The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Bruce A Buckingham - One of the best experts on this subject based on the ideXlab platform.
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127 lb longevity of the coated convatec Infusion Set with lantern technology
Diabetes, 2019Co-Authors: Pernelle K Schondorff, Matthias Heschel, Bruce A BuckinghamAbstract:Objective: Current insulin Infusion Sets are approved for 2-3 days of wear; however, glucose sensors are approved for 7-14 days of wear. A commonly reported reason for discontinuing use of CGM within 1 year is not wanting to wear devices on two sites of the body. Any attempt to create a combined glucose sensor and Infusion Set for closed-loop control requires a Set with greater longevity. The coated ConvaTec Infusion Set with Lantern Technology is a new Infusion Set with multiple slits and coating intended to reduce foreign body response and occlusion from bending or kinking. Methods: A pilot safety and extended wear tolerability study is being performed at Stanford University. To date, 15 adult subjects on tethered insulin pump therapy using insulin aspart or lispro have completed the study. Each participant places the Set and wears it for 10 days or until Set failure to establish a maximum length of Infusion Set wear when 80% of Sets are still functional (excluding accidental “pull-outs”). Infusion Set failures are based on: (1) Presence of serum ketones with hyperglycemia; (2) Unexplained hyperglycemia, unresolved with correction dose; (3) Signs of infection at the Infusion site; (4) Pump occlusion alarm; and (5) Adhesive failure. Results: Two subjects did not meet failure criteria and were excluded. Of the remaining, 6 (46%) wore the novel Infusion Set the full 10 days and all Sets lasted 7 days or more (mean 8.8 days). 3 premature Set failures were associated with persistent hyperglycemia unresponsive to correction boluses on days 7-8, 3 with adhesive failure on days 7-9, and 1 with infection on day 9. Conclusions: In our previous studies assessing 353 Infusion Set insertions for 7 days, average length of wear was 5.1 ± 1.7 days. Thus far, the novel Set has demonstrated increased longevity. The duration of wear established in this pilot study will be used to perform a masked, randomized controlled crossover study comparing the coated ConvaTec Infusion Set with Lantern Technology against standard Infusion Sets. Disclosure R. Lal: Consultant; Self; Abbott. P.K. Schondorff: Employee; Self; ConvaTec Inc. L. Hsu: None. M. Heschel: Employee; Self; Unomedical a/s. B.A. Buckingham: Advisory Panel; Self; ConvaTec Inc., Novo Nordisk Inc., Profusa, Inc. Consultant; Self; Medtronic MiniMed, Inc. Research Support; Self; Beta Bionics, ConvaTec Inc., Dexcom, Inc., Insulet Corporation, Medtronic MiniMed, Inc., Tandem Diabetes Care. Other Relationship; Self; Insulet Corporation, Tandem Diabetes Care.
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continuous glucose monitoring enables the detection of losses in Infusion Set actuation lisas
Sensors, 2017Co-Authors: Daniel P Howsmon, Bruce A Buckingham, Trang T. Ly, Gregory P. Forlenza, Nihat Baysal, Faye Cameron, David M Maahs, Juergen Hahn, B W BequetteAbstract:Reliable continuous glucose monitoring (CGM) enables a variety of advanced technology for the treatment of type 1 diabetes. In addition to artificial pancreas algorithms that use CGM to automate continuous subcutaneous insulin Infusion (CSII), CGM can also inform fault detection algorithms that alert patients to problems in CGM or CSII. Losses in Infusion Set actuation (LISAs) can adversely affect clinical outcomes, resulting in hyperglycemia due to impaired insulin delivery. Prolonged hyperglycemia may lead to diabetic ketoacidosis—a serious metabolic complication in type 1 diabetes. Therefore, an algorithm for the detection of LISAs based on CGM and CSII signals was developed to improve patient safety. The LISA detection algorithm is trained retrospectively on data from 62 Infusion Set insertions from 20 patients. The algorithm collects glucose and insulin data, and computes relevant fault metrics over two different sliding windows; an alarm sounds when these fault metrics are exceeded. With the chosen algorithm parameters, the LISA detection strategy achieved a sensitivity of 71.8% and issued 0.28 false positives per day on the training data. Validation on two independent data Sets confirmed that similar performance is seen on data that was not used for training. The developed algorithm is able to effectively alert patients to possible Infusion Set failures in open-loop scenarios, with limited evidence of its extension to closed-loop scenarios.
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early detection of Infusion Set failure during insulin pump therapy in type 1 diabetes
Journal of diabetes science and technology, 2016Co-Authors: Marzia Cescon, Bruce A Buckingham, Trang T. Ly, Laurel H. Messer, Daniel J. Desalvo, David M Maahs, Francis J Doyle, Eyal DassauAbstract:Background:Insulin Infusion Set failure resulting in prolonged hyperglycemia or diabetic ketoacidosis can occur with pump therapy in type 1 diabetes. Set failures are frequently characterized by va...
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Improving Patient Experience With Insulin Infusion Sets Practical Guidelines and Future Directions
The Diabetes Educator, 2016Co-Authors: Alison B. Evert, Bruce A Buckingham, Carol A Verderese, Bruce W. Bode, Elizabeth Nardacci, Phyllis Wolff-mcdonagh, John Walsh, Irl B. HirschAbstract:PurposeInsulin Infusion Sets (IISs) are an essential component of safe and effective insulin pump therapy. Establishing best practices for their use has been impeded by a lack of formal study and limited resources for clinician and patient education. Recent innovations in IIS science promise to change this status quo by increasing awareness of such problems as unexplained hyperglycemia and Infusion Set occlusion.MethodsIn August 2015, a panel of diabetologists and certified diabetes educators from various disciplines was convened to reconsider IIS-related complications of pump therapy, to better characterize Infusion Set factors affecting patient experience, and to update priorities for optimizing current technologies. Actionable guidelines were provided for addressing common issues, including skin reactions, site rotation and Set changes, dislodgment of the Infusion Set, and partial or complete blockage of the catheter. These issues may underlie episodes of IIS failure and/or unexplained hyperglycemia.Co...
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Randomized Trial of Infusion Set Function: Steel Versus Teflon
Diabetes Technology & Therapeutics, 2014Co-Authors: Parul J. Patel, Kari Benasi, Gina Ferrari, Satya Shanmugham, Mark G. Evans, Darrell M. Wilson, Bruce A BuckinghamAbstract:BACKGROUND: This study compared Infusion Set function for up to 1 week using either a Teflon(®) (Dupont(™), Wilmington, DE) catheter or a steel catheter for insulin pump therapy in type 1 diabetes mellitus.\n\nSUBJECTS AND METHODS: Twenty subjects participating in a randomized, open-labeled, crossover study were asked to wear two Quick-Set(®) and two Sure-T(®) Infusion Sets (both from Medtronic Minimed, Northridge, CA) until the Infusion Set failed or was worn for 1 week. All subjects wore a MiniMed continuous glucose monitoring system for the duration of the study.\n\nRESULTS: One subject withdrew from the study. There were 38 weeks of Sure-T wear and 39 weeks of Quick-Set wear with no difference in the survival curves of the Infusion Sets. There was, however, a 15% initial failure rate with the Teflon Infusion Set. After 7 days, both types of Infusion Sets had a 64% failure rate. Overall, 30% failed because of hyperglycemia and a failed correction dose, 13% were removed for pain, 10% were pulled out by accident, 10% had erythema and/or induration of>10 mm, 5% fell out because of loss of adhesion, and 4% were removed for infection. The main predictor of length of wear was the individual subject. There was no increase in hyperglycemia or daily insulin requirements when an Infusion Set was successfully used for 7 days (n=25 of 77 weeks).\n\nCONCLUSIONS: We found no difference between steel and Teflon Infusion Sets in their function over 7 days, although 15% of Teflon Sets failed because of kinking on insertion. The strongest predictor of prolonged 7-day Infusion Set function was the individual subject, not the type of Infusion Set.
Daniel J. Desalvo - One of the best experts on this subject based on the ideXlab platform.
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early detection of Infusion Set failure during insulin pump therapy in type 1 diabetes
Journal of diabetes science and technology, 2016Co-Authors: Marzia Cescon, Bruce A Buckingham, Trang T. Ly, Laurel H. Messer, Daniel J. Desalvo, David M Maahs, Francis J Doyle, Eyal DassauAbstract:Background:Insulin Infusion Set failure resulting in prolonged hyperglycemia or diabetic ketoacidosis can occur with pump therapy in type 1 diabetes. Set failures are frequently characterized by va...
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duration of Infusion Set survival in lipohypertrophy versus nonlipohypertrophied tissue in patients with type 1 diabetes
Diabetes Technology & Therapeutics, 2016Co-Authors: A.w. Karlin, Trang T. Ly, Laura Pyle, Gregory P. Forlenza, Laurel H. Messer, R.p. Wadwa, Daniel J. DesalvoAbstract:Abstract Background: Improved insulin Infusion Set survival and faster insulin action are important issues for pump users and for the development of an artificial pancreas. The current recommendation is to change Infusion Sets every 3 days. Our objectives were to determine the effect of lipohypertrophy (LH) on Infusion Set survival and continuous glucose monitoring glucose levels. Research Design and Methods: In this multicenter crossover trial, we recruited 20 subjects (age 28.1 ± 9.0 years) with type 1 diabetes (duration 17.5 ± 8.8 years) and an area of lipohypertrophied tissue >3 cm. Subjects alternated weekly wearing a Teflon Infusion Set in an area of either LH or non-LH for 4 weeks. Sets were changed after (a) failure or (b) surviving 7 days of use. Results: The least-squares mean duration of Infusion Set survival for Sets that lasted <7 days in lipohypertrophied tissue was 4.31 days compared with 4.12 days in nonlipohypertrophied tissue (P = 0.71). The average duration of Set survival for individua...
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Duration of Infusion Set Survival in Lipohypertrophy Versus Nonlipohypertrophied Tissue in Patients with Type 1 Diabetes
Diabetes Technology & Therapeutics, 2016Co-Authors: A.w. Karlin, Trang T. Ly, Laura Pyle, Gregory P. Forlenza, Laurel H. Messer, R.p. Wadwa, Daniel J. Desalvo, Sydney L. Payne, Sarah J. Hanes, Paula ClintonAbstract:Abstract Background: Improved insulin Infusion Set survival and faster insulin action are important issues for pump users and for the development of an artificial pancreas. The current recommendation is to change Infusion Sets every 3 days. Our objectives were to determine the effect of lipohypertrophy (LH) on Infusion Set survival and continuous glucose monitoring glucose levels. Research Design and Methods: In this multicenter crossover trial, we recruited 20 subjects (age 28.1 ± 9.0 years) with type 1 diabetes (duration 17.5 ± 8.8 years) and an area of lipohypertrophied tissue >3 cm. Subjects alternated weekly wearing a Teflon Infusion Set in an area of either LH or non-LH for 4 weeks. Sets were changed after (a) failure or (b) surviving 7 days of use. Results: The least-squares mean duration of Infusion Set survival for Sets that lasted
Trang T. Ly - One of the best experts on this subject based on the ideXlab platform.
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application of zone model predictive control artificial pancreas during extended use of Infusion Set and sensor a randomized crossover controlled home use trial
Diabetes Care, 2017Co-Authors: Gregory P. Forlenza, Trang T. Ly, Nihat Baysal, Daniel P Howsmon, Faye Cameron, Sunil Deshpande, Eric Mauritzen, Tatiana Marcal, Lindsey Towers, Wayne B. BequetteAbstract:OBJECTIVE As artificial pancreas (AP) becomes standard of care, consideration of extended use of insulin Infusion Sets (IIS) and continuous glucose monitors (CGMs) becomes vital. We conducted an outpatient randomized crossover study to test the safety and efficacy of a zone model predictive control (zone-MPC)–based AP system versus sensor augmented pump (SAP) therapy in which IIS and CGM failures were provoked via extended wear to 7 and 21 days, respectively. RESEARCH DESIGN AND METHODS A smartphone-based AP system was used by 19 adults (median age 23 years [IQR 10], mean 8.0 ± 1.7% HbA 1c ) over 2 weeks and compared with SAP therapy for 2 weeks in a crossover, unblinded outpatient study with remote monitoring in both study arms. RESULTS AP improved percent time 70–140 mg/dL (48.1 vs. 39.2%; P = 0.016) and time 70–180 mg/dL (71.6 vs. 65.2%; P = 0.008) and decreased median glucose (141 vs. 153 mg/dL; P = 0.036) and glycemic variability (SD 52 vs. 55 mg/dL; P = 0.044) while decreasing percent time P = 0.001). AP also improved overnight control, as measured by mean glucose at 0600 h (140 vs. 158 mg/dL; P = 0.02). IIS failures (1.26 ± 1.44 vs. 0.78 ± 0.78 events; P = 0.13) and sensor failures (0.84 ± 0.6 vs. 1.1 ± 0.73 events; P = 0.25) were similar between AP and SAP arms. Higher percent time in closed loop was associated with better glycemic outcomes. CONCLUSIONS Zone-MPC significantly and safely improved glycemic control in a home-use environment despite prolonged CGM and IIS wear. This project represents the first home-use AP study attempting to provoke and detect component failure while successfully maintaining safety and effective glucose control.
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continuous glucose monitoring enables the detection of losses in Infusion Set actuation lisas
Sensors, 2017Co-Authors: Daniel P Howsmon, Bruce A Buckingham, Trang T. Ly, Gregory P. Forlenza, Nihat Baysal, Faye Cameron, David M Maahs, Juergen Hahn, B W BequetteAbstract:Reliable continuous glucose monitoring (CGM) enables a variety of advanced technology for the treatment of type 1 diabetes. In addition to artificial pancreas algorithms that use CGM to automate continuous subcutaneous insulin Infusion (CSII), CGM can also inform fault detection algorithms that alert patients to problems in CGM or CSII. Losses in Infusion Set actuation (LISAs) can adversely affect clinical outcomes, resulting in hyperglycemia due to impaired insulin delivery. Prolonged hyperglycemia may lead to diabetic ketoacidosis—a serious metabolic complication in type 1 diabetes. Therefore, an algorithm for the detection of LISAs based on CGM and CSII signals was developed to improve patient safety. The LISA detection algorithm is trained retrospectively on data from 62 Infusion Set insertions from 20 patients. The algorithm collects glucose and insulin data, and computes relevant fault metrics over two different sliding windows; an alarm sounds when these fault metrics are exceeded. With the chosen algorithm parameters, the LISA detection strategy achieved a sensitivity of 71.8% and issued 0.28 false positives per day on the training data. Validation on two independent data Sets confirmed that similar performance is seen on data that was not used for training. The developed algorithm is able to effectively alert patients to possible Infusion Set failures in open-loop scenarios, with limited evidence of its extension to closed-loop scenarios.
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early detection of Infusion Set failure during insulin pump therapy in type 1 diabetes
Journal of diabetes science and technology, 2016Co-Authors: Marzia Cescon, Bruce A Buckingham, Trang T. Ly, Laurel H. Messer, Daniel J. Desalvo, David M Maahs, Francis J Doyle, Eyal DassauAbstract:Background:Insulin Infusion Set failure resulting in prolonged hyperglycemia or diabetic ketoacidosis can occur with pump therapy in type 1 diabetes. Set failures are frequently characterized by va...
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duration of Infusion Set survival in lipohypertrophy versus nonlipohypertrophied tissue in patients with type 1 diabetes
Diabetes Technology & Therapeutics, 2016Co-Authors: A.w. Karlin, Trang T. Ly, Laura Pyle, Gregory P. Forlenza, Laurel H. Messer, R.p. Wadwa, Daniel J. DesalvoAbstract:Abstract Background: Improved insulin Infusion Set survival and faster insulin action are important issues for pump users and for the development of an artificial pancreas. The current recommendation is to change Infusion Sets every 3 days. Our objectives were to determine the effect of lipohypertrophy (LH) on Infusion Set survival and continuous glucose monitoring glucose levels. Research Design and Methods: In this multicenter crossover trial, we recruited 20 subjects (age 28.1 ± 9.0 years) with type 1 diabetes (duration 17.5 ± 8.8 years) and an area of lipohypertrophied tissue >3 cm. Subjects alternated weekly wearing a Teflon Infusion Set in an area of either LH or non-LH for 4 weeks. Sets were changed after (a) failure or (b) surviving 7 days of use. Results: The least-squares mean duration of Infusion Set survival for Sets that lasted <7 days in lipohypertrophied tissue was 4.31 days compared with 4.12 days in nonlipohypertrophied tissue (P = 0.71). The average duration of Set survival for individua...
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Duration of Infusion Set Survival in Lipohypertrophy Versus Nonlipohypertrophied Tissue in Patients with Type 1 Diabetes
Diabetes Technology & Therapeutics, 2016Co-Authors: A.w. Karlin, Trang T. Ly, Laura Pyle, Gregory P. Forlenza, Laurel H. Messer, R.p. Wadwa, Daniel J. Desalvo, Sydney L. Payne, Sarah J. Hanes, Paula ClintonAbstract:Abstract Background: Improved insulin Infusion Set survival and faster insulin action are important issues for pump users and for the development of an artificial pancreas. The current recommendation is to change Infusion Sets every 3 days. Our objectives were to determine the effect of lipohypertrophy (LH) on Infusion Set survival and continuous glucose monitoring glucose levels. Research Design and Methods: In this multicenter crossover trial, we recruited 20 subjects (age 28.1 ± 9.0 years) with type 1 diabetes (duration 17.5 ± 8.8 years) and an area of lipohypertrophied tissue >3 cm. Subjects alternated weekly wearing a Teflon Infusion Set in an area of either LH or non-LH for 4 weeks. Sets were changed after (a) failure or (b) surviving 7 days of use. Results: The least-squares mean duration of Infusion Set survival for Sets that lasted
Lutz Heinemann - One of the best experts on this subject based on the ideXlab platform.
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Insulin Infusion Sets: A Critical Reappraisal
Diabetes Technology & Therapeutics, 2016Co-Authors: Lutz HeinemannAbstract:Abstract An insulin Infusion Set (IIS) is a key component of insulin pumps. In daily practice issues with the IIS appear to be as relevant for a successful insulin therapy as the pumps themselves. The insulin is applied to the subcutaneous tissue via a Teflon® (Dupont, Wilmington, DE) or steel cannula. There are intensive discussions about the impact the choice of material for insulin application has on insulin pharmacokinetics. In this review, this factor and others that are known to have an impact on the successful usage of IIS are discussed.
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insulin pump risks and benefits a clinical appraisal of pump safety standards adverse event reporting and research needs a joint statement of the european association for the study of diabetes and the american diabetes association diabetes technology
Diabetes Care, 2015Co-Authors: Lutz Heinemann, James Robertson Petrie, Richard M. Bergenstal, Reinhard W Holl, Alexander G Fleming, Anne L. PetersAbstract:Insulin pump therapy, also known as continuous subcutaneous insulin Infusion (CSII), is an important and evolving form of insulin delivery, which is mainly used for people with type 1 diabetes. However, even with modern insulin pumps, errors of insulin Infusion can occur due to pump failure, insulin Infusion Set (IIS) blockage, Infusion site problems, insulin stability issues, user error or a combination of these. Users are therefore exposed to significant and potentially fatal hazards: interruption of insulin Infusion can result in hyperglycaemia and ketoacidosis; conversely, delivery of excessive insulin can cause severe hypoglycaemia. Nevertheless, the available evidence on the safety and efficacy of CSII remains limited. The European Association for the Study of Diabetes (EASD) and American Diabetes Association (ADA) have therefore joined forces to review the systems in place for evaluating the safety of pumps from a clinical perspective. We found that useful information held by the manufacturing companies is not currently shared in a sufficiently transparent manner. Public availability of adverse event (AE) reports on the US Food and Drug Administration’s Manufacturer and User Facility Device Experience (MAUDE) database is potentially a rich source of safety information but is insufficiently utilised due to the current configuration of the system; the comparable database in Europe (European Databank on Medical Devices, EUDAMED) is not publicly accessible. Many AEs appear to be attributable to human factors and/or user error, but the extent to which manufacturing companies are required by regulators to consider the interactions of users with the technical features of their products is limited. The clinical studies required by regulators prior to marketing are small and over-reliant on bench testing in relation to ‘predicate’ products. Once a pump is available on the market, insufficient data are made publicly available on its long-term use in a real-world Setting; such data could provide vital information to help healthcare teams to educate and support users, and thereby prevent AEs. As well as requiring more from the manufacturing companies, we call for public funding of more research addressing clinically important questions in relation to pump therapy: both observational studies and clinical trials. At present there are significant differences in the regulatory systems between the USA and European Union at both pre- and post-marketing stages; improvements in the European system are more urgently required. This statement concludes with a series of recommended specific actions for ‘meknovigilance’ (i.e. a standardised safety approach to technology) which could be implemented to address the shortcomings we highlight.
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Insulin pump risks and benefits: A clinical appraisal of pump safety standards, adverse event reporting, and research needs
Diabetes Care, 2015Co-Authors: Lutz Heinemann, G. Alexander Fleming, James Robertson Petrie, Richard M. Bergenstal, Reinhard W Holl, Anne L. PetersAbstract:Insulin pump therapy, also known as continuous subcutaneous insulin Infusion (CSII), is an important and evolving form of insulin delivery, which is mainly used for people with type 1 diabetes. However, even with modern insulin pumps, errors of insulin Infusion can occur due to pump failure, insulin Infusion Set (IIS) blockage, Infusion site problems, insulin stability issues, user error, or a combination of these. Users are therefore exposed to significant and potentially fatal hazards: interruption of insulin Infusion can result in hyperglycemia and ketoacidosis; conversely, delivery of excessive insulin can cause severe hypoglycemia. Nevertheless, the available evidence on the safety and efficacy of CSII remains limited. The European Association for the Study of Diabetes (EASD) and the American Diabetes Association (ADA) have therefore joined forces to review the systems in place for evaluating the safety of pumps from a clinical perspective. We found that useful information held by the manufacturing companies is not currently shared in a sufficiently transparent manner. Public availability of adverse event (AE) reports on the US Food and Drug Administration’s Manufacturer and User Facility Device Experience (MAUDE) database is potentially a rich source of safety information but is insufficiently utilized due to the current configuration of the system; the comparable database in Europe (European Databank on Medical Devices [EUDAMED]) is not publicly accessible. Many AEs appear to be attributable to human factors and/or user error, but the extent to which manufacturing companies are required by regulators to consider the interactions of users with the technical features of their products is limited. The clinical studies required by regulators prior to marketing are small and over-reliant on bench testing in relation to “predicate” products. Once a pump is available on the market, insufficient data are made publicly available on its long-term use in a real-world Setting; such data could provide vital information to help health care teams to educate and support users and thereby prevent AEs. As well as requiring more from the manufacturing companies, we call for public funding of more research addressing clinically important questions in relation to pump therapy: both observational studies and clinical trials. At present, there are significant differences in the regulatory systems between the US and European Union at both pre- and postmarketing stages; improvements in the European system are more urgently required. This statement concludes with a series of recommended specific actions for “meknovigilance” (i.e., a standardized safety approach to technology) that could be implemented to address the shortcomings we highlight.
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insulin Infusion Set the achilles heel of continuous subcutaneous insulin Infusion
Journal of diabetes science and technology, 2012Co-Authors: Lutz Heinemann, Lars KrinelkeAbstract:Continuous subcutaneous insulin Infusion from an insulin pump depends on reliable transfer of the pumped insulin to the subcutaneous insulin depot by means of an insulin Infusion Set (IIS). Despite their widespread use, the published knowledge about IISs and related issues regarding the impact of placement and wear time on insulin absorption/insulin action is relatively small. We also have to acknowledge that our knowledge is limited with regard to how often patients encounter issues with IISs. Reading pump wearer blogs, for instance, suggests that these are a frequent source of trouble. There are no prospective clinical studies available on current IIS and insulin formulations that provide representative data on the type and frequency of issues with Infusion Sets. The introduction of new IISs and patch pumps may foster a reassessment of available products and of patient problems related to their use. The aim of this review is to summarize the current knowledge and recommendations about IISs and to highlight potential directions of IIS development in order to make insulin absorption safer and more efficient.
Gregory P. Forlenza - One of the best experts on this subject based on the ideXlab platform.
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application of zone model predictive control artificial pancreas during extended use of Infusion Set and sensor a randomized crossover controlled home use trial
Diabetes Care, 2017Co-Authors: Gregory P. Forlenza, Trang T. Ly, Nihat Baysal, Daniel P Howsmon, Faye Cameron, Sunil Deshpande, Eric Mauritzen, Tatiana Marcal, Lindsey Towers, Wayne B. BequetteAbstract:OBJECTIVE As artificial pancreas (AP) becomes standard of care, consideration of extended use of insulin Infusion Sets (IIS) and continuous glucose monitors (CGMs) becomes vital. We conducted an outpatient randomized crossover study to test the safety and efficacy of a zone model predictive control (zone-MPC)–based AP system versus sensor augmented pump (SAP) therapy in which IIS and CGM failures were provoked via extended wear to 7 and 21 days, respectively. RESEARCH DESIGN AND METHODS A smartphone-based AP system was used by 19 adults (median age 23 years [IQR 10], mean 8.0 ± 1.7% HbA 1c ) over 2 weeks and compared with SAP therapy for 2 weeks in a crossover, unblinded outpatient study with remote monitoring in both study arms. RESULTS AP improved percent time 70–140 mg/dL (48.1 vs. 39.2%; P = 0.016) and time 70–180 mg/dL (71.6 vs. 65.2%; P = 0.008) and decreased median glucose (141 vs. 153 mg/dL; P = 0.036) and glycemic variability (SD 52 vs. 55 mg/dL; P = 0.044) while decreasing percent time P = 0.001). AP also improved overnight control, as measured by mean glucose at 0600 h (140 vs. 158 mg/dL; P = 0.02). IIS failures (1.26 ± 1.44 vs. 0.78 ± 0.78 events; P = 0.13) and sensor failures (0.84 ± 0.6 vs. 1.1 ± 0.73 events; P = 0.25) were similar between AP and SAP arms. Higher percent time in closed loop was associated with better glycemic outcomes. CONCLUSIONS Zone-MPC significantly and safely improved glycemic control in a home-use environment despite prolonged CGM and IIS wear. This project represents the first home-use AP study attempting to provoke and detect component failure while successfully maintaining safety and effective glucose control.
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continuous glucose monitoring enables the detection of losses in Infusion Set actuation lisas
Sensors, 2017Co-Authors: Daniel P Howsmon, Bruce A Buckingham, Trang T. Ly, Gregory P. Forlenza, Nihat Baysal, Faye Cameron, David M Maahs, Juergen Hahn, B W BequetteAbstract:Reliable continuous glucose monitoring (CGM) enables a variety of advanced technology for the treatment of type 1 diabetes. In addition to artificial pancreas algorithms that use CGM to automate continuous subcutaneous insulin Infusion (CSII), CGM can also inform fault detection algorithms that alert patients to problems in CGM or CSII. Losses in Infusion Set actuation (LISAs) can adversely affect clinical outcomes, resulting in hyperglycemia due to impaired insulin delivery. Prolonged hyperglycemia may lead to diabetic ketoacidosis—a serious metabolic complication in type 1 diabetes. Therefore, an algorithm for the detection of LISAs based on CGM and CSII signals was developed to improve patient safety. The LISA detection algorithm is trained retrospectively on data from 62 Infusion Set insertions from 20 patients. The algorithm collects glucose and insulin data, and computes relevant fault metrics over two different sliding windows; an alarm sounds when these fault metrics are exceeded. With the chosen algorithm parameters, the LISA detection strategy achieved a sensitivity of 71.8% and issued 0.28 false positives per day on the training data. Validation on two independent data Sets confirmed that similar performance is seen on data that was not used for training. The developed algorithm is able to effectively alert patients to possible Infusion Set failures in open-loop scenarios, with limited evidence of its extension to closed-loop scenarios.
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duration of Infusion Set survival in lipohypertrophy versus nonlipohypertrophied tissue in patients with type 1 diabetes
Diabetes Technology & Therapeutics, 2016Co-Authors: A.w. Karlin, Trang T. Ly, Laura Pyle, Gregory P. Forlenza, Laurel H. Messer, R.p. Wadwa, Daniel J. DesalvoAbstract:Abstract Background: Improved insulin Infusion Set survival and faster insulin action are important issues for pump users and for the development of an artificial pancreas. The current recommendation is to change Infusion Sets every 3 days. Our objectives were to determine the effect of lipohypertrophy (LH) on Infusion Set survival and continuous glucose monitoring glucose levels. Research Design and Methods: In this multicenter crossover trial, we recruited 20 subjects (age 28.1 ± 9.0 years) with type 1 diabetes (duration 17.5 ± 8.8 years) and an area of lipohypertrophied tissue >3 cm. Subjects alternated weekly wearing a Teflon Infusion Set in an area of either LH or non-LH for 4 weeks. Sets were changed after (a) failure or (b) surviving 7 days of use. Results: The least-squares mean duration of Infusion Set survival for Sets that lasted <7 days in lipohypertrophied tissue was 4.31 days compared with 4.12 days in nonlipohypertrophied tissue (P = 0.71). The average duration of Set survival for individua...
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Duration of Infusion Set Survival in Lipohypertrophy Versus Nonlipohypertrophied Tissue in Patients with Type 1 Diabetes
Diabetes Technology & Therapeutics, 2016Co-Authors: A.w. Karlin, Trang T. Ly, Laura Pyle, Gregory P. Forlenza, Laurel H. Messer, R.p. Wadwa, Daniel J. Desalvo, Sydney L. Payne, Sarah J. Hanes, Paula ClintonAbstract:Abstract Background: Improved insulin Infusion Set survival and faster insulin action are important issues for pump users and for the development of an artificial pancreas. The current recommendation is to change Infusion Sets every 3 days. Our objectives were to determine the effect of lipohypertrophy (LH) on Infusion Set survival and continuous glucose monitoring glucose levels. Research Design and Methods: In this multicenter crossover trial, we recruited 20 subjects (age 28.1 ± 9.0 years) with type 1 diabetes (duration 17.5 ± 8.8 years) and an area of lipohypertrophied tissue >3 cm. Subjects alternated weekly wearing a Teflon Infusion Set in an area of either LH or non-LH for 4 weeks. Sets were changed after (a) failure or (b) surviving 7 days of use. Results: The least-squares mean duration of Infusion Set survival for Sets that lasted