This study evaluated the efficacy of using a hybrid closed loop (HCL) system in restoring hypoglycemia awareness in individuals with impaired awareness of hypoglycemia (IAH).
Participants with IAH ...(Gold score ≥4) were recruited into a randomized crossover pilot study. They participated in two 8-week periods using a HCL system (Medtronic 670G™) (intervention) and standard insulin pump therapy (control). Hyperinsulinemic hypoglycemic clamp studies were undertaken at baseline and at the end of each study period for the evaluation of the counter-regulatory hormonal and symptomatic responses to hypoglycemia.
Seventeen participants (mean age standard deviation 35.8 years 11.2 years) were included in the study. Peak epinephrine levels (median, interquartile range IQR) in response to hypoglycemia were similar postintervention and control periods; 234.7 pmol/L (109.2; 938.9) versus 188.3 pmol/L (133.7; 402.9),
= 0.233. However, both peak adrenergic and neuroglycopenic symptom scores were higher after intervention; 5.0 (4.5; 9.0) versus 4.0 (4.0; 5.5),
= 0.009, and 8.5 (6.0; 15.0) versus 6.5 (6.0; 7.0)
= 0.014, respectively. Self-reported hypoglycemia awareness improved: median (IQR) Gold score was 4.0 (3.0; 5.5) versus 5.5 (4.5; 6.0); intervention versus control,
= 0.033. Time spent <3.9 and <3.0 mmol/L was lower in the intervention group than in control,
= 0.002. Other patient-reported outcomes (hypoglycemia fear and diabetes treatment satisfaction) did not change.
A short-term use of a HCL system failed to demonstrate an improvement in counter-regulatory hormonal responses. However, higher hypoglycemia symptom scores during controlled hypoglycemia, better self-reported hypoglycemia awareness, and less time spent in hypoglycemia suggest the potential benefits of a HCL system in people with IAH.
anzctr.org.au Identifier: ACTRN12616000909426.
This study examines the problem of fault-tolerant sliding mode control (SMC) design subject to actuator saturation for a class of Takagi–Sugeno fuzzy systems with time-varying delay and external ...disturbances. Our main attention is to propose the fault-tolerant SMC such that for given any initial condition, the system trajectories are forced to reach the sliding surface within a finite time. On the basis of the SM surface and Lyapunov stability theorem, a new set of sufficient conditions in terms of linear matrix inequalities (LMIs) is established to not only guarantee the passivity and asymptotically stability of the resulting closed-loop system in the designed sliding surface, but also cover the issues of actuator saturation and performance constraints. Then, the desired gain matrix of the fault-tolerant SMC is obtained in respect of the previously established LMIs such that the reachability of the predefined sliding surface is ensured. It is worth pointing out that the obtained sufficient conditions can preserve the trade-off between the maximisation of admissible upper bound of time-varying delay and enlarging the estimation about the domain of attraction for the closed-loop system. Eventually, the effectiveness and robustness of the proposed control approach are demonstrated via simulation results.
Background
Interest is growing in how closed‐loop systems can support attainment of within‐target glucose levels amongst pregnant women with type 1 diabetes. We explored healthcare professionals' ...views about how, and why, pregnant women benefitted from using the CamAPS FX system during the AiDAPT trial.
Methods
We interviewed 19 healthcare professionals who supported women using closed‐loop during the trial. Our analysis focused on identifying descriptive and analytical themes relevant to clinical practice.
Results
Healthcare professionals highlighted clinical and quality‐of‐life benefits to using closed‐loop in pregnancy; albeit, they attributed some of these to the continuous glucose monitoring component. They emphasised that the closed‐loop was not a panacea and that, to gain maximum benefit, an effective collaboration between themselves, the woman and the closed‐loop was needed. Optimal performance of the technology, as they further noted, also required women to interact with the system sufficiently, but not excessively; a requirement that they felt some women had found challenging. Even where healthcare professionals felt that this balance was not achieved, they suggested that women had still benefitted from using the system. Healthcare professionals reported difficulties predicting how specific women would engage with the technology. In light of their trial experiences, healthcare professionals favoured an inclusive approach to closed‐loop rollout in routine clinical care.
Conclusions
Healthcare professionals recommended that closed‐loop systems be offered to all pregnant women with type 1 diabetes in the future. Presenting closed‐loop systems to pregnant women and healthcare teams as one pillar of a three‐party collaboration may help promote optimal use.
In this study, by means of the techniques of adaptive multi-dimensional Taylor network (MTN) control, the tracking problem of a class of stochastic non-linear systems with input delay is studied. ...Firstly, based on the Padé approximation method, a new variable is employed to overcome the problem of input delay, and MTNs are applied to estimate the non-linear functions in the design of the controller. Secondly, an adaptive MTN controller design scheme is developed in the framework of backstepping. Thirdly, the stability of the closed-loop system is analysed using Lyapunov's stability theory. Finally, the effectiveness of the proposed design approach is demonstrated by two examples.
Automation in diabetes technology is rapidly evolving. The aim was to evaluate the real-world glycemic outcomes and user acceptance after 3 months of using the Medtronic 780G Advanced Hybrid ...Closed-Loop (AHCL) system.
A prospective analysis was performed. A glucose target of 100 mg/dl and an active insulin time of 2 h were set. Capillary HbA1c, 2-week of pump and sensor data and several satisfaction questionnaire scores were compared at baseline and after 3 months of using the AHCL system.
52 subjects were selected (age: 43 ± 12 years, sex: 73% female, diabetes duration: 27 ± 11 years, higher education: 31%). Time in range (TIR) 70–180 mg/dl increased from 67.3 ± 13.6% to 80.1 ± 7.5% and time >180 mg/dl and >250 mg/dl were reduced (16.8 ± 8.4 vs 29.4 ± 15.1%, 2.7 ± 3.0% vs 6.9 ± 7.8%, respectively) (all p < 0.001), while time in hypoglycaemia remained below recommended targets. Time in Auto-Mode and sensor use were 94 ± 10% and 90 ± 11%, respectively. Auto-correction boluses represented 29 ± 12% of bolus insulin. Fear of hypoglycaemia, diabetes quality of life, sleep quality and satisfaction with the monitoring system improved after 3 months.
The real-world use of the AHCL system Medtronic 780G provides an 80.1% TIR 70–180 mg/dl with minimal hypoglycaemia and an increased level of patient satisfaction.
The COVID-19 pandemic has caused most waste recycling activities to be terminated due to several factors, such as concerns about the spread of coronavirus through the collected solid waste. This ...study investigates the socio-economic impact of the situation of the closed-loop system of solid waste recycling. Several recommendations for tackling this problem are presented in this research. Primary data collection for the waste bank and informal recycling sector was carried out in the eastern part of Surabaya during large-scale social restrictions. In-depth interviews were conducted with waste bank customers, waste bank unit representatives and the informal recycling sector to understand the pandemic’s socio-economic impact on the closed-loop system. Results show that this pandemic has significant impacts on individuals and stakeholders engaged in waste recycling activities. Customers of waste banks, who mostly belong to low-income communities, mentioned that the waste bank closure gave rise to social and economic problems, such as increasing unmanaged solid waste and decreasing income. This result also applied to the informal recycling sector. The government can use the recommendations in this study to generate related policies, such as enforcing the health protocol within solid waste management to keep the recycling system in place and the business alive.
A novel closed-loop numerical algorithm for subspace state space system identification (CN4SID) is proposed in this paper. Different from standard schemes, CN4SID algorithm can extend the standard LQ ...decomposition to the closed-loop cases by incorporating the controller information. Moreover, the proposed method can deliver unbiased pole estimation in the closed-loop framework. To this end, CN4SID algorithm shows superior pole estimation performance compared with a class of subspace identification method via principal component analysis algorithms. The effectiveness of the proposed CN4SID algorithm is finally verified through a practical dc motor system.
A post hoc analysis of the Diabeloop WP7 multicentre, randomized controlled trial was performed to investigate the efficacy of the Diabeloop Generation‐1 (DBLG1) closed‐loop system in controlling the ...hypoglycaemia induced by physical activity (PA) in real‐life conditions. Glycaemic outcomes were compared between days with and without PA in 56 patients with type 1 diabetes (T1D) using DBLG1 for 12 weeks. After the patient announces a PA, DBLG1 reduces insulin delivery and, if necessary, calculates the amount of preventive carbohydrates (CHO). Daily time spent in the interstitial glucose range less than 70 mg/dL was not significantly different between days with and without PA (2.0% ± 1.5% vs. 2.2% ± 1.1%), regardless of the intensity or duration of the PA. Preventive CHO intake recommended by the system was significantly higher in days with PA (41.1 ± 35.5 vs. 21.8 ± 28.5 g/day; P < .0001), and insulin delivery was significantly lower (31.5 ± 10.5 vs. 34.0 ± 10.5 U/day; P < .0001). The time spent in hyperglycaemia and the glycaemic variation coefficient increased significantly on days with PA. In real‐life conditions, the use of DBLG1 avoids PA‐induced hypoglycaemia. Insulin adjustments and preventive CHO recommendation may explain this therapeutic benefit.
In this study, a non-singular fast terminal sliding mode finite-time tracking control strategy is presented to improve response rapidity and control precision of a pneumatic servo system via an ...extended state observer. The extended state observer is designed to estimate total disturbances of the system. Moreover, the proposed controller is established to ensure good performances of the closed-loop system. In addition, both sufficiently small observation error and stabilisation of the closed-loop system are proved in finite time. Finally, experimental results show the effectiveness of the proposed method.
We recently reported that use of an "advanced" hybrid closed-loop system reduced hyperglycemia without increasing hypoglycemia compared to a first-generation system. The aim of this analysis was to ...evaluate whether this improved performance was specifically related to better mealtime glycemic control.
We conducted a secondary analysis of postprandial glycemic control in an open-label, multinational, randomized crossover trial of 112 participants with type 1 diabetes, aged 14-29, of the Medtronic MiniMed™ 670G hybrid closed-loop system (670G) versus the Medtronic advanced hybrid closed-loop (AHCL) system, for 12 weeks each. We compared glycemic and insulin delivery metrics over a 3 h horizon across all meals to assess system performance and outcomes.
Overall meal size and premeal insulin on board were similar during run-in and between 670G and AHCL arms. Compared with 670G arm, premeal, peak, and mean glucose levels were numerically lower in the AHCL arm (167 ± 23, 231 ± 23, and 177 ± 20 mg/dL vs. 175 ± 23, 235 ± 23, and 180 ± 19 mg/dL, respectively), with a trend to lower hyperglycemia level 2 in AHCL arm. Adjusting for premeal glucose level, all postmeal outcomes between 670G and AHCL were statistically similar. Prandial insulin delivery also was similar in both treatment arms (21 ± 9 vs. 23 ± 10 U), with a shift in basal/bolus ratio from 28%/71% in 670G arm to 20%/80% in AHCL arm.
Reduced hyperglycemia with AHCL compared to 670G was not related to early postprandial glycemic excursions after adjusting for premeal glucose level (<3 h after meal), but likely to later (>3 h) postprandial or overnight improvements. Further refinements to mealtime bolus algorithms and strategies may more optimally control prandial glycemic excursions.
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