Objective: Hemodialysis patients usually receive an arteriovenous fistula (AVF) in the arm as vascular access conduit to allow dialysis 2-3 times a week. This AVF introduces the high flow necessary for dialysis, but over time the ever-present supraphysiological flow is the leading cause of complications. This study aims to develop an implantable device able to non-invasively remove the high flow outside dialysis sessions. Methods: The developed prototype features a magnetic ring allowing external coupling and torque transmission to non-invasively control an AVF valve. Mock-up devices were implanted into arm and sheep cadavers to test sizes and locations. The transmission torque, output force, and valve closure are measured for different representative skin thicknesses. Results: The prototype was placed successfully into arm and sheep cadavers. In the prototype, a maximum output force of 78.9 ± 4.2 N, 46.7 ± 1.9 N, 25.6 ± 0.7 N, 13.5 ± 0.6 N and 6.3 ± 0.4 N could be achieved non-invasively through skin thicknesses of 1-5 mm respectively. The fistula was fully collapsible in every measurement through skin thickness up to the required 4 mm. Conclusion: The prototype satisfies the design requirements. It is fully implantable and allows closure and control of an AVF through non-invasive torque transmission. In vivo studies are pivotal in assessing functionality and understanding systemic effects. Significance: A method is introduced to transfer large amounts of energy to a medical implant for actuation of a mechanical valve trough a closed surface. This system allows non-invasive control of an AVF to reduce complications related to the permanent high flow in conventional AVFs.

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Introduction: The recent introduction of the European Medical Device Regulation poses stricter legislation for manufacturers developing medical devices in the EU. Many devices have been placed into a higher risk category, thus requiring more data before market approval, and a much larger focus has been placed on safety. For implantable and Class III devices, the highest risk class, clinical evidence is a necessity. However, the requirements of clinical study design and developmental outcomes are only described in general terms due to the diversity of devices. Methods: A structured approach to determining the requirements for the clinical development of high-risk medical devices is introduced, utilizing the question-based development framework, which is already used for pharmaceutical drug development. An example of a novel implantable device for haemodialysis demonstrates how to set up a relevant target product profile defining the device requirements and criteria. The framework can be used in the medical device design phase to define specific questions to be answered during the ensuing clinical development, based upon five general questions, specified by the question-based framework. Results: The result is a clear and evaluable overview of requirements and methodologies to verify and track these requirements in the clinical development phase. Development organizations will be guided to the optimal route, also to abandon projects destined for failure early on to minimize development risks. Conclusion: The framework could facilitate communication with funding agencies, regulators and clinicians, while highlighting remaining ‘known unknowns’ that require answering in the post-market phase after sufficient benefit is established relative to the risks.

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The need for data to study the relationship between fatigued healthcare professionals and performance outcomes is evident, however, it is unclear which methodology is most appropriate to provide these insights. To address this issue, we performed a systematic review of relevant articles by searching the MEDLINE, EMBASE, Cochrane, Web of Science, and CINAHL databases. The literature search identified 2960 unique references, of which 82 were identified eligible. The impact on performance was studied on clinical outcomes, medical simulation, neurocognitive performance, sleep quantification and subjective assessment. In general results on performance are conflicting; impairment, no effect, and improvement were found. This review outlines the various methods currently available for assessing fatigue-impaired performance. The contrasting outcomes can be attributed to three main factors: differences in the operationalisation of fatigue, incomplete control data, and the wide variety in the methods used. We recommend the implementation of a clinically applicable tool that can provide uniform data. Until these data become available, caution should be used when developing regulations that can have implications for physicians, education, manpower planning, and ‒ ultimately ‒ patient care.@en

Objective: To analyze the rate of infections and complications after surgeon-performed, largely ultrasound-guided, central venous catheter (CVC) placement in a pediatric population and to identify patients at high risk of complications. Methods: All children aged between 4 months and 19 years with a percutaneous CVC inserted between January 1, 2000, and July 31, 2013, were included. Patient records were reviewed retrospectively for the occurrence of infection and other complications until CVC removal or the last outpatient clinic visit and compared between patient groups and with the recent literature. Results: A total of 538 CVCs were placed in 345 patients. Eight patients (1.5%) suffered complications during placement. There were 84 cases of a suspected CVC infection (15.6%). Catheter-related infections with a positive catheter tip culture occurred in 25 cases (4.6%). Older patients (odds ratio [OR] 0.88; 95% confidence interval [CI] 0.78-0.98) or patients with a double-lumen 7 French Bard-Hickman catheter (OR 0.32; 95% CI 0.11-1.00) had a significantly lower risk of infection. Older patients (OR 0.94; 95% CI 0.89-0.99) and patients with beta-thalassemia (OR 0.35; 95% CI 0.17-0.71) also had a significantly lower risk of suspected infection. Conclusion: In general, infection rates in our series were similar to those in the recent literature. Younger patients seem to be at higher risk for CVC removal because of infection prior to the end of treatment. Patients with beta-thalassemia or receiving a double-lumen 7F Bard-Hickman catheter had a lower risk of infection.@en