bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of debris-flow initiation through the analysis of seismic signals
Authors: Ioriatti Elena , Coviello Velio , Berti Matteo , Comiti Francesco
Published: August 2023

Monitoring data gathered in the headwaters of the Gadria catchment, eastern Italian Alps, have been analysed to study debris-flow initiation. The active channel, located at 2200 m a.s.l., was instrumented with a geophone, a time-lapse video camera and a rain gauge. The peak amplitude and duration of the seismic signals and their frequency content were analysed and compared with video images. Results showed that different seismic sources produced signals with different characteristics and that it is possible to discriminate the most intense runoff by analysing the combination of peak amplitude and duration of the seismic signal. The further development of this research would be to create an algorithm able to automatically classify the seismic sources and identify intense channel processes that can generate debris flows. In perspective, the combination of seismic detection in the initiation area with monitoring just above the infrastructures at risk could represent an effective solution to expand the lead time of an early warning system.
Pulse-Doppler radar measurements of debris flows: High-resolution monitoring of surge dynamics from two events in the Gadria Creek (Italy)
Authors: Schöffl Tobias , Nagl Georg , Hübl Johannes , Kaitna Roland
Published: August 2023

As a consequence of their spontaneous occurrence, and frequent formation of multiple surges with high sediment loads, debris flows are considered one of the most hazardous gravity-driven mass movements in montane regions. Field measurements of surface velocities are an essential link in the chain of understanding fundamental process dynamics and applied protection against debris flows. In order to measure the velocities of multiple consecutive surges within a single debris-flow event, a PD radar (pulse-Doppler high-frequency radar) sensor for high-resolution real-time debris-flow monitoring has been developed. In this contribution we present PD radar measurements of two debris flows, that occurred at the Gadria creek in Italy on July 26, 2019, and August 10, 2020, over a torrent length of 250 meters. We record over 55 high-amplitude surges that overlap and superimpose at the front of the debris flow, but also subsequently throughout the debris-flow body. Our results demonstrate applicability of a PD radar for debris-flow monitoring and serve as a data source for modelling surge dynamics in debris flows.
Seismic Measurements of Roll Waves in Debris Flows
Authors: Walter Fabian , Zhang Zhen , Aaron Jordan , McArdell Brian , Graf Christoph
Published: August 2023

Accurate debris-flow modelling depends on the ability to simulate surging and pulsing behaviour. However, our understanding of these phenomena is starved of observational constraints. Here we propose the use of seismic measurements, which resolve the arrival of coarse-grained roll wave fronts in debris flows at Illgraben, Switzerland. Roll waves likely play a key role in flow pulses but are typically only observed with point measurements like depth gauges. We compare in-torrent force plate measurements with near-torrent seismic records and discuss how these data can test existing roll wave theories.
Study on the relationship between rainfall, topography and landslide volume in the recent debris flow disasters in Hiroshima, Japan
Authors: Eguchi Tomoaki , Umemura Hiroya , Arai Mizuho , Okamoto Atsushi , Sakai Yusuke , Uchida Taro , Hayashi Shinichiro , Ohyama Makoto
Published: August 2023

Three types of sediment volume estimation equations were developed by analyzing the relationship between rainfall, topography (e.g. slope gradient, relative height) and the volume of collapsed sediment in 1 km grid for heavy rainfall events (2014 and 2018 events) in Hiroshima Prefecture where intensive slope failures and debris flows occurred. All three equations showed a tendency for the volume of collapsed sediment per unit area to increase with increasing rainfall. However, some equations showed the rate of increase tends to gradually plateau.
Field Investigation of Sandstone Escarpment Stability at East Mountain, Utah, USA
Authors: Maleki Hamid , Semborski Chuck , Fleck Ken
Published: August 2023

During the last three decades, a significant amount of research has been directed to developing predictive tools for assessing the stability of the Castlegate Sandstone escarpment, travel distances for the debris and the need for any control measures in Central Utah. The cliff-forming Castlegate Sandstone is 60 m thick at the study mine in Utah and lies approximately 250 m above multiple-seam coal reserves. To assess escarpment stability, the authors used multiple regression analysis and extensive data on geology, mining, and escarpment stability collected over many years. The volume of failed rocks was used as the response variable. Mine layout options were developed to minimize cliff instability and frequency of mining-induced surface fractures. Geologic and geometric variables were obtained along 3.7 km of escarpment exposure at 180 study locations. A regression analysis of data from 29 study locations showed that surface topography plays a critical role in influencing escarpment stability. With additional data collected over the next longwall block, important variables were identified including canyon slope, thickness of Castlegate Sandstone and mining influence angle. Finally, the model was used for prediction of escarpment stability in area 3. In remote mining areas of Utah, warning signs were posted at the study areas.
Keynote lecture. The debris flow event of 29 October 2018 in the Rio Rotiano (Italy) and its challenges for the mathematical and numerical modelling
Authors: Rosatti Giorgio , Zugliani Daniel , Fraccarollo Luigi
Published: August 2023

The debris flow that interested the Rio Rotiano, a creek located in the Province of Trento (Italy) on 29 October 2018, is an event that, because of its peculiar features, presents formidable challenges in terms of mathematical and numerical modelling. Here we present some results of our research, which required both physical and mathematical modelling, aimed at developing a numerical tool necessary to face the back analysis of the event and the validation of the planned protection works. Exploiting some results of the laboratory tests and coupling an advanced description of the debris flow dynamics (TRENT2D model) over fixed and mobile bed with a sub-surface flow model, we obtained a model that can be defined as a mobile-bed rainfall-runoff model, where the runoff is composed by both water and sediments and represents a new paradigm in the field of debris flow simulations. First applications give promising results but some further developments are required before completing the back analysis of the Rio Rotiano event.
Spatial Variation in Specific Sediment Discharge Volume from First-Order Catchment due to Heavy Rainfall and its Factors
Authors: Tsushima Misa , Uchida Taro
Published: August 2023

In this study, we evaluated the variations in sediment discharge between basins from the first- order catchment of the Akatani River watershed, where sediment discharges as a result of heavy rainfall. We tested the correlation between sediment discharge, topography, and rainfall magnitude using LiDAR datasets. The results showed that the specific eroded sediment volume in the first-order catchment was sufficiently greater than the specific deposited sediment volume, and the variation of the specific discharge sediment volume from the first-order catchment was determined by the variation of the specific eroded sediment volume. The spatial variations of specific discharged sediment volumes could not be evaluated solely by topography and rainfall indices; even in the catchment, where the topographic condition and rainfall magnitude were almost the same, the specific sediment discharge varied by more than one magnitude.
Advancing debris flow hazard and risk assessments using debris flow modeling and radar derived rainfall intensity data
Authors: Wasklewicz Thad , Guthrie Richard , Knibbs Graham , Rossi Rebecca
Published: August 2023

Debris flow hazard and risk assessments are critical tools in mitigating and planning for these events. Existing debris flow hazard assessments can provide a rapid view of the likelihood of debris flows in recently burned watersheds and along stream segments within the watershed. Furthermore, debris flow volumes can be predicted for these watersheds and along the stream segments. Advances in modeling and remote-sensing data can add further value to the rapid assessments. Here, modeled debris flow volumes and a more detailed understanding of rainfall conditions highlight a need to reconcile debris flow probabilities and volumes using local conditions. Modeled debris flow volumes are consistently lower than even the lowest predicted volumes from empirical models used in the debris flow hazard assessments. Watershed probability and volume relations also over predict based on our probabilities derived from rainfall intensity from Multi-Radar/Multi-Sensor System 1-hr data. Probability and volume measures need to be further considered as the conservative measures of the rapid assessments have implication for risk analyses required for planning and management decisions, and ultimately for design and cost of mitigation to manage risk.
Log Crib Check Dam Performance under Multiple Debris-Flow Loadings – East Gate Landslide, British Columbia, Canada
Authors: Busslinger Matthias , Jakob Matthias , Singer Richard , Calder Ryan
Published: August 2023

Check dams are used in gullies to prevent vertical downcutting of the thalweg. Check dams built as log crib structures are common in steep creeks prone to floods or debris floods. Recent experience with performance of log crib check dams subject to debris flow loadings is less common, as those check dams are often made from reinforced concrete, steel or masonry. This paper summarizes our experience with six log crib check dams built in a gully at East Gate Landslide, between Revelstoke and Golden, BC, Canada. The log crib check dams are subjected to multiple debris flow events every year. The project started as a pilot study and the design is adjusted before the next construction season, based on performance experience with previously built structures.
Debris flow mitigation by using biopolymers as a soil stabilizer
Authors: Fatehi Hadi , Ong Dominic , Yu Jimmy , Chang Ilhan
Published: August 2023

Towards rising the attention to the use of green materials in geotechnical applications, this study aims to introduce carrageenan as a new environment-friendly polymer for slope surface stabilization. A set of experiments were conducted to evaluate the performance of the biopolymer-treated soil to form a resistant surface against the surface erosion and debris flow. samples were tested by changing a variety of effective parameters including biopolymer content, moisture content, curing time, soil type, and durability under wet- dry cycles. Kaolinite soil along with river sand in different combinations were employed and treated by various biopolymer proportions to optimize the biopolymer and soil parameters. Subsequently, the optimum mixture of each biopolymer-treated soil was subjected to 5 cycles of wetting and drying. A broad microstructural study by performing FTIR analysis and scanning electron microscopy (SEM) images was conducted and an analytical model was developed to clarify how biopolymer stabilize the slope surface. The results confirm the successful performance of carrageenan in connecting soil grains, increasing mechanical strength and durability of soil against surface erosion. It can be concluded that carrageenan can be considered as a sustainable alternative to conventional materials such as cement and lime.
Physical model investigation of the transition of a debris flow from the aerial to the water phase
Authors: Tognacca Christian , Toschini Enea , Benagli Mattia , Maddalena Gioele
Published: August 2023

In order to study the phenomena of debris flow motion and deposition at the transition between a channel and an underwater storage area, experiments were carried out on a physical model. The current situation and the planned works were reproduced in two idealised 1:100 scale models. The experiments show that the flows experience an abrupt transition into water with the creation of a water wave and enter the lake undergoing a decrease in front velocity, but without creating upstream stagnation or local deposits due to the sudden phase change. Instead, the debris flows move to the lower part of the model, where they are deposited in the horizontal plane and in the lower parts of the conoid. The construction of a retention basin in the lake does not decisively influence the dynamics of the transition between the aerial and underwater phases. The results of the physical modelling provide indispensable data for the validation of the 3D numerical codes currently being tested.
A simplified numerical model for evaluating sediment control by open-type sabo dams in the Joganji River basin
Authors: Yamazaki Yusuke , Noro Tomoyuki , Miwa Kenji , Mizuyama Takahisa , Fujita Masaharu , Miyata Shusuke , Ikeda Akihiko , Furuya Tomohiko , Nagayama Takahiko , Itoh Takahiro
Published: August 2023

The present study proposes a method to estimate sediment runoff by introducing a dam function of the relationship between inflow sediment and sediment runoff through a slit dam. The model can process rainfall runoff, sediment yield and runoff of a mountainous basin, and the model is applied to the upper reaches of the Joganji River basin, which is known for its huge amount of sediment runoff and intense bed variation because of the sediment yield caused by the earthquake in 1858. The performance of the calculations of sediment control of the slit dam is evaluated by the model. The result indicates that sediment deposition is significantly changed by sediment runoff. The proposed method can be expected to evaluate sediment transport with sabo dams on a basin scale.
Keynote lecture. Impact dynamics of debris flow against slit dam: Experimental and numerical investigation
Authors: Zhou Gordon G.D. , Cui Kahlil F. E. , Du Junhan , Li Nanjun , Lu Xueqiang , Xie Yunxu
Published: August 2023

Debris flows are gravity-driven phenomena common in mountainous regions that are hazardous to downstream facilities. To mitigate the impacts of these disastrous processes, structural countermeasures such as slit dams are constructed in gullies and along mountain slopes. Existing studies on the impact dynamics of debris flows against slit dams typically focus only on the flow characteristics but fail to take the geometry of the structure into account. Here we develop an analytical model, derived from the momentum approach, that allows for the estimation of the runup height and impact load of debris flows on slit dams. The model is validated against discrete element simulations and small-scale flume experiments. It is found that the runup height is controlled by both the Froude number and slit size. The proposed analytical model can predict the runup height well within a certain range of Froude numbers. Results from experiments further reveal that the fontal dynamic pressure is sensitive to the flow properties whereas the peak dynamic pressure is strongly affected by the slit size.
Runout model evaluation based on back-calculation of building damage
Authors: Barnhart Katherine R. , Kean Jason W.
Published: August 2023

We evaluated the ability of three debris-flow runout models (RAMMS, FLO2D and D-Claw) to predict the number of damaged buildings in simulations of the 9 January 2019 Montecito, California, debrisflow event. Observations of building damage after the event were combined with OpenStreetMap building footprints to construct a database of all potentially impacted buildings. At the estimated event volume, all models overpredict the number of damaged buildings by a factor of 1.5–3.
Guided organic growth: A paradigm shift in new city making
Authors: Elhanafy Heba
Published: August 2023

Planning is a discipline of shifting paradigms, from the functional modern city to the rational-comprehensive approach, to the current return of place. But how has (or will) the discipline shift in response to the rise in recent decades of new city building around the globe? With at least 100 new cities in conception or under construction in India; dozens more under way in each of Southeast Asia, the Middle East, sub-Saharan Africa, and Latin America; and over 600 new cities currently either being designed or being built in China—the answer to this question will affect the lives of potentially millions of individuals. As it stands, most new cities built recently or currently being developed are over-planned. Currently, urban plans often follow either the Chinese-grid planning paradigm or an American-suburban model. Those approaches leave little to no space for local adaptation, emergent market forces, and the agency of residents to shape their cities over time. New cities can be an excellent opportunity to inject urban economic vibrancy, solving market failures, and unlocking innovation. However, until a deliberate shift occurs in the planning paradigms of these new city developments, they will continue to suffer from common challenges. This paper aims to rethink new city making in the Global South and suggests a definite need for a paradigm shift.
A Comparative Study of Urban House Price Prediction using Machine Learning Algorithms
Authors: El Mouna Lale , Silkan Hassan , Haynf Youssef , Nann Mohamedade Farouk , Tekouabou Stéphane C. K.
Published: August 2023

Accurate housing price forecasts are essential for several reasons. First, it allows individuals to make informed decisions about buying or selling real estate and to determine appropriate prices. Secondly, it helps real estate agents and investors make better investment decisions and negotiate contracts more effectively. In addition, housing prices are often an indication of the general state of the economy. A price decrease may indicate an economic recession, while an increase in prices may signal economic growth. In this study, we proposed to address this subject by predicting house prices using machine learning by choosing three types of machine learning: Linear Regression (LN), Random Forest (RF) and GradientBoosting (GB). We tested our models on the Melbourne real estate dataset, which includes 34,857 property sales and 21 features.
Estimating Passenger Demand Using Machine Learning Models: A Systematic Review
Authors: Boateng Adjei , Anum Adams Charlse , Kofi Akowuah Emmanuel
Published: August 2023

This article investigated machine learning models used to estimate passenger demand. These models have the potential to provide valuable insights into passenger trip behaviour and other inferences. The estimate of passenger demand using machine learning model research and the methodologies used are fragmented. To synchronise these studies, this paper conducts a systematic review of machine learning models to estimate passenger demand. The review investigates how passenger demand is estimated using machine learning models. A comprehensive search strategy is conducted across the three main online publishing databases to locate 911 unique records. Relevant record titles, abstracts, and publication information are extracted, leaving 102 articles. Furthermore, articles are evaluated according to eligibility requirements. This procedure yields 21 full-text papers for data extraction. 3 research thematic questions covering passenger data collection techniques, passenger demand interventions, and intervention performance are reviewed in detail. The results of this study suggest that mobility records, LSTM-based models, and performance metrics play a critical role in conducting passenger demand prediction studies. The model evaluation was mostly restricted to 3 performance metrics which needs improved metric for evaluation. Furthermore, the review determined an overreliance on the longand short-term memory model to estimate passenger demand. Therefore, minimising the limitation of the LSTM model will generally improve the estimation models. Furthermore, having an acceptable trainset to avoid overfitting is crucial. In addition, it is advisable to consider multiple metrics to have a more comprehensive evaluation.
The Role of Inclusive Educational Technologies in Transforming African Cities into Inclusive Smart Cities
Authors: Kameni Eric Désiré , Tekouabou Koumetio Stéphane Cédric
Published: August 2023

Inclusive smart cities aim to create a more equitable and accessible urban environment for all citizens, including people with disabilities, low-income individuals, and marginalized communities. This concept involves using technology and data to improve urban services and infrastructure while ensuring that everyone can benefit from these advances. The observation is that nowadays, in the majority of African countries, the city’s transformation into a smart city only concerns a small portion of the population, those in the metropolises who have skills and access to technological tools. Those in rural areas or precarious urban quarters that are not business centres are simply excluded or ignored from the process, perhaps because they do not have the skills or access to emerging technological tools due to their geographical location. Smart education and therefore educational technologies are among the most sensitive in this context. Therefore, Inclusive educational technology can play a significant role in this case by providing access to education and training for all citizens, regardless of their socioeconomic status or physical abilities. It ensures that everyone has access to the skills and knowledge needed to participate in the digital economy and benefit from the opportunities it offers. This work identifies the roles that inclusive educational technologies can play in transforming cities into inclusive smart cities.
Introducing Project-Based Climate Education in Moroccan Universities via a New Air Quality Monitoring Network in Rabat
Authors: Lbadaoui-Darvas Mária , Lbadaoui Abdeljalil , Labjar Najoua , El Hajjaji Souad , Nenes Athanasios , Takahama Satoshi , Roy Arindam
Published: August 2023

Morocco’s economy has recently seen an unprecedented growth, which made the country emerge into the 5th strongest economy of the African continent. As other countries at the same stage of development, Morocco is also undergoing rapid urbanization, which results in increased anthropogenic air-pollution levels. The geographical location of the country makes it vulnerable to both short and longterm impacts of climate change. Despite the elevated risk and vulnerability, the current air pollution and climate change monitoring strategy of the country needs improvement. The present paper introduces a novel strategy to improve the air quality monitoring system in the capital combined with developing a project-based climate education curriculum, and promises to raise public awareness to the risks related to air pollution and climate change. The sustainability of the project is guaranteed by the low cost of instruments and the educational aspect which ensures that future experts are well-trained for the maintenance of the system that we propose to install.
Oxygenator Evaluation: Maxima 1380 Versus Maxima Plus
Authors: Engle James H. , Ploessl Jay , Sutton Robin
Published: August 2023

Continual improvement of oxygenators has been important in the growing demands of patient safety and support during cardiopulmonary bypass. The purpose of this study was to compare the Maxima 1380 oxygenator to the upgraded Maxima Plus oxygenator.

Thirty-two adult patients were randomized to either the 1380 group or the Plus group. Information was recorded on the patients' weight, age, body surface area, esophageal temperature, arterial temperature, venous oxygen saturation, arterial pO2, arterial pCO2, blood flow, hematocrit, gas sweep, and FiO2.

No significant difference was found between the two groups' mean weight, body surface area, arterial pO2 arterial pCO2, age, esophageal temperature, arterial temperature, venous oxygen saturation, and blood flow (p > 0.05). The Plus group demonstrated significantly lower mean gas sweep rates and FiO2 settings than the 1380 group. FiO2 of the 1380 was dependent on age, body surface area, blood flow, and esophageal temperature (r = 0.89, p < 0.001). FiO2 of the Plus was correlated with weight, esophageal temperature, arterial temperature, and arterial pO2 (r = 0.93, p < 0.001). Gas sweep rate of the 1380 was dependent on age, weight, esophageal temperature, blood flow, arterial temperature, and arterial pCO2 (r = 0.84, p < 0.001). The gas sweep rate of the Plus was dependent on weight and esophageal temperature (r = 0.55, p < 0.001). Based on these analyses, the new Maxima Plus oxygenator is more efficient in oxygen and carbon dioxide transport than the Maxima 1380.
Surface Activation of Whole Blood: Clot Detection with a Thrombelastograph
Authors: Stover Todd M. , Stammers Alfred H.
Published: August 2023

Various methods are used to decrease the length of time required to generate useful data from thrombelastography (TEG). The quicker this data can be produced and analyzed the sooner decisions can be made for hemostasis management. The present study was designed to determine the effects of glass compared to plastic with respect to their effect on the activation of the intrinsic pathway of coagulation. Thirty-seven samples of native whole blood (NWB) were drawn via radial artery catheter, internal jugular sheath or by direct venous puncture. Half of each sample was placed in a glass test tube and the other half in a plastic (polypropylene) container, and allowed to sit for periods of 1 minute (n = 4 ), 1.5 minutes (n = 5), 2 minutes (n = 9), 2.5 minutes (n = 9) and 3 minutes (n = 10). The glass activated samples were placed in plastic TEG cups that had been randomized to one of the two TEG channels, with the plastic activated samples being placed in metal TEG cups in the opposite channel. This resulted in a total of seventy-four TEG profiles.

There were no significant correlations (p < 0.05) between any of the inter- or intra-related TEG parameters, reaction time (R time), kinetic time (K time), maximum amplitude (MA), or alpha angle (AA). However, the R time of the glass activated samples showed a linear decrease in time required to achieve this value. The plastic activated samples did not exhibit this linear decrease in R time. The thrombelastograph index (TI) showed an initial hypocoagulability at 1 min for glass (-1.84 ± 3.46) when compared to plastic ( + 1.58 ± 0.23). At 1.5 minutes, the TI for glass ( -0.12 ± 2.97) approached those for plastic ( +0.035 ± 1.68) and remained relatively close until3 min of activation when the glass samples TI (2.48 ± 3.16) proved to be hypercoagulable when compared to the plastic at 3 min, TI (1.97 ± 2.64). The MA, K time and alpha angle seemed to be largely unaffected by the different activation times.

This study has shown that glass activation may be used effectively to decrease the time required to generate TEG data from NWB samples, and that the glass activation does not seem to affect the TEG parameters significantly other than the R time.
Surgical Removal of a Left Atrial Myxoma Utilizing Cardiopulmonary Bypass
Authors: Kerins Paul , Vertrees Roger A , Brownstein Louis , Weiss Richard L. , DelRossi Anthony J.
Published: August 2023

An atrial myxoma is a benign intracavitary tumor of the heart. Clinical manifestations of the myxoma depend upon the location within the heart and the degree of obstruction to blood flow. This case report presents a patient who displayed all the clinical symptomology of mitral valve dysfunction, due to the presence of a left atrial myxoma. The diagnosis and subsequent surgical removal of the tumor, utilizing cardiopulmonary bypass, are the subject of this report.
Proinflammatory Mediator Response in Coronary Bypass Surgery Using a Centrifugal or a Roller Pump
Authors: Salo Matti , Perttilä Juha , Pulkki Karl , Grönroos Juha , Mertsola Jussi , Peltola Olli , Nevalainen Timo
Published: August 2023

Major surgery, trauma, and infection induce a proinflammatory mediator response which, if excessive, may cause tissue injury. The response was measured during elective coronary bypass surgery when a centrifugal pump or a roller pump, differing in their basic working principles, was used for extracorporeal circulation (ECC). Eight patients were perfused with a centrifugal pump and eight patients with a roller pump during ECC. Plasma interleukin-1β(IL-1β), IL-2, IL-6, tumor necrosis factorα (TNFα), group II phospholipase A2, (PLA2), endotoxin, fibronectin and serum C-reactive protein (CRP) concentrations were measured. The operation increased plasma IL-6, group II PLA2, and serum CRP concentration and decreased plasma fibronectin concentrations. IL-1β and TNFα concentrations did not change. IL-2 ocurred only occasionally, and endotoxin did not occur in any patient. No differences were seen between the group using a centrifugal pump and the group using the roller pump. Cardiac surgery with a perfusion time of less than two hours thus caused a proinflammatory mediator response which was similar whether a centrifugal or a roller pump was used for ECC.
The Buffering Ability of Commonly Employed Cardiopulmonary Bypass Solutions and Alkalizing Agents
Authors: Crawford RE , Bliss LM , Schneider ME , Phelps VK , Gilmore RV , Harris HK , Westendorff BE , Koenig GK , Mashburn PC , Galloway MW , Ecklund JM , Riley JB , Wolk DR
Published: August 2023

This experiment evaluated the hydrogen ion (H+) buffering capacity (BC) of solutions and alkalizing agents employed during cardiopulmonary bypass (CPB). A solution's BC can be determined when a known quantity of H+ is titrated into the solution and the change ( ) in pH (-log of the hydrogen ion activity ([H+]a)) is measured ( [H+]/ mmole H +). Eleven solutions were studied: Lactated Ringers (LR), 0.9% NaCI (NS), Plasma-Lyte A ™, Hespan ™ (6% hetastarch), banked donor blood with citrate phosphate dextrose adenine (CPDA-1), fresh donor blood, THAM™, sodium bicarbonate (NaHCO3 ; 1 mEq/ml), high potassium crystalloid cardioplegic solution (HKCCPS), oxygenated crystalloid cardioplegic solution (OCCPS), and adult crystalloid priming solution (AP) per institutional protocol. The solutions were studied at three temperatures: 37°C, 28°C, and 18°C. The null hypothesis stated there was no difference in the BC of the solutions studied. The solutions were first titrated to the same starting pH of 8.0. The solutions were then titrated with a predetermined concentration of hydrochloric acid (HCI) to a pH of 7.0. A higher quantity of H+ added to a solution indicated a greater ability of that solution to buffer H+ within pH limits of 8.0 to 7.0. The data was analyzed with a two way ANOV A and Bonferonni method. A p value <0.05 was considered to be statistically significant. The significant results of our study indicated that THAM™ demonstrated the best BC, followed in decreasing order by NaHCO3, banked blood, fresh blood, HKCCPS, AP, OCCPS, Plasmalyte™, LR, Hespan™, and NS.
The Relationship Between Oxygen Transfer and FIO2 in a Clinical Study of the AffinityTM Hollow Fiber Oxygenator
Authors: Svenmarker Staffan , Appelblad Micael , Häggmark Sören , Jansson Erica , Lindholm Ronny
Published: August 2023

On-line computation of body oxygen consumption (V̇O2) was performed in twelve (n=12) cardiac surgical patients utilizing cardiopulmonary bypass. Two in-line monitors, the CDI 400™ and CDI 100™ were interfaced with a personal computer. Arterial oxygen partial pressure, saturation and temperature from the CDI 400™ and venous saturation and hemoglobin values from the CDI 100™ enabled a real time computerized V̇O2 calculation. Paired V̇O2 and fractions of inspired oxygen (FIO) values made it possible to plot an oxygen transfer equation (OTE) for the AVECOR Affinity™ hollow fiber oxygenator. Regression analysis of 124 V̇O2-FIO2 pairs established the following relationship: V̇O2 = 368.4 * FIO2 - 15.6, with a correlation of 0.89 (p<0.001). This regression line presented as an OTE-plot suggests that the Affinity™ oxgenator is capable of transferring approximately 350 ml/min of oxygen at an FIO2 = 1.0. In conclusion, on-line CPB-monitoring interfaced with a personal computer may be used for real time V̇O2 - calculations and to establish an oxygen transfer equation of a given oxygenator.
Scavenging Anesthetic Gas from a Membrane Oxygenator During Cardiopulmonary Bypass
Authors: Homishak Michael , Widmer Steven , Stauffer Richard
Published: August 2023

Concerns remain about the acute and chronic effects on personnel of waste anesthetic gases in the operating room environment. This study demonstrates a simple and effective means of scavenging waste anesthetic gases when halogenated anesthetics are administered through the pump oxygenator during cardiopulmonary bypass. This technique safeguards workers’ health by reducing ambient anesthetic levels below the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limits.
Supplemental Use of Antithrombin Ill Concentrate in the Pediatric Patient
Authors: Cunningham Beth A. , Ecklund Jodie M. , Riley Jeffrey B.
Published: August 2023

Decreased AT-III levels during cardiopulmonary bypass (CPB) have been observed in pediatric patients and are attributable to hemodilution. Prebypass administration of AT-III to the pediatric patient has been shown to prevent decreases in serum AT-III levels and elevated fibrinopeptide A (FPA) levels before and after bypass. We compared the clinical outcome of patients receiving supplemental AT-III injectate to control patients. Patients with preoperative AT-III levels less than 80% received AT-III injectate prior to heparinization.

A retrospective analysis of 149 patients (31 study patients vs. 118 controls) revealed that a greater percentage of patients receiving AT-III were cyanotic (p=0.001) and underwent more complex cardiac repairs (p=0.001). Compared to patients not receiving AT-III, surgeries were performed at lower temperatures (p=0.040) with longer CPB times (p=0.031) and circulatory arrest times (p=0.047). Baseline AT-III levels were significantly lower in the treated group (p<0.0001) but were significantly higher during CPB (p=0.0001). Total postoperative blood loss, blood product administration, rate of reoperation, total time in ICU and mortality proved not to be significantly different between the groups after adjusting for above covariates (p=NS). It appears that maintenance of higher AT-III levels did not affect the clinically measurable outcome variables associated with hemostasis.
Do Heparinase Thrombelastographs Predict Postoperative Bleeding?
Authors: Mashburn Paulla , Ecklund Jodie , Riley Jeffrey
Published: August 2023

Postoperative hemorrhage is a major cause of morbidity and mortality in patients who undergo cardiopulmonary bypass (CPB). The thrombelastograph (TEG) is a viscoelastic whole blood test that measures clot dynamics from clot formation through clot lysis. Previous studies have shown that post-bypass TEGs are accurate predictors of postoperative bleeding.

TEGs from heparinized blood reversed with heparinase may be employed during CPB to evaluate coagulation. CPB heparinase TEGs may allow for earlier recognition of patients who may bleed after bypass. Earlier TEG analysis would allow targeting of specific therapies to begin before the patient bleeds excessively. Fifty-four heparinase TEGs during warming and fifty-four native TEGs post-protamine administration were collected. Parameters evaluated were R, K, alpha angle, MA, MA60, coagulation index, activated clotting time. hematocrit, prothrombin time, partial thromboplastin time, thrombin time, fibrinogen concentration, platelet count, blood loss during and after CPB, and blood and blood product administration. Coagulation indexes for CPB heparinase TEGs that were less than -2 or heparinase TEGs that were fibrinolytic were 87% accurate in predicting patients with excessive intraoperative blood loss, but were not predictive of blood product administration. The sensitivity was 12.5% and the specificity was I 00% in predicting excessive intraoperative bleeding. Post-protamine coagulation index inversely correlated with intraoperative red blood cell administration (r=-0.403, p<0.05), but was not predictive. Patients with fibrinolytic TEGs required blood products to compensate for expected blood loss associated with the fibrinolytic state. Simultaneous routine coagulation tests did not correlate significantly with blood loss or blood product administration, nor were they predictive. The findings of this study suggest that the presence of fibrinolysis in either a heparinase TEG on bypass or a post-protamine TEG is the most important predictor of blood and blood product administration. But, since only 20% of the patients in the study exhibited fibrinolytic TEGs, a study that included a much larger sample of patients would need to be done to confirm this finding.
New Roller Pump Disposable Provides Safety and Simplifies Occlusion Setting
Authors: Lee-Sensiba Kerri , Azzaretto Nancy , Carolina Clifford , DiCarmine Nancy , Hymowitz Don , Kay Stuart , Kooker Karlene , Salogub Michelle , Wong Elaine , Tamari Yehuda
Published: August 2023

A new disposable insert for the arterial roller pump, the Better-Header™, provides safety and functionality beyond what standard tubing provides. It automatically limits pump outlet pressure to a level determined by the user and provides a self-contained, simple means to set pump occlusion. The Better-Header™ consists of a Starling-like pressure relief valve connected across standard header tubing. As long as arterial line pressure at the pump outlet remains below a set limit, the valve is closed. If line pressure approaches the pressure limit, the valve opens, preventing overpressurization by shunting blood from pump outlet to inlet. The BetterHeader ™ can also be used to set occlusion by the “dynamic method” to obtain nonocclusive settings.

The Better-Header™ was evaluated in the lab for its pressure-flow characteristics. Even when the arterial line was completely clamped at a pump flow of 7 Llmin, line pressure was limited to a safe level and all circuit connections were preserved.

The Better-Header™ has been used successfully at North Shore University Hospital in over 500 clinical cases covering a wide range of patients and procedures. In several instances, the user was alerted to high pressure situations by fluid flow through the valve and by an audible alarm, allowing rapid correction of the source of pressure. Compared to the standard setup, the Better-Header™ maintains outlet pressure within safe, user-settable limits, and permits consistent, nonocclusive settings with predictable retrograde flow.
Massive Volume Loss During Cardiopulmonary Bypass and its Association with Meckel’s Diverticulum
Authors: Buzzelli Timothy J. , Trittipoe Rebekah E.
Published: August 2023

The occurrence of any gastrointestinal (GI) complication concurrent with cardiac surgery may greatly increase a patient’s morbidity and mortality. The most frequently discussed GI complication associated with cardiac surgery is hemorrhage from peptic ulcerations and the exacerbation of this condition through heparinization. However, there are consequences of other GI problems which the clinical perfusionist needs to be aware of. This paper presents a case of a 65 year old female undergoing routine coronary artery bypass grafting. Although this patient was an uric, an excessive amount of fluid loss and replacement occurred. This paper reviews the case management and the eventual diagnosis of acute peritonitis as a result of perforated Meckel’s diverticulum and describes the subsequent surgical intervention for repair of the perforation.
Use of the Abiomed BVS 5000 Ventricular Assist Device for Myocardial Support Following Left Ventricular Aneurysmectomy: Case Report
Authors: Samuels Louis E. , Havdala Jack S. , Kaufman Marla S. , Morris Rohinton J. , Brockman Stanley K.
Published: August 2023

Left ventricular aneurysms (LVA) are most commonly the result of a large transmural myocardial infarction, usually in the distribution of an occluded left anterior descending coronary artery. We investigated a case at Allegheny University Hospitals, Hahnemann Division, Philadelphia, PA, involving the use of the Abiomed BVS 5000 ventricular assist device (VAD) for LVA repair. The patient was successfully weaned from cardiopulmonary bypass using the Abiomed BVS Left Ventricular Assist Device (LVAD). The LVAD was successfully removed on the fourth postoperative day. In summary, we report the successful support of the myocardium with the Abiomed BVS 5000 Ventricular Assist Device after left ventricular aneurysmectomy. We favor mechanical over high dose inotropic support of the myocardium with a V AD in postcardiotomy patients with severe ventricular dysfunction.
Extracorporeal Circuit Sterility after 168 Hours
Authors: Young William V. , Heemsoth Christopher H. , Georgiafandis George , Mitchell Daryl C. , Hackett Dennis K. , Bahna Donald G.
Published: August 2023

One of the most important tasks of the perfusionist is the proper assembly of the extracorporeal circuit (ECC) prior to the initiation of cardiopulmonary bypass (CPB). The ECC is usually assembled, primed and debubbled 30 minutes to one hour prior to the patient entering the operating room. But there are occasions when the ECC may have been set up and the previously scheduled procedure cancelled. Perfusionists in this situation have found themselves in a quandary; dispose of the ECC because of required nursing compliance and the sterility question, or keep it and use it later because of the economic impact on the "bottom line". Some hospitals may have satisfactorily answered the question of ECC sterility after 24 hours without observation, but the few reported papers regarding this issue, and our desire to save these circuits, inspired us to find out if they were in fact sterile after having been open for a long period of time.

The purpose of this study was to evaluate ECC sterility using an open reservoir oxygenator, over a time period of seven days. After obtaining 792 bacterial cultures from three sites within the ECC, the study was terminated. There were no positive bacterial cultures during the study period. Assuming there is no deliberate contamination, pump circuits assembled in an unused operating room can be maintained sterile for a period of seven days.
An In Vitro Comparison of Gas Transfer and Pressure Drop of the Bentley Duraflo Coated Spiral Gold and the Medtronic Carmeda Coated Maxima Hollow Fiber Membrane Oxygenators
Authors: Vocelka Craig R. , Thomas Robert , Verrier Edward , Kunzelman Karyn
Published: August 2023

Two models of heparin coated, hollow fiber membrane oxygenators were tested in vitro to compare gas transfer and transoxygenator pressure drop using an established protocol. Oxygen and carbon dioxide transfer rates were measured at blood flows of 2.5 and 5.0 liters per minute with gas flow : blood flow ratios of 1:1 and 2:1 at both blood flows. All testing was performed under normothermic conditions. The data shows that oxygen transfer increases as blood flow is increased in both oxygenators. Similarly, carbon dioxide transfer is increased by both increased blood and gas flows. Finally, the pressure drop was dependent on blood flow rate alone. This study demonstrated these two oxygenators to be comparable in both oxygen and carbon dioxide transfer and also in transoxygenator pressure drop.
laboratory Evaluation of a New Membrane Oxygenator with a Built-In Hemoconcentrator
Authors: Nishida Hiroshi , Suzuki Susumu , Endo Masahiro , Koyanagi Hitoshi , Kuwana Katsuyuki , Nakanishi Hikaru , Aoki Masato
Published: August 2023

In order to facilitate the handling of cardiopulmonary bypass (CPB) and simplify the circuit, we have developed a new membrane oxyganator with a hemofiltration function. The hollow fiber units for gas exchange and hemofiltration were combined in concentric circles in a cylindrical housing. The total priming volume was 190 ml. Because we used a silicon-coated hollow fiber membrane for gas exchange, this oxygenator was completely resistant to serum leakage. The gas exchange and hemofiltration sections both have a blood-outside flow configuration. All blood flows in a radial direction from around the central core to the surrounding hollow fiber units, first to the hemofiltration portion and then to the gas exchange section. Filtered fluid was easily collected through a stopcock mechanism. The oxygen transfer rate was 312 ml/min at a blood flow rate of 6 L/min, and the ultrafiltration rate was 3.5 L/hour at a blood flow rate of 4 L/min with 25% hematocrit and 200 mmHg transmembrane pressure in an in vitro study. The pressure drop was 62 mmHg at a blood flow rate of 4 L/min. We found no adverse effects in an in vivo study using a mongrel dog. In conclusion, this durable combined device could achieve excellent and simplified hemoconcentration by having all the blood in the unit flow through the hemofiltration portion, and may be useful not only in CPB during open heart surgery, but also in extracorporeal membrane oxygenation.
Pumpless Extracorporeal Lung Assist
Authors: Phillipp A. , Behr R. , Rengr M. , Kaiser M. , Birnbaum D.
Published: August 2023

Extracorporeallung assist (ECLA) is an established form of treatment for acute pulmonary insufficiency. Classically, it takes the form of veno-venous bypass. The femoral vein and the subclavian vein are favored cannulation sites. Blood is pumped with either a roller or a centrifugal pump. Sometimes heparin-coated cannulae, membrane oxygenators (MO), and tubing are used, which may significantly reduce the risk of bleeding. A device pumping 1.0 to 4.0 liters per minute nevertheless signifies a persistent mechanical stress for the cellular blood components and causes some degree of hemolysis.

A 42 year old patient with acute pancreatitis and marginal clotting parameters developed profound pulmonary insufficiency. All modes of mechanical ventilation were exhausted and proved to be inadequate. Under good hemodynamic conditions, an arterio-venous pumpless ECLA was instituted for a duration of 10 days, when the patient could be successfully weaned. The membrane oxygenator was connected via cannulae in the femoral artery and femoral vein.
Evolution of a Cardiovascular Information System
Authors: Frank Douglas A , Williams Thomas E. , Hankins Thomas D. , Chudik J. Michael
Published: August 2023

The competitive nature of our evolving health care system mandates a concomitant increase in the level of sophistication of the cardiovascular information system. The new paradigms in health care also mandate a re-engineering of the process of data collection and analysis. This paper deals with a variety of hardware, software, and human issues encountered at our institution.

Topics covered include implementation of service line management, utilization of an interdisciplinary medical informatics model, database conversion, and application development. Special attention will be paid to the development of a system which is a comprehensive information system for clinical and financial management of the cardiovascular patient, not just a quality-of-care database.