Suture-based vs. pure plug-based vascular closure devices for VA-ECMO decannulation–A retrospective observational study

BackgroundVeno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a valuable treatment option for patients in cardiogenic shock, but complications during decannulation may worsen the overall outcome. Therefore, the aim of this study was to compare the efficacy and safety of suture-based to pure plug-based vascular closure devices for VA-ECMO decannulation.MethodsIn this retrospective study, the procedural outcome of 33 patients with suture-based Perclose ProGlide closure devices was compared to 38 patients with MANTA plug-based closure devices.ResultsRate of technically correct placement of closure devices was 88% in the suture-based group and 97% in the plug-based group (p = 0.27). There was a significant reduction of severe bleeding events during VA-ECMO decannulation in plug-based versus suture-based systems (3% vs. 21%, p = 0.04). Ischemic complications occurred in 6% with suture-based and 5% with plug-based device (p = 1.00). Pseudoaneurysm formation was detected in 3% in both groups (p = 1.00). No switch to vascular surgery due to bleeding after decannulation was necessary in both groups.ConclusionBased on our retrospective analysis, we propose that plug-based vascular closure should be the preferred option for VA-ECMO decannulation. This hypothesis should be further tested in a randomized trial

Tree loss impacts on ecological connectivity: Developing models for assessment

Trees along linear features are important landscape features, and their loss threatens ecological connectivity. Until recently, trees outside of woodlands (TOWs) were largely unmapped however; the development of innovation mapping techniques provides opportunities to understand the distribution of such trees and to apply spatially explicit models to explore the importance of trees for connectivity. In this study, we demonstrate the utility of models when investigating tree loss and impacts on connectivity. Specifically, we investigated the consequences of tree loss due to the removal of roadside trees, a common management response for diseased or damaged trees, on wider landscape functional connectivity. We simulated the loss of roadside trees within six focal areas of the south east of the UK. We used a spatially explicit individual-based modelling platform, RangeShifter, to model the movement of 81 hypothetical actively dispersing woodland breeding species across these agriculturally fragmented landscapes. We investigated the extent to which removal of trees, from roadsides within the wider landscape, affected the total number of successful dispersers in any given year and the number of breeding woodlands that became isolated through time. On average roadside trees accounted for < 2% of land cover, but removing 60% of them (~ 1.2% of land cover) nevertheless decreased the number of successful dispersers by up to 17%. The impact was greatest when roadside trees represented a greater proportion of canopy cover. The study therefore demonstrates that models such as RangeShifter can provide valuable tools for assessing the consequences of losing trees outside of woodlands

Leistungsbewertung Strukturierter Overlay Netze

Overlay networks establish logical connections between users on top of the physical network. While randomly connected overlay networks provide only a best effort service, a new generation of structured overlay systems based on Distributed Hash Tables (DHTs) was proposed by the research community. However, there is still a lack of understanding the performance of such DHTs. Additionally, those architectures are highly distributed and therefore appear as a black box to the operator. Yet an operator does not want to lose control over his system and needs to be able to continuously observe and examine its current state at runtime. This work addresses both problems and shows how the solutions can be combined into a more self-organizing overlay concept. At first, we evaluate the performance of structured overlay networks under different aspects and thereby illuminate in how far such architectures are able to support carrier-grade applications. Secondly, to enable operators to monitor and understand their deployed system in more detail, we introduce both active as well as passive methods to gather information about the current state of the overlay network.Unter einem Overlay Netz versteht man den Zusammenschluss mehrerer Komponenten zu einer logischen Topologie, die auf einer existierenden physikalischen Infrastruktur aufsetzt. Da zufällige Verbindungen zwischen den einzelnen Teilnehmern aber sehr ineffizient sind, wurden strukturierte Overlay Netze entworfen, bei denen die Beziehungen zwischen den einzelnen Teilnehmern fest vorgeschrieben sind. Solche strukturierten Mechanismen versprechen zwar ein großes Potential, dieses wurde aber noch nicht ausreichend untersucht bzw. wissenschaftlich nachgewiesen. In dieser Arbeit wird mit mathematischen Methoden und ereignisorientierter Simulation die Leistungsfähigkeit von strukturierten Overlay Netzen untersucht. Da diese stark von der aktuellen Situation im Overlay abhängt, entwickeln wir Methoden, mit denen sich sowohl passiv, als auch aktiv, wichtige Systemparameter zur Laufzeit abschätzen bzw. messen lassen. Zusammen führen die vorgeschlagenen Methoden zu selbstorganisierenden Mechanismen, die den aktuellen Zustand des Overlays überwachen, diesen bewerten und sich gegebenenfalls automatisch an die aktuellen Verhältnisse anpasse

MPLS Traffic Engineering in OSPF Networks - a combined Approach

One of the main reasons for the development of MPLS was the need for flexible Traffic Engineering (TE) in IP networks ([8], [1]). Additionally a lot of IP service providers have found that Traffic Engineering of their networks can have a tactical and strategic value [2]. The first part of the paper introduces a linear optimization approach for Traffic Engineering in MPLS networks. Most remarkable on the presented approach is the additive objective function, which optimizes both the maximum utilization as well as the average utilization. In practice, most of the existing OSPF or IS-IS networks will have a transition phase between the pure IGP routing and the MPLS driven approach. Thus, we extend our optimization approach from a regular IGP network to a mixed IGP-MPLS environment. To avoid configuration complexity and state space explosion in MPLS devices, it could also make sense to start with a MPLS environment and take advantage of the configuration simplicity and the state space reduction capability of IGP protocols. In addition the paper includes a performance comparison between default configured OSPF, weight optimized OSPF and pure MPLS networks and show the benefit of OSPF optimization and MPLS Traffic Engineering. Based on this comparison we can offer some valuable clues to decide in favor of a local or global TE system