Reduced Silent Occlusions with a Novel Catheter Infusion Set (BD FlowSmart): Results from Two Open-Label Comparative Studies

Supervised and Unsupervised Approaches for the Real-Time Detection of Undesired Insulin Suspension Caused by Malfunctions

BACKGROUND

Automated insulin delivery (AID) systems, permit improved treatment of type 1 diabetes (T1D). Unfortunately, malfunctioning in the insulin pump or in the infusion set can prevent insulin from being administered, reducing the AID efficacy and posing the patient at risk. Different data-driven methods available in the literature can be used to deal with the problem of automatically detecting complete insulin suspension in real-time. This article investigates both supervised and unsupervised strategies and proposes a fair comparison under either population or personalized settings.

METHODS

Several algorithms are compared using data generated through the UVA/Padova T1D simulator, a computer simulator widely used to test control strategies in silico and accepted by the Food and Drugs Administration (FDA) as a substitute to animal pre-clinical trials. Two synthetic data sets, each consisting of 100 virtual subjects monitored for 1 month, were generated. Occasional faults of the insulin pump are simulated as complete occlusions by suspending the therapy administration. Personalized algorithms are investigated with unsupervised approaches only, since personalized labels are hardly available.

RESULTS

In the population scenario, the supervised approach outperforms the unsupervised strategy. In particular, logistic regression and random forest achieves a recall of 72% and 82%, with 0.12 and 0.21 false positives (FP) per day, respectively. In the personalized setting scenario, the unsupervised algorithms are tailored on each patient and outperform the population ones, in particular isolation forest achieves a recall 80% and 0.06 FPs per day.

CONCLUSIONS

This article suggests that unsupervised personalized approach, by addressing the large variability in glucose response among individuals with T1D, is superior to other one-fits-all approaches in detecting insulin suspensions caused by malfunctioning. Population methodologies can be effectively used while waiting to collect sufficient patient data, when the system is installed on a new patient.

Patient-Controlled Subcutaneous Analgesia with Hydromorphone versus Oral Oxycontin for Opioid Titration of Cancer Pain: A Prospective Multicenter Randomized Trial

Background

Studies have shown that oral oxycontin tablets can be used for opioid titration. The European Society for Medical Oncology (ESMO) guidelines for adult cancer pain recommend opioid titration through the parenteral route, usually the intravenous or subcutaneous route. Patient-controlled subcutaneous analgesia (PCSA) with hydromorphone needs further evaluation for opioid titration. This prospective multicenter study was designed to compare the efficacy and safety of hydromorphone PCSA with oral oxycontin tablets for opioid titration of cancer pain.

Patients and Methods

Eligible patients with cancer pain were randomly assigned in a 1:1 ratio to the PCSA group or the oxycontin group for dose titration. Different titration methods were given in both groups depending on whether the patient had an opioid tolerance. The primary endpoint of this study was time to successful titration (TST).

Results

A total of 256 patients completed this study. The PCSA group had a significantly lower TST compared with the oxycontin group (median [95% confidence interval (CI)], 5.5[95% CI:2.5-11.5] hours vs.16.0 [95% CI:11.5-22.5] hours; p<0.001). The frequency (median; interquartile) of breakthrough pain (Btp) over 24 hours was significantly lower in the PCSA group (2.5;2.0-3.5) than in the oxycontin group.(3.0; 2.5-4.5) (p=0.04). The pain was evaluated by numeric rating scale (NRS) score at 12 hours after the start of titration. The pain score (median; interquartile) was significantly lower in the PCSA versus the oxycontin group (2.5;1.5-3.0) vs 4.5;3.0-6.0) (p=0.02). The equivalent dose of oral morphine (EDOM) for a successful titration was similar in both groups (p=0.29), but there was a significant improvement in quality of life (QoL) in both groups (p=0.03). No between-group difference in the incidence of opioid-related adverse effects was observed (p=0.32).

Conclusion

Compared with oral oxycontin tablet, the use of PCSA with hydromorphone achieved a shorter titration duration for patients with cancer pain (p<0.001), without significantly increasing adverse events (p=0.32).

MyD88-dependent Toll-like receptor 2 signaling modulates macrophage activation on lysate-adsorbed Teflon™ AF surfaces in an in vitro biomaterial host response model

The adsorbed protein layer on an implanted biomaterial surface is known to mediate downstream cell-material interactions that drive the host response. While the adsorption of plasma-derived proteins has been studied extensively, the adsorption of damage-associated molecular patterns (DAMPs) derived from damaged cells and matrix surrounding the implant remains poorly understood. Previously, our group developed a DAMP-adsorption model in which 3T3 fibroblast lysates were used as a complex source of cell-derived DAMPs and we demonstrated that biomaterials with adsorbed lysate potently activated RAW-Blue macrophages via Toll-like receptor 2 (TLR2). In the present study, we characterized the response of mouse bone marrow derived macrophages (BMDM) from wildtype (WT), TLR2-/- and MyD88-/- mice on Teflon™ AF surfaces pre-adsorbed with 10% plasma or lysate-spiked plasma (10% w/w total protein from 3T3 fibroblast lysate) for 24 hours. WT BMDM cultured on adsorbates derived from 10% lysate in plasma had significantly higher gene and protein expression of IL-1β, IL-6, TNF-α, IL-10, RANTES/CCL5 and CXCL1/KC, compared to 10% plasma-adsorbed surfaces. Furthermore, the upregulation of pro-inflammatory cytokine and chemokine expression in the 10% lysate in plasma condition was attenuated in TLR2-/- and MyD88-/- BMDM. Proteomic analysis of the adsorbed protein layers showed that even this relatively small addition of lysate-derived proteins within plasma (10% w/w) caused a significant change to the adsorbed protein profile. The 10% plasma condition had fibrinogen, albumin, apolipoproteins, complement, and fibronectin among the top 25 most abundant proteins. While proteins layers generated from 10% lysate in plasma retained fibrinogen and fibronectin among the top 25 proteins, there was a disproportionate increase in intracellular proteins, including histones, tubulins, actins, and vimentin. Furthermore, we identified 7 DAMPs or DAMP-related proteins enriched in the 10% plasma condition (fibrinogen, apolipoproteins), compared to 39 DAMPs enriched in the 10% lysate in plasma condition, including high mobility group box 1 and histones. Together, these findings indicate that DAMPs and other intracellular proteins readily adsorb to biomaterial surfaces in competition with plasma proteins, and that adsorbed DAMPs induce an inflammatory response in adherent macrophages that is mediated by the MyD88-dependent TLR2 signaling pathway.

Frequency and Detection of Insulin Infusion Site Failure in the Type 1 Diabetes Exchange Online Community

Insulin infusion site (IIS) failures are a weakness in insulin pump therapy. We examined experience with IIS failures among U.S. individuals with diabetes on insulin pump through survey distributed to the T1D Exchange Online Community. Demographic factors, IIS characteristics, and diabetes-related perceptions were assessed by logistic regression to determine odds of higher (≥1 per month) or lower (<1 per month) reported IIS failure frequency. IIS failures were common; 41.4% reported ≥1 per month. IIS failure is usually detected through development of hyperglycemia rather than pump alarm. No assessed demographic factor or IIS characteristic was predictive; however, higher odds of ≥1 failure per month were associated with feelings of burnout (odds ratios [OR] 1.489 [1.024, 2.165]) and considering pump discontinuation (OR 2.233 [1.455, 3.427]). IIS failures are frequent and unpredictable, typically require hyperglycemia for detection, and are associated with negative perceptions. More should be done toward preventing IIS failures and/or detecting them sooner.

Evaluation of Extended Infusion Set Performance in Adults with Type 1 Diabetes: Infusion Set Survival Rate and Glycemic Outcomes from a Pivotal Trial

Background: Standard insulin infusion sets (IISs) are to be replaced every 2 to 3 days to avoid complications and diabetic ketosis due to set failure. This pivotal trial evaluated the safety and performance of a new extended-wear infusion set (EIS) when used for 7 days by adults with type 1 diabetes (T1D). Methods: This single-arm, nonrandomized trial enrolled adults (18-80 years of age) with T1D, who used their own MiniMed™ 670G system with insulin lispro or insulin aspart and the EIS for up to 7 days, across 12 consecutive wears. Safety endpoints included incidence of serious adverse events (SAEs), serious adverse device effects (SADEs), unanticipated adverse device effects (UADEs), severe hypoglycemia (SevHypo), severe hyperglycemia (SevHyper), diabetic ketoacidosis (DKA), and skin infection. The EIS failure rate due to unexplained hyperglycemia (i.e., suspected occlusion), the overall EIS survival rate, glycemic control outcomes (i.e., A1C, mean sensor glucose and time spent in established glucose ranges), total daily insulin delivered, and satisfaction with the EIS were determined. Results: The intention to treat population (n = 259, 48% men, 45.0 ± 14.1 years) wore a total of 3041 EIS devices. No SADE, UADE, or DKA events was reported. Overall rates of SAEs, SevHypo, SevHyper, and skin infection were 3.8, 2.5, 104.1, and 20.1 events per 100 participant-years. The rate of EIS failure due to unexplained hyperglycemia at the end of day 7 was 0.1% (95% confidence interval [CI]: 0.03-0.51) and 0.4% (95% CI: 0.16-1.00) for insulin lispro and aspart use, respectively. Overall EIS survival rate at the end of day 7 was 77.8% (95% CI: 76.2-79.3), glycemic control did not change, and participants reported greater satisfaction with the EIS compared with standard IISs worn before the study (P < 0.001). Conclusions: This investigation demonstrates that the EIS, when worn for up to 7 days, was safe and rated with high satisfaction, without adversely affecting glycemic control in adults with T1D. Clinical Trial Registration number: NCT04113694 (https://clinicaltrials.gov/ct2/show/NCT04113694).

Insulin Pump Therapy

BACKGROUND

Advances in pump technology have increased the popularity of this treatment modality among patients with type 1 diabetes and recently also among patients with type 2 diabetes.

AREAS OF UNCERTAINTY

Four decades after the incorporation of the insulin pump in clinical use, questions regarding its efficacy, occurrence rate of short-term complications as hypoglycemia and diabetes ketoacidosis, timing of pump initiation, and selected populations for use remain unanswered.

DATA SOURCES

A review of the literature was performed using the PubMed database to identify all articles published up till December 2018, with the search terms including insulin pump therapy/continuous subcutaneous insulin delivery. The Cochrane database was searched for meta-analysis evaluating controlled randomized trials. Consensuses guidelines published by the International Society for Pediatric and Adolescent Diabetes, American Diabetes Association, and Advanced Technologies and Treatments for Diabetes year books were additionally reviewed for relevant cited articles.

THERAPEUTIC ADVANCES

Insulin pump therapy offers flexible management of diabetes. It enables adjustment of basal insulin to daily requirements and circadian needs, offers more precise treatment for meals and physical activity, and, when integrated with continuous glucose monitoring, allows glucose responsive insulin delivery. The ability to download and transmit data for analysis allow for treatment optimization. Newer pumps are simple to operate and increase user experience. Studies support the efficacy of pump therapy in improving glycemic control and reducing the occurrence of hypoglycemia without increasing episodes of diabetes ketoacidosis. They also improve quality of life. Recent evidence suggests a role for pump therapy in reducing microvascular and macrovascular diabetes-related complications.

CONCLUSIONS

Insulin pump therapy appears to be effective and safe in people with T1D regardless of age. Future advancements will include incorporation of closed loop and various decision support systems to aid and improve metabolic control and quality of life.

Patient-controlled subcutaneous analgesia using sufentainil or morphine in home care treatment in patients with stage III-IV cancer: A multi-center randomized controlled clinical trial

Purpose

Patient‐controlled subcutaneous analgesia (PCSA) with sufentanil is an alternative analgesia strategy in patients with stage III‐IV cancer; however, its efficacy and safety have not been fully investigated.

Methods

From May 10, 2017 to November 10, 2017, 120 patients with stage III‐IV cancer suffering from moderate to severe pain were prospectively enrolled from six hospitals and randomized to receive PCSA with morphine (control group) or sufentanil (intervention group). Before the PCSA and on days 1, 3, 7, 14, 28, and 56 after treatment, the numeric rating scale (NRS) and 36‐item Short Form health survey (SF‐36) were completed for each patient and the side effects were also recorded.

RESULTS

No significant differences (P > .05) were observed in the preoperative NRS score and the SF‐36 parameters between the two groups. Patients in the intervention group achieved better pain relief, as indicated by lower NRS scores at days 14 (P = .040), 28 (P < .001), and 56 (P < .001) after PCSA device implantation (vs control group). Furthermore, the patients in the intervention group also achieved a better life quality, as indicated by the physical role, general health, social function body pain, and mental health scores. Finally, the patients receiving sufentanil showed lower levels of nausea and somnolence than those in the control group.

Conclusion

PCSA with sufentanil achieves better pain control and life quality as well as fewer adverse reactions in stage III‐IV cancer patients with pain and may be a promising pain management in these patients.

Trial registration

This study was registered at chictr.org.cn with the trial number: ChiCTR‐IPR‐17011280.

Insulin Distribution in Human Adipose Tissue via a Novel Insulin Infusion Catheter

Continuous subcutaneous insulin infusion (CSII) is a widely used treatment for diabetes patients. Insulin infusion sets (CSII-catheters) are continuously optimized regarding size, handling and safety, but recurring dysfunction (kinking or occlusion), due to different user situations, behavior or chain of events, demand new ways to improve the functionality and safety in patients experiencing these issues. A novel CSII-catheter design (Lantern) features additional lateral perforations, which guarantee functionality even in case of kinking or occlusion. This study aimed to compare functionality, insulin distribution, and failure rate of Lantern and standard catheters using excised human adipose tissue samples. Novel Lantern CSII-catheters (open and artificially occluded) and commercially available standard CSII-catheters were inserted into adipose tissue samples. A mixture of insulin and contrast agent was infused as single bolus (7 IU) with an insulin infusion pump at highest flow rate (1 IU/s). Microtomography images and surface-to-volume ratios were used to assess insulin distribution and depot volume indicating the functionality of CSII-catheters. Failure rate was measured by flow-stop alerts of the pump. We found no difference in the volume of insulin depots compared with the nominal volume of 70 μL. Surface-to-volume ratios showed no significant difference among CSII-catheters. None of the catheters triggered any flow-stop alarm. The novel Lantern CSII-catheter design achieved similar insulin distribution as commercially available CSII-catheters. Moreover, functionality of Lantern CSII-catheters was guaranteed during occlusion, which is an improvement compared with standard CSII-catheters. We conclude that the novel CSII-catheter design has the potential to provide a valuable contribution to patient well-being and safety.

Nitric oxide-releasing semi-crystalline thermoplastic polymers: preparation, characterization and application to devise anti-inflammatory and bactericidal implants

Semi-crystalline thermoplastics are an important class of biomaterials with applications in creating extracorporeal and implantable medical devices. In situ release of nitric oxide (NO) from medical devices can enhance their performance via NO's potent anti-thrombotic, bactericidal, anti-inflammatory, and angiogenic activity. However, NO-releasing semi-crystalline thermoplastic systems are limited and the relationship between polymer crystallinity and NO release profile is unknown. In this paper, the functionalization of poly(ether-block-amide) (PEBA), Nylon 12, and polyurethane tubes, as examples of semi-crystalline polymers, with the NO donor S-nitroso-N-acetylpenicillamine (SNAP) within, is demonstrated via a polymer swelling method. The degree of crystallinity of the polymer plays a crucial role in both SNAP impregnation and NO release. Nylon 12, which has a relatively high degree of crystallinity, exhibits an unprecedented NO release duration of over 5 months at a low NO level, while PEBA tubing exhibits NO release over days to weeks. As a new biomedical application of NO, the NO-releasing PEBA tubing is examined as a cannula for continuous subcutaneous insulin infusion. The released NO is shown to enhance insulin absorption into the bloodstream probably by suppressing the tissue inflammatory response, and thereby could benefit insulin pump therapy for diabetes management.

Capabilities of Next-Generation Patch Pump: Improved Precision, Instant Occlusion Detection, and Dual-Hormone Therapy

Insulin pumps allow patients to attain better blood glucose control with more lifestyle flexibility. Their size and cost, however, limit their usefulness. Current CSII pumps are bulky, intrusive, and expensive. SFC Fluidics is addressing these problems by developing a new type of wearable patch pump based on the patented electro-chemiosmotic (ECO) microfluidic pumping technology. This nonmechanical pumping technology allows accurate and precise delivery of very small amounts of insulin and/or other drugs, including concentrated insulin. The pump engine is small and can be made inexpensively from injection molded parts, allowing its use in a disposable or semidisposable pod format. In addition, a single ECO pump engine can be used to deliver two drugs through independent pathways. Other features of SFC Fluidics' pod include latching safety valves that prevent accidental overdosing of insulin due to pressure changes and an instantaneous occlusion sensor that can immediately detect delivery failure at the first missed dose. These features allow for the development of a series of patch pumps that will offer users the benefit of CSII therapy in a more discreet and reliable patch pump form.

In vivo investigation of the tissue response to commercial Teflon insulin infusion sets in large swine for 14 days: the effect of angle of insertion on tissue histology and insulin spread within the subcutaneous tissue

OBJECTIVE

This study investigated the effects of the inflammatory tissue response (ITR) to an insulin infusion set (IIS) on insulin bolus spread over wear time, as well as the effect of cannula insertion angle on the ITR, bolus shape, and pump tubing pressure.

RESEARCH DESIGN AND METHODS

Angled or straight IISs were inserted every other day for 14 days into the subcutaneous tissue of 11 swine and insulin was delivered continuously. Prior to euthanasia, a 70 µL bolus of insulin/X-ray contrast agent was infused while recording a pressure profile (peak tubing pressure, p_max; area under the pressure curve, AUC), followed by the excision of the tissue-catheter specimen. Bolus surface area (SA) and volume (V) were assessed via micro-CT. Tissue was stained to analyze total area of inflammation (TAI) and inflammatory layer thickness (ILT) surrounding the cannula.

RESULTS

A bolus delivered through an angled IIS had a larger mean SA than a bolus delivered through a straight cannula (314.0±84.2 mm² vs 229.0±99.7 mm², p<0.001) and a larger volume (198.7±66.9 mm³ vs 145.0±65.9 mm³, p=0.001). Both decreased significantly over wear time, independent of angle. There was a significant difference in TAI (angled, 9.1±4.0 mm² vs straight, 14.3±8.6 mm², p<0.001) and ILT (angled, 0.7±0.4 vs straight, 1.2±0.7 mm, p<0.001). p_max (p=0.005) and AUC (p=0.014) were lower using angled IIS. As ILT increased, p_max increased, while SA and V decreased.

CONCLUSIONS

The progression of the ITR directly affected bolus shape and tubing pressure. Although straight insertion is clinically preferred, our data suggest that an angled IIS elicits lower grades of ITR and delivers a bolus with lower tubing pressure and greater SA and V. The subcutaneous environment plays a crucial role in IIS longevity, and the insertion angle needs to be considered in future IIS designs and clinical trials.

Perceptions and experiences of adult patients with type 1 diabetes using continuous subcutaneous insulin infusion therapy: Results of an online survey

AIMS

To assess perceptions of patients using subcutaneous insulin infusion (CSII) about metabolic control, pump malfunctions, technical and insertion site adverse events (AEs) related to infusion sets/catheters as well as patients' practices.

METHODS

Online survey (from June 2016 to January 2017) using an actualized 39-item questionnaire directed to adults with type 1 diabetes (T1D) using CSII therapy and living in the province of Quebec, Canada.

RESULTS

Participants with T1D (n = 115, 72% females, 39.7 ± 14.0 years, diabetes duration: 20.9 ± 12.2 years, CSII use: 6.2 ± 4.1 years) adequately completed the survey. Infusion sets were changed every 3.3 ± 0.9 day. Improved glucose control and decreased number/severity of hypoglycemic episodes were reported by 80% and 68%/50% of subjects, respectively. Over the past year of CSII use, participants perceived no increase in anxiety/worry (84%), no negative impact on life (89%) or on time off from work/school (82%). Conversely, many experienced at least one clinical AEs at insertion site [pain (84%), adhesion (76%), irritation (69%), lipodystrophy (45%)] and technical issues [blockage (52%), cannula kinking (50%), pump stop (55%), air bubbles (46%)]. No significant association was observed between catheter wear-time and AEs. All participants had one or more problems related to CSII use, although only 37% reported addressing these issues with health professionals.

CONCLUSION

Our study suggests that patients positively perceived CSII use although they experienced a high frequency of clinical and technical AEs. This warrants further attention by health professionals, investigators and manufacturers to optimize CSII therapy.

Risk and Relevance of Insulin Pump Therapy in the Aetiology of Ketoacidosis in People with Type 1 Diabetes

OBJECTIVE

The aim of this systematic data analysis was to determine the prevalence of diabetic ketoacidosis (DKA) as well as hypoglycemic and hyperglycemic disorders during insulin pump therapy (CSII) in patients with type 1 diabetes. The main focus was to investigate whether CSII patients have more DKA than the general type 1 diabetes population.

SUBJECTS AND METHODS

This retrospective study with patients who were treated in our treatment center from 2003 to 2016 includes data from 229 patients (52.4% male, 47.6% female, 37.2±16.3 years; DKA: 93, hypoglycemia: 66, hyperglycemia: 70).

RESULTS

Intensified insulin therapy was the most common treatment regimen in the study cohort (73.4%), followed by CSII (24%). However, 32.3% of the patients with DKA were on CSII. This number of DKA cases among the insulin pump users in our study cohort was higher than the prevalence reported in a previously published study by Reichel et al. (2013; p<0.05) and in a customer database (p<0.005). Most common causes of DKA in our study cohort were patient errors (43.3%) or insulin resistance induced by an underlying infection (29.8%). Device malfunction caused 13.5% of all DKA cases with an overwhelming majority on insulin pump treatment (93%). Overall, patient errors caused more DKA cases than device malfunctions.

CONCLUSIONS

Our findings suggest that despite development of more sophisticated insulin pump devices, DKA is still more frequent with CSII than with other kinds of insulin treatment.

Duration of Catheter Use in Patients with Diabetes Using Continuous Subcutaneous Insulin Infusion: A Review

Increasing proportions of patients with diabetes use continuous subcutaneous insulin infusion (CSII) therapy mostly due to its clinical efficacy and flexibility for insulin dosing and adjustments. Some challenges are nevertheless associated with this technology. A key and underlooked component of CSII technical difficulties is the subcutaneous catheter used to infuse insulin. Several adverse events (AEs) have been experienced by patients in relation to catheters, such as blockage, kinking, and insertion site reactions, including irritation, infections, lipohypertrophies etc., all of which could compromise the metabolic control. With the objective of minimizing these AEs, recommendations for changing catheters every 2-3 days have historically been provided by manufacturers based on reports derived from small studies and anecdotal data. The aim of this review was to provide an updated analysis of current recommendations and patients' practices in relation to frequency of catheter change. Our main findings are: (1) adequately designed and powered studies investigating optimal catheter wearing time are still lacking; (2) increasing catheter wearing time is generally associated with increased frequency of catheter AEs; (3) however, interpatient variability is large, with some individuals needing to change their catheters every 2-3 days, whereas others probably being able to keep them in place for longer periods without problems. Further research is thus warranted to provide more solid and evidence-based recommendations while exploring personalized approaches at the same time. Increasing catheter wear life without significant side effects is an important goal to simplify CSII therapy and reduce its associated costs and burdens.

Real-Time Detection of Infusion Site Failures in a Closed-Loop Artificial Pancreas

BACKGROUND

As evidence emerges that artificial pancreas systems improve clinical outcomes for patients with type 1 diabetes, the burden of this disease will hopefully begin to be alleviated for many patients and caregivers. However, reliance on automated insulin delivery potentially means patients will be slower to act when devices stop functioning appropriately. One such scenario involves an insulin infusion site failure, where the insulin that is recorded as delivered fails to affect the patient's glucose as expected. Alerting patients to these events in real time would potentially reduce hyperglycemia and ketosis associated with infusion site failures.

METHODS

An infusion site failure detection algorithm was deployed in a randomized crossover study with artificial pancreas and sensor-augmented pump arms in an outpatient setting. Each arm lasted two weeks. Nineteen participants wore infusion sets for up to 7 days. Clinicians contacted patients to confirm infusion site failures detected by the algorithm and instructed on set replacement if failure was confirmed.

RESULTS

In real time and under zone model predictive control, the infusion site failure detection algorithm achieved a sensitivity of 88.0% (n = 25) while issuing only 0.22 false positives per day, compared with a sensitivity of 73.3% (n = 15) and 0.27 false positives per day in the SAP arm (as indicated by retrospective analysis). No association between intervention strategy and duration of infusion sets was observed ( P = .58).

CONCLUSIONS

As patient burden is reduced by each generation of advanced diabetes technology, fault detection algorithms will help ensure that patients are alerted when they need to manually intervene. Clinical Trial Identifier: www.clinicaltrials.gov,NCT02773875.

Occlusion Detection Time in Insulin Pumps at Two Different Basal Rates

BACKGROUND

The detection of insulin infusion set (IIS) occlusions is an important feature of insulin pumps with regard to patient safety. However, there are no requirements for a time limit until an alarm has to be triggered after an occlusion occurred. The standard IEC 60601-2-24 is applicable for insulin pumps and describes test settings and procedures to determine occlusion detection time (ODT).

METHODS

In this study, ODT of six different insulin pump models with different IIS (in total 10 different insulin pump systems) was tested for two basal rates (1.0 U/h and 0.1 U/h).

RESULTS

Differences were seen between the tested pump systems. At a basal rate of 1.0 U/h all insulin pump systems showed an acceptable ODT of less than 5 hours. However, at a basal rate of 0.1 U/h, as often used in children, the median ODT ranged from approximately 4 hours to more than 40 hours. With the lower basal rate, median ODT was longer than 6-8 hours for 9 of the 10 systems.

CONCLUSIONS

Insulin pump users should not blindly rely on occlusion alarms but perform regular glucose monitoring and manufacturers should develop mechanisms that allow an earlier detection at low basal rates.

Impact of targeted education on managing warning and error signals by children and adolescents with type 1 diabetes using the Accu-Chek Combo Insulin Pump System

PURPOSE

Insulin pumps are widely used in diabetes. They are equipped with safety alarms to alert users. Pump manuals contain alarm codes and how to troubleshoot them. However, these manuals are lengthy and difficult to use, particularly in emergencies. We aim to assess the impact of targeted education on warnings and errors in improving competency to troubleshoot the alarms.

METHODS

Twenty-one patients, with a median age of 13, were recruited over a 5-month period. Each patient had 2 study visits. The frequencies and types of alarms were recorded, and patients were given a summary sheet that outlined common alarms encountered and troubleshooting tips. In visit 2, the frequencies and types of alarms were compared to those of visit 1. The patients were asked to fill a questionnaire and to rate the education session given in visit 1, their level of competency in decrypting alarm codes, and their promptness in responding to alarms.

RESULTS

Low cartridge (W1), low battery (W2), and bolus cancelled (W8) were the commonest warnings. The most noted errors were occlusion (E4), power interruption (E8), empty battery (E2), set not primed (E11), and cartridge empty (E1). The numbers of warning and error signals markedly decreased after targeted education (P<0.05). The ability in decrypting warning signals significantly improved (P=0.02), and the frequency of response to pump alarms significantly increased (P=0.001).

CONCLUSIONS

Certain warnings and errors are more common than others in insulin pumps. Targeted education is useful in improving competency and response of patients in managing pump alarms.

Continuous subcutaneous insulin infusion: Special needs for children

Continuous subcutaneous insulin infusion (CSII) is a very common therapy for children with type 1 diabetes. Due to physiological differences they have other requirements for their insulin pump than adults. The main difference is the need for very low basal rates. Even though most available insulin pumps reach a high accuracy at usual basal rates, accuracy decreases for lower rates. In addition, the lowest delivered amount at 1 time is limiting the fine tuning of the basal rate as well as the option for temporary basal rates. Alarms in case of occlusions depend on accumulation of a certain amount of insulin in the catheter, and therefore the time until such an alarm is triggered is much longer with lower basal rates. Accordingly, the risk for hyperglycemia developing into diabetic ketoacidosis increases. The availability of bolus advisors facilitates the calculation of meal and correction boluses for children and their parents. However, there are some differences between the calculators, and the settings that the calculation is based on are very important. Better connectivity, for example with a system for continuous glucose monitoring, might help to further increase safety in the use of CSII in children. When selecting an insulin pump for a child, the features and characteristics of available pumps should be properly compared to ensure an effective and safe therapy.

Moving Toward a Unified Platform for Insulin Delivery and Sensing of Inputs Relevant to an Artificial Pancreas

Advances in insulin pump and continuous glucose monitoring technology have primarily focused on optimizing glycemic control for people with type 1 diabetes. There remains a need to identify ways to minimize the physical burden of this technology. A unified platform with closely positioned or colocalized interstitial fluid glucose sensing and hormone delivery components is a potential solution. Present challenges to combining these components are interference of glucose sensing from proximate insulin delivery and the large discrepancy between the life span of current insulin infusion sets and glucose sensors. Addressing these concerns is of importance given that the future physical burden of this technology is likely to be even greater with the ongoing development of the artificial pancreas, potentially incorporating multiple hormone delivery, glucose sensing redundancy, and sensing of other clinically relevant nonglucose biochemical inputs.

New Insulin Delivery Recommendations

Many primary care professionals manage injection or infusion therapies in patients with diabetes. Few published guidelines have been available to help such professionals and their patients manage these therapies. Herein, we present new, practical, and comprehensive recommendations for diabetes injections and infusions. These recommendations were informed by a large international survey of current practice and were written and vetted by 183 diabetes experts from 54 countries at the Forum for Injection Technique and Therapy: Expert Recommendations (FITTER) workshop held in Rome, Italy, in 2015. Recommendations are organized around the themes of anatomy, physiology, pathology, psychology, and technology. Key among the recommendations are that the shortest needles (currently the 4-mm pen and 6-mm syringe needles) are safe, effective, and less painful and should be the first-line choice in all patient categories; intramuscular injections should be avoided, especially with long-acting insulins, because severe hypoglycemia may result; lipohypertrophy is a frequent complication of therapy that distorts insulin absorption, and, therefore, injections and infusions should not be given into these lesions and correct site rotation will help prevent them; effective long-term therapy with insulin is critically dependent on addressing psychological hurdles upstream, even before insulin has been started; inappropriate disposal of used sharps poses a risk of infection with blood-borne pathogens; and mitigation is possible with proper training, effective disposal strategies, and the use of safety devices. Adherence to these new recommendations should lead to more effective therapies, improved outcomes, and lower costs for patients with diabetes.

Insulin Infusion Set Use: European Perspectives and Recommendations

Insulin pump users worldwide depend on insulin infusion sets (IISs) for predictable delivery of insulin to the subcutaneous tissue. Yet emerging data indicates that IISs are associated with many pump-related adverse events and may contribute to potentially life-threatening problem of unexplained hyperglycemia. The relative scarcity of published research on IISs to date, the heterogeneity of regional IIS practices, and the increasing demand for international standards guiding their use prompted convening of a panel of diabetologists and diabetes nurse educators last February, in Milan, Italy, to discuss a framework for optimizing IIS practice in Europe. The multinational panel was tasked, first, with identifying the often-overlooked IIS issues that can affect patients' experience of pump therapy-e.g., partial or complete blockage of the cannula, skin pathologies, unpredictable variations in insulin absorption, dislodgment, and the demands of site rotation and set changes-and, second, with establishing direction for developing cohesive protocols to assure long-term success. As reported in this article, the panel examined IIS-related complications of pump therapy encountered in clinical practice, considered country-wide policies to prevent and mitigate such complications, and updated priorities for improving IIS education on issues of device selection, skin care, and troubleshooting unexplained hyperglycemia. These recommendations may be more relevant with the possibility of closed-loop systems available in the near future.

Improving Patient Experience With Insulin Infusion Sets

Purpose

Insulin 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.

Methods

In 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.

Conclusion

Development of practical tools and standardized guidelines for empowering patients to prevent, diagnose, and troubleshoot IIS problems that contribute to unexplained hyperglycemia will be necessary to realize the full benefit of insulin pump therapy along the continuum of diabetes education.