scholarly journals Evaluation of Stochastic Adjustment for Glucose Sensor Bias During Closed-Loop Insulin Delivery

2014 ◽  
Vol 16 (3) ◽  
pp. 186-192 ◽  
Author(s):  
Craig Kollman ◽  
Peter Calhoun ◽  
John Lum ◽  
Werner Sauer ◽  
Roy W. Beck
Keyword(s):  
Closed Loop ◽  
Glucose Sensor ◽  
Insulin Delivery

Glucose Sensor Characteristics for Miniaturized Portable Closed-Loop Insulin Delivery: A Step Toward Implantation

Diabetes Care ◽  
1982 ◽  
Vol 5 (3) ◽  
pp. 213-217 ◽  
Author(s):  
B. J. Oberhardt ◽  
E. J. Fogt ◽  
A. H. Clemens
Keyword(s):  
Closed Loop ◽  
Glucose Sensor ◽  
Insulin Delivery

scholarly journals A Wearable Closed-Loop Insulin Delivery System Based on Low-Power SoCs

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 612 ◽  
Author(s):  
Jesús Berián ◽  
Ignacio Bravo ◽  
Alfredo Gardel ◽  
José Luis Lázaro ◽  
Sergio Hernández
Keyword(s):  
Embedded System ◽  
Closed Loop ◽  
Ad Hoc ◽  
Glucose Sensor ◽  
Insulin Pump ◽  
Insulin Delivery ◽  
Open Loop ◽  
Number Of Patients ◽  
Do It Yourself ◽  
Conventional Manner

The number of patients living with diabetes has increased significantly in recent years due to several factors. Many of these patients are choosing to use insulin pumps for their treatment, artificial systems that administer their insulin and consist of a glucometer and an automatic insulin supply working in an open loop. Currently, only a few closed-loop insulin delivery devices are commercially available. The most widespread systems among patients are what have been called the “Do-It-Yourself Hybrid Closed-Loop systems.” These systems require the use of platforms with high computing power. In this paper, we will present a novel wearable system for insulin delivery that reduces the energy and computing consumption of the platform without affecting the computation requirements. Patients’ information is obtained from a commercial continuous glucose sensor and a commercial insulin pump operating in a conventional manner. An ad-hoc embedded system will connect with the pump and the sensor to collect the glucose data and process it. That connection is accomplished through a radiofrequency channel that provides a suitable system for the patient. Thus, this system does not require to be connected to any other processor, which increases the overall stability. Using parameters configured by the patient, the control system will make automatic adjustments in the basal insulin infusion thereby bringing the patient’s glycaemia to the target set by a doctor’s prescription. The results obtained will be satisfactory as long as the configured parameters faithfully match the specific characteristics of the patient. Results from the simulation of 30 virtual patients (10 adolescents, 10 adults, and 10 children), using a python implementation of the FDA-approved (Food and Drug Administration) UVa (University of Virginia)/Padova Simulator and a python implementation of the proposed algorithm, are presented.

scholarly journals Control to Range for Diabetes: Functionality and Modular Architecture

2009 ◽  
Vol 3 (5) ◽  
pp. 1058-1065 ◽  
Author(s):  
Boris Kovatchev ◽  
Stephen Patek ◽  
Eyal Dassau ◽  
Francis J. Doyle ◽  
Lalo Magni ◽  
...  
Keyword(s):  
Closed Loop ◽  
Glucose Sensor ◽  
Insulin Pump ◽  
Insulin Delivery ◽  
Open Loop ◽  
Target Range ◽  
Closed Loop Control ◽  
Modular Architecture ◽  
Loop Control ◽  
Range Correction

Background: Closed-loop control of type 1 diabetes is receiving increasing attention due to advancement in glucose sensor and insulin pump technology. Here the function and structure of a class of control algorithms designed to exert control to range, defined as insulin treatment optimizing glycemia within a predefined target range by preventing extreme glucose fluctuations, are studied. Methods: The main contribution of the article is definition of a modular architecture for control to range. Emphasis is on system specifications rather than algorithmic realization. The key system architecture elements are two interacting modules: range correction module, which assesses the risk for incipient hyper- or hypoglycemia and adjusts insulin rate accordingly, and safety supervision module, which assesses the risk for hypoglycemia and attenuates or discontinues insulin delivery when necessary. The novel engineering concept of range correction module is that algorithm action is relative to a nominal open-loop strategy—a predefined combination of basal rate and boluses believed to be optimal under nominal conditions. Results: A proof of concept of the feasibility of our control-to-range strategy is illustrated by using a prototypal implementation tested in silico on patient use cases. These functional and architectural distinctions provide several advantages, including (i) significant insulin delivery corrections are only made if relevant risks are detected; (ii) drawbacks of integral action are avoided, e.g., undershoots with consequent hypoglycemic risks; (iii) a simple linear model is sufficient and complex algorithmic constraints are replaced by safety supervision; and (iv) the nominal profile provides straightforward individualization for each patient. Conclusions: We believe that the modular control-to-range system is the best approach to incremental development, regulatory approval, industrial deployment, and clinical acceptance of closed-loop control for diabetes.

scholarly journals Clinical experience with an implanted closed-loop insulin delivery system

2008 ◽  
Vol 52 (2) ◽  
pp. 349-354 ◽  
Author(s):  
Eric Renard
Keyword(s):  
Beta Cell ◽  
Clinical Experience ◽  
Closed Loop ◽  
Glucose Sensor ◽  
Insulin Delivery ◽  
Glucose Measurement ◽  
Diabetic Patients ◽  
Intravenous Glucose ◽  
Artificial Beta Cell ◽  
Sensor Structure

AIM: To report the first clinical experience with a prototype of implanted artificial beta-cell. METHODS: The Long-Term Sensor System® project assessed the feasibility of glucose control by the combined implantation of a pump for peritoneal insulin delivery and a central intravenous glucose sensor, connected physically by a subcutaneous lead and functionally by PID algorithms. It was performed in 10 type 1 diabetic patients from 2000 to 2007. RESULTS: No harmful complication related to implants occurred. Insulin delivery was affected by iterative but reversible pump slowdowns due to insulin precipitation. Glucose measurement by the intravenous sensors correlated well with meter values (r = 0.83-0.93, with a mean absolute deviation of 16.5%) for an average duration of 9 months. Uploading of pump electronics by PID algorithms designed for closed-loop insulin delivery allowed in-patient 48 hourtrials. CONCLUSION: Although the concept of a fully implantable artificial beta-cell has been shown as feasible, improvements in the sensor structure to increase its longevity and decrease sensor delay that affected closed-loop control at meal-times are expected.

scholarly journals Exploration of the Performance of a Hybrid Closed Loop Insulin Delivery Algorithm That Includes Insulin Delivery Limits Designed to Protect Against Hypoglycemia

2016 ◽  
Vol 11 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Martin de Bock ◽  
Julie Dart ◽  
Anirban Roy ◽  
Raymond Davey ◽  
Wayne Soon ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Closed Loop ◽  
Glucose Sensor ◽  
Insulin Delivery ◽  
Moderate Exercise ◽  
Closed Loop System ◽  
Carbohydrate Counting ◽  
Exercise Induced

Background: Hypoglycemia remains a risk for closed loop insulin delivery particularly following exercise or if the glucose sensor is inaccurate. The aim of this study was to test whether an algorithm that includes a limit to insulin delivery is effective at protecting against hypoglycemia under those circumstances. Methods: An observational study on 8 participants with type 1 diabetes was conducted, where a hybrid closed loop system (HCL) (Medtronic™ 670G) was challenged with hypoglycemic stimuli: exercise and an overreading glucose sensor. Results: There was no overnight or exercise-induced hypoglycemia during HCL insulin delivery. All daytime hypoglycemia was attributable to postmeal bolused insulin in those participants with a more aggressive carbohydrate factor. Conclusion: HCL systems rely on accurate carbohydrate ratios and carbohydrate counting to avoid hypoglycemia. The algorithm that was tested against moderate exercise and an overreading glucose sensor performed well in terms of hypoglycemia avoidance. Algorithm refinement continues in preparation for long-term outpatient trials.

1065-P: The Effect of a Closed-Loop Insulin Delivery System on Glycemic Control in Type 1 Diabetes

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 1065-P ◽  
Author(s):  
ANASTASIOS KOUTSOVASILIS ◽  
ALEXIOS SOTIROPOULOS ◽  
ANASTASIA ANTONIOU ◽  
VASILIOS KORDINAS ◽  
DESPINA PAPADAKI ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Glycemic Control ◽  
Delivery System ◽  
Closed Loop ◽  
Insulin Delivery ◽  
Insulin Delivery System

725-P: Reducing Hypoglycemic Risk during Postprandial Exercise with Closed-Loop Insulin Delivery in Adults with Type 1 Diabetes: Announced and Unannounced Exercise

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 725-P
Author(s):  
SEMAH TAGOUGUI ◽  
NADINE TALEB ◽  
CORINNE SUPPERE ◽  
INÈS BOUKABOUS ◽  
VIRGINIE MESSIER ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Closed Loop ◽  
Insulin Delivery
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