bluuebunny/crossref_metadata_2025 huggingface dataset:
Field investigation and design of debris nets in an environmentally sensitive area
Authors: Kane William , McElhany Joseph , Forsthoff Brian
Published: August 2023

Flexible debris nets are an excellent choice for emergency debris protection. They are lightweight, have a small footprint, and are relatively easy to construct. Available design methodology based on testing and modelling makes engineering simplified with straightforward calculations. After a huge wildfire, Montecito, California sustained devasting debris flows. The need to quickly design and construct protection was made possible proven methodologies under difficult environmental restrictions.
Mitigation Strategy for Low-frequency Large-magnitude Debris Flows in Hong Kong
Authors: Ko Florence , Chan Chris , Ho Hoi-yan , So Kevin
Published: August 2023

Potential hazards arising from low-frequency large-magnitude debris flows have become apparent under the adverse impact of climate change and extreme weather. Hong Kong has systematically managed landslide risks arising from man-made slopes and natural hillsides since 1977, owing to its unique geographic location, steep terrain, deep weathering profile and post-war rapid urban development. In recent years, evaluation of potential hazards arising from low-frequency large-magnitude debris flows and their possible dire consequences has developed into a key part of the landslide mitigation effort in Hong Kong in light of the occurrence of more frequent and more severe extreme rainfall events. Valuable experience is gained in identifying potential low-frequency large-magnitude debris flow hazards, assessing their potential impacts to the public located at the densely populated foothills and developing a holistic strategy to mitigate against potentially catastrophic consequences. This paper sets out the mitigation strategy for mitigating low-frequency large-magnitude debris flows in Hong Kong and gives a case study to demonstrate the approach.
MurGame: Protect your village from debris flows!
Authors: Berger Catherine , Zimmermann Florian , Mauerhofer Ralf , Christen Marc
Published: August 2023

Past debris flow events, like in Bondo (2017) and Brienz (2005) in Switzerland have been heavily covered in the (Swiss) media, illustrating how destructive such events can get. Protection measures play an important role in dealing with natural hazards. Debris flows are considered to be very rare, complex and multidimensional processes. Imagining and foreseeing the course and progression of a debris flow as well as estimating the potential damage and the influence of protection measures is a difficult task. Serious games offer a possibility to simulate these kinds of situations. With the MurGame, we have developed an application for natural hazard prevention. In the three-dimensional, interactive game, a village is created by selecting different objects, such as residential buildings or schools. Debris flow simulations show, which buildings would be destroyed and what damage would occur in the event of a debris flow. Different protection measures can be implemented to protect the village and their effectiveness can be monitored during the simulations. After the event, it is necessary to evaluate which measures offer the desired protection, what they may cost and how the needs of the population are met. The MurGame can be played online at www.murgame.ch.
Debris-flow risk-to-life: Upper-bound preliminary screening
Authors: Davies Tim , Bloomberg Mark , Palmer Dave , Robinson Tom
Published: August 2023

Where the potential for future debris-flow occurrence is unrecognised, developments can be unknowingly exposed to debris-flow impact, with corresponding risks to lives. Debris-flow modelling is unsuited to routine local office use, so a simple screening procedure is proposed to enable local officials to identify locations where debris flow risk-to-life may be unacceptable, and prioritise where expert modelling and risk analysis are most urgently required for risk-management decision-making . This procedure calculates catchment Melton ratio R from topographic data, uses a linear upper bound of field data relating R to the annual probability of debris-flow occurrence, and matches a model-based debris-flow risk-to-life analysis for Matata, New Zealand. Our data suggest that any development exposed to debris flows will require a detailed risk assessment to ensure that risk-to-life does not exceed acceptable levels.
A CFD-DEM Based Numerical Investigation of Debris Flow on Ballasted Railway Track
Authors: Gong Yufeng , Qian Yu
Published: August 2023

Debris flow occurring in mountainous areas can cause issues to railway tracks. Debris flow may cause large track deformation and even track breakage and introduce server ballast fouling afterwards. After the flash of a debris flow, the fine particles can be retained in the ballast layer and significantly reduce track drainage, leading to lower bearing capacity and a higher risk of track lateral stability problems. Moreover, these solid particles may deposit on the railway surface and endanger the train directly. Unfortunately, those debris flow introduced track issues have not been thoroughly investigated. This study presents a numerical investigation of the impact of the debris flow on the railway track. Various factors governing the debris flow are considered, including particle size and solid fraction. Besides, those factors affecting the ballast are also discussed, such as fouling condition and initial void ratio. A coupled computational fluid dynamics and discrete element method (CFD-DEM) approach is developed to capture the interactions between particles/particles, water/air, and particles/fluid. The results from this study may help the railway to improve track resilience before the debris flow and to improve maintenance strategy after the debris flow flashing.
A time-independent reliability based design approach for debris flow flexible barriers
Authors: Marchelli Maddalena , Deangeli Chiara
Published: August 2023

The design of debris flow protective structures has represented a challenge since the last decades. The design process might consider several variables related to actions and resistances, mainly linked to impact pressure and dynamic pressure resistance. Debris flow events do not have always the same magnitude, and small events can occur with a high probability. Therefore, an events frequency-magnitude relationship might be considered in the design of protective structures. In the Eurocodes framework, the fixed partial safety factors design approach not considering the intrinsic site variability of these phenomena, does not allow obtaining a specific probability of failure. Reliability-based approaches reveal to be compelling solutions. Focusing on flexible barriers, the paper presents a novel time-independent reliability approach, which considers all the possible debris flow events and provides the failure probability of a barrier in a given temporal interval.
Improvement of the energy efficiency of buildings: Thermal characterization of an ecological building material based on industrial cotton waste
Authors: Alakouko Abdou Raimi , Semassou Clarence , Ahouansou Roger , Amadji Armel , Toukourou Chakirou , Kiki Gratien
Published: August 2023

The aim of this work is to study the thermal characteristics of a concrete reinforced with cotton waste fiber for building construction. The concrete used was formulated with the Dreux-Gorisse method and has a compressive strength of 14.13 MPa. The fiber-reinforced concrete contains 0.1% to 0.8% of fibers by mass. The thermal properties were determined by the asymmetric hot plane method used with a DesProTherm device. Other properties were also computed. The results show that the density of the concretes decreases with the percentage of fibers, from 2.205 t/m3 for the concrete without fiber to 2.001 t/m3 for the concrete containing 0.8% of fibers. The thermal conductivity and thermal diffusivity also decrease with the percentage of fibers, they range respectively from 1.021 W/m.K to 0.448 W/m.K and from 5.64 10-7 m²/s to 2.19 10-7 m²/s. As for the thermal capacity, it is almost constant with 0.1% of fibers (1810 to 1800 kJ/m3.K) then increases progressively up to 2046 kJ/m3.K for 0.8% of fiber. These results show that the incorporation of fibres improves the thermal characteristics of concrete. The use of this material would provide better thermal conditions inside the buildings, and consequently the reduction of energy consumption.
Carpooling in West Africa: The Shared Mobility Revolution Just a Click Away!
Authors: Ballo Raynald
Published: August 2023

The article focuses on the potential of carpooling in West Africa, highlighting several key findings. The study analyzes the specific challenges faced by users and carpooling platforms in the region, including the popularity of carpooling, trust and security issues, and the difficulty of finding reliable carpooling partners. By examining different forms of carpooling present in the region, the article highlights formal and informal carpooling models, taking into account differences between urban and rural areas. The analysis provides solutions to overcome the trust, security, and unknown factors specific to West Africa. Through a literature review and a survey conducted with 300 individuals in Cotonou and Abomey-Calavi, Benin, the article examines existing forms of carpooling, the challenges faced, and the issue of the unknown in the region. The study considers socio-economic, cultural, and environmental factors that influence mobility in West Africa, providing insights for the future development of carpooling in the region. The results emphasize that carpooling offers an interesting alternative solution for road users in a region where traffic congestion is a major problem and motorization rates are relatively low. The article contributes to a better understanding of the challenges of carpooling in West Africa and proposes development prospects for this practice that is still not widespread in the region.
Antegrade versus Retrograde Cardioplegia for Uncomplicated Coronary Artery Disease: A Comparative Study
Authors: Hunt Allen , Stammers Alfred , Robinson Lary A.
Published: August 2023

Since the introduction of the retrograde administration of cardioplegic solutions in cardiac surgery in the mid-1980's, the technique has been widely adopted for routine use in high risk patients with impaired ventricular function, based on favorable results demonstrated in clinical series. However, we sought to evaluate the benefits of routine use of this method in low risk patients by means of a retrospective review of 34 consecutive non-repeat, isolated coronary artery bypass grafting patients with left ventricular ejection fractions > 35%. Seventeen patients received intermittent ante grade cardioplegia exclusively and 17 received ante grade induction followed by intermittent retrograde cardioplegia maintenance. No significant baseline differences were found between the two groups. There were no deaths or major complications in either group. Retrograde cardioplegia patients had significantly lower pulmonary artery diastolic pressures in the first 24 hours postoperatively, accompanied by a non-significant trend toward higher cardiac indices during this same period. Phenylephrine infusions were used more frequently during the postoperative period in the retrograde group (p = 0.021). Fewer pulmonary complications were seen in the retrograde cardioplegia group (p=0.042), in addition to non-significant trends toward less atrial arrhythmias and less hospital days. No adverse effects or increased operative time could be attributed to the retrograde administration of cardioplegic solution in this study population.

Based on the results from this small clinical series, retrograde cardioplegia administration offers distinct advantages for myocardial protection in low risk coronary bypass patients, as manifested by improved postoperative hemodynamic performance, with no significant adverse effects. A prospective, randomized trial of this technique in a larger, similar patient population is likely to show even more compelling positive results favoring the routine use of retrograde administration of cardioplegic solutions.
Evaluation of Blood Loss and Transfusion Requirements in Diabetic and Non-Diabetic Patients Undergoing Coronary Revascularization
Authors: Maca Patricia E. , Stammers Alfred H. , Galbraith Timothy , Alonso Anselmo
Published: August 2023

Hematological abnormalities associated with the diabetic state include reduced platelet function, enhanced factor activation and hyperfibrinolysis. The present investigation evaluated blood loss and the transfusion requirements in diabetic and non-diabetic patients undergoing extracorporeal circulation and cardiac surgery.

A retrospective study of 151 consecutive patients undergoing primary coronary revascularization were classified into one of three groups based on their diabetic disease state: Insulin Dependent Diabetics (IDDM, n=5), Non-Insulin Dependent Diabetics (NIDDM, n=33), and Non-Diabetics (NDM, n=113). IDDM patients were significantly younger than either NIDDM or NDM patients, were 80% female, and had lower preoperative red cell mass. The IDDM group had a greater red blood cell transfusion volume (1650 ± 1485 ml) than NIDDM (958 ± 593 ml) and NDM (997 ± 827 ml) patients (p=0.21). There were no significant differences in homologous blood exposure or chest tube drainage in any group. Mean length of hospital stay (days) in the IDDM group (19.8 ± 18.3) was significantly greater than the NIDDM (9.9 ± 3.7), and the NDM (10.8 ± 5.8) patients (p<.001).

In conclusion, diabetic patients do not appear to be at increased risk for developing postcardiotomy coagulopathies, despite having greater morbidity, which results in increased hospital stay.
Extracorporeal Circulation for Great Vessels Surgery: A Review of 131 Cases
Authors: Dong Peiqing , Sun Yanqing , Yang Jing , Yang Chuanrui , He Meiling
Published: August 2023

A retrospective analysis of 131 cases of major vascular surgery, mainly aneurysms of the ascending and descending aorta, was undertaken to determine whether use of different bypass methods chosen according to location of the individual lesions resulted in improved results.

For the 93 cases of ascending aortic aneurysm, the method for cardiac protection was improved by the use of continuous retrograde coronary sinus perfusion with cardioplegic blood. In sixteen cases with dissection involving the aortic arch, deep hypothermic circulatory arrest and continuous retrograde cerebral perfusion through the superior vena cava was employed for brain protection. The safe brain circulation arrest time was thus prolonged to the longest record of 81 minutes. Among the group of 93 cases, there were four operative and four hospital deaths, giving a mortality rate of 8.6% (8/93). For the 34 cases of descending aortic aneurysms, left heart bypass was employed to avoid ischemia of the heart, lungs, brain, and the abdominal organs; the operative mortality rate was 8.8% (3/34). In three cases of interrupted aortic arch, separate upper and lower body perfusion under deep hypothermia with low flow rate perfusion for the upper body provided the necessary conditions for radical surgery. In one patient with Budd-Chiari syndrome, a total corrective surgery was achieved under right heart bypass.
Validation of Two Flow Probes Using Bovine, Porcine, Ovine and Human Blood
Authors: Reagor J.A. , Delucia A. , Sutton Robin G. , Richenbacher W.E.
Published: August 2023

In-line electromagnetic and doppler flow probes employed in extracorporeal circuits are calibrated for use with human blood. This study was performed to compare the accuracy of the Sarns Delphin II Doppler and the Medtronic Bio-Medicus electromagnetic flow probes to actual flow using bovine, porcine, ovine and human blood. The flow probes were incorporated into an in vitro extracorporeal circuit. Hematocrit, temperature and flow were randomized over ranges of 15-45% (increment 10%), 22-37°C (increment 5°C) and 1-5 L/min (interval 1 L/min), respectively. Probe flow readings were compared to the measured flow.

Flow probe readings in all species significantly correlated with actual flow (p <0.05). Doppler and electromagnetic probe flow readings significantly differed within species (p <0.001). The doppler percent error positively correlated with hematocrit (p <0.001) in all species except human. The electromagnetic percent error did not consistently correlate with hematocrit or temperature. Neither of the flow probe percent errors correlated with erythrocyte diameter or mean corpuscular volume utilizing the average population measurement. Regression equations were developed to derive actual flow from the doppler probe readings in ruminants. These data will allow investigators to select a flow probe appropriate for the experimental conditions and animal model.
Circulatory Support for the Patient in Cardiac Arrest: Some Research Perspectives
Authors: Beckley Philip D. , Angelos Mark G.
Published: August 2023

Cardiopulmonary resuscitation (CPR), as a treatment for the patient in cardiac arrest, has been met with varying degrees of success. Two of the problems which have been identified include variations in the application of the technique and the initiation of the treatment with respect to the time of arrest. Modifications to the technique, such as active compression-decompression CPR, interposed abdominal compression CPR, and open chest CPR, have not significantly improved survival. It is clear that the major problem is the technique's inability to provide the necessary myocardial and cerebral blood flow required for recovery. It would seem that extracorporeal perfusion as a resuscitative technique should solve the problems associated with CPR. Extracorporeal circulatory support has met success in some applications but has not been found to be a universal answer for the patient in cardiac arrest. The purpose of this paper is to review the current status of CPR and extracorporeal circulatory support, overview the techniques employed, and summarize applied research that is ongoing in this institution.
Heparin Content of Cell-Salvaged Blood After Cardiopulmonary Bypass
Authors: Pivalizza Evan G. , Abramson David C. , Gottschalk Lewis I.
Published: August 2023

Blood remaining in the extracorporeal circuit (ECC) is frequently concentrated and washed before transfusion to the patient after termination of cardiopulmonary bypass. As additional doses of protamine are often administered to reverse the effects of suspected heparin content of this blood, we determined activated clotting times (ACTs) and heparin concentration pre and post cell salvaged blood administration. After a I liter normal saline wash, administration of the cells obtained using the Cobe Baylor Rapid Autologous Transfusion (BRAT) system caused no change in either patient ACT (p=0.19) or plasma heparin concentrations. We conclude that additional protamine administration is unwarranted after transfusion of concentrated, washed red blood cells (RBCs) from the ECC with the Cobe BRAT cell salvage device.
Significant Safety Advantages Gained with an Improved PressureRegulated Blood Pump
Authors: Montoya J. Patrick , Merz Scott I. , Bartlett Robert H.
Published: August 2023

A prototype of a non-occlusive pressure-regulated blood pump (M-pump) was evaluated in-vitro for safety in a comparative study with the roller and centrifugal pumps. The M-pump consists of collapsible tubing of unique design wrapped under tension around a rotor without a stator. The prototype M-pumps were tested in vitro to evaluate performance with respect to flow/pressure characteristics, hemolysis, bubble generation (cavitation) and durability. The M-pump and centrifugal pump did not overpressurize at any RPM when the pump outlet was occluded, but the roller pump reached pressures in excess of 1000 mmHg. The M-pump did not generate negative pressures upon occlusion of the inlet, whereas the roller and centrifugal pumps produced near-vacuum pressures. Furthermore, the M-pump was unable to empty a blood reservoir when the height of the pump inlet was placed slightly above the reservoir outlet. The levels of micro bubbles in the M-pump were significantly lower than the roller and centrifugal pumps upon sudden restriction of the pump inlet as determined with an ultrasonic bubble detector. The results of our in-vitro evaluation of the M-pump have shown it to have lower hemolysis than the centrifugal pump and lower or comparable hemolysis to roller pumps at flowrates of 0.1, 0.5, 4.0 and 6 L/min. We determined that the M-pump design possesses important safety advantages over roller and centrifugal pumps for cardiopulmonary bypass applications.
Investigation of Fatigue Failure of S-65-HL “Super Tygon” Roller Pump Tubing
Authors: Snyder Edward J. , McElwee Dorothy L. , Harb Hassan M. , Cullen James A. , Tackel Ira S. , Baumgart Stephen , lskandarani Bassel , Elkind Alexander , Shaker Manal
Published: August 2023

A failure analysis was performed on Norton S-65-HL Tygon00AE tubing. Fatigue testing was performed on four sizes of this tubing, and essentially showed how the tubing wears out. A dynamic “life hours to failure” test, which was performed on the 3/8" internal diameter (ID) size, quantified when the tubing ruptured. Based on results of laboratory testing and the institution's clinical extracorporeal membrane oxygenation (ECMO) experience, a reasonable life expectancy for the 3/8" S-65-HL Tygon® size was determined for use in this institution's neonatal ECMO system.

An understanding of the expected performance of roller pump tubing - an integral component of the ECMO system - is imperative to providing safe, effective extracorporeallife support.
Non-Destructive Evaluation of Membrane Lung Gas Exchange Performance
Authors: Tallman Richard D. , Guardia Zenon A. , Gruber Marcia A.
Published: August 2023

This paper describes a method of evaluating the gas exchange effectiveness of hollow fiber oxygenators utilizing gas on both sides of the membrane. The goal of the study was to develop an evaluation technique which was accurate, reliable, and did not harm or contaminate a new. sterile oxygenator. Three pediatric oxygenators were tested and compared: the Medtronic Minimax Plus, the Terumo Capiox 320, and the Sorin Masterflo 34 (all with rated blood flows of 2-2.5 L/min). Gas entering the "blood" side was a mixture of CO2, O2, and N2 in a mixture matching typical venous blood partial pressures. The "blood" flows used were 0.5, 1, 1.5, or 2 L/min. Gas entering the gas port had an FiO2 of 0.4 flowing at 0.5, 1, 1.5, 2, 2.5, 3, or 3.5 L/min. Fractional contents of CO2 and O2 at all inlets and outlets were determined using a gas analyzer and converted to partial pressures. Efficacy indices and gas transfer rates were calculated and compared. Of the devices studied, the Masterflo 34 had the highest gas transport rates and effectiveness followed by the Minimax-Plus and the Capiox 320. Reversing the direction of the flow through the "blood" phase of the Minimax-Plus greatly changed its gas exchange effectiveness. The techniques described in this study should allow for a more uniform and consistent evaluation of gas exchange by membrane lungs which can be made inexpensively and relatively quickly. In addition, these methods should allow manufactures to evaluate gas exchange effectiveness and transfer rates of individual units during production as well as reduce the complexity involved when evaluating newly developed oxygenators.
Evaluation of the Thrombelastograph Targeted Coagulation Assessment
Authors: Bonness Andrew S. , Stammers Alfred H. , Huffman Suzanne M. , Ficek Suzanne J. , Brady Chad P.
Published: August 2023

Extracorporeal circulation predisposes patients to hemorrhagic risk which may increase both homologous transfusion requirements and the need for pharmacological intervention. The aim of this study was to evaluate the efficacy of a new diagnostic coagulation assay utilizing the thrombelastograph (TEG).

Following Institutional Review Board approval, blood was drawn from healthy, non-medicated volunteers and four in vitro coagulopathic conditions were created, which included: hyperfibrinolysis (100% lysis), hypofibrinogenemia (<50 mg/dl), and both qualitative (1000 ug/ml nitroglycerin) and quantitative (<50 K/mm3) platelet abnormalities. Each of these four blood samples was then divided among four vials that contained known quantities of either: aminocaproic acid, fresh frozen plasma (FFP), platelet concentrate, or heparinase, and TEG profiles were completed.

Twenty-one samples were evaluated and the following results were obtained. Hyperfibrinolysis- 100% correction of fibrinolytic potential in the aminocaproic acid vial, but none in the other vials. Qualitative platelet dysfunction- significantly improved time to coagulation in the platelet vial but not in the FFP, heparinase or aminocaproic acid vials. Quantitative platelet dysfunction- no significant difference observed between any vials. Hypofibrinogenemia- significant improvement in the TEG index in the FFP vial (-2.7 ± 0.5) when compared to the aminocaproic acid ( -8.6 ± 2.5, p<.001), platelet (-6.5 ± 0.5, p<.01) and heparinase (-8.8 ± 2.5, p<.001) vials.

We conclude that this coagulation assessment assay may help in identifying the specific source of bleeding during surgeries where hyperfibrinolysis, hypofibrinogenemia, or qualitative platelet dysfunctions are present.
Adding Hetastarch to the Adult Cardiopulmonary Bypass Prime Does Not Affect Patient Outcomes
Authors: Boykin Melany P. , Ecklund Jodie M. , Riley Jeffrey B. , McCall Mary M.
Published: August 2023

Hespan™ (hetastarch), a synthetic colloid, is often used in priming cardiopulmonary bypass circuits. The purpose of this study is to determine the efficacy of adding hetastarch to the prime compared to adding no hetastarch. Twenty-four adult patients undergoing cardiopulmonary bypass received Hespan™ in the prime, while twenty-nine patients did not. Outcomes were compared using paired t-test, analysis of variance, analysis of covariance, and descriptive statistics, where p<0.05 was considered significant. There were no significant differences in change in lung compliance, weight gain, time on the ventilator, or length of stay in the intensive care unit. Adding colloids to the adult CPB prime does not improve patient outcomes over priming exclusively with crystalloids.
Evaluation of the Hemochron 8000 Rx/Dx System for Heparin Management
Authors: Johnson Howard D. , Morgan Marc S. , Koenig Gary R. , Utley Joe R. , Leyland Steven A. , Whittle Thomas B. , Conn John M.
Published: August 2023

The Hemochron Rx/Dx uses an ACT and a heparin response tube to calculate the heparin dose to identify heparin sensitive/resistant patients. We evaluated the Rx/Dx system in 37 patients to determine if the ACT after the predicted heparin loading dose was adequate to initiate CPB.

The mean heparin dose calculated by the Rx/Dx was 31,700 IU ± 8,700 IU (370 IU/kg) with a mean post ACT of 463 ± 124 sec. Our standard heparin dose (400 IU/kg) would have given an additional 2,800 IU over the Rx/Dx.

Four patients (6.5%) were predicted to be heparin sensitive and all four achieved an ACT over 450 sec. Twenty-one patients (56.8%) were predicted to be resistant and yet failed to raise the ACT over 450 sec in 17 (81.0% ). Twelve patients (32.4%) were predicted to have a normal heparin response, and four (33.3%) did not achieve an ACT over 450 sec. In all, 21 patients (56.8%) did not achieve an ACT greater than 450 sec.

Each institution should evaluate their heparin loading dose and the resultant ACT. In this study, we found the number of times the Rx/Dx system did not raise the ACT over 450 sec too great to justify the additional expense.
Cracked Acrylic Ventricular Assist Devices after Using a Doppler Stethoscope and Ultrasound Transmission Gel to Predict Impending Pump Failure: A Case Report
Authors: Nelson Verna E.
Published: August 2023

At Saint Louis University Health Sciences Center, hi-ventricular assist devices were placed in a patient after failure to wean from bypass. These acrylic devices are known to be used for post cardiotomy failure. Acrylics and other plastics are used in extracorporeal circuitry. Plastics have been known to crack when exposed to certain chemicals and conditions. This case describes the use of ultrasound transmission gel as another ingredient that causes cracking of centrifugal assist devices made of acrylic plastic.
Perflubron Emulsion Does Not Cause Neutrophil (PMN) Activation In- Vivo.
Authors: Wilson Donald S. , Hokama Jason Y. , Lai George , Gorman Grace F. , Susa Nancy J. , Copeland Jack G. , McDonagh Paul F.
Published: August 2023

Earlier, we reported that in-vitro incubation of blood for ten minutes with the perfluorocarbon (PFC) emulsion Fluosol increased leukocyte activation as determined by adhesion to nylon fiber. In this study, we examined if in-vivo treatment with these PFC emulsions affected the expression of the leukocyte adhesion protein CD11b (primarily found on PMNs) and the generation of leukocyte-derived reactive oxygen species (ROS, oxygen free radicals). Rats were anesthetized and catheterized. Three groups were studied: 1) a phosphate buffered saline (PBS) control group (n=6), 2) a group treated with Fluosol emulsion (1.08g PFC/kg, n=6) and 3) a group treated with perflubron emulsion (1.08g PFC/kg, n=6). Blood samples were taken before and 10, 20, 40 and 60 minutes after treatment for hematology and analysis of PMN CD11b expression and ROS production using flow cytometry. We found that Fluosol caused significant increases in both neutrophil surface expression of CD11b and ROS generation (p<0.05, ANOVA). In the Fluosol group, the peak responses in PMN CD11b expression and ROS production were observed ten minutes after treatment. In contrast, treatment with perflubron emulsion did not cause a significant increase in CD11b expression nor an increase in ROS production at any time after treatment. These findings suggest that Fluosol causes a transient PMN activation in-vivo. The activation of circulating PMNs, in-vivo, is sufficient to significantly enhance oxygen derived free radical production. The lack of a PMN response to perflubron emulsion in-vivo suggests that this agent is not likely to induce a leukocyte-mediated inflammatory response.
Evaluation of a New Generation Cardioplegia Administration System
Authors: Sydzyik R. Troy , Stammers Alfred H. , Zavadil Douglas P. , Deptula Joseph J. , Christensen Kevin A.
Published: August 2023

The delivery of cardioplegia has traditionally been constrained by the physical limitations of the mechanical devices in use, yet myocardial protective strategies may vary both according to patient condition and operative requirements. The need for a cardioplegia administration device that allows flexibility and safety is evident. The purpose of this study was to evaluate the performance of the Quest Myocardial Protection System™ (MPS) during clinically simulated conditions.

The MPS was evaluated in an in vitro setting under the following conditions: blood to crystalloid ratios (1:1, 4:1, 8:1, all blood), potassium concentrations ([K+]) of 10 and 25 mmol/L, calcium concentrations ([Ca++>l) of 1.4 and 2.8 mmol/L, and at flow rates of 100 and 300 ml/min. Predicted values from the MPS were compared with measured values, with statistically significance accepted at p<.05 level.

Significant differences were seen between measured and MPS cardioplegia delivery volumes at the 4:1, 8:1 and all blood ratios with a flow rate of 300 ml/min. There were no significant differences seen between measured and expected [K+] and [Ca++] delivery values across all combination of flow rates and ratios. Differences between delivery pressures of the MPS and measured values for flow rates of 100, 250 and 500 ml/min were 0.4, 1.2 and 7.6 mmHg respectively. The mean cardioplegia cooling time from 37°C to 9°C was 37±4.5 seconds, while rewarming from 7°C to 37°C, to 9°C, took 53±10.4 seconds.

In conclusion, the Myocardial Protection System performance characteristics were precise in ratio delivery, concen.trations of potassium agents, additive agent concentration, temperature, and pressure across all experimental conditions, with the exception of delivery volume.
Utility of In Vitro Heparin and Protamine Titration for Dosing During Cardiopulmonary Bypass Surgery
Authors: Zucker M.L. , Barrett C.L. , Bennett K. , LaDuca F.M.
Published: August 2023

Methods used to maintain a hemostatic balance during cardiopulmonary bypass surgery include the optimization of heparin and protamine dosing. Higher heparin doses have been associated with increased bleeding, while other studies have attributed reduced blood loss and transfusion requirements to lower protamine doses. We have evaluated the use of an in vitro heparin and protamine titration system and compared it to standard dosing in patients undergoing surgery requiring cardiopulmonary bypass. Based upon the principle of the Hemochron® RxDx® system, Heparin Response Tests (HRT) and Protamine Response Tests (PRT) were performed for 40 patients undergoing cardiac surgery at three hospital centers. The Activated Clotting Time (ACT) was used to monitor adequate heparin dosing prior to placing the patient on bypass, and to monitor heparin reversal after protamine dosing. The efficacy of heparin reversal was determined using the Protamine Dose Assay (PDA-O) test. All centers used standard hospital pharmaceutical preparations of heparin and protamine.

Heparin and protamine RxDx dosing was compared to standard hospital practice for each site. Based on the HRT, the average heparin dose was not different from empirical dosing; however, individual differences were as high as 11,000 units. Only a single patient required a second heparin bolus prior to initiation of bypass. On average, the protamine dose predicted by the PRT was only 67% of the empirical protamine dose. The PDA-O test identified the need for additional protamine in 13% of patients. Patients administered additional protamine at the request of the surgical team, despite the presence of a normal PDA-O test, had no further decrease in ACT.

In summary, the in vitro HRT and PRT system did not alter the initial heparin dose yet significantly decreased the protamine doses administered. Based on prior clinical outcome studies, this reduction is expected to have a beneficial effect on postoperative bleeding and transfusion requirements.
The Design and Application of a Pediatric Centrifugal Pump
Authors: Ding Wen-xiang , Yu Xiao-qing , Su Zhao-kang , Huang Hui-min
Published: August 2023

This centrifugal pump (CP) includes two parts: the blood pump and the driving apparatus. They are connected by six twin magnetic disc plates and driven by a magnetic DC motor (120W). The blood pump had six leaves deadlocked between two plastic discs. Six leaves were set at 30° angles, separately. In the lower chamber of the CP, there was an inlay magnetic disc, which is connected with the disc leaves by an axis. This axis was sealed by silicon rubber and a ceramic ring. The priming volume of the blood chamber was 34 ml.

In vitro testing showed that the free hemoglobin caused by the CP was much less than that caused by a roller pump after 180 min. The effect of this CP on blood cell damage was also studied in an animal model. Six goats were placed on cardiopulmonary bypass for 180 min. Perfusion flow rates were maintained between 1.5 and 2.5 L/min. The plasma free hemoglobin was lower in the CP group (6.04 mg/dL) than in the roller pump group (32.25 mg/dL), p < 0.01.

The CP has been used in ten pediatric patients undergoing cardiopulmonary bypass surgery. The patients' ages were from three to five years, and body weights were from 15 to 20 kg. Perfusion flow rates were maintained between 1.8 and 2.5 L/min, and bypass times were from 30 to 50 min. The rotation speeds were from 2000 to 2500 rpm. All the patients recovered smoothly, and no hemoglobinuria occurred.
Application of Polygeline in Pediatric Cardiac Surgery
Authors: Zhu De-Ming , Chen Hong , Wang Wei , Chen Ying
Published: August 2023

The purpose of this study was to determine the effect of using polygeline as part of the cardiopulmonary bypass solution in pediatric cardiac surgery.

A total of 40 cases were divided into two groups, a polygeline group (H group, n=20) and a plasma group (P group, n=20). Operations were performed under routine extracorporeal circulation. The dose of polygeline or plasma used was calculated to maintain the patient's plasma colloid oncotic pressure at 10-12 mmHg.

The results showed that in the polygeline group, no patient developed allergic or coagulation disorders even after large volumes of polygeline were used (45 ml/kg). At the initiation and completion of cardiopulmonary bypass (CPB), the concentrations of calcium were higher in the H group (1.38 ± 0.19, 1.21 ± 0.11) than those (0.72 ± 0.11, 0.95 ± 0.10) in the P group. There were no other statistically significant differences between the two groups. There were no organ problems in the patients included in the study.

This study demonstrated that polygeline could be used as part of prime solution instead of plasma to keep an ideal plasma colloid oncotic pressure, reduce infections caused by blood product transfusions and lower the cost to the patients.
Kongressnachlese
Authors: Thonack Christina
Published: August 2023

Kindernephrologie in Krisenzeiten – dies ist ein Thema, das facettenreich an vielen Stellen berührt, sowohl emotional als auch fachspezifisch. Im Rahmen der 54. Jahrestagung der GPN im Mai in Marburg wurde Raum zur Reflexion und Diskussion gegeben. Darüber hinaus wurden Erkrankungen des Tubulussystems und der Genetik von Nierenerkrankungen klassische Schwerpunkte der Marburger Kindernephrologie in den Mittelpunkt gestellt und wissenschaftlich diskutiert. Wie sieht die Zukunft der Kindernierentransplantation aus und was sind die wissenschaftlichen Entwicklungen in den Bereichen der pädiatrischen Nierenersatztherapie, u. a. bei Kindern mit angeborenen Fehlbildungen? Dieser Themenkomplex besaß ebenfalls eine besondere Aufmerksamkeit auf dem Kongress.
Berufliche Belastungen von Long-Covid-Rehabilitand*innen und
Rückkehr zur Arbeit nach einer pneumologischen
Rehabilitation
Authors: Rutsch Mercedes , Deck Ruth
Published: August 2023

Hintergrund Das durch SARS-CoV-2 verursachte Long Covid-Syndrom
beeinträchtigt Betroffene aufgrund von anhaltenden Symptomen und
Einschränkungen im sozialen wie beruflichen Leben. Die medizinische
Rehabilitation zielt darauf ab, Teilhabeeinschränkungen zu reduzieren
und die Erwerbsfähigkeit der Betroffenen wiederherzustellen. Bislang ist
nicht bekannt, wie sich die berufliche Situation von Long Covid-Betroffenen nach
einer pneumologischen Rehabilitation entwickelt.

Methodik Die Gesamtstudie ist als multizentrische, prospektive
Beobachtungsstudie im Mixed-Method-Design angelegt. Rekrutiert wurden
Covid-19-Rehabilitand*innen in der pneumologischen Rehabilitation im
Alter von 18 bis 65 Jahren. In dieser Auswertung wurden die Fragebogendaten von
zur Baseline erwerbstätigen Personen berücksichtigt. Die
schriftliche Befragung fand am Anfang und Ende der Rehabilitation sowie nach
sechs Monaten statt. Erhoben wurden u. a. Return to Work, berufliche
Belastungen und Veränderungen, subjektive Prognose der
Erwerbstätigkeit (SPE) und berufliche Leistungs- sowie
Arbeitsfähigkeit (WAI).

Ergebnisse Die Stichprobe umfasst N=173 Teilnehmer*innen
(68,2% weiblich) und ist im Durchschnitt 52,5 Jahre alt. 85,5%
der Rehabilitand*innen waren sechs Monate nach der Rehabilitation
arbeitsfähig und kehrten an einen Arbeitsplatz zurück. Die
Fehlzeiten, die subjektiv empfundene Leistungsfähigkeit und
Arbeitsfähigkeit verbesserten sich im zeitlichen Verlauf statistisch
signifikant (p<0,01). Die Gefahr einer frühzeitigen Berentung
besteht auch noch sechs Monate nach der Rehabilitation bei 41,3% der
Studienteilnehmer*innen. Die Teilhabeeinschränkungen reduzieren
sich im Follow-up statistisch signifikant und mit mittlerer Effektstärke
(ES=0,60, p<0,01). In der logistischen Regression erwies sich
der WAI als signifikant protektiver Prädiktor auf die Rückkehr
zur Arbeit, kognitive Corona-Symptome und hohe Werte der kognitiven Fatigue
erwiesen sich als Risikofaktoren.

Schlussfolgerungen Der Großteil der Rehabilitand*innen ist
ein halbes Jahr nach einer pneumologischen Rehabilitation erwerbstätig,
obwohl auch über die Rehabilitation hinaus von anhaltenden Symptomen und
einer beeinträchtigten Arbeitsfähigkeit berichtet wird. In der
Rehabilitation Erwerbstätiger könnten berufsbezogene Elemente,
beispielsweise die Klärung beruflicher Fragen und Vorbereitung auf
berufliche Anforderungen (z. B. Konzentration, Stress,
körperliche Anforderungen), einen nachhaltigen Return to Work
unterstützen.
The Role of 68Ga FAPI-04 and 18F-FDG PET/CT in Detecting Liver Metastases in Different Types of Cancer
Authors: Kaplan İhsan , Kepenek Ferat , Güzel Yunus , Can Canan , Kömek Halil
Published: August 2023

Objective We compared the diagnostic accuracies of 68Ga FAPI-04 PET/CT and 18F-FDG PET/CT for detecting liver metastases (LMs) in patients with different cancer types.

Materials and Methods This retrospective study included 63 patients with liver lesions who underwent 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT between May 2020 and May 2022. Patients with histopathologically confirmed primary diagnoses, data that could be accessed retrospectively, liver lesions confirmed by biopsy over at least 3–6 months of follow-up (via ultrasonography, CT, magnetic resonance imaging, PET/CT, or laboratory tests) were included. Patients with secondary malignancies or primary liver malignancies, and/or who could not be followed-up, were excluded.

Results Of the 63 total patients, 34 (54%) were female, and the mean age was 61 (30–92) years. There were 582 LMs in 51 patients and 35 benign liver lesions in 20 (12 patients had only benign and 8 both benign and malignant lesions). Of the 582 LMs, 472 (81.1%) evidenced 18F-FDG uptake and 572 (98.2%) 68Ga-FAPI uptake. The diagnostic accuracies of 68Ga-FAPI PET/CT and 18F-FDG PET/CT were 98% and 82%, respectively (p < 0.001; McNemar test). When the LMs were compared, the maximum standardized uptake (SUVmax) value was significantly higher on 18F-FDG PET/CT than 68Ga-FAPI PET/CT (median: 6.0 vs. 5.4; p = 0.016). However, the LM-to-background ratio (TBR) was significantly higher on 68Ga-FAPI PET/CT than 18F-FDG PET/CT (median: 4.1 vs. 2.1; p < 0.001).

Conclusion
68Ga-FAPI PET/CT detected more LMs than did 18F-FDG PET/CT, and TBR was significantly higher on 68Ga-FAPI PET/CT than 18F-FDG PET/CT.
Optimal Temperature of Irrigation Fluid for Hemostasis in Neurosurgery: A Narrative Literature Review
Authors: Bretherton Dylan , Baker Lucy , Eftekhar Behzad
Published: August 2023

Background Hemostasis in neurosurgery is crucial to patient and surgery outcomes, with many techniques developed for this. One area that is not appropriately characterized despite continuous anecdotal evidence the temperature of the irrigation fluid (IF) used and its effects on stemming hemorrhages. Given the ubiquitous use of IF in neurosurgery for clearing blood from the surgical field, it is important to explore its role as a hemostat and whether or not the temperature of the IF influences its hemostatic capacity. This review explored the literature for an optimal IF temperature for hemostasis in neurosurgery.

Methods Database searches were conducted using MEDLINE, Scopus, Web of Science, and CINAHL, with citation chaining occurring where applicable. Standard terms around neurosurgery, hemostasis, and irrigation were used.

Results Seven articles were identified. No optimal temperature for hemostasis could be confidently synthesized from the literature owing to lack of primary investigation on the subject. After collating available information into common themes, it is suggested that that temperatures >38°C are preferred.

Conclusion The literature in this area is limited. Despite a lack of applicable systematic investigation on the topic, by exploring the physiology of hemostasis and IF, best practice guidelines for IF, and the literature on the role of the temperature of IF in other surgical specialties, it is suggested that a temperature in the range of 38 to 40°C would be most applicable to a value optimal for neurosurgery.
Medical Emergencies in Pulmonary Hypertension
Authors: Seitler Samuel , Dimopoulos Konstantinos , Ernst Sabine , Price Laura C.
Published: August 2023

The management of acute medical emergencies in patients with pulmonary hypertension (PH) can be challenging. Patients with preexisting PH can rapidly deteriorate due to right ventricular decompensation when faced with acute physiological challenges that would usually be considered low-risk scenarios. This review considers the assessment and management of acute medical emergencies in patients with PH, encompassing both pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH), acknowledging these comprise the more severe groups of PH. Management protocols are described in a systems-based approach. Respiratory emergencies include pulmonary embolism, airways disease, and pneumonia; cardiac emergencies including arrhythmia and chest pain with acute myocardial infarction are discussed, alongside PH-specific emergencies such as pulmonary artery dissection and extrinsic coronary artery compression by a dilated proximal pulmonary artery. Other emergencies including sepsis, severe gastroenteritis with dehydration, syncope, and liver failure are also considered. We propose management recommendations for medical emergencies based on available evidence, international guidelines, and expert consensus. We aim to provide advice to the specialist alongside the generalist, and emergency doctors, nurses, and acute physicians in nonspecialist centers. A multidisciplinary team approach is essential in the management of patients with PH, and communication with local and specialist PH centers is paramount. Close hemodynamic monitoring during medical emergencies in patients with preexisting PH is vital, with early referral to critical care recommended given the frequent deterioration and high mortality in this setting.
Cooperation in the presence of zealots and assortative interaction
Authors: Shapiro Maura
Published: August 2023

Evolutionary game theory simulation demonstrated that commonalities between individuals influenced cooperation in the presence of zealous individuals.