Broadening of the Divertor Heat Flux Profile in High Confinement Tokamak Fusion Plasmas with Edge Pedestals Limited by Turbulence in DIII-D.

Multimachine empirical scaling predicts an extremely narrow heat exhaust layer in future high magnetic field tokamaks, producing high power densities that require mitigation. In the experiments presented, the width of this exhaust layer is nearly doubled using actuators to increase turbulent transport in the plasma edge. This is achieved in low collisionality, high confinement edge pedestals with their gradients limited by turbulent transport instead of large-scale, coherent instabilities. The exhaust heat flux profile width and divertor leg diffusive spreading both double as a high frequency band of turbulent fluctuations propagating in the electron diamagnetic direction doubles in amplitude. The results are quantitatively reproduced in electromagnetic XGC particle-in-cell simulations which show the heat flux carried by electrons emerges to broaden the heat flux profile, directly supported by Langmuir probe measurements.

Characterization of thermal and optical properties in porcine pancreas tissue.

BACKGROUND: Photothermal therapies have shown promise for treating pancreatic ductal adenocarcinoma when they can be applied selectively, but off-target heating can frustrate treatment outcomes. Improved strategies leveraging selective binding and localized heating are possible with precision medical approaches such as functionalized gold nanoparticles, but careful control of optical dosage and thermal generation would be imperative. However, the literature review revealed many groups assume liver properties for pancreas tissue or rely on insufficiently rigorous characterization studies. OBJECTIVE: The objective of this study was to determine the thermal conductivity and optical properties at 808/1064 nm wavelengths in healthy samples of fresh and frozen porcine pancreas ex vivo. METHODS: Thermal conductivity of the porcine pancreas tissue was measured by utilizing a hot plate and two K-type thermocouples. Experimental variables such as tissue sample thickness, hot plate temperature, and heat convection coefficient were estimated through the control experiments utilizing specimens with known thermal conductivity. Optical evaluations assessed light attenuation at the 808 and 1064 nm wavelengths (continuous wave, collimated beam) by measuring the light transmittance and reflectance of different tissue thicknesses. In turn, these measurements were input into an inverse adding-doubling program to estimate the optical absorption and reduced scattering coefficients. RESULTS: Interestingly, pancreas tissue thermal conductivity was demonstrated to have no significant difference (p > 0.5) between samples that were fresh, frozen for 7 days, or frozen for 14 days. Conversely, optical property assessment exhibited a significant difference (p < 0.001) between fresh and frozen tissue samples, with increased absorbance and reflectance within the frozen group. However, the optical attenuation values measured were substantially less than that of the liver or reported in previous pancreas studies, suggesting a wide overestimation of these properties. CONCLUSIONS: These thermal and optical properties are critical to the development of novel therapeutic strategies like plasmonic photothermal therapy, but perhaps more importantly, are invaluable towards informing better surgical planning and operative technique among the existing thermal approaches for treating pancreas tissue.

Portable Medical Suction and Aspirator Devices: Are the Design and Performance Standards Relevant?

Airway clearance refers to the clearing of any airway blockage caused due to foreign objects such as mud, gravel, and biomaterials such as blood, vomit, or teeth fragments using the technology of choice, portable suction devices. Currently available devices are either too heavy and bulky to be carried, or insufficiently powered to be useful despite being in accordance with the ISO 10079-1 standards. When applied to portable suction, the design and testing standards lack clinical relevancy, which is evidenced by how available portable suction devices are sparingly used in pre-hospital situations. Lack of clinical relevancy despite being in accordance with design/manufacturing standards arise due to little if any collaboration between those developing clinical standards and the bodies that maintain design and manufacturing standards. An updated set of standards is required that accurately reflects evidence-based requirements and specifications, which should promote valid, rational, and relevant engineering designs and manufacturing standards in consideration of the unique scenarios facing prehospital casualty care. This paper aims to critically review the existing standards for portable suction devices and propose modifications based on the evidence and requirements, especially for civilian prehospital and combat casualty care situations.

Nanofluidic microsystem for sustained intraocular delivery of therapeutics.

Globally, 145.2 million people suffer from moderate to severe vision impairment or blindness due to preventable or treatable causes. However, patient adherence to topical or intravitreal treatment is a leading cause of poor outcomes. To address this issue, we designed an intraocularly implantable device called the nanofluidic Vitreal System for Therapeutic Administration (nViSTA) for continuous and controlled drug release based on a nanochannel membrane that obviates the need for pumps or actuation. In vitro release analysis demonstrated that our device achieves sustained release of bimatoprost (BIM) and dexamethasone (DEX) at concentrations within clinically relevant therapeutic window. In this proof of concept study, we constructed an anatomically similar in silico human eye model to simulate DEX release from our implant and gain insight into intraocular pharmacokinetics profile. Overall, our drug-agnostic intraocular implant represents a potentially viable platform for long-term treatment of various chronic ophthalmologic diseases, including diabetic macular edema and uveitis.

Peri-operative neurological complications.

Brain injury from cardiac surgery is an important source of patient morbidity and mortality. The relationship between risk of brain injury and advanced age portends a rising frequency of these complications due to an increasing proportion of elderly patients undergoing cardiac surgery. This review will explore the aetiology and risk factors for peri-operative stroke, postoperative cognitive dysfunction and postoperative delirium. The prevention of each of these conditions will also be discussed, with a focus on brain protection strategies and the avoidance of cerebral embolism and hypoperfusion.

Sustained zero-order delivery of GC-1 from a nanochannel membrane device alleviates metabolic syndrome.

BACKGROUND/OBJECTIVES: Our objective was to assess the sustained, low-dose and constant administration of the thyroid receptor-ß (TRß)-selective agonist GC-1 (sobetirome) from a novel nanochannel membrane device (NMD) for drug delivery. As it known to speed up metabolism, accomplish weight loss, improve cholesterol levels and possess anti-diabetic effects, GC-1 was steadily administered by our NMD, consisting of an implantable nanochannel membrane, as an alternative to conventional daily administration, which is subject to compliance issues in clinical settings. SUBJECTS/METHODS: Diet-induced obese C57BL/J6 male mice were fed a very high-fat diet (VHFD) and received NMD implants subcutaneously. Ten mice per group received capsules containing GC-1 or phosphate-buffered saline (control). Weight, lean and fat mass, as well as cholesterol, triglycerides, insulin and glucose, were monitored for 24 days. After treatment, plasma levels of thyroid-stimulating hormone (TSH) and thyroxine were compared. mRNA levels of a panel of thermogenic markers were examined using real-time PCR in white adipose tissue (WAT) and brown adipose tissue (BAT). Adipose tissue, liver and local inflammatory response to the implant were examined histologically. Pancreatic islet number and ß-cell area were assessed. RESULTS: GC-1 released from the NMD reversed VHFD-induced obesity and normalized serum cholesterol and glycemia. Significant reductions in body weight and fat mass were observed within 10 days, whereas reductions in serum cholesterol and glucose levels were seen within 7 days. The significant decrease in TSH was consistent with TRß selectivity for GC-1. Levels of transcript for Ucp1 and thermogenic genes PGC1a, Cidea, Dio2 and Cox5a showed significant upregulation in WAT in NMD-GC-1-treated mice, but decreased in BAT. Although mice treated by NMD-GC-1 showed a similar number of pancreatic islets, they exhibited significant increase in ß-cell area. CONCLUSIONS: Our data demonstrate that the NMD implant achieves steady administration of GC-1, offering an effective and tightly controlled molecular delivery system for treatment of obesity and metabolic disease, thereby addressing compliance.

Impedance characterization, degradation, and in vitro biocompatibility for platinum electrodes on BioMEMS.

Fine control of molecular transport through microfluidic systems can be obtained by modulation of an applied electrical field across channels with the use of electrodes. In BioMEMS designed for biological fluids and in vivo applications, electrodes must be biocompatible, biorobust and stable. In this work, the analysis and characterization of platinum (Pt) electrodes integrated on silicon substrates for biomedical applications are presented. Electrodes were incorporated on the surface of silicon chips by adhesion of laminated Pt foils or deposited at 30°, 45° or 90° angle by e-beam or physical vapor (sputtering) methods. Electrical and physical properties of the electrodes were quantified and evaluated using electrical impedance spectroscopy and modelling of the electrode-electrolyte interfaces. Electrode degradation in saline solution at pH 7.4 was tested at room temperature and under accelerated conditions (90 °C), both in the presence and absence of an applied electrical potential. Degradation was quantified using atomic force microscopy (AFM) and inductively coupled plasma mass spectroscopy (ICP-MS). Biocompatibility was assessed by MTT proliferation assay with human dermal fibroblasts. Results demonstrated that the deposited electrodes were biocompatible with negligible material degradation and exhibited electrochemical behavior similar to Pt foils, especially for e-beam deposited electrodes. Finally, Pt electrodes e-beam deposited on silicon nanofabricated nanochannel membranes were evaluated for controlled drug delivery applications. By tuning a low applied electrical potential (<1.5 VDC) to the electrodes, temporal modulation of the dendritic fullerene 1 (DF-1) release from a source reservoir was successfully achieved as a proof of concept, highlighting the potential of deposited electrodes in biomedical applications.

Modeling and forecasting the distribution of Vibrio vulnificus in Chesapeake Bay.

AIM: To construct statistical models to predict the presence, abundance and potential virulence of Vibrio vulnificus in surface waters of Chesapeake Bay for implementation in ecological forecasting systems. METHODS AND RESULTS: We evaluated and applied previously published qPCR assays to water samples (n = 1636) collected from Chesapeake Bay from 2007-2010 in conjunction with State water quality monitoring programmes. A variety of statistical techniques were used in concert to identify water quality parameters associated with V. vulnificus presence, abundance and virulence markers in the interest of developing strong predictive models for use in regional oceanographic modeling systems. A suite of models are provided to represent the best model fit and alternatives using environmental variables that allow them to be put to immediate use in current ecological forecasting efforts. CONCLUSIONS: Environmental parameters such as temperature, salinity and turbidity are capable of accurately predicting abundance and distribution of V. vulnificus in Chesapeake Bay. Forcing these empirical models with output from ocean modeling systems allows for spatially explicit forecasts for up to 48 h in the future. SIGNIFICANCE AND IMPACT OF THE STUDY: This study uses one of the largest data sets compiled to model Vibrio in an estuary, enhances our understanding of environmental correlates with abundance, distribution and presence of potentially virulent strains and offers a method to forecast these pathogens that may be replicated in other regions.

Fiberoptic microneedle device facilitates volumetric infusate dispersion during convection-enhanced delivery in the brain.

BACKGROUND AND OBJECTIVES: A fiberoptic microneedle device (FMD) was designed and fabricated for the purpose of enhancing the volumetric dispersal of macromolecules delivered to the brain through convection-enhanced delivery (CED) by concurrent delivery of sub-lethal photothermal hyperthermia. This study's objective was to demonstrate enhanced dispersal of fluid tracer molecules through co-delivery of 1,064 nm laser energy in an in vivo rodent model. MATERIALS AND METHODS: FMDs capable of co-delivering fluids and laser energy through a single light-guiding capillary tube were fabricated. FMDs were stereotactically inserted symmetrically into both cerebral hemispheres of 16 anesthetized rats to a depth of 1.5 mm. Laser irradiation (1,064 nm) at 0 (control), 100, and 200 mW was administered concurrently with CED infusions of liposomal rhodamine (LR) or gadolinium-Evans blue-serum albumin conjugated complex (Gd-EBA) at a flow rate of 0.1 µl/min for 1 hour. Line pressures were monitored during the infusions. Rodents were sacrificed immediately following infusion and their brains were harvested, frozen, and serially cryosectioned for histopathologic and volumetric analyses. RESULTS: Analysis by ANOVA methods demonstrated that co-delivery enhanced volumetric dispersal significantly, with measured volumes of 15.8 ± 0.6 mm(3) for 100 mW compared to 10.0 ± 0.4 mm(3) for its fluid only control and 18.0 ± 0.3 mm(3) for 200 mW compared to 10.3 ± 0.7 mm(3) for its fluid only control. Brains treated with 200 mW co-delivery exhibited thermal lesions, while 100 mW co-deliveries were associated with preservation of brain cytoarchitecture. CONCLUSION: Both lethal and sub-lethal photothermal hyperthermia substantially increase the rate of volumetric dispersal in a 1 hour CED infusion. This suggests that the FMD co-delivery method could reduce infusion times and the number of catheter insertions into the brain during CED procedures.

Intracranial hyperthermia through local photothermal heating with a fiberoptic microneedle device.

BACKGROUND AND OBJECTIVES: The fiberoptic microneedle device (FMD) seeks to leverage advantages of both laser-induced thermal therapy (LITT) and convection-enhanced delivery (CED) to increase volumetric dispersal of locally infused chemotherapeutics through sub-lethal photothermal heat generation. This study focused on determination of photothermal damage thresholds with 1,064 nm light delivered through the FMD into in vivo rat models. MATERIALS AND METHODS: FMDs capable of co-delivering laser energy and fluid agents were fabricated through a novel off-center splicing technique involving fusion of a multimode fiberoptic to light-guiding capillary tubing. FMDs were positioned at a depth of 2.5 mm within the cerebrum of male rats with fluoroptic temperature probes placed within 1 mm of the FMD tip. Irradiation (without fluid infusion) was conducted at laser powers of 0 (sham), 100, 200, 500, or 750 mW. Evans blue-serum albumin conjugated complex solution (EBA) and laser energy co-delivery were performed in a second set of preliminary experiments. RESULTS: Maximum, steady-state temperatures of 38.7 ± 1.6 and 42.0 ± 0.9 °C were measured for the 100 and 200 mW experimental groups, respectively. Histological investigation demonstrated needle insertion damage alone for sham and 100 mW irradiations. Photothermal damage was detected at 200 mW, although observable thermal damage was limited to a small penumbra of cerebral cortical microcavitation and necrosis that immediately surrounded the region of FMD insertion. Co-delivery of EBA and laser energy presented increased volumetric dispersal relative to infusion-only controls. CONCLUSION: Fluoroptic temperature sensing and histopathological assessments demonstrated that a laser power of 100 mW results in sub-lethal brain hyperthermia, and the optimum, sub-lethal target energy range is likely 100-200 mW. The preliminary FMD-CED experiments confirmed the feasibility of augmenting fluid dispersal using slight photothermal heat generation, demonstrating the FMD's potential as a way to increase the efficacy of CED in treating MG.

Spatially controlled photothermal heating of bladder tissue through single-walled carbon nanohorns delivered with a fiberoptic microneedle device.

Laser-based photothermal therapies for urothelial cell carcinoma (UCC) are limited to thermal ablation of superficial tumors, as treatment of invasive lesions is hampered by shallow light penetration in bladder tissue at commonly used therapeutic wavelengths. This study evaluates the utilization of sharp, silica, fiberoptic microneedle devices (FMDs) to deliver single-walled carbon nanohorns (SWNHs) serving as exogenous chromophores in conjunction with a 1,064-nm laser to amplify thermal treatment doses in a spatially controlled manner. Experiments were conducted to determine the lateral and depth dispersal of SWNHs in aqueous solution (0.05 mg/mL) infused through FMDs into the wall of healthy, inflated, ex vivo porcine bladders. SWNH-perfused bladder regions were irradiated with a free-space, CW, 1,064-nm laser in order to determine the SWNH efficacy as exogenous chromophores within the organ. SWNHs infused at a rate of 50 µL/min resulted in an average lateral expansion rate of 0.36 ± 0.08 cm(2)/min. Infused SWNHs dispersal depth was limited to the urothelium and muscular propria for 50 µL/min infusions of 10 min or less, but dispersed through the entire thickness after a 15-min infusion period. Irradiation of SWNH-perfused bladder tissue with 1,064 nm laser light at 0.95 W/cm(2) over 40 s exhibited a maximum increase of approximately 19 °C compared with an increase of approximately 3 °C in a non-perfused control. The results indicate that these silica FMDs can successfully penetrate into the bladder wall to rapidly distribute SWNHs with some degree of lateral and depth control and that SWNHs may be a viable exogenous chromophore for photothermal amplification of laser-based UCC treatments.

An Innovative Polymeric Platform for Controlled and Localized Drug Delivery.

Precision medicine aims to optimize pharmacological treatments by considering patients' genetic, phenotypic, and environmental factors, enabling dosages personalized to the individual. To address challenges associated with oral and injectable administration approaches, implantable drug delivery systems have been developed. These systems overcome issues like patient adherence, bioavailability, and first-pass metabolism. Utilizing new combinations of biodegradable polymers, the proposed solution, a Polymeric Controlled Release System (PCRS), allows minimally invasive placement and controlled drug administration over several weeks. This study's objective was to show that the PCRS exhibits a linear biphasic controlled release profile, which would indicate potential as an effective treatment vehicle for cervical malignancies. An injection mold technique was developed for batch manufacturing of devices, and in vitro experiments demonstrated that the device's geometry and surface area could be varied to achieve various drug release profiles. This study's results motivate additional development of the PCRS to treat cervical cancer, as well as other malignancies, such as lung, testicular, and ovarian cancers.

Movement of cerebrospinal fluid tracer into brain parenchyma and outflow to nasal mucosa is reduced at 24 h but not 2 weeks post-stroke in mice.

BACKGROUND: Recent data indicates that cerebrospinal fluid (CSF) dynamics are disturbed after stroke. Our lab has previously shown that intracranial pressure rises dramatically 24 h after experimental stroke and that this reduces blood flow to ischaemic tissue. CSF outflow resistance is increased at this time point. We hypothesised that reduced transit of CSF through brain parenchyma and reduced outflow of CSF via the cribriform plate at 24 h after stroke may contribute to the previously identified post-stroke intracranial pressure elevation. METHODS: Using a photothrombotic permanent occlusion model of stroke in C57BL/6 adult male mice, we examined the movement of an intracisternally infused 0.5% Texas Red dextran throughout the brain and measured tracer efflux into the nasal mucosa via the cribriform plate at 24 h or two weeks after stroke. Brain tissue and nasal mucosa were collected ex vivo and imaged using fluorescent microscopy to determine the change in CSF tracer intensity in these tissues. RESULTS: At 24 h after stroke, we found that CSF tracer load was significantly reduced in brain tissue from stroke animals in both the ipsilateral and contralateral hemispheres when compared to sham. CSF tracer load was also reduced in the lateral region of the ipsilateral hemisphere when compared to the contralateral hemisphere in stroke brains. In addition, we identified an 81% reduction in CSF tracer load in the nasal mucosa in stroke animals compared to sham. These alterations to the movement of CSF-borne tracer were not present at two weeks after stroke. CONCLUSIONS: Our data indicates that influx of CSF into the brain tissue and efflux via the cribriform plate are reduced 24 h after stroke. This may contribute to reported increases in intracranial pressure at 24 h after stroke and thus worsen stroke outcomes.

Military Standard Testing of Commercially Available Supraglottic Airway Devices for Use in a Military Combat Setting.

INTRODUCTION: Airway obstruction is the second leading cause of death on the battlefield. The harsh conditions of the military combat setting require that devices be able to withstand extreme circumstances. Military standards (MIL-STD) testing is necessary before devices are fielded. We sought to determine the ability of supraglottic airway (SGA) devices to withstand MIL-STD testing. METHODS: We tested 10 SGA models according to nine MIL-STD-810H test methods. We selected these tests by polling five military and civilian emergency-medicine subject matter experts (SMEs), who weighed the relevance of each test. We performed tests on three devices for each model, with operational and visual examinations, to assign a score (1 to 10) for each device after each test. We calculated the final score of each SGA model by averaging the score of each device and multiplying that by the weight for each test, for a possible final score of 2.6 to 26.3. RESULTS: The scores for the SGA models were LMA Classic Airway, 25.9; AuraGain Disposable Laryngeal Mask, 25.5; i-gel Supraglottic Airway, 25.2; Solus Laryngeal Mask Airway, 24.4; LMA Fastrach Airway, 24.4; AuraStraight Disposable Laryngeal Mask, 24.1; King LTS-D Disposable Laryngeal Tube, 22.1; LMA Supreme Airway, 21.0; air-Q Disposable Intubating Laryngeal Airway, 20.1; and Baska Mask Supraglottic Airway, 18.1. The limited (one to three) samples available for testing provide adequate preliminary information but restrict the range of failures that could be discovered. CONCLUSIONS: Lower scoring SGA models may not be optimal for military field use. Models scoring sufficiently close to the top performers (LMA Classic, AuraGain, i-gel, Solus, LMA Fastrach, AuraStraight) may be viable for use in the military setting. The findings of our testing should help guide device procurement appropriate for different battlefield conditions.

Extended X-ray absorption fine structure of dynamically-compressed copper up to 1 terapascal.

Large laser facilities have recently enabled material characterization at the pressures of Earth and Super-Earth cores. However, the temperature of the compressed materials has been largely unknown, or solely relied on models and simulations, due to lack of diagnostics under these challenging conditions. Here, we report on temperature, density, pressure, and local structure of copper determined from extended x-ray absorption fine structure and velocimetry up to 1 Terapascal. These results nearly double the highest pressure at which extended x-ray absorption fine structure has been reported in any material. In this work, the copper temperature is unexpectedly found to be much higher than predicted when adjacent to diamond layer(s), demonstrating the important influence of the sample environment on the thermal state of materials; this effect may introduce additional temperature uncertainties in some previous experiments using diamond and provides new guidance for future experimental design.

Mechanical strengthening of fiberoptic microneedles using an elastomeric support.

BACKGROUND AND OBJECTIVES: Microneedles made from silica fiberoptics permit transmission and collection of light, which is an important functional advantage over metal or silicon microneedles. This added functionality may enhance or even enable new percutaneous light-based clinical diagnostic and therapeutic procedures. Micron-diameter fiberoptic microneedles, created from solid fibers capable of light emission and detection, are designed to penetrate several millimeters into tissue while minimizing tissue invasion and disruption. The mechanical strength (critical buckling force) of high aspect ratio (length to diameter) microneedles is a potential problem, which has motivated our invention of an elastomeric support device. In this study, we have tested our hypothesis that embedding the microneedles in an elastomeric support medium may increase microneedle critical buckling force. MATERIALS AND METHODS: The critical buckling force of silica microneedles with 55, 70, and 110 µm diameters and 3 mm lengths were measured with and without a surrounding elastomeric support (PDMS, polydimethylsiloxane). These experimental results were compared to theoretical calculations generated by the Rayleigh-Ritz buckling model. The insertion force required to penetrate ex vivo porcine skin was measured for microneedles with 55 and 70 µm diameters. RESULTS: Use of the PDMS support increased critical buckling force for microneedles of 55, 70, and 110 µm diameters by an average of 610%, 290%, and 33%, respectively. Theoretical calculations by the Rayleigh-Ritz model consistently overestimated the experimentally determined strengthening, but correlated highly with the greater enhancement offered to thinner microneedles. Aided by mechanical strengthening, microneedles 55 µm in diameter were able to repeatedly penetrate. CONCLUSIONS: The critical buckling force of microneedles can be increased substantially to allow extremely high-aspect ratio microneedles, 55-110 µm in diameter and 3 mm in length, to penetrate ex vivo porcine skin. By this strengthening method, the safety and reliability of microneedles in potential clinical applications can be considerably enhanced.

The Difficult Airway Redefined.

There is no all-encompassing or universally accepted definition of the difficult airway, and it has traditionally been approached as a problem chiefly rooted in anesthesiology. However, with airway obstruction reported as the second leading cause of mortality on the battlefield and first-pass success (FPS) rates for out-of-hospital endotracheal intubation (ETI) as low as 46.4%, the need to better understand the difficult airway in the context of the prehospital setting is clear. In this review, we seek to redefine the concept of the "difficult airway" so that future research can target solutions better tailored for prehospital, and more specifically, combat casualty care. Contrasting the most common definitions, which narrow the scope of practice to physicians and a handful of interventions, we propose that the difficult airway is simply one that cannot be quickly obtained. This implies that it is a situation arrived at through a multitude of factors, namely the Patient, Operator, Setting, and Technology (POST), but also more importantly, the interplay between these elements. Using this amended definition and approach to the difficult to manage airway, we outline a target-specific approach to new research questions rooted in this system-based approach to better address the difficult airway in the prehospital and combat casualty care settings.

A Market Review of Available Airway Suction Technology.

INTRODUCTION: Airway injuries are the second leading cause of potentially survivable battlefield death and often require airway management strategies. Airway suction, the act of using negative pressure in a patient's upper airway, removes debris that can prevent respiration, decreases possible aspiration risks, and allows clearer viewing of the airway for intubation. The most important characteristics for a portable airway suction device for prehospital combat care are portability, strong suction, and ease of use. METHODS: This market review searched academic papers, military publications, Google searches, and Amazon to identify devices. The search included specific characteristics that would increase the likelihood that the devices would be suitable for battlefield use including weight, size, battery life, noise emission, canister size, tubing, and suction power. RESULTS: Sixty portable airway suction devices were resulted, 31 of which met inclusion criteria - 11 manually powered devices and 20 battery-operated devices. One type of manual suction pump was a bag-like design with a squeezable suction pump that was extremely lightweight but had limited suction capabilities (vacuum pressure of 100mmHg). Another type of manual suction pump had a trigger-like design which is pulled back to create suction with a firm collection canister that had increased suction capabilities (vacuum pressures of 188-600mmHg), though still less than the battery operated, and was slightly heavier (0.23-0.458kg). Battery-operated devices had increased suction capabilities and were easier to use, but they were larger and weighed more (1.18-11.0kg). CONCLUSION: Future research should work to lighten and debulk battery-operated suction devices with high suction performance.

The Use of Portable Oxygen Concentrators in Low-Resource Settings: A Systematic Review.

INTRODUCTION: Portable oxygen concentrators (POCs) are medical devices that use physical means to separate oxygen from the atmosphere to produce concentrated, medical-grade gas. Providing oxygen to low-resources environments, such as austere locations, military combat zones, rural Emergency Medical Services (EMS), and during disasters, becomes expensive and logistically intensive. Recent advances in separation technology have promoted the development of POC systems ruggedized for austere use. This review provides a comprehensive summary of the available data regarding POCs in these challenge environments. METHODS: PubMed, Google Scholar, and the Defense Technical Information Center were searched from inception to November 2021. Articles addressing the use of POCs in low-resource settings were selected. Three authors were independently involved in the search, review, and synthesis of the articles. Evidence was graded using Oxford Centre for Evidence-Based Medicine guidelines. RESULTS: The initial search identified 349 articles, of which 40 articles were included in the review. A total of 724 study subjects were associated with the included articles. There were no Level I systematic reviews or randomized controlled trials. DISCUSSION: Generally, POCs are a low-cost, light-weight tool that may fill gaps in austere, military, veterinary, EMS, and disaster medicine. They are cost-effective in low-resource areas, such as rural and high-altitude hospitals in developing nations, despite relatively high capital costs associated with initial equipment purchase. Implementation of POC in low-resource locations is limited primarily on access to electricity but can otherwise operate for thousands of hours without maintenance. They provide a unique advantage in combat operations as there is no risk of explosive if oxygen tanks are struck by high-velocity projectiles. Despite their deployment throughout the battlespace, there were no manuscripts identified during the review involving the efficacy of POCs for combat casualties or clinical outcomes in combat. Veterinary medicine and animal studies have provided the most robust data on the physiological effectiveness of POCs. The success of POCs during the coronavirus disease 2019 (COVID-19) pandemic highlights the potential for POCs during future mass-casualty events. There is emerging technology available that combines a larger oxygen concentrator with a compressor system capable of refilling small oxygen cylinders, which could transform the delivery of oxygen in austere environments if ruggedized and miniaturized. Future clinical research is needed to quantify the clinical efficacy of POCs in low-resource settings.

Evaluating the Performance of a Nonelectronic, Versatile Oxygenating Perfusion System across Viscosities Representative of Clinical Perfusion Solutions Used for Organ Preservation.

Introduction: On the United States' Organ Transplantation Waitlist, approximately 17 people die each day waiting for an organ. The situation continues to deteriorate as the discrepancy between harvested organs and the number of patients in need is increasing. Static cold storage is the clinical standard method for preserving a harvested organ but is associated with several drawbacks. Machine perfusion of an organ has been shown to improve preservation quality as well as preservation time over static cold storage. While there are machine perfusion devices clinically available, they are costly and limited to specific organs and preservation solutions. This study presents a versatile oxygenating perfusion system (VOPS) that supplies oxygen and pulsatile perfusion. Materials and Methods: Experiments evaluated the system's performance with a human kidney mimicking hydraulic analog using multiple compressed oxygen supply pressures and aqueous solutions with viscosities ranging from 1 to 6.5 cP, which simulated viscosities of commonly used organ preservation solutions. Results and Conclusions: The VOPS produced mean flow rates ranging from 0.6 to 28.2 mL/min and perfusion pressures from 4.8 to 96.8 mmHg, which successfully achieved the desired perfusion parameters for human kidneys. This work provides evidence that the VOPS described herein has the versatility to perfuse organs using many of the clinically available preservation solutions.