Children with end-stage lung failure awaiting lung transplant would benefit from improvements in artificial lung technology allowing for wearable pulmonary support as a bridge-to-transplant therapy. In this work, we designed, fabricated, and tested the Pediatric MLung-a dual-inlet hollow fiber artificial lung based on concentric gating, which has a rated flow of 1 L/min, and a pressure drop of 25 mm Hg at rated flow. This device and future iterations of the current design are designed to relieve pulmonary arterial hypertension, provide pulmonary support, reduce ventilator-associated injury, and allow for more effective therapy of patients with end-stage lung disease, including bridge-to-transplant treatment. Keywords extracorporeal life support; hollow fiber oxygenator; wearable artificial lung One in five children with end-stage lung failure (ESLF) die while awaiting transplant. 1 Hollow fiber oxygenators or artificial lungs (ALs) are commonly used to provide pulmonary support in acute and bridge-to-transplant applications. In these devices, blood flows around a bundle of hollow fibers, while a sweep gas supplied to the fibers' lumens facilitates gas transfer via diffusion through the fiber wall. The benefits of a particular AL depend on the design properties and engineering of the AL, and device development must be thoughtfully targeted to the intended patient population to achieve optimal results. In this work, we design, fabricate, and test the performance of a paracorporeal, pumpless device intended for pediatric patients. This device, called the "Pediatric MLung," can be used as a bridge to transplant for children with ESLF.

No abstract

Aluminium leaching from cooking utensils is a source of dietary aluminium and there are differing reports in the literature concerning the effects of fluoride ions on aluminium leaching. This paper reports that aluminium leaching may be increased by around 5% when fluoride ion at 1 mg/litre is present. More dramatic increases in aluminium leaching occur if the fluoride ion concentration is increased to 20 mg/litre, but this would rarely, if ever, be found in a culinary situation. At fluoride ion concentrations likely to be encountered in cooking, the increased leaching due to fluoride is very small in relation to the effects of pH on aluminium leaching.

Introduction:In radiofrequency ablation procedures for cardiac arrhythmia, the efficacy of creating repeated lesions at the same location ("insurance lesions") remains poorly studied. We assessed the effect of type of tissue, power, and time on the resulting lesion geometry during such multiple ablation procedures.Methods: A custom ex vivo ablation model was used to assess lesion formation. An ablation catheter was oriented perpendicular to the tissue and used to create lesions that varied by type of tissue (atrial or ventricular free wall), power (30 or 50 W), and time (30, 40, or 50 s for standard ablations and 5, 10, or 15 s for high-power, shortduration [HPSD] ablations). Lesion dimensions were recorded and then analyzed.Radiofrequency ablations were performed on 57 atrial tissue samples (28 HPSD, 29 standard) and 28 ventricular tissue samples (all standard).Results: With ablation parameters held constant, performing multiple ablations significantly increased lesion depth in ventricular tissue when ablations were performed at 30 W for 50 s. No other set of ablation parameters was shown to

Re-entrant arrhythmias—the leading cause of sudden cardiac death—are caused by diseased and delayed myocardial conduction. Access to the coronary veins that cross the “culprit” scarred regions where re-entry originates provides improved pacing to prevent ventricular arrhythmias and circumvent the need for painful defibrillation, risky cardiac ablation, or toxic and often ineffective antiarrhythmic medications. To date, this goal has not been achieved due to the lack of pacing electrodes which are small or focal enough to navigate these tributaries. We have developed an injectable conductive hydrogel that can fill the epicardial coronary veins and their mid-myocardial tributaries. When connected to a standard pacing lead, these injected hydrogels can be converted into flexible electrodes that directly pace the previously inaccessible mid-myocardial tissue. In our two-component system, hydrogel precursor solutions can be injected through a dual lumen catheter in a minimally invasive deployment strategy to provide direct access to the diseased regions with relative precision and ease. Mixing of the two solutions upon injection into the vein activates redox-initiated crosslinking of the gel for rapid in situ cure without an external stimulus. An ex vivo porcine model was used to identify the requisite viscosity and cure rate for gel retention and homogeneity. Ionic species added to the hydrogel precursor solutions conferred conductivity above target myocardium values that was retained after implantation. Successful in vivo deployment demonstrated that the hydrogel electrode filled the anterior interventricular vein with extension into the septal (mid-myocardial) venous tributaries, far deeper than current technologies allow. In addition to successful capture and pacing of the porcine heart, analysis of surface ECG tracings revealed a novel pacing paradigm not observed in traditional single-point pacing: capture of extensive swaths of the native conduction system. This is the first report of an injectable electrode used to successfully pace the mid-myocardium and mimic physiologic conduction. As such, this injectable hydrogel electrode can be deployed to any region affected by prior myocardial infarction and consequent scar tissue to provide a reliable pacing modality that most closely resembles native conduction.Abstract FigureOne Sentence SummaryInjectable hydrogel electrodes achieve pacing that mimics physiologic conduction by capturing midmyocardial tissue.

No abstract

Cardiac arrhythmias are a leading cause of morbidity and mortality in the developed world. A common mechanism underlying many of these arrhythmias is re-entry, which may occur when native conduction pathways are disrupted, often by myocardial infarction. Presently, re-entrant arrhythmias are most commonly treated with antiarrhythmic drugs and myocardial ablation, although both treatment methods are associated with adverse side effects and limited efficacy. In recent years, significant advancements in the field of biomaterials science have spurred increased interest in the development of novel therapies that enable restoration of native conduction in damaged or diseased myocardium. In this review, we assess the current landscape of materials-based approaches to eliminating re-entrant arrhythmias. These approaches potentially pave the way for the eventual replacement of myocardial ablation as a preferred therapy for such pathologies.

No abstract