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 A Review of Continuous Glucose Monitoring Data Interpretation in the Age of Automated Insulin Delivery

2019 ◽  
Vol 13 (4) ◽  
pp. 645-663 ◽  
Author(s):  
Laya Ekhlaspour ◽  
Ideen Tabatabai ◽  
Bruce Buckingham
Keyword(s):  
Closed Loop ◽  
Insulin Pump ◽  
Glucose Monitoring ◽  
Insulin Delivery ◽  
Data Interpretation ◽  
The United States ◽  
Continuous Glucose Monitor ◽  
Standard Format ◽  
Closed Loop Systems ◽  
Do It Yourself

Using a continuous glucose monitor (CGM) improves glycemic control in patients with type 1 diabetes. The ambulatory glucose profile (AGP) has been recommended as a standard method for reporting CGM data. However, in recently developed automated insulin delivery (AID) systems, a standard format for reporting data has not yet been developed. Instead, reports are specific to each system being used. Currently, the only FDA approved AID system is a hybrid closed-loop insulin pump. In these systems, the patient is still required to announce a meal, respond to alerts, and keep the system in automated insulin delivery. The integrated pump and sensor information provides insights into how the system is performing, and how to make changes to tunable parameters, such as carbohydrate to insulin ratios. The reports also offer a window into human behavior related to performing diabetes tasks, responding to alarms, reasons for exiting HCL, and how glycemic goals are being met. This article reviews the pump and CGM data provided by several of the current closed-loop systems with a focus on systems that are currently approved in the United States (MiniMed™ 670G, Tandem Basal:IQ) and those used by patients using do-it-yourself systems. A step-wise approach to reviewing the nuances of these systems is provided. The comparison may reinforce the importance of the continued need for streamlining a standard report for providers to be able to interpret the CGM data of these systems.

scholarly journals The Modelling, Simulation and FPGA-Based Implementation for Stepper Motor Wide Range Speed Closed-Loop Drive System Design

Machines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 56 ◽  
Author(s):  
Chiu-Keng Lai ◽  
Jhang-Shan Ciou ◽  
Chia-Che Tsai
Keyword(s):  
Embedded System ◽  
High Speed ◽  
Closed Loop ◽  
Open Loop ◽  
Drive System ◽  
Stepper Motor ◽  
Motor Drive ◽  
Digital Controllers ◽  
Loop Control ◽  
Wide Range

Owing to the benefits of programmable and parallel processing of field programmable gate arrays (FPGAs), they have been widely used for the realization of digital controllers and motor drive systems. Furthermore, they can be used to integrate several functions as an embedded system. In this paper, based on Matrix Laboratory (Matlab)/Simulink and the FPGA chip, we design and implement a stepper motor drive. Generally, motion control systems driven by a stepper motor can be in open-loop or closed-loop form, and pulse generators are used to generate a series of pulse commands, according to the desired acceleration/run/deceleration, in order to the drive system to rotate the motor. In this paper, the speed and position are designed in closed-loop control, and a vector control strategy is applied to the obtained rotor angle to regulate the phase current of the stepper motor to achieve the performance of operating it in low, medium, and high speed situations. The results of simulations and practical experiments based on the FPGA implemented control system are given to show the performances for wide range speed control.

The Role of Biomaterials in Insulin Delivery Systems

1980 ◽  
Vol 3 (5) ◽  
pp. 299-304 ◽  
Author(s):  
S.D. Bruck
Keyword(s):  
Blood Glucose ◽  
Glucose Sensor ◽  
Insulin Delivery ◽  
The United States ◽  
Delivery Systems ◽  
Open Loop ◽  
Health Concern ◽  
Glucose Levels ◽  
Blood Glucose Levels

The control of blood glucose levels in diabetes involving devices are critically reviewed, and the role of blood-contacting biomaterial components analyzed. These include mechanical insulin-delivery systems of the closed-loop type that require an electronic glucose sensor and feedback, and open-loop systems that deliver insulin without a sensor and feedback. Whole pancreatic and islet transplantations, islet encapsulation, and the potential role of polymeric sustained drug delivery systems are discussed. The medical and social impacts of diabetes mellitus are of prime public health concern and of even greater magnitude than those of heart disease in the United States. While future advances in device design, miniaturization, and biometrials technology will significantly add to the arsenal of therapeutic alternatives, devices capable of controlling blood glucose levels ought to be viewed as mere interim phases rather than as final goals of the problem.

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 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

Artificial Pancreas With Carbohydrate Suggestion Performance for Unannounced and Announced Exercise in Type 1 Diabetes

2020 ◽  
Vol 106 (1) ◽  
pp. 55-63
Author(s):  
Clara Viñals ◽  
Aleix Beneyto ◽  
Juan-Fernando Martín-SanJosé ◽  
Clara Furió-Novejarque ◽  
Arthur Bertachi ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Closed Loop ◽  
Insulin Pump ◽  
Artificial Pancreas ◽  
Cycle Ergometer ◽  
Open Loop ◽  
Target Range ◽  
Exercise Session ◽  
And Performance

Abstract Objective To evaluate the safety and performance of a new multivariable closed-loop (MCL) glucose controller with automatic carbohydrate recommendation during and after unannounced and announced exercise in adults with type 1 diabetes (T1D). Research Design and Methods A randomized, 3-arm, crossover clinical trial was conducted. Participants completed a heavy aerobic exercise session including three 15-minute sets on a cycle ergometer with 5 minutes rest in between. In a randomly determined order, we compared MCL control with unannounced (CLNA) and announced (CLA) exercise to open-loop therapy (OL). Adults with T1D, insulin pump users, and those with hemoglobin (Hb)A1c between 6.0% and 8.5% were eligible. We investigated glucose control during and 3 hours after exercise. Results Ten participants (aged 40.8 ± 7.0 years; HbA1c of 7.3 ± 0.8%) participated. The use of the MCL in both closed-loop arms decreased the time spent <70 mg/dL of sensor glucose (0.0%, [0.0-16.8] and 0.0%, [0.0-19.2] vs 16.2%, [0.0-26.0], (%, [percentile 10-90]) CLNA and CLA vs OL respectively; P = 0.047, P = 0.063) and the number of hypoglycemic events when compared with OL (CLNA 4 and CLA 3 vs OL 8; P = 0.218, P = 0.250). The use of the MCL system increased the proportion of time within 70 to 180 mg/dL (87.8%, [51.1-100] and 91.9%, [58.7-100] vs 81.1%, [65.4-87.0], (%, [percentile 10-90]) CLNA and CLA vs OL respectively; P = 0.227, P = 0.039). This was achieved with the administration of similar doses of insulin and a reduced amount of carbohydrates. Conclusions The MCL with automatic carbohydrate recommendation performed well and was safe during and after both unannounced and announced exercise, maintaining glucose mostly within the target range and reducing the risk of hypoglycemia despite a reduced amount of carbohydrate intake. Register Clinicaltrials.gov: NCT03577158

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