bluuebunny/crossref_metadata_2025 huggingface dataset:
Dissolution Behavior of Carbonate Rocks from Brazilian Pre-Salt at Reservoir Conditions by LSWI
Authors: Borges Tálisson Carvalho , Vidal Vargas Janeth Alina , Koroishi Erika Tomie , Kim Nilo Ricardo , Trevisan Osvair Vidal , Bassani Gabriel Soares
Published: October 2019

The low salinity water injection (LSWI) is one of the most studied techniques applied to enhanced oil recovery (EOR) from carbonates reservoirs. Wettability alteration and dissolution reaction are mechanisms that support the understanding of this technique. However, the dissolution behavior of Brazilian pre-salt carbonates rocks when treated by LSWI is not yet known. Therefore, the purpose of this work is to evaluate the dissolution effects provided by low salinity water injection in carbonate rocks from a Brazilian pre-salt reservoir using two different injection flow rates in core flooding tests at reservoir conditions. Porosity variation along the length was determined by Computerized Tomography scan analysis. Permeability was determined through pressure drop data. Ions identification and concentration were determined by ions chromatography. The experiments consisted in carrying out two core flooding tests assembled in series at 8100 psi of injection pressure and 65°C. It was performed two different injection flow rates (1 mL/min and 0.1 mL/min) of 16 times diluted synthetic seawater. It was possible to observe three different porosity behaviors along the sample length in both flow rates tested and for both core holder samples. However, the porosity behavior intensity is different from each case. There are regions of predictable behavior, regions of random behavior and inert regions. According to the porosity plots, the sample from the second core holder of the series presented more interaction with the injection fluid. Probably, the mineralogical heterogeneity has influenced in the dissolution phenomenon. The permeability profile remained almost constant for both samples. The ion chromatography analysis revealed a huge variation of magnesium and calcium ions concentration in the first injected porous volume and, subsequently, a constant trend towards the base-line values.
Forecasting Smart Well Production via Deep Learning and Data Driven Optimization
Authors: Calvette Taisa , Gurwicz Allan , Abreu Ana Carolina , Cavalcanti Pacheco Marco Aurélio
Published: October 2019

As smart well technology is increasingly being adopted in oilfield development projects, the need to optimize controls emerged in order to justify its higher initial investment by considerably increasing net present value. While there are numerous methodologies to achieve this goal, a common fact in all is the need for a great number of computationally expensive reservoir simulations, hindering extensive optimizations. This paper proposes the use of deep learning algorithms in proxy models, in order to accurately replicate the behavior of the simulator by forecasting production based on previous data. Thus, a smaller number of simulations are required for a training dataset, and the proxy can then be used in lieu of the simulator for optimization purposes. Other benefits in the use of the proposed methodology include the gathering of insights on production, as problems might be occurring if measured production noticeably deviates from the forecast. Two case studies were done, and the results indicate that a Long Short-Term Memory Network-based proxy is able to forecast production with a remarkably low error, validating the methodology and supporting its use.
On the Ultimate Limit State Strength Models and Its Application for Casing Design
Authors: Nogueira Araújo João Paulo , Pereira Gouveia Lucas , Toledo Lima Junior Eduardo , Barbosa Silva Thiago , Lopes Rodrigues Anjos Jorel , Lima Oliveira Felipe , Matos Lira William Wagner , Lima Santos João Paulo
Published: October 2019

It is proposed a new methodology for calculating safety factors in triaxial casing design, regarding Ultimate Limit State (ULS) models. The definition of an equivalent axial force allows an unified graphical approach, in which both ULS and Serviceability Limit State (SLS) envelopes are represented in the same space. A review of the ULS casing design proposed in the API TR 5C3 (2008) standard is presented, and some considerations are made on the usage of Klever-Stewart and Kever-Tamano models. Both are defined for combined load analysis but are not effective for triaxial casing design routine, for they only compare the applied internal/external pressures to the design limit. Thus, two additional limit states are verified: axial and triaxial. Furthermore, the ULS envelopes (Klever-Stewart and Klever-Tamano) are plotted in the same load space as the SLS envelopes, allowing for an analysis on both limit states in a single graphic. During studies of the Klever-Stewart and Klever-Tamano formulations it was verified that, despite both being combined models (the external/internal pressure and axial load influence the internal/external pressure resistance), the consideration of their uniaxial safety factors might not be enough to ensure if the tubular is about to fail. There are some special load cases where other failures might occur prior to burst/collapse. The ULS envelopes are revisited, using the very same equations proposed by the API TR 5C3 (2008), but in a different load space, which also allows the representation of SLS envelopes, providing a complete evaluation of the tubular strength against the load scenario. The studies also revealed some drawbacks inherent to the Klever-Stewart and Klever-Tamano models, as the existence of inadmissible pressure resistance beyond the axial ultimate tensile strength. The new paradigm of ULS is challenging and it is not well established in terms of design practice. In the light of this, it is presented a new methodology for computing safety factors in ULS analysis, effectively comparing them to the SLS approach, in order to support the decision-making process in casing design and the well integrity verification.
Optimization Methodology of Artificial Lift Rates for Brazilian Offshore Field
Authors: Bezerra Matheus De Freitas , Vigano Guilherme Cosme , Giuriatto Jean Luis
Published: October 2019

Nowadays gas-lift is still a very expressive artificial lift method, for instance considering the whole Brazilian oil production profiles, gas lifted wells are responsible for 30% of monthly production. Due this huge importance, the injection efficiency should be ensured to avoid lid gas losses and maximize the production. Then, this study had as objective to develop a Gas Lift Optimization workflow and define the optimum lift rates to increase the reservoir recovery and improve gas usability due to platform constraints of a Brazilian deep-water field. That workflow comprises a reservoir and flow assurance simulators, achieving more accurate responses compared to regular workflows. Taking advantages of the proposed method, multidisciplinary teams could work together which increases the representativeness of such studies providing important outcomes for decision makers. At this study, due to a gas-lift optimization was observed an increase of 0.5% at cumulative production with a huge gas-lift reduction of around 40%, resulting in a better financial balance of the project, saving a considerable amount of lift-gas. The methodology adopted to optimize the injected gas lift rate and consequently increase/maintain cumulative oil production proved adequate for application in oil fields that are highly dependent on artificial lift methods. Therefore, exploration and production projects can be financial healthier.
Detailed CFD Simulations of Green Water Flow on FPSO Deck
Authors: Silva Daniel Fonseca de Carvalho e
Published: October 2019

Oil production in ultra-deep waters places some new challenges for floating units. As an FPSO is one of most common types of production units adopted by Petrobras, its behavior in extreme conditions has to be fully tested and verified. During extreme sea storms, ship type floating structures may be subjected to water on deck events (green water). In order to allow a detailed structural analysis, Computational Fluid Dynamics (CFD) techniques may be used to investigate detailed loads due to water on deck propagation, especially in beam sea conditions, which are not traditionally covered by maritime rules.

Based on model test results, water ingress and water on deck propagation are simulated through CFD analysis. The methodology adopted consists of two different approaches: (i) The influence of a riser balcony lateral extent is analyzed based on a 2D wave propagation model and; (ii) the complex flow behavior through topside equipment is discussed by using a 3D simulation of a restricted deck area, including some strategies for impact protection.

The results of the simulations allow investigation of the complex flow behavior depending on the riser balcony extent and topside configuration, as well as the resulting loads on critical structures. For a side hull balcony, its protective effect against wave run-up in beam waves is only effective with a lateral extent of 8m. By performing water on deck simulations, the benefits of "V" type protections are quantified leading to 20% loading reduction when compared to flat plates.

The simulations reveal CFD as a very powerful tool to assess detailed transient pressure distributions for optimized structural design.
P-67: Review of Dry Transportation of FLNG’s/FSRU’s/FPSO’s
Authors: Lira André de , Pinheiro Marcio , Leuwen John Van , Seij Michel , Goetheer Ronald
Published: October 2019

Boskalis Offshore executed the dry transportation of the P-67 FPSO in 2018 from Qingdao China to Rio de Janeiro in Brazil. One of the main challenges for this project is the sheer size and weight of the P-67 FPSO. In order to transport the P-67 FPSO in a safe and controlled manner, new loading concepts and support structures have been developed.

This paper addresses the challenges and lessons learned of the P67 FPSO transportation project. By means of several tangible examples and comparison with wet-tow the reader is explained how the dry-tow method benefits the transport of the P67 FPSO. The P67 FPSO is a critical asset for gas production, and as a result benefits deepwater FLNG in general.

High level these benefits can be found in: Design optimizations - Stationary structures can be designed lighter and equipment can be optimized for local environment.Schedule optimizations - Dry transport increases schedule reliability and reduces time to market.Risk reduction - Reduced duration of exposure to risks at sea and specifically in critical areas.
Hybrid Composite Flexible Risers in Free Hanging Catenary Configuration and Flowlines for UDW Projects
Authors: Loureiro Jr. Walter Carrara , Sobreira Rafael Guimarães de Mello , Buckley Adriana Loureiro da Silva
Published: October 2019

Large diameter UDW flexible pipes usually require lazy-wave configuration to withstand operational fatigue life. In a response to the current uncertain oil/gas price, the opportunity to design and deploy Free Hanging Catenary risers has been identified as the means to significantly lower CAPEX of flexible risers installed while securing the required life-cycle performance, including optimized offshore installation, 30-year fatigue duties.

The most promising concepts to deliver free hanging configuration are based on composite flexible pipe designs, but these solutions rely on new technology (or at least new application of technology) and will need to undergo all new technology development phases including "Field Qualification" stage before they are ready to be considered as a base case for any UDW Project.

Composite flexible pipe considers the adoption of new composite materials layers replacing one or multiple layers of a conventional flexible pipe for at least one pipe section. Several new hybrid pipe concepts can be developed considering this approach. Considering current Industry Standards and Brazil Regulations many challenges can be identified to deploy this type of new technology. These pipe concepts do not fit in the definition of existing Standards. In addition, the unknown behavior of these material and layers in a flexible pipe will increase the integrity assessment complexity.

During the development phase the integrity assessment challenges and potential gaps in industry standards will have to be addressed as well to avoid misalignment or conflicts with regulatory requirements.
Electrocoagulation Treatment for Reverse Electrodialysis Wastewater from Petroleum Refinery
Authors: Gonçalves Filipe Mattos , Galdino Duarte Tocafundo Dhayannie Hellen , Alvarenga Santos André Luiz , Nigri Elbert Muller , Ferreira Rocha Sônia Denise
Published: October 2019

The present study investigated an evaluation efficiency of electrocoagulation (EC) for the pretreatment of a saline concentrated effluent from the reverse electrodialysis (RED-C) stage from an oil refinery, aiming at water reuse in the industrial process. In this approach, an electrocoagulation system with 1 L capacity was set up for batch treatment using aluminum electrodes. Initially, experiments with a semi-synthetic RED-C effluent were assessed for contaminants removal using fixed current density of 8.30 mA/cm2 and 1 cm distance between electrodes. The influence of initial pH (5 and 7), controlled temperature (20, 30 and 40°C) and operation time (60 and 120 min) on removal efficiency was investigated and solid residue were measured. The results showed that the optimum conditions were at pH 7 and 20-30°C with removal rates around 70%, 57%, 10% and 44% for Ca, Sr, Na and COD, respectively. Thereafter, experiments were conducted with a real RED-C using the best condition founded in preliminary tests, this time applying a current density of 5 and 10 mA/cm2 and 0.5 cm distance at room temperature (approximately 23°C). Regarding the tests with real RED-C, for both current densities the removals were greater due to decrease in distance between electrodes and larger temperature range that improved electrocoagulation. In general, the use of current density of 10 mA/cm2 and reduction of inter-electrode distance increased EC efficiency which exhibited removal rates of 88%, 77%, 26% and 24% for Ca, Sr, Na and COD, respectively. Although, it was observed a decrease in COD removal from real RED-C due to the addition of inorganic ions in the semisynthetic effluent that precipitated as salts, removing more organic as a coadjuvant compound. The solid slugde production for this same condition were 5.65 g/L.
Estimation of Three-phase Oil Relative Permeability in WAG Experiments
Authors: Aghabozorgi Shokoufeh , Sohrabi Mehran , Facanha Juliana
Published: October 2019

Simulation of many enhanced oil recovery (EOR) methods such as water alternative gas (WAG) requires accurate determination of relative permeability (kr) data under different saturation histories. Relative permeability is a function of several factors such as wettability, spreading coefficient and fluid pore occupancy. Experimental measurements of three phase kr data are time consuming and difficult considering infinite possible flow paths in the three-phase flow regime. There are several models in the literature to estimate the oil relative permeability data in three phase systems (3P-Kr models). However, the available models can not accurately estimate the oil production in low oil saturation region observed in WAG experiments.

In this paper, Stone I model has been modified to improve the estimation of oil kr data. To this aim, the behaviors of three phase flow in immiscible and near miscible WAG experiments were considered. It was shown that the Stone model overestimates the oil relative permeability data in the low oil saturation regions. In addition, it was revealed that Stone's exponent model cannot simulate the gradual decreace in the oil kr data. To improve the results, a new coefficient is incorporated into the model to consider the impacts of the disconnected oil clusters during the cyclic injection. In addition, the end-of-cycle residual oil saturation (Som), which was required based on the Stone model, is no longer needed in this modified model.
Compact Hydrate Dissociation Plant: Combined Direct and Indirect Heating for Increased Efficiency
Authors: Margotto Romulo Mantovani Augusto , Franklin Gabriel , Cunha Jeferson
Published: October 2019

Hydrate formation in production and control lines has been a serious issue in the oil industry, especially in the deepwater offshore market. This article focuses on a compact temporary plant designed to be assembled on offshore rigs for heating and injecting high flow rate water to break hydrates.

Hydrates are formed under determined conditions (high pressure at low temperature) in which natural gas hydrocarbon molecules are trapped in ice molecules, forming crystal structures and plugging or choking lines, causing operational problems. When preventive solutions, such as chemical inhibitors or thermal insulation, do not work, the formed hydrate must be broken or dissociated to set the lines free. One option is active heating, in which hot fluid is circulated to increase the temperature and break the hydrate ice structures. Consequently, a compact plant, with combined direct and indirect heating, was designed to deliver a customized solution for an offshore rig.

Drill or salt water pumps were used to supply cold water at 12 bpm at 25 °C, and two steam generators were used to inject steam into the flow, mixing inline and delivering water at 49 °C at the mud tanks. This tank water was pumped through mud pumps at 12 bpm, passing through four steam heat exchangers (SHE) to deliver water at a final temperature of 90 °C. The total process used six steam generators and four SHE to heat water from 25 to 90 °C at 12 bpm.

The compact design for the high flow rate injection plant was only possible with combined and independent processes. Direct heating by steam injection was used inline downstream from the drill water pump to preheat the water to 49 °C while feeding the mud tank. Indirect heating used four SHE downstream of the mud pump to deliver water at 90 °C at the seabed.
Application of Highly Inclined Well to Optimizing Well Pattern: Case Study of a Giant Carbonate Reservoir in the Middle East
Authors: Sun Liang , Wei Liang , Zhao Hang , Li Baozhu , Li Yong
Published: October 2019

Carbonate reservoirs in the Middle East are characterized by strong heterogeneity, fairly subtle barriers and baffles, which result in low water flood swept volume and poor displacement efficiency. Therefore, optimum well pattern deployment is critical for high-efficiency development of such reservoirs. This paper focuses on a giant carbonate reservoir and discusses the application of highly inclined well to optimizing the deployment of well pattern.

In this paper, first, based on the productivity formulae of slanted and horizontal wells proposed by Besson, the adaptability of highly inclined well in giant carbonate reservoir was evaluated. Then, the well design parameters were optimized by using numerical simulation. Finally, the optimum well pattern of "water injection in vertical well and oil production in highly inclined well" was established, and sound development strategies were determined. This provided us the foundation to propose customized water flooding plan. The successful application of this development scheme for M carbonate reservoir in Iraq validated the technical feasibility, which achieved considerable economic benefits.

The results indicate that highly inclined well has advantages in productivity and adaptability of well type to this kind of reservoirs. The production of top low-permeability layers and bottom low-permeability layers in M reservoir with inclined interval and horizontal interval respectively makes full use of highly inclined well, which balances injectivity and productivity of different reservoir properties. The proper length of highly inclined well is 2953∼3281 feet, and the ratio of inclined interval to horizontal interval is about 2. The optimized well pattern of "water injection in vertical well and oil production in highly inclined well" improves water injection sweep efficiency and recovery factor. The M reservoir in Iraq has achieved an annual yield of more than 1.5 million barrels.

The water injection development for large-scale carbonate reservoirs in the Middle East is still at exploration stage and lack of mature experience. The proposed development pattern in this paper provides a methodology for the efficient development of similar reservoirs.
Research on Engineering Technologies to Develop China's Complex Reservoirs and their Feasibility in Development of Marginal Oilfields in South America
Authors: Fu Jin , Wang Xi , Zhang Shunyuan , Liu Bingshan , Chen Chen , Yang Guobin
Published: October 2019

Marginal Oilfields are refered to as those oilfields that are hardly developed efficiently with current technical and ecomonical conditions, characterized as high costs of development and low profit margins. However, under certain economical and technical circumstances, marginal oilfields may be transferred to be conventional ones. Since Petrobras developed the first ever offshore deep reservoir (Lula) by scale in 2006, Brazil has been conducting a progressive campaign targeting hydrocarbons buried under deep water, which contributes to discovery of Lula, Carioca, Jupiter, Buzios, Libra and other giant presalt reservoirs in Santos Basin. CNPC signed a cooperation contract with Petrobras in 2013, taking 10% of the total shares. How to efficiently develop the oilfield has been a challenging issue.

Technologies of smart water injection in Shengli Oilfield have been studied, while the field development and environment (deep water) of Libra Oilfield have been analyzed, in order that the smart water injection technologies may be modified to develop the marginal oilfield more efficiently.

Different from conventional zonal water injection technologies, the remote wireless control water injection technologies take advantages of packers that are connected with each other via preset cables, which achieves downhole testing and water injection simultaneously. Being run via tubing, the water injection string locates a nozzle for each reservoir that is isolated by a packer. All nozzles are connected with packers via the preset cables that work as power lines for the whole string, so that downhole data such as pressures, flows and temperatures are all transferred to the processing computer on the surface. The computer program is used to convert pressure and formation signals into curves that are transferred to Company via WIFI or mobile 2G/3G/4G webs, in order that technicians there may understand and learn about downhole pressures, temperatures, flows and nozzle conditions in real time. They are able to open and close the nozzles totally or partially by giving orders that are transferred as signals via cables. In order to cope with offshore environment of Libra Oilfield in Santos Basin, pre-set cable packers have been modified accordingly, so that highly deviated wells may be developed with the smart water injection technologies.

A field trial deployed in BM-C-33 Block Libra Oilfield shows that the modified smart water injection technologies are feasible for Libra Oilfield, as a novel solution to inject water in highly-deviated and horizontal wells in offshore oilfields.
Increasing Fire Safety – Fire and Life Safety Ecosystem
Authors: Candido Anderson Queiroz
Published: October 2019

While we are currently seeing less fires, statistically, if you do have a fire in your home, you are more likely to die today than you were 20 years ago. Add to that, that every 24 seconds, a U.S. fire department responds to a fire somewhere in the country. Nationwide, a civilian died in a fire every 2 hours and 34 minutes. (From the 2017 U.S. Fire Loss Report)

The reality is, we do have many of the tools to prevent damaging fires – sprinklers, smoke alarms, codes and enforcement – but they are met with resistance from everyone from policymakers and enforcers to builders and the public. Over the years we've underused, ignored or allowed codes and safety standards to become outdated.
Structural Integrity of HSLA Steels under Hydrogen Embrittlement Condition
Authors: Melo Guilherme Freitas , Bose Filho Waldek Wladimir , Alvarenga Rodrigo Freitas da Silva , Paes Marcelo Torres Piza , Ferreira Daniel Correia F. , Franco Sinésio Domingues
Published: October 2019

High strength steels have large applicability in the gas and oil industry and are often used in aggressive environments, requiring the use of cathodic protection, with the consequent generation of atomic hydrogen in the cathode that may lead to hydrogen embrittlement, HE. The aim of this work was to evaluate the fracture toughness and HE susceptibility of two high strength steels, named as 38CrMo4 and 30CrMo6,

used as components for oil extraction from the seabed. J-Δa curves for JIC evaluation were carried out following the ASTM E1820 [1] at room temperature in laboratorial air using C(T) specimen. For KTH evaluation the tests were based on NACE TM0177 standard [2], using sharply notched DCB specimens. For this test a 3.5 wt% NaCl aqueous solution with −1.2 V cathodic protection for the in-situ hydrogen charging were used. From the results it was observed that both steels presented predominantly martensitic/bainitic microstructures, with 30CrMo6 steel exhibiting lower mechanical strength and higher total elongation. The great microstructural differences rely mainly on the prior austenite grain size and in the S and Ca contents. 30CrMo6 steel presented a very fine prior austenite grain and mostly spherical CaS inclusions instead of the elongated MnS. These microstructural features lead to much higher KJIC value and it did not exhibit HE in the conditions analyzed here.
Preliminary Study of Radial Flow Effects on Rotor Blades
Authors: Harris Franklin D.
Published: October 2019

The accumulation of experimental flight‐test and model rotor data, has permitted a stall delaying phenomenon to be observed, such that the most advanced rotor‐performance theory tends to be unduly conservative in estimating rotor lift capability. An example of this conservativeness
is shown in Figure A. Despite this lift augmentation, there is no experimental indication of a reduction in the separation drag at the predicted stall point; the theoretical calculations using the refined aerodynamic theory are in reasonable agreement with experimental drag results.
Vascular flora of Milan Malpensa airport (Lombardy, Italy). Part I: checklist
Authors: Martignoni Marco , Banfi Enrico , Galasso Gabriele
Published: October 2019

Airport areas have, among flight infrastructures, large green spaces which, not having production purposes, are managed through interventions of minimal disturbance on habitats, with potentially positive effects on the conservation of biodiversity. The checklist of the vascular flora of the airport of Milan Malpensa is here presented. This airport extends for 12.44 km2 in the southwestern portion of the province of Varese (Lombardy, Italy) in the administrative districts of Cardano al Campo, Casorate Sempione, Ferno, Lonate Pozzolo, Samarate, Somma Lombardo and Vizzola Ticino. The collection campaigns were carried out between August 2010 and September 2018. The specimens collected are now kept in the herbarium facility of the Natural History Museum of Milan (MSNM). The floristic list was organized following the arrangement and the nomenclature of the recently published Italian flora checklists. It includes 395 taxa of specific and subspecific rank (9.35% of the entire flora of Lombardy) belonging to 247 genera and 72 families. The native taxa are 318, while the alien ones are 77. The native/aliens ratio is comparable to the one calculated at the regional level (4.10 vs. 4.42). The endemic contingent includes two taxa: Centaurea nigrescens subsp. pinnatifida, Italian endemic, and Euphrasia cisalpina, endemic to the Alps. The Malpensa airport is still the only site confirmed at the national level for Lepidium heterophyllum and, at the regional level, for Festuca muralis and Euphrasia cisalpina. The ecological characteristics and the data analysis will be discussed in a second contribution.
Validity of chest ultrasound in the diagnosis of acute chest disorders in children
Authors: Kabil Ahmed E , Aboseif Ahmed I , Kamal Sherif M , Sorour Ehab I , Mohammed Abd El Salam R
Published: October 2019

Introduction

Chest ultrasonography (US) is a promising tool in the evaluation of chest diseases as it is fast, user-friendly, noninvasive, easily reproducible, portable, widely available, inexpensive, and involves no ionizing radiation.

Aim

To assess the role of chest US in the diagnosis of acute chest disorders in children comparing it with conventional chest radiographs (CXR).

Patients and methods

This was a prospective, observational study, conducted at the Pediatric and Chest Departments of Al-Hussein and Sayed Galal, Al-Azhar University Hospitals, Cairo. Children aged from 1 month to 12 years, suffering from acute respiratory distress were included in this study. Full history taking, clinical examination, CXR, and chest US were performed for each patient. Computed tomography chest was performed in some cases where there was a doubt in diagnosis (e.g. lung abscess, mediastinal mass, and small pneumothorax). The main outcome was the correspondence between chest US findings and the patients’ final diagnosis based on history, clinical examination, laboratory results, and radiological finding.

Results

A total of 100 patients were included, 66 men and 34 women. Thirty patients had uncomplicated pneumonia, 17 patients had pneumonia complicated with effusion, 13 patients had nonpneumonic effusion, 12 patients had pneumothorax, four patients had lung collapse, 19 patients had acute bronchiolitis, three patients had lung abscess, and two cases had mediastinal masses. Chest US was true positive for the diagnosis in 83% of cases compared with 77% by the CXR (the conventional imaging technique).

Conclusion

The chest US is a valid, simple, safe, available, inexpensive method, and comparable to CXR for the diagnosis of acute chest disorders in children.

Recommendation

This study recommends administration of chest US as a diagnostic tool in the management of acute chest disorders in children.
Role of computed tomography and magnetic resonance imaging in the assessment of temporal bone pre-cochlear and postcochlear implantation
Authors: El-Zayat Tarek M , Elfeshawy Mohamed S , Khashaba Ahmed H , El-Raouf Mohamed E
Published: October 2019

Introduction

Multidetector computed tomography (CT) and MRI play a critical role in the evaluation and management of different causes of hearing loss, which require many therapeutic techniques including cochlear implantation. Multidetector CT has proven its efficacy in the postoperative imaging of cochlear implant patients. CT confirms the intracochlear position of the implant. It has also been shown that malpositioning and kinking can be detected by CT imaging.

Aim of the work

To evaluate the role of various imaging modalities (CT and MRI) in the preoperative and postoperative evaluation of cochlear implant candidates. Patients and methods The study included a total of 20 patients referred to the Radiodiagnosis Department from the ENT Department in Al Galaa Military Hospital. CT and MRI were performed for the assessment of the cochlear state before cochlear implantation operation. Postoperative CT was done to underline the position of the implanted electrode.

Setting and design

This study involves prospective, randomized, controlled trials.

Ethics

Informed consent from a parent or guardian.

Results

This study included 20 patients with bilateral severe to profound sensorineural hearing loss. The study was performed on eight (40%) men and 12 (60%) women. Only 17 (85%) patients underwent cochlear implantation, the other three (15%) cases were diagnosed as Michel deformity, Cochlear hypoplasia, and Labyrinthine ossificans. Full electrode array insertion was reported in all cases who underwent cochlear implantation.

Conclusion

Preoperative CT and MRI assessment is critical for determining implant candidacy. Postoperative CT confirms the intracochlear position of the implant.
The value of ascitic fluid calprotectin and calprotectin-to-albumin ratio in the diagnosis and prognosis of spontaneous bacterial peritonitis
Authors: Ali Samia T , Mohamed Nagwa A. E
Published: October 2019

Introduction

Spontaneous bacterial peritonitis (SBP) is a potentially fatal condition, characterized by infection of ascitic fluid (AF) in the absence of any intra-abdominal surgically treatable source of infection. It is the most frequent and severe complication of cirrhotic ascites. SBP is a condition that requires a high index of suspicion, rapid and accurate diagnosis, in addition to prompt and effective therapy.

Aim

The aim of this study was to evaluate AF calprotectin as a diagnostic marker in detecting SBP. In addition, we have evaluated AF calprotectin-to-albumin ratio in the diagnosis and prognosis of SBP.

Patients and methods

A total of 72 patients with cirrhotic ascites were included in this study. They were divided into two groups: SBP group included 50 patients with cirrhotic ascites and SBP diagnosed by presence of polymorphonuclear leukocyte count at least 250 cells/mm3 in AF with or without positive AF culture, and non-SBP group included 22 patients with cirrhotic ascites without evidence of SBP. All patients were subjected to complete clinical evaluation, laboratory investigations, diagnostic abdominal paracentesis, serum and AF C-reactive protein levels, which were assessed quantitatively, and AF calprotectin levels, which were measured by quantitative sandwich enzyme-linked immunosorbent assay.

Results

AF calprotectin was significantly elevated in patients with SBP in comparison with non-SBP patients (P<0.001), with the best cutoff value for the detection of SBP (372 ng/ml) with a sensitivity, specificity, positive predictive value, negative predictive value, and an accuracy of 100% for each. Moreover, there was a positive correlation with total leukocytic count, polymorphonuclear leukocyte, and C-reactive protein in serum and AF. Moreover, calprotectin-to-albumin ratio was increased in SBP group versus non-SBP group (P<0.001).

Conclusion

AF calprotectin can be used as a valuable marker in rapid diagnosis of SBP. Moreover, calprotectin-to-albumin ratio in ascites is useful in the diagnosis of SBP, as well as it provides prognostic information on short-term survival of patients with SBP with follow-up treatment.
Minimally invasive double-level osteotomy of the first metatarsus for treatment of severe hallux valgus
Authors: Abdel-Hameed Said K , Ewais Waleed M , Omar Mohamed A
Published: October 2019

Background

Surgery for the treatment of severe hallux valgus (HV) is commenced to correct the forefoot deformity, provide metatarsalgia relief, and provide a stable biomechanically functional foot. Many surgeons advocate moving from open surgery to minimally invasive techniques, replacing large incisions with smaller ones through which the surgeon can work. Minimally invasive techniques have been successfully used for mild to moderate HV deformities; however, controversy exists for their use in cases with more severe involvement. The aim of this prospective study was to assess the clinical and radiological outcomes of a minimally invasive technique for management of severe HV deformity.

Patients and methods

Between March 2015 and August 2017, a total of 24 feet in 18 active patients, comprising 11 female and seven male patients, with six patients having bilateral involvement, met our selection criteria for symptomatic severe HV deformity and were treated with a minimally invasive double-level metatarsal osteotomy technique. The surgery is done through simple transverse osteotomy, with lateral translation, of the first metatarsus both proximally and distally combined with selective distal soft-tissue dissection. The average age of patients was 37.7 years. Clinically, the American Orthopedic Foot and Ankle Society score and the subjective patient's satisfaction were evaluated. Radiologically, HV angle, distal metatarsal articular angle, and intermetatarsal angle and joint congruity were measured preoperatively, postoperatively, and at the end of the follow-up period. All data were statistically analyzed.

Results

The mean follow-up period was 22.7 months (range, 18–30 months). Union was achieved in all osteotomies in a mean of 6.67±0.45 weeks. Each radiological and clinical parameter showed a statistically significant improvement (P<0.001), with negligible first-ray shortening (P=0.547) and a few complications. At the end of follow-up period, no patient was dissatisfied.

Conclusion

Minimally invasive double-level first metatarsal osteotomy technique with selective distal soft-tissue dissection provides a simple, effective procedure, and reproducible alternative for treatment of severe HV deformity.
Comparative study between magnesium sulfate and ketamine added to lidocaine in ultrasound-guided supraclavicular brachial plexus block in upper limb surgery
Authors: Ashry Enas M , Awad Amira Abo E , El Kemary Fatma A , Ahmed Mona M
Published: October 2019

Introduction

Supraclavicular brachial plexus (SBP) block is an excellent substitute for general anesthesia during upper limb operations. It prevents undesirable effects of using general anesthesia and upper airway instruments. Moreover, it reduces the duration of hospitalization and costs and provides complete muscle relaxation. The ultrasound-guided technique requires a lower anesthetic volume to provide an efficient block and decreases the risk associated with intravascular injections and trauma to the surrounding tissues.

Aim

We conducted this study to compare the effect of ketamine versus magnesium sulfate as additives to lidocaine on onset and duration of sensory and motor block and duration of analgesia time, postoperative visual analog scale (VAS), total analgesic need, stress response (cortisol and blood glucose), and adverse effects in ultrasound-guided supraclavicular brachial plexus (SBP) block for patients who electively underwent upper limb surgeries.

Patients and methods

A total of 90 patients aged 21–65 years, with American Society of Anesthesiologists status I, II, and III, scheduled for elective upper limb surgeries under SBP block, were divided into three equal groups in a randomized controlled fashion: group C (n=30) received 25 ml 2% lidocaine plus 5 cm saline, group K (n=30) received 25 ml 2% lidocaine plus 2 mg/kg ketamine, and group M (n=30) received 25 ml 2% lidocaine plus 250 mg magnesium sulfate (total volume in all groups 30 ml). Hemodynamic variables such as mean arterial blood pressure and heart rate, onset and duration of sensory and motor block, postoperative VAS, time to first analgesic request, total analgesic need, stress response (cortisol and blood glucose), and adverse effects were recorded for each patient.

Results

The sensory block duration was 438.0±80.4 min in group K, 280.2±42.6 min in group M, and 132.0±24.6 min in group C, with a P value less than 0.001, which was statistically significant, whereas the motor block duration was 500±79 min in the group K, 342±50 min in group M, and 200±35 min in group C, with a P value less than 0.001, which was statistically significant, indicating a prolongation in block duration in the ketamine group followed by magnesium group and then control group. The most significant and highest VAS pain scores were found in the control group at all time points (P<0.001), whereas the K group had the lowest VAS. Postoperative analgesic requirement was less in K group when compared with other groups (P<0.001).

Conclusion

Both ketamine and magnesium sulfate prolong the duration of analgesia without any major adverse effects. Ketamine is a better adjuvant to lidocaine for SBP than magnesium sulfate, as it has lower VAS and less postoperative analgesic requirement in upper limb surgeries.
Comparative study between the effect of opioid-free anesthesia versus opioid-based anesthesia in morbid obese patients
Authors: Elsaye Ruqaya M , Gaafary AMaaly M , Elsaeid Asmaa M
Published: October 2019

Introduction

Multimodal techniques for pain management involve using two or more analgesic drugs with different mechanisms of action working in synergy. These drugs may be given by either the same or different routes of administration preoperatively, intraoperatively, and/or postoperatively [1]. By targeting different pain pathways within the central and peripheral nervous systems, the use of multiple agents with different mechanisms of action allows for lower doses of individual agents, which in turn results in a lower risk of adverse effects.

Aim

We have conducted this study to compare the effect of opioid-free anesthesia (OFA) with opioid-based anesthesia (OA) on postoperative pain relief as a primary outcome and hemodynamic variables, including mean arterial blood pressure (MAP), heart rate (HR) and oxygen saturation%, total pethidin consumption 24 h postoperatively, and postoperative complications developed in postanesthetic care unit (PACU), such as hypoxia, shivering, nausea, and vomiting as secondary outcomes in morbid obese patients.

Patients and methods

A total of 40 patients (morbidly obese) aged 25–50 years with BMI of at least 35, having ASA status II scheduled for laparoscopic cholecystectomy were divided into two groups in a randomized controlled fashion: group 1 was the OA group (n=20), which received general anesthesia with propofol, muscle relaxant (rocuronium), and fentanyl as the main anesthetic adjuvant and analgesic, and group 2 was the OFA group (n=20), which received general anesthesia with propofol, muscle relaxant (rocuronium), dexmedetomidine, magnesium sulfate, and lidocaine as anesthetic adjuvant and analgesic. Hemodynamic variables such as MAP, HR, and oxygen saturation% were recorded preoperatively, postintubation, and every 15 min till the end of surgery. Postoperative visual analog scale done immediately postoperatively, and at 2, 6, 12, and 24 h postoperatively; total pethidine consumption in 24 h postoperatively; and postoperative complications developed in PACU such as hypoxia, shivering, nausea, and vomiting were also recorded for each patient.

Results

There were no differences between the two groups regarding demographic data. There was a statistically significant decrease in HR in OFA group compared with OA group from 15 min after induction to 15 min postoperatively and a statistically significant decrease in MAP in group II (OFA) compared with group I (OA) from 30 min after induction to 90 min postoperatively in PACU. Visual analog scale for pain postoperatively was lower in nonopioid group than opioid group. The postoperative pethidine consumption was significantly lower in OFA versus OA. Postoperative complications like nausea, vomiting, shivering, and hypoxia were significantly higher in the OA group.

Conclusion

OFA provides postoperative pain relief and intraoperative hemodynamic stability without significant associated adverse effects compared with OA.
Surgical management of cerebrospinal fluid rhinorrhea factors affecting success
Authors: Ismael Shymaa A , Elhussiny Fatma M , Saif Doaa A , Elsayed Asmaa F
Published: October 2019

Introduction

Cerebrospinal fluid (CSF) rhinorrhea was defined firstly by Willis in 1676 owing to breakdown of the layers of the meninges, the bone of the skull, the periosteum, and the nasal mucosa. Multiple causes can induce CSF rhinorrhea. These causes may be traumatic (accidental or iatrogenic after endoscopic sinus surgery) or spontaneous. The most common symptom is unilateral rhinorrhea which may be increased by stooping or performing valsalva maneuver. Other manifestations like irritability caused by pneumocephalus can also occur.

Aim

The management of cerebrospinal fluid (CSF) rhinorrhea is challenging. Many factors affect its success and can prevent recurrence or failure. This study aims to investigate the outcome of surgical management for CSF rhinorrhea and the factors associated with it.

Patients and methods

A total of 30 patients were admitted for surgery for nasal CSF fistula. Patients with rhinorrhea with more than 2 weeks of conservative treatment, some patients who underwent open surgery, and others who underwent endoscopic surgery were included in our study. The follow-up was continued for 6–18 months after surgery. Many factors were studied to recognize the causes of recurrence and failure such as intracranial hypertension, site of defect, etiology of leak, size of graft, using of fibrin glue, packing of defect, and type of graft.

Results

Among the included patients, 22 (73.3%) had a history of increased intracranial tension (ICT). The defect was in the cribriform plate in 10 (33.3%) patients, ethmoidal in five (16.7%) patients, sphenoidal in five (16.7%) patients, and in the frontal sinus in two (6.7%) patients. The success of surgery was observed in 20 patients, whereas failure occurred in seven patients, and recurrence occurred in three patients. The most important two factors affecting the outcome are the increased ICT (P=0.006) and the size of graft (P=0.003).

Conclusion

For successful surgical management of CSF rhinorrhea, increased ICT must be treated thoroughly preoperatively and postoperatively. Furthermore, the size of graft must be large in relation to the size of defect.
Role of nitric oxide and malondialdehyde biomarkers in relapsing-remitting multiple sclerosis
Authors: Saif Eldeen Eman M. S , El Sharkawy Rasha E , Abd El Azim Ghada S , Mohamed Nagwa A , Abd Elmajed Mona Z
Published: October 2019

Background

Oxidative stress (OS) contributes to several mechanisms underlying the pathogenesis of multiple sclerosis (MS).

Aim

To assess the role of OS biomarkers in pathogenesis of MS and the effect of interferon-β (IFN-β) on OS in MS.

Patients and methods

A total of 40 patients diagnosed as having relapsing-remitting MS with age ranged from 20 to 40 years participated in the study. Of them, 20 patients were on IFN-β for at least 6 months, and 20 patients were not receiving any disease-modifying therapy. Another 20 apparently healthy participants, age matched with the patients, were considered as a control group. Serum levels of malondialdehyde (MDA) and nitric oxide (NO) were evaluated in both patients and control groups.

Results

The serum levels of NO and MDA were significantly higher in patients with relapsing-remitting MS than control group, and in those not taking disease-modifying therapy than patients on IFN-β. Serum levels of both MDA and NO were correlated with degree of disability assessed by expanded disability status scale.

Conclusion

NO and MDA are reliable markers of OS and could be used as markers of disease progression and treatment response in patients with MS. IFN-β has a strong effect on OS and it may exhibit its effect in the management of MS by acting as antioxidant in addition to its anti-inflammatory effect.