Does Size Matter? The Effect of Size of Distal Perfusion Catheter on Acute Limb Ischemia: A Meta-Analysis

Prevention of limb ischemia in patients with venoarterial extracorporeal membrane oxygenation (VA-ECMO) is primarily achieved through the use of distal perfusion catheters (DPC). Our objective was to assess the role of DPC, and specifically the size of the catheter, in reducing the incidence of acute limb ischemia (ALI) through a meta-analysis. Seventeen studies met criteria for analysis. Pooled analysis included a total of 2,040 patients, of which 904 patients received ECMO with DPC and 1,136 patients underwent ECMO without DPC. Compared with ECMO alone, ECMO with DPC, regardless of size, significantly decreased ALI (relative risk [RR]: 0.49, 95% confidence interval [CI]: 0.31-0.77; p = 0.002). When comparing reactive versus prophylactic placement of DPC, prophylactic DPC was associated with significantly decreased ALI (RR: 0.41, 95% CI: 0.24-0.71; p = 0.02). No differences in mortality (RR: 0.89, 95% CI: 0.76-1.03; p = 0.12) and bleeding events (RR: 1.43, 95% CI: 0.41-4.96; p = 0.58) were observed between the two groups. This analysis demonstrates that the placement of DPC, if done prophylactically and regardless of size, is associated with a reduced risk of ALI versus the absence of DPC placement, but is not associated with differences in mortality or bleeding events.

XPS™ Jensen lung as a low-cost, high-fidelity training adjunct to ex-vivo lung perfusion

BACKGROUND

Ex vivo lung perfusion (EVLP) enables lung resuscitation before transplantation, and training is key, particularly in low-volume settings. To enable technique refinement and continuing education, we sought to demonstrate the value of a low-cost, high-fidelity EVLP simulator that would allow reproducible clinical scenarios.

METHODS

In partnership with our EVLP manufacturer, we utilized the XPS™ Jensen Lung with our clinical system. The Jensen Lung has two simulated lung bladders and an in-line polymethylpentene fiber oxygenator. It allows titration of ventilator support which aids in accurate clinical simulation. For simulations, blood gases (BGs) were obtained and compared with integrated in-line perfusate gas monitors (PGMs). PaO2 , PCO2 , and pH were measured and compared.

RESULTS

The PGM and BG values were not significantly different throughout the range of FiO2 and sweep gas flow rates evaluated. The "delta" PaO2 was measured between LA and PA and did not show any change between approaches. The pH measurement between BG and PGM was not significantly different.

CONCLUSIONS

The XPS™ Jensen Lung simulator allows for a high-fidelity simulator of clinical EVLP. The correlation of the PGM and the BG measurement of the PaO2 and pH allow for a low-cost simulation, as the PGMs are in line in the circuit, and enable real-time tracking of perfusate gas parameters with the PGM. Implementation of a standardized clinical EVLP training program allows the maintenance of technique and enables clinical simulation training without the need for costly animal perfusions and the use of multiple BG measurements.

Out-of-hospital cardiac arrest due to refractory pulseless ventricular tachycardia and/or ventricular fibrillation

Background

Survival rates for out-of-hospital cardiac arrest (OOHCA) are extremely low and neurologic recovery is poor. Extracorporeal cardiopulmonary resuscitation (ECPR), which combines extracorporeal membrane oxygenation (ECMO) with cardiopulmonary resuscitation (CPR), has emerged as a viable strategy to improve outcomes in OOHCA. A collaborative ECPR program for out-of-hospital refractory pulseless ventricular tachycardia (VT) and/or ventricular fibrillation (VF) has been developed between The Ohio State University Wexner Medical Center and Columbus Division of Fire Emergency Medical Services (EMS).

Purpose

Outcomes for patients who present as an ECPR alert from the field, but did not meet predefined criteria for placement of extracorporeal membrane oxygenation (ECMO) in the cardiac catheterization laboratory (CCL) is described.

Methods

Between September 15, 2017 and October 12, 2019, 50 subjects presented as an ECPR alert for OOHCA secondary to pulseless VT/VF refractory to defibrillation. All subjects were placed on an automated CPR device prior to transfer to the CCL. From these 50 individuals, 28 (56%) did not meet prespecified laboratory criteria (lactate ≤15 mg/dL, partial pressure of oxygen (PaO2) ≥50 mm Hg, end-tidal carbon dioxide (ETCO2) of ≥10) and did not have a shockable rhythm in the CCL, thus ECMO was not placed and usual care for cardiac arrest was administered.

Results

Nine (32%) of the 28 patients achieved return of spontaneous circulation (ROSC), while the remaining 19 (68%) where pronounced deceased in the CCL. All 9 patients who achieved ROSC underwent a coronary angiography with 4 (44%) requiring percutaneous coronary intervention and 4 (44%) requiring an acute mechanical circulatory support device (Impella with 1 change out to ECMO). Of the patients that achieved ROSC, 4 (44%) were discharged from the hospital with good neurologic recovery; the remaining 5 (56%) ultimately expired during the hospitalization. From the initial 28 patient cohort, there were 4 (14%) patients discharged alive. Patients who achieved ROSC as compared to no ROSC were found on presentation in the CCL to have a significantly lower lactate (12.3±4.3 vs 16.2±3.6, respectively; p=0.03) and greater PaO2 (145±125 vs 47±9, respectively; p=0.01); there was no significant differences between groups in ETCO2, age or emergency services dispatch to CCL arrival time.

Conclusion

This study demonstrates that an ECPR program for OOHCA due to refractory VT/VF may provide benefit to patients that do not meet the predefined criteria for ECMO. This may be due to minimizing no flow/low flow time by early recognition and ongoing CPR en route to the CCL by a skilled EMS team, high efficiency citywide expedited transport/triage, the provision of high quality uninterrupted chest compressions using the mechanical CPR device during transport, and the care provided by highly trained multidisciplinary team members in the CCL.

Funding Acknowledgement

Type of funding sources: None.

Endovascular repair and open repair surgery of thoraco-abdominal aortic aneurysms cause drastically different types of spinal cord injury

Both endovascular repair (EVR) and open repair (OR) surgery of thoraco-abdominal aortic aneurysms cause spinal cord (SC) injury that can lead to paraparesis or paraplegia. It has been assumed that mechanisms responsible for SC damage after EVR are similar to those after OR. This pilot study compared the pathophysiology of SC injury after EVR versus OR using a newly developed EVR dog model. An increasing number of stents similar to those used in patients were inserted in the aorta of three dogs to ensure thoracic or thoracic plus lumbar coverage. The aorta of OR dogs was cross-clamped for 45 min. Behavior assessment demonstrated unique patterns of proprioceptive ataxia and evolving paraparesis in EVR versus irreversible paraplegia in OR. MRI showed posterior signal in lumbar SC after EVR versus central cord edema after OR. Histopathology showed white matter edema in L3-L5 localized to the dorsal column medial lemniscus area associated with loss of myelin basic protein but not neurons after EVR, versus massive neuronal loss in the gray matter in L3-L5 after OR. Metabolome analysis demonstrates a distinctive chemical fingerprint of cellular processes in both interventions. Our results call for the development of new therapeutics tailored to these distinct pathophysiologic findings.

Hydrogen Sensors Based on Flexible Carbon Nanotube-Palladium Composite Sheets Integrated with Ripstop Fabric

This work describes the design and fabrication of free-standing carbon nanotube-palladium (CNT-Pd) composite sheets for hydrogen gas sensing. The CNT-Pd composites were made by electroplating palladium onto a solvent-densified and oxygen plasma-treated CNT sheet. The latter was prepared using high purity CNTs drawn from a dense, vertically aligned array grown by chemical vapor deposition on silicon substrates. The CNT-Pd sheets were characterized by energy-dispersive spectroscopy, scanning electron microscopy, and X-ray diffraction. The amount of palladium in the composite was 16.5 wt % as measured via thermogravimetric analysis. Thin strips of the CNT-Pd sheets were assembled as chemiresistor sensors and tested for hydrogen gas detection. The sensors demonstrated a limit of detection of 0.1 mol % and displayed signal reversibility without the need for oxygen removal or heat treatment. A decrease in signal reversibility was observed after multiple exposure cycles; however, redensification with ethanol significantly restored the original reversibility. The sensor showed the Freundlich adsorption isotherm behavior when exposed to hydrogen. The material's potential application toward a wearable, flexible sensor was demonstrated by integrating the chemiresistor onto a fabric material using hot-press processing and testing the composite for hydrogen sensitivity.

Oxide-Free Actuation of Gallium Liquid Metal Alloys Enabled by Novel Acidified Siloxane Oils

Electrowetting and electrocapillarity of liquid metals have a long history, and a recent explosion of renewed interest. Liquid metals have electromagnetic properties and surface tensions (>500 mN/m) that enable new forms of reconfigurable devices. However, the only nontoxic option, gallium alloys, suffer from immediate formation of a semirigid surface oxide. Although acids or electrochemical reduction can remove this oxide, these approaches surround the gallium alloy in a fluid that is also electrically conducting, diminishing electromagnetic effectiveness and precluding electrowetting actuation. Reported here are acidified siloxanes that remove and prevent oxide formation. Importantly, the siloxane oil associatively incorporates hydrochloric or hydrobromic acids, is electrically insulating, is chemically stable, removes etching byproducts (including water), and allows robust electrowetting. This work opens up new opportunities for liquid metal reconfiguration, and is of fundamental interest due to the unexpected chemical stability of the acidified siloxanes and their application to other materials and surfaces.

In-vitro depth-dependent hyperthermia of human mammary gland adenocarcinoma

Nanoparticle mediated photothermal ablation of cancerous tissue shows promising results and applicability as a highly efficacious treatment method. As a majority of the photothermal work has been conducted with minimal attenuation of the laser before reaching the nanoparticles within surface seeded tumors in-vivo or through buffered media in-vitro, it is important to understand the effects of greater laser attenuation on photothermal efficacy mediated by changes in the scattering and absorption of the laser. Photothermal efficacy using a near infrared (NIR) 785nm laser irradiating polystyrene (PS) stabilized magnetite (Fe3O4) nanoparticles (PS-Fe3O4) is examined on MDA-MB-231 human mammary gland adenocarcinoma in-vitro. Agarose gel columns of various heights were created to simulate soft tissue and subsequently used for NIR laser attenuation. Polystyrene was found to significantly improve magnetite nanoparticle stability in serum containing media and modified Hank's Balanced Salt Solution and was able to induce significant hyperthermic ablation at mass concentrations which also did not elicit significant innate toxicity. Furthermore it was found that the polystyrene coating significantly reduced innate toxicity over 48h compared to uncoated magnetite. Agar gel layers provided similar optical attenuation in the NIR region to skin and prostate.

A fluorescent hormone biosensor reveals the dynamics of jasmonate signalling in plants

Activated forms of jasmonic acid (JA) are central signals coordinating plant responses to stresses, yet tools to analyse their spatial and temporal distribution are lacking. Here we describe a JA perception biosensor termed Jas9-VENUS that allows the quantification of dynamic changes in JA distribution in response to stress with high spatiotemporal sensitivity. We show that Jas9-VENUS abundance is dependent on bioactive JA isoforms, the COI1 co-receptor, a functional Jas motif and proteasome activity. We demonstrate the utility of Jas9-VENUS to analyse responses to JA in planta at a cellular scale, both quantitatively and dynamically. This included using Jas9-VENUS to determine the cotyledon-to-root JA signal velocities on wounding, revealing two distinct phases of JA activity in the root. Our results demonstrate the value of developing quantitative sensors such as Jas9-VENUS to provide high-resolution spatiotemporal data about hormone distribution in response to plant abiotic and biotic stresses.

Jasmonate regulates multiple aspects of plant growth, development and stress responses. Here, Larrieu et al. develop a fluorescent biosensor that allows jasmonate perception to be monitored at previously unobtainable levels of spatiotemporal resolution in Arabidopsis.

Polymer Coating of Carbon Nanotube Fibers for Electric Microcables

Carbon nanotubes (CNTs) are considered the most promising candidates to replace Cu and Al in a large number of electrical, mechanical and thermal applications. Although most CNT industrial applications require macro and micro size CNT fiber assemblies, several techniques to make conducting CNT fibers, threads, yarns and ropes have been reported to this day, and improvement of their electrical and mechanical conductivity continues. Some electrical applications of these CNT conducting fibers require an insulating layer for electrical insulation and protection against mechanical tearing. Ideally, a flexible insulator such as hydrogenated nitrile butadiene rubber (HNBR) on the CNT fiber can allow fabrication of CNT coils that can be assembled into lightweight, corrosion resistant electrical motors and transformers. HNBR is a largely used commercial polymer that unlike other cable-coating polymers such as polyvinyl chloride (PVC), it provides unique continuous and uniform coating on the CNT fibers. The polymer coated/insulated CNT fibers have a 26.54 μm average diameter—which is approximately four times the diameter of a red blood cell—is produced by a simple dip-coating process. Our results confirm that HNBR in solution creates a few microns uniform insulation and mechanical protection over a CNT fiber that is used as the electrically conducting core.

Plasma Coating and Enhanced Dispersion of Carbon Nanotubes

Ultrathin polymer films have been deposited on both multi-wall and aligned carbon nanotubes using a plasma polymerization treatment. TEM experimental results showed that a thin film of polystyrene layer (several nanometers) was uniformly deposited on the surfaces of the nanotubes including inner wall surfaces of the multi-wall nanotubes. The coated multi-wall nanotubes were mixed in polymer solutions for studying the effects of plasma coating on dispersion. It was found that the dispersion of multi-wall carbon nanotubes in polystyrene composite was significantly improved. The deposition mechanisms and the effects of plasma treatment parameters are discussed.

Desorption kinetics of oxygen in plasma treated SWNTs by in situ thermoelectric power measurements

The functionalization and defect formation of SWNTs caused by isotropic plasma treatments were studied using oxygen desorption/adsorption kinetics by measuring the time dependence of the in situ thermoelectric power (TEP). It is shown that the plasma treatments result in the formation of low binding energy sites for oxygen adsorption. Raman and x-ray photoelectron spectroscopy (XPS) data are in good agreement with the results.

Developing rapid detection of mycobacteria using microwaves

In this paper, we describe the development of a culture-based biochip device for rapid detection of mycobacteria in environmental samples. Individual biochips rely upon the unique paraffinophilic nature of mycobacteria to rapidly and selectively adhere to the surface of the device. We used prototype biochips to experimentally demonstrate the concept of rapid and selective detection of mycobacteria by testing pure cultures and using epifluorescence microscopy to visualize microorganisms on the surface. As an alternative, rapid approach for identifying the biomass on the biochip surface, we used microwaves in the 10 to 26 GHz frequency range. The results of this study indicate that different microorganisms are responsible for specific shifts in resonance frequencies of a microwave cavity. By combing the semi-selective paraffin surface of the biochip with the microorganism-specific response to the microwaves, we have developed an improved analytical system with the potential to rapidly identify and enumerate mycobacteria in environmental samples in as little as 2 h.

Use of intraperitoneal solutions for preventing pelvic adhesions in the rat

The fewest postoperative intrapelvic adhesions were observed in rats subjected to intraabdominal infusion of 20 ml of Ringer's lactate containing hydrocortisone (100 mg/liter), dexamethasone (5 mg/liter) and ampicillin (100 mg/liter). Significant prevention of adhesions also followed intrapelvic administration of heparinized Ringer's lactate (2,000 IU/liter), Ringer's lactate with dexamethasone (5 mg/liter), Ringer's lactate with ampicillin (100 mg/liter) and Ringer's lactate with human albumin (8 gm/liter). Comparable volumes of hyperosmolar dextran caused drastic shifts in fluids and electrolytes, with the death of all the animals. Smaller volumes of this agent did not prevent adhesion formation. Thus, physicians should be cautious about the volume of dextran administered in the human pelvis. It is hoped that the single-dose intraperitoneal application of Ringer's lactate containing ampicillin and corticosteroids will be evaluated prospectively in women.

Addicted Women and Their Relationships with Men

The information for this descriptive study comes from Andersen's (1980) research funded through the National Institute on Drug Abuse. Although Andersen's questionnaires do not directly gather data about the relationship between the woman's drug use and her relationships with men, the authors were drawn to explore this area because of the large number of female drug users who described this connection. In reviewing the initial and termination data on 72 clients, it was found that 43% reported a variety of ways their usage was affected by men. These anecdotal descriptions provided by the female drug users are summarized under seven headings; some anecdotal notes are included in the text. The categories are not mutually exclusive. The findings reported in this article concur with the recent literature on drug dependent women.

Maximum duration of phonation: objective tool for assessment of voice

30 male and 30 female adults sustained the vowel /a/ under specified conditions. Analysis of the data for 10 trials suggests that four trials produced at a comfortable pitch and loudness level and interrupted by a 60-sec. rest would reliably evaluate prolonged vocalization. Males' superior performance was noted. Clinical applications and research implications are discussed.

[Postoperative total parenteral feeding with a carbohydrate mixture (autor's transl)]

After gastric operations, patients were fed completely by the parenteral route. Aminoacids, caloric nutrients and electrolytes were infused simultaneously and continuously 24 hours daily until the fourth postoperative day. The daily supply of aminoacids amounted to 80 g. Glucose, fructose and xylite in equal proportions were used to supply calories. The total daily amount was 605 g. The important electrolytes were contained in the infusion solutions in amounts corresponding to basic requirement. The results of the investigation confirmed that patients can be successfully nourished parenterally after extensive operations with the combined daily additives we have selected.

[Behavior of the metabolism in gastric patients during a 4-day-long postoperative complete parenteral feeding with amino acids and a glucose-levulose-xylitol combination solution]

In a clinical study we tested the following parameters: free fatty acids, beta-hydroxybutyrate, acid-base-balance, lactate, bilirubin, uric-acid, fructose, xylitole, glucose in blood and urine. The tests were executed in 9 patients who were undergoing stomac operations. The cardio pulmonary system of all patients was normal, and there was a homeostasis in water and electrolytes preoperatively. In combination with the amino-acids we received a ratio of 1:1:1 for glucose, levulose and xylitole. Totally, the patients received 0.36 g per kg body weight and per hour of carbohydrates. Beta-hydroxybutyrate, aceto-acetat, and free fatty acids show normal values under conditions of parenteral nutrition as well as lactate, uric acid, and acid-base-balance. The ratio of the different carbohydrates in serum and urine prove that the infusion time and volume were extremely favourable. The loss of carbohydrates in urine was very low.

[Metabolic behavior in total parenteral nutrition during the postoperative phase]

In patients who had undergone gastric operation, total postoperative parenteral nutrition was effected using a combination of two infusion solutions having complementary constituents. 80 g L-amino acids and about 2,500 kcal in the form of a glucose-levulose-xylitol mixture together with electrolytes and trace elements were infused daily. Metabolic parameters, serum levels and the concentrations of the most important administered substances excreted in the urine were determined every day at the same time. The 1:1:1 glucose-levulose-xylitol ratio of the caloric carrier proved to be a favourable combination with respect to metabolic behaviour and the necessary daily supply of calories. The basic electrolyte requirement of the patients was to a large extent met by the quantities contained in the solutions.

Stoffwechselverhalten bei totaler parenteraler Ernährung in der postoperativen Phase

Bei magenoperierten Patienten wurde eine postoperative totale parenterale Ernährung mit einer Kombination zweier sich in ihrer Zusammensetzung ergänzender Infusionslösungen durchgeführt. Täglich wurden 80 g L-Aminosäuren, zirka 2500 kcal in Form eines Glukose-Lävulose-Xylit-Gemisches sowie Elektrolyte und Spurenelemente infundiert. Stoffwechselparameter, Serumspiegel und Urinausscheidung der wichtigsten zugeführten Substanzen wurden täglich zum gleichen Zeitpunkt bestimmt. Die Relation der Kalorienträger Glukose: Lävulose: Xylit = 1:1:1 erwies sich dabei als günstige Kombination in bezug auf Stoffwechselverhalten sowie notwendige tägliche Kalorienzufuhr. Der Basisbedarf der Patienten an Elektrolyten wurde durch die in den Lösungen enthaltene Menge weitgehend gedeckt.