mean±SD), and mean arterial blood glucose was 6.8±0.4 mmol/L. No severe hypoglycemic episodes (<2.2 mmol/L) occurred, and the percentage of time within 2.2 and 3.3 mmol/L was low (0.03±0.07%). The sampling interval was 2.0±0.4 h. The mean insulin dose was 93.5±80.1 IU/day, and the adherence to the given insulin dose advice was high (98.3%). A total of 11 unintended therapy interruptions (0.08 events/treatment day) caused by software problems occurred in four patients.
SGC is a safe and efficient method to control blood glucose in critically ill patients in the medical intensive care unit.
[Show abstract][Hide abstract] ABSTRACT: Continuous subcutaneous glucose monitoring has been tested in type 1 diabetes (T1D). Since in critically ill patients vascular access is granted vascular microdialysis may be preferential. To test this hypothesis comparative accuracy data for microdialysis applied for peripheral venous and subcutaneous glucose monitoring was obtained in experiments in T1D patients. Twelve T1D patients were investigated for up to 30 h. Extracorporeal vascular (MDv) and subcutaneous microdialysis (MDs) was performed. Microdialysis samples were collected in 15-60 min intervals, analyzed for glucose and calibrated to reference. MDv and MDs glucose levels were compared against reference. Median absolute relative difference was 14.0 (5.0; 28.0)% (MDv) and 9.2 (4.4; 18.4)% (MDs). Clarke Error Grid analysis showed that 100% (MDv) and 98.8% (MDv) were within zones A and B. Extracorporeal vascular and standard subcutaneous microdialysis indicated similar performance in T1D. We suggest microdialysis as a versatile technology for metabolite monitoring in subcutaneous tissue and whole blood.
Diabetes research and clinical practice 03/2012; 97(1):112-8. · 2.74 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In hypertensive diabetic patients, reducing blood pressure is among the best evaluated and most effective interventions for lowering mortality and morbidity. First line antihypertensive agents are: chlorthalidone or other thiazide-type diuretics, β-blockers and ACE-inhibitors. In type 2 diabetic patients with left ventricular hypertrophy, the ARB Cosaar has been proven to be effective. To achieve an effective blood pressure reduction, a combination of different antihypertensive agents is necessary for most patients. Specially structured patient education programmes are another effective means of achieving this goal.
Wiener Medizinische Wochenschrift 08/2011; 153(21-22).
[Show abstract][Hide abstract] ABSTRACT: Numerous guidelines and algorithms exist to achieve glycemic control. Their strengths and weaknesses are difficult to assess without head-to-head comparison in time-consuming clinical trials. We hypothesized that computer simulations may be useful.
Two open-label randomized clinical trials were replicated using computer simulations. One study compared performance of the enhanced model predictive control (eMPC) algorithm at two intensive care units in the United Kingdom and Belgium. The other study compared three glucose control algorithms-eMPC, Matias (the absolute glucose protocol), and Bath (the relative glucose change protocol)-in a single intensive care unit. Computer simulations utilized a virtual population of 56 critically ill subjects derived from routine data collected at four European surgical and medical intensive care units.
In agreement with the first clinical study, computer simulations reproduced the main finding and discriminated between the two intensive care units in terms of the sampling interval (1.3 h vs. 1.8 h, United Kingdom vs. Belgium; P < 0.01). Other glucose control metrics were comparable between simulations and clinical results. The principal outcome of the second study was also reproduced. The eMPC demonstrated better performance compared with the Matias and Bath algorithms as assessed by the time when plasma glucose was in the target range between 4.4 and 6.1 mmol/L (65% vs. 43% vs. 42% [P < 0.001], eMPC vs. Matias vs. Bath) without increasing the risk of severe hypoglycemia.
Computer simulations may provide resource-efficient means for preclinical evaluation of algorithms for glycemic control in the critically ill.
[Show abstract][Hide abstract] ABSTRACT: This study evaluated the predictive capability of simple linear extrapolation of continuous glucose data in postsurgical patients undergoing intensive care.
Twenty patients, both with or without an established diagnosis of diabetes mellitus, scheduled to undergo cardiothoracic surgery were included. Glucose was continuously monitored in the intensive care unit with a microdialysis-based subcutaneous glucose monitoring system. The prediction horizon (PH) with respect to a given glucose reading was calculated by extrapolating the linear trend of the glucose signal and subjected to both analytical and clinical assessment (by calculation of the average duration of consecutive positive and negative glucose signal trends, the root mean squared error [RMSE], and by insulin titration error grid [ITEG] analysis, respectively).
In total, 609 h of continuous glucose data from 17 patients were analyzed. The average duration of consecutive positive and negative glucose signal trends was 7.97 (3.99-19.98) min (median, interquartile range). An increase in the RMSE of 0.5 mmol/L (9 mg/dL) was associated with a PH of 37 min. A strong increase in the number of data points in the unacceptable violation zone of the ITEG was associated with a PH of approximately 20 min.
Our data provide evidence that simple linear extrapolation of glucose trend information obtained by continuous glucose monitoring can be used to predict the course of glycemia in critically ill patients for up to 20-30 min. This "glimpse into the future" can be used to proactively prevent the occurrence of adverse events.
[Show abstract][Hide abstract] ABSTRACT: Diabetes mellitus is one of the most widespread diseases in the world. People with diabetes usually have long stays in hospitals and need specific treatment. In order to support in-patient care, we designed a prototypical mobile in-patient glucose management system with decision support for insulin dosing. In this paper we discuss the engineering process and the lessons learned from the iterative design and development phases of the prototype. We followed a user-centered development process, including real-life usability testing from the outset. Paper mock-ups in particular proved to be very valuable in gaining insight into the workflows and processes, with the result that user interfaces could be designed exactly to the specific needs of the hospital personnel in their daily routine.
Studies in health technology and informatics 01/2011; 169:950-4.
[Show abstract][Hide abstract] ABSTRACT: Glycemic control of intensive care patients can be beneficial for this patient group but the continuous determination of their glucose concentration is challenging. Current continuous glucose monitoring systems based on the measurement of interstitial fluid glucose concentration struggle with sensitivity losses, resulting from biofouling or inflammation reactions. Their use as decision support systems for the therapeutic treatment is moreover hampered by physiological time delays as well as gradients in glucose concentration between plasma and interstitial fluid. To overcome these drawbacks, we developed and clinically evaluated a system based on microdialysis of whole blood. Venous blood is heparinised at the tip of a double lumen catheter and pumped through a membrane based micro-fluidic device where protein-free microdialysate samples are extracted. Glucose recovery as an indicator of long term stability was studied in vitro with heparinised bovine blood and remained highly stable for 72 h. Clinical performance was tested in a clinical trial in eight healthy volunteers undergoing an oral glucose tolerance test. Glucose concentrations of the new system and the reference method correlated at a level of 0.96 and their mean relative difference was 1.9 +/- 11.2%. Clinical evaluation using Clark's Error Grid analysis revealed that the obtained glucose concentrations were accurate and clinically acceptable in 99.6% of all cases. In conclusion, results of the technical and clinical evaluation suggest that the presented device delivers microdialysate samples suitable for accurate and long term stable continuous glucose monitoring in blood.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to investigate the performance of the enhanced Model Predictive Control (eMPC) algorithm for glycemic control in medical critically ill patients for the whole length of intensive care unit (ICU) stay.
The trial was designed as a single-center, open, noncontrolled clinical investigation in a nine-bed medical ICU in a tertiary teaching hospital. In 20 patients, blood glucose (BG) was controlled with a laptop-based bedside version of the eMPC. Efficacy was assessed by percentage of time within the target range (4.4-6.1 mM; primary end point), mean BG, and BG sampling interval. Safety was assessed by the number of severe hypoglycemic episodes (<2.2 mM).
Twenty patients (69 +/- 11 years old; body mass index, 27.4 +/- 4.5 kg/m(2); APACHE II, 25.5 +/- 5.2) were included for a period of 7.3 days (median; interquartile range, 4.4-10.2 days) in the study. Time within target range was 58.12 +/- 10.05% (mean +/- SD). For all patients with at least 7 days in the ICU, there was no statistically significant difference between the daily mean percentage of times in target range in respect of the averages. Mean arterial BG was 5.8 +/- 0.5 mM, insulin requirement was 101.3 +/- 50.7 IU/day, and mean carbohydrate intake (enteral and parenteral nutrition) was 176.4 +/- 61.9 g/day. Three hypoglycemic episodes occurred in three subjects, corresponding to a rate of 0.02 per treatment day.
In our single-center, noncontrolled study the eMPC algorithm was a safe and reliable method to control BG in critically medical ICU patients for the whole length of ICU stay.
[Show abstract][Hide abstract] ABSTRACT: To compare the accuracy of two marketed subcutaneous glucose monitoring devices (Guardian RT, GRT; GlucoDay S, GDS) and standard microdialysis (CMA60; MD) in Type 1 diabetic patients.
Seven male Type diabetic patients were investigated over a period of 26 h simulating real-life meal glucose excursions. Catheters of the three systems were inserted into subcutaneous adipose tissue of the abdominal region. For MD, interstitial fluid was sampled at 30- to 60-min intervals for offline glucose determination. Reference samples were taken at 15- to 60-min intervals. All three systems were prospectively calibrated to reference. Median differences, median absolute relative differences (MARD), median absolute differences (MAD), Bland-Altman plot and Clark Error Grid were used to determine accuracy.
Bland-Altman analysis indicated a mean glucose difference (2 standard deviations) between reference and interstitial glucose of -10.5 (41.8) % for GRT, 20.2 (55.9) % for GDS and 6.5 (35.2) % for MD, respectively. Overall MAD (interquartile range) was 1.07 (0.39; 2.04) mmol/l for GRT, 1.59 (0.54; 3.08) mmol/l for GDS and 0.76 (0.26; 1.58) mmol/l for MD. Overall MARD was 15.0 (5.6; 23.4) % (GRT), 19.7 (6.1; 37.6) % (GDS) and 8.7 (4.1; 18.3) % (MD), respectively. Total sensor failure occurred in two subjects using GRT and one subject using GDS.
The three investigated technologies had comparable performance. Whereas GRT underestimated actual blood glucose, GDS and MD overestimated blood glucose. Considerable deviations during daily life meal glucose excursions from reference glucose were observed for all three investigated technologies. Present technologies may require further improvement until individual data can lead to direct and automated generation of therapeutic advice in diabetes management.
Diabetic Medicine 03/2010; 27(3):332-8. · 3.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cytokines are inflammatory mediators of major relevance during sepsis. Recent evidence shows that adipose tissue can produce many distinct cytokines under physiological and pathological conditions, but the role of cytokines produced in adipose tissue was not addressed in sepsis. In the present study the open-flow microperfusion (OFM) technique was used to investigate whether the cytokines produced in subcutaneous adipose tissue (SAT) of patients with severe sepsis correlate with clinical variables. Interstitial fluid effluent samples were collected using an OFM catheter inserted in the abdominal SAT of nine patients with severe sepsis. Blood samples were withdrawn concomitantly and interleukin-1beta (IL-1beta), IL-8, IL-6 and tumor necrosis factor alpha (TNF-alpha) were measured both in SAT effluent and serum samples. Different time profiles were registered for each cytokine. IL-1beta increased in a time-dependent manner, indicating a localized response against the catheter insertion. Interleukin-1beta, 6 and 8 were higher in SAT than in serum suggesting they were locally produced. Diastolic blood pressure (DBP) negatively correlated with IL-1beta, IL-6 and IL-8 in SAT indicating a possible interaction between adipose tissue inflammation and vascular tone regulation. A multiple regression analysis disclosed that mean DBP was significantly related to IL-6 concentrations in SAT (B=-43.9; R-square=0.82; P=0.002).