bluuebunny/crossref_metadata_2025 huggingface dataset:
The Granular Lubricated Journal Bearing: Evidence of Lift Formation
Authors: Jasti Venkata K. , Marinack Martin C. , Patil Deepak , Fred Higgs C.
Published: January 2019

This work demonstrates that granular flows (i.e., macroscale, noncohesive spheres) entrained into an eccentrically converging gap can indeed actually exhibit lubrication behavior as prior models postulated. The physics of hydrodynamic lubrication is quite well understood and liquid lubricants perform well for conventional applications. Unfortunately, in certain cases such as high-speed and high-temperature environments, liquid lubricants break down making it impossible to establish a stable liquid film. Therefore, it has been previously proposed that granular media in sliding convergent interfaces can generate load carrying capacity, and thus, granular flow lubrication. It is a possible alternative lubrication mechanism that researchers have been exploring for extreme environments, or wheel-regolith traction, or for elucidating the spreadability of additive manufacturing materials. While the load carrying capacity of granular flows has been previously demonstrated, this work attempts to more directly uncover the hydrodynamic-like granular flow behavior in an experimental journal bearing configuration. An enlarged granular lubricated journal bearing (GLJB) setup has been developed and demonstrated. The setup was made transparent in order to visualize and video capture the granular collision activity at high resolution. In addition, a computational image processing program has been developed to process the resulting images and to noninvasively track the “lift” generated by granular flow during the journal bearing operation. The results of the lift caused by granular flow as a function of journal rotation rate are presented as well.
To Study the Role of WC Reinforcement and Deep Cryogenic Treatment on AZ91 MMNC Wear Behavior Using Multilevel Factorial Design
Authors: Karuppusamy P. , Lingadurai K. , Sivananth V.
Published: January 2019

The present investigation explores the collective outcome of hard particle reinforcement with deep cryogenic treatment (DCT) on wear responses of magnesium metal matrix nanocomposites (MMNC). A multilevel factorial design of experiments with control factors of applied load (20 and 40 N), sliding speed (1.3, 1.7, 2.2, and 3.3 m/s), reinforcement % (0% and 1.5%), and cryogenic treatment (cryogenic-treated and nontreated) was deployed. Around 1.5 wt % WC-reinforced MMNC were fabricated using stir-casting process. DCT was performed at −190 °C with soaking time of 24 h. The dry sliding wear trials were done on pin-on-disk tribometer with MMNC pin and EN8 steel disk for a constant sliding distance of 2 km. The WC reinforcement contributed toward the improvement in wear rate of MMNC appreciably by absorbing the load and frictional heat at all loads and speeds. During DCT of AZ91, the secondary ß-phase (Mg17Al12) was precipitated that enriched the wear resistance, only for the higher load of 40 N. Scanning electron microscope analyses of the cryogenic-treated MMNC ensured the existence of both ß-phase precipitates and WC in the contact area. As a result, the adhesiveness of this pin was lesser, which attributed to the improved wear resistance (approximately 33%) as compared to base alloy. The coefficient of friction was also less for cryogenic-treated MMNC. A regression analysis was made to correlate the control elements and the responses.
Development of Thinned Aluminum Flat Heat Pipe Through Inclined Wall and Press Process
Authors: Moon Seok-Hwan , Hong Su-Hyun , Kim Hyun-Tak
Published: January 2019

Heat pipes, commonly used for heat dissipation and thermal management in small electronic and communication devices, are regarded as an excellent solution. Heat pipes must be in surface rather than line contact to be applied to the module and system-level heat dissipation package. As such, a round copper heat pipe is transformed into a plate-like shape through a secondary press process. In this study, an extrusion structure is designed to be sloped to solve the difficulty of making it relatively thin compared with the large area of the plate structure. Specifically, substantial partitions separating the working fluid flow space in the plate-type heat pipe are designed to be inclined at 45 deg, and the extruded envelope is developed to obtain the desired total thickness through the secondary press process. The capillary structure is inserted and positioned within the envelope prior to the secondary press process. In this study, an aluminum flat heat pipe (AFHP) with 0.95 mm total thickness, 150 mm total length, and a capillary structure with braided or carbon wire bundles added thereto was designed and manufactured. Performance test results indicated that the heat transfer performance of the AFHP with inclined wall did not show any deterioration characteristic compared with the AFHP with a normal vertical wall. The isothermal characteristics and heat transfer rate of the AFHP with Cu braid wick were superior to those of AFHP with a simple rectangular groove wick. By contrast, when the carbon wire bundle is added in the Cu braid, the isothermal characteristic was enhanced twice, and the heat transfer rate was 15.5 W by improving approximately 42% under the conditions that inclination angle is −90 deg and the evaporator temperature does not exceed 110 °C.
L-System-Generated Mechanism Topology Optimization Using Graph-Based Interpretation
Authors: Bielefeldt Brent R. , Akleman Ergun , Reich Gregory W. , Beran Philip S. , Hartl Darren J.
Published: January 2019

Traditional topology optimization techniques, such as density-based and level set methods, have proven successful in identifying potential design configurations for structures and mechanisms but suffer from rapidly increasing design space dimensionality and the possibility of converging to local minima. A heuristic alternative to these approaches couples a genetic algorithm with a Lindenmayer system (L-system), which encodes design variables and governs the development of the structure when coupled with an interpreter to translate genomic information into structural topologies. This work discusses the development of a graph-based interpretation scheme referred to as spatial interpretation for the development of reconfigurable structures (SPIDRS). This framework allows for the effective exploration of mechanism design spaces using a limited number of design variables. The theory and implementation of this method are detailed, and multiple case studies are presented to demonstrate the ability of SPIDRS to generate adaptive structures capable of achieving multiple design goals.
Wrench Analysis of Cable-Suspended Parallel Robots Actuated by Quadrotor Unmanned Aerial Vehicles
Authors: Erskine Julian , Chriette Abdelhamid , Caro Stéphane
Published: January 2019

Aerial cable towed systems (ACTSs) can be created by joining unmanned aerial vehicles (UAVs) to a payload to extend the capabilities of the system beyond those of an individual UAV. This paper describes a systematic method for evaluating the available wrench set and the robustness of equilibrium of ACTSs by adapting wrench analysis techniques used in traditional cable-driven parallel robots to account for the constraints of quadrotor actuation and dynamics. Case studies and experimental results are provided to demonstrate the analysis of different classes of ACTSs, as a means of evaluating the design and operating configurations.
Verification and Validation of the FLAG Hydrocode for Impact Cratering Simulations
Authors: Caldwell Wendy K. , Hunter Abigail , Plesko Catherine S. , Wirkus Stephen
Published: January 2019

Verification and validation (V&V) are necessary processes to ensure accuracy of the computational methods used to solve problems key to vast numbers of applications and industries. Simulations are essential for addressing impact cratering problems, because these problems often exceed experimental capabilities. Here, we show that the free Lagrange (FLAG) hydrocode, developed at Los Alamos National Laboratory (Los Alamos, NM), can be used for impact cratering simulations by verifying FLAG against two analytical models of aluminum-on-aluminum impacts at different impact velocities and validating FLAG against a glass-into-water laboratory impact experiment. Our verification results show good agreement with the theoretical maximum pressures, with relative errors as low in magnitude as 1.00%. Our validation results demonstrate FLAG's ability to model various stages of impact cratering, with crater radius relative errors as low as 3.48% and crater depth relative errors as low as 0.79%. Our mesh resolution study shows that FLAG converges at resolutions low enough to reduce the required computation time from about 28 h to about 25 min. We anticipate that FLAG can be used to model larger impact cratering problems with increased accuracy and decreased computational cost on current systems relative to other hydrocodes tested by Pierazzo et al. (2008, “Validation of Numerical Codes for Impact and Explosion Cratering: Impacts on Strengthless and Metal Targets,” MAPS, 43(12), pp. 1917–1938).
Direct observation of shift and ballistic photovoltaic currents
Authors: Burger Aaron M. , Agarwal Radhe , Aprelev Alexey , Schruba Edward , Gutierrez-Perez Alejandro , Fridkin Vladimir M. , Spanier Jonathan E.
Published: January 2019

Shift and ballistic photovoltaic currents, previously indistinguishable experimentally, can now be separated.
Rapid, continuous additive manufacturing by volumetric polymerization inhibition patterning
Authors: de Beer Martin P. , van der Laan Harry L. , Cole Megan A. , Whelan Riley J. , Burns Mark A. , Scott Timothy F.
Published: January 2019

Photopatterning polymerization inhibition volumes by two-color irradiation enables exceptional 3D printing speed and functionality.
Tumor-infiltrating human CD4
+
regulatory T cells display a distinct TCR repertoire and exhibit tumor and neoantigen reactivity
Authors: Ahmadzadeh Mojgan , Pasetto Anna , Jia Li , Deniger Drew C. , Stevanović Sanja , Robbins Paul F. , Rosenberg Steven A.
Published: January 2019

Intratumoral T
reg
cells are tumor/neoantigen reactive.
Immune responses at the maternal-fetal interface
Authors: Ander Stephanie E. , Diamond Michael S. , Coyne Carolyn B.
Published: January 2019

The placenta promotes tolerance of the semiallogeneic fetus while protecting against vertical transmission of infections.
Multicentre study of physical abuse and limb fractures in young children in the East Anglia Region, UK
Authors: Mitchell Piers D , Brown Richard , Wang Tengyao , Shah Rajen D , Samworth Richard J , Deakin Sue , Edge Phillip , Hudson Ivan , Hutchinson Rachel , Stohr Kuldeep , Latimer Mark , Natarajan Rajan , Qasim Sultan , Rehm Andreas , Sanghrajka Anish , Tissingh Elizabeth , Wright Georgina M
Published: January 2019

Objective

To determine if the detection of physical abuse in young children with fractures is of uniform high standard in the East Anglia Region of the UK, and whether we can identify areas for improvement in our detection of high-risk groups.

Design

Multicentre retrospective 4-year study.

Setting

7 hospitals across the East Anglia Region of Britain (East Anglia Paediatric Physical Abuse and Fractures study).

Participants

Age groups and fractures indicated as being at higher risk for physical abuse (all children under 12 months of age, and fractures of humerus and femur in children under 36 months of age).

Outcome measures

Our criterion for physical abuse was the decision of a multiagency child protection case conference (CPCC).

Results

Probability of CPCC decision of physical abuse was highest in infants, ranging from 50% of fractures sustained in the first month of life (excluding obstetric injuries) to 10% at 12 months of age. Only 46%–86% of infants (under 12 months) with a fracture were assessed by a paediatrician for physical abuse after their fracture. Significant variation in the use of skeletal surveys and in CPCC decision of physical abuse was noted in children attending different hospitals.

Conclusions

It is a concern that significant variation between hospitals was found in the investigation and detection of physical abuse as confirmed by CPCC decisions. To minimise failure to detect true cases of physical abuse, we recommend that all high-risk children should be assessed by a paediatrician prior to discharge from the emergency department. Our proposed criteria for assessment (where we found probability of CPCC decision of physical abuse was at least 10%) are any child under the age of 12 months with any fracture, under 18 months of age with femur fracture and under 24 months with humeral shaft fracture (not supracondylar).
Inner macular layer thickness by spectral domain optical coherence tomography in children and adults: a hospital-based study
Authors: Yoo Yung Ju , Hwang Jeong-Min , Yang Hee Kyung
Published: January 2019

Purpose

To establish the normative ranges of macular ganglion cell layer (mGCL) and macular inner plexiform layer (mIPL) thickness using Spectralis spectral domain optical coherence tomography (SD-OCT) (Heidelberg Engineering, Inc., Heidelberg, Germany) in both Korean children and adults, and to determine factors associated with mGCL and mIPL thickness.

Methods

We conducted a retrospective, observational study of 573 healthy subjects (5–70 years old) who underwent comprehensive ophthalmic examinations in a single institution. Each inner retinal layer thickness was measured using SD-OCT and automatic segmentation software. Cross-sectional analysis was used to evaluate the effect of gender, age and ocular parameters on mGCL and mIPL thickness. Normative ranges of mGCL and mIPL thickness according to age, gender and factors associated with mGCL and mIPL thickness were measured.

Results

The mean mGCL and mIPL thickness were 40.6±2.8 and 33.8±2.0 µm, respectively. Determinants of inner sector mGCL thickness were circumpapillary retinal nerve fibre layer (cpRNFL) thickness (β=1.172, p<0.001), age (β=−0.019, p=0.021) and male gender (β=1.452, p<0.001). Determinants of inner sector mIPL thickness were cpRNFL (β=0.952, p<0.001) and male gender (β=1.163, p<0.001). The inner sector mGCL and mIPL thickness increased significantly with age in children (β=0.174, p=0.009 and β=0.115, p=0.013), and then decreased in adults (β=−0.070, p<0.001 and β=−0.024, p=0.032). In the case of outer sectors, mGCL and mIPL thickness were not significantly related to age and gender.

Conclusions

This study ensured a normative range of the mGCL and mIPL thickness using Spectralis OCT. Gender, age and cpRNFL thickness significantly correlated with mGCL and mIPL thickness. This information should be considered in the interpretation of SD-OCT data.
Utility of CLOCK CHART binocular edition for self-checking the binocular visual field in patients with glaucoma
Authors: Ishibashi Marika , Matsumoto Chota , Hashimoto Shigeki , Eura Mariko , Okuyama Sachiko , Nomoto Hiroki , Tanabe Fumi , Kayazawa Tomoyasu , Numata Takuya , Kusaka Shunji
Published: January 2019

Background/aims

Car accidents caused by drivers unaware of their visual field (VF) defects under binocular vision have become an issue. We developed a simple self-check chart (CLOCK CHART binocular edition (CCBE)) to help patients with glaucoma recognise their abnormalities in the binocular VF and evaluated its usefulness.

Methods

The chart has four targets displayed at 10°, 15°, 20° and 25° eccentricities. The examinee gradually rotates the chart 360° clockwise. At every 30°, the examinee confirms the fixation and indicates if all four targets can be seen. This study enrolled 88 eyes of 44 patients with glaucoma (mean age, 64.4±13.1 years) and 64 eyes of 32 visually normal individuals (mean age, 32.0±8.4 years). Except the CCBE test, static VF testing using the Humphrey field analyser (HFA) Swedish Interactive Threshold Algorithm-Standard 30-2 and binocular Esterman programmes was also performed for the subjects with glaucoma.

Results

VF abnormality was defined as two or more contiguous points with a sensitivity of <10 dB within the central 30°. The CCBE test had sensitivities of 85% and 82% with respect to the HFA and Esterman results, respectively. We also used the British VF standards for Group 1 (car/motorcycle) drivers, and a sensitivity of 88% was obtained for the CCBE. The chart had a specificity of 100% for the visually normal subjects.

Conclusion

The CCBE test enables drivers with glaucoma to notice their VF abnormalities under binocular condition. The application of this simple self-check method appears promising for occasions such as driver licensing.
Imaging in myopia: potential biomarkers, current challenges and future developments
Authors: Ang Marcus , Wong Chee Wai , Hoang Quan V , Cheung Gemmy Chui Ming , Lee Shu Yen , Chia Audrey , Saw Seang Mei , Ohno-Matsui Kyoko , Schmetterer Leopold
Published: January 2019

Myopia is rapidly increasing in Asia and around the world, while it is recognised that complications from high myopia may cause significant visual impairment. Thus, imaging the myopic eye is important for the diagnosis of sight-threatening complications, monitoring of disease progression and evaluation of treatments. For example, recent advances in high-resolution imaging using optical coherence tomography may delineate early myopic macula pathology, optical coherence tomography angiography may aid early choroidal neovascularisation detection, while multimodal imaging is important for monitoring treatment response. However, imaging the eye with high myopia accurately has its challenges and limitations, which are important for clinicians to understand in order to choose the best imaging modality and interpret the images accurately. In this review, we present the current imaging modalities available from the anterior to posterior segment of the myopic eye, including the optic nerve. We summarise the clinical indications, image interpretation and future developments that may overcome current technological limitations. We also discuss potential biomarkers for myopic progression or development of complications, including basement membrane defects, and choroidal atrophy or choroidal thickness measurements. Finally, we present future developments in the field of myopia imaging, such as photoacoustic imaging and corneal or scleral biomechanics, which may lead to innovative treatment modalities for myopia.
Dual-target, real-time PCR for the diagnosis of intraocularToxoplasma gondiiinfections
Authors: Gomez Carlos A , Sahoo Malaya K , Kahn Ghazala Yasmeen , Zhong Lina , Montoya José G , Pinsky Benjamin A , Doan Thuy
Published: January 2019

Background

Toxoplasma gondiiis the most common infectious cause of posterior uveitis worldwide. Two multicopy targets (B1 and Rep529) are commonly used inT. gondiiPCR assays, but studies evaluating these targets in ocular fluid samples are limited. Herein, we determine the analytical characteristics of a single-reaction, internally controlled, dual-target, real-timeT. gondiiPCR and evaluate the clinical performance of this assay in intraocular fluid samples obtained at a reference ophthalmologic centre in the USA.

Methods

Lower limits of detection for the B1 and Rep529 components of the dual-target assay were determined using serial dilutions of culturedT. gondiistrain Z185. The dual-target assay was then used to test 148 archived intraocular samples (132 vitreous,16 aqueous humour) collected at the Francis I. Proctor Foundation between January 2010 and December 2015 for testing by a nested, conventional PCR targeting the B1 gene.

Results

The 95% lower limits of detection for the dual-target assay was determined to be 1.05 tachyzoites/mL for B1 and 0.83 tachyzoites/mL for Rep529. Using archived clinical intraocular specimens, the dual-target assay demonstrated 97.2% positive per cent agreement (n=35/36; 95% CI 83.7% to 99.9%) and 99.1% negative per cent agreement (n=111/112; 95% CI 94.4% to 100%) compared with the nested, conventional B1 PCR.

Conclusion

This single-reaction, internally controlled, dual-target (B1, Rep529) real-time PCR for the detection ofT. gondiiDNA in intraocular specimens demonstrated excellent agreement with nested, conventional, B1 PCR. The dual-target design may ensureT. gondiidetection when variation is present in one of two target regions.
Characterising ICU–ward handoffs at three academic medical centres: process and perceptions
Authors: Santhosh Lekshmi , Lyons Patrick G , Rojas Juan C , Ciesielski Thomas M , Beach Shire , Farnan Jeanne M , Arora Vineet
Published: January 2019

Background

There is limited literature about physician handoffs between the intensive care unit (ICU) and the ward, and best practices have not been described. These patients are uniquely vulnerable given their medical complexity, diagnostic uncertainty and reduced monitoring intensity. We aimed to characterise the structure, perceptions and processes of ICU–ward handoffs across three teaching hospitals using multimodal methods: by identifying the handoff components involved in communication failures and describing common processes of patient transfer.

Methods

We conducted a study at three academic medical centres using two methods to characterise the structure, perceptions and processes of ICU–ward transfers: (1) an anonymous resident survey characterising handoff communication during ICU–ward transfer, and (2) comparison of process maps to identify similarities and differences between ICU–ward transfer processes across the three hospitals.

Results

Of the 295 internal medicine residents approached, 175 (59%) completed the survey. 87% of the respondents recalled at least one adverse event related to communication failure during ICU–ward transfer. 95% agreed that a well-structured handoff template would improve ICU–ward transfer. Rehabilitation needs, intravenous access/hardware and risk assessments for readmission to the ICU were the most frequently omitted or incorrectly communicated components of handoff notes. More than 60% of the respondents reported that notes omitted or miscommunicated pending results, active subspecialty consultants, nutrition and intravenous fluids, antibiotics, and healthcare decision-maker information at least twice per month. Despite variable process across the three sites, all process maps demonstrated flaws and potential for harm in critical steps of the ICU–ward transition.

Conclusion

In this multisite study, despite significant process variation across sites, almost all resident physicians recalled an adverse event related to the ICU–ward handoff. Future work is needed to determine best practices for ICU–ward handoffs at academic medical centres.
Variation in the delivery of telephone advice by emergency medical services: a qualitative study in three services
Authors: O'Hara Rachel , Bishop-Edwards Lindsey , Knowles Emma , O'Cathain Alicia
Published: January 2019

Background

An emergency ambulance is not always the appropriate response for emergency medical service patients. Telephone advice aims to resolve low acuity calls over the phone, without sending an ambulance. In England, variation in rates of telephone advice and patient recontact between services raises concerns about inequities in care. To understand this variation, this study aimed to explore operational factors influencing the provision of telephone advice.

Methods

This is a multimethod qualitative study in three emergency medical services in England with different rates of telephone advice and recontact. Non-participant observation (120 hours) involved 20 call handlers and 27 clinicians (eg, paramedics). Interviews were conducted with call handlers, clinicians and clinician managers (n=20).

Results

Services varied in their views of the role of telephone advice, selection of their workforce, tasks clinicians were expected and permitted to do, and access to non-ambulance responses. Telephone advice was viewed either as an acceptable approach to managing demand or a way of managing risk. The workforce could be selected for their expertise or their inability to work ‘on-the-road’. Some services permitted proactive identification of calls for a lower priority response and provided access to a wider range of response options. The findings aligned with telephone advice rates for each service, particularly explaining why one service had lower rates.

Conclusion

Some of the variation observed can be explained by operational differences between services and some of it by access to alternative response options in the wider urgent and emergency care system. The findings indicate scope for greater consistency in the delivery of telephone advice to ensure the widest range of options to meet the needs of different populations, regardless of geographical location.
Subcutaneous dexmedetomidine for baclofen withdrawal during palliative sedation
Authors: Laroche Jean-Philippe
Published: January 2019

Sudden cessation of baclofen can produce a withdrawal syndrome even if it was previously orally administered. We present the case of a man who exhibited signs of baclofen withdrawal syndrome during palliative sedation. Attempts were made to induce muscle relaxation with ever-increasing doses of benzodiazepine. Ultimately, control over the withdrawal syndrome was regained by using a continuous subcutaneous infusion (CSCI) of dexmedetomidine, a highly selective α2adrenergic agonist. Very limited published reports concerning CSCI of dexmedetomidine exist. To our knowledge, this is the first case to report its use as an adjunctive agent to treat baclofen withdrawal syndrome through the subcutaneous route in the palliative care setting.
Getting better all the time? Facilitating accurate team self-assessments through simulation
Authors: Gardner Aimee K , Abdelfattah Kareem
Published: January 2019

Introduction

Our study explores the extent to which teams are accurate assessors of their own performance and teamwork, and how simulation can help this critical skill develop over time.

Methods

Surgery residents in teams of three completed five daily simulations. After each scenario, each team reviewed their performance and jointly completed a scenario-specific team performance evaluation and a 17-item Communication and Teamwork Skills tool. Videos were rated to obtain discrepancy values. Paired-samples t-tests and mean comparisons were used to examine changes in team self-assessment accuracy and comparisons between high-performing and low-performing teams.

Results

Resident (n=30) teams rated team performance higher than faculty across the first 3 days (p<0.01), but provided similar ratings thereafter. Agreement of team performance from day 1 to 5 significantly improved (p<0.001). Teams rated their teamwork higher than faculty across all days (p<0.01). Top performing teams provided more accurate self-assessments for both teamwork (average discrepancy 8% vs 39%) and team performance (average discrepancy 12% vs 23%).

Conclusion

Teams that continue to work together over time may become more accurate judges of their own performance, but do not become more accurate assessors of teamwork competencies.
First UK experience of endoscopic vacuum therapy for the management of oesophageal perforations and postoperative leaks
Authors: Alakkari Alaa , Sood Ruchit , Everett Simon M , Rembacken Bjorn J , Hayden Jeremy , Sarela Abeezar , Mohammed Noor
Published: January 2019

Oesophageal perforations and anastomotic leaks are associated with high morbidity and mortality. Endoscopic vacuum therapy (EVT) is a promising novel treatment that promotes healing and avoids sepsis. There are no data reporting its use in the UK. We report the first British experience of EVT in two elderly frail patients. Two patients were treated in our institution with EVT using Eso-SPONGE®. One patient had spontaneous oesophageal perforation and the other had anastomotic leakage post-Merendino oesophageal reconstruction (oesophagogastric continuity with jejunal interposition anastomosis). Both patients were over 65 years of age. One patient had 13 endoscopic Eso-SPONGE® exchanges over 8 weeks, while the other one had 6 exchanges over 4 weeks. Complete resolution of oesophageal leakage was achieved in both cases. EVT should be considered in the management of patients with oesophageal perforations and postoperative leaks. This novel therapeutic intervention has the potential to significantly reduce morbidity and mortality in these patients.
Individual preferences on the balancing of good and harm of cardiovascular disease screening
Authors: Hansen Tina Birgitte , Lindholt Jes Sanddal , Diederichsen Axel Cosmus Pyndt , Bliemer Michiel C J , Lambrechtsen Jess , Steffensen Flemming Hald , Søgaard Rikke
Published: January 2019

Objective

Transition towards value-based healthcare requires insight into what makes value to the individual. The aim was to elicit individual preferences for cardiovascular disease screening with respect to the difficult balancing of good and harm as well as mode of delivery.

Methods

A discrete choice experiment was conducted as a cross-sectional survey among 1231 male screening participants at three Danish hospitals between June and December 2017. Participants chose between hypothetical screening programmes characterised by varying levels of mortality risk reduction, avoidance of overtreatment, avoidance of regretting participation, screening duration and location. A multinomial mixed logit model was used to model the preferences and the willingness to trade mortality risk reduction for improvements on other characteristics.

Results

Respondents expressed preferences for improvements on all programme characteristics. They were willing to give up 0.09 (95% CI 0.08 to 0.09) lives saved per 1000 screened to avoid one individual being over treated. Similarly, respondents were willing to give up 1.22 (95% CI 0.90 to 1.55) or 5.21 (95% CI 4.78 to 5.67) lives saved per 1000 screened to upgrade the location from general practice to a hospital or to a high-tech hospital, respectively. Subgroup analysis revealed important preference heterogeneity with respect to smoking status, level of health literacy and self-perceived risk of cardiovascular disease.

Conclusions

Individuals are able to express clear preferences about what makes value to them. Not only health benefit but also time with health professionals and access to specialised facilities were important. This information could guide the optimal programme design in search of value-based healthcare.
Qualitative study of cardiologists’ perceptions of factors influencing clinical practice decisions
Authors: Manja Veena , Guyatt Gordon , You John , Monteiro Sandra , Jack Susan
Published: January 2019

Background

Healthcare costs are increasing in the USA and Canada and a substantial portion of health spending is devoted to services that do not improve health outcomes. Efforts to reduce waste by adopting evidence-based clinical practice guideline recommendations have had limited success. We sought insight into improving health system efficiency through understanding cardiologists’ perceptions of factors that influence clinical decision-making.

Methods

In this descriptive qualitative study, we conducted in-depth interviews with 18 American and 3 Canadian cardiologists. We used conventional content analysis including inductive and deductive approaches for data analysis and mapped findings to the ecological systems framework.

Results

Physicians reported that major determinants of practice included interpersonal interactions with peers, patients and administrators; financial incentives and system factors. Patients’ insurance status represented an important consideration for some cardiologists. Other major influences included time constraints, fear of litigation (less prominent in Canada), a sense that their obligation was never to miss any underlying pathology, and patient demands. The need to bring income into their health system influenced American cardiologists’ practice; personal income implications influenced Canadian cardiologists’ practice. Cardiologists reported that knowledge limitations and logistical challenges limit their ability to assist patients with cost considerations. All these considerations were more influential than guidelines; some cardiologists expressed a high level of scepticism regarding guidelines.

Conclusions

Clinical decision-making by cardiologists is shaped by individual, interpersonal, organisational, environmental, financial and sociopolitical influences and only to a limited extent by guideline recommendations. Successful strategies to achieve efficient, evidence-based care will require addressing socioecological influences on decision-making.
Role of CT-guided transthoracic biopsy in the diagnosis of mycobacterial infection
Authors: Beck Kyongmin Sarah , Han Dae Hee , Lee Kyo Young , Kim Seung Joon
Published: January 2019

Mycobacterial infection(MI) is sometimes diagnosed using CT-guided transthoracic needle biopsy (TNB). However, the exact role of CT-guided TNB in this diagnostic process is not clearly known. The purpose of this study is to analyze the role of CT-guided TNB in patients with MI who present with a focal lung lesion. Of 1233 patients who underwent CT-guided TNB from January 2010 through February 2016 at our institution, patients with a final diagnosis of MI were included for analysis. Clinical characteristics and biopsy-related factors were compared between patients whose diagnosis could be established using TNB samples alone (group 1) and those whose samples from additional tests were necessary for diagnosis (group 2). We also analyzed the possible benefit of CT-guided TNB as compared with bronchoscopy in a subgroup who underwent both procedures. 47 patients with MI were included in the study, with 37 patients (78.7%) in group 1 and 10 patients (21.2%) in group 2. There was no statistically significant difference in clinical characteristics or biopsy-related factors between the two groups. Of 41 patients with MI who underwent both bronchoscopy and TNB, success in diagnosis was solely attributable to TNB in 16 (39.0%) patients; in 19 (46.0%) patients, diagnosis could be made based on bronchoscopy results alone. MI can be successfully diagnosed by CT-guided TNB in about 80% of patients with MI who underwent TNB, but 46% of the patients could have been diagnosed with bronchoscopy results alone. CT-guided TNB is inferior to bronchoscopy in the differentiation of Mycobacterium species even in peripheral lung lesions.
Application of Pilates-based exercises in the treatment of chronic non-specific low back pain: state of the art
Authors: Eliks Małgorzata , Zgorzalewicz-Stachowiak Małgorzata , Zeńczak-Praga Krystyna
Published: January 2019

According to the current recommendations on the management of chronic non-specific low back pain (CNLBP), the intervention in this group of patients should include a programme of exercises. Pilates is a system of exercises widely used in patients with low back pain. The practices based on this method have promoted the restoration of the function of muscles involved in lumbopelvic stabilisation, that is, transversus abdominis, multifidus, diaphragm and pelvic floor muscles. During each exercise, specific principles of this method should be followed to restore or sustain the motor control of the lumbar spine and proper body posture. The aim of this study is to present the current state of knowledge concerning the application of Pilates method in the management of CNLBP as well as to define factors (eg, duration, frequency, exercises performed on a mat or specific equipment) influencing the effectiveness of Pilates in these individuals.
Perioperative impact of sleep apnea in a high-volume specialty practice with a strong focus on regional anesthesia: a database analysis
Authors: Pichler Lukas , Weinstein Sarah M , Cozowicz Crispiana , Poeran Jashvant , Liu Jiabin , Poultsides Lazaros A , Saleh Jawad N , Memtsoudis Stavros G
Published: January 2019

Background and objectives

Obstructive sleep apnea (OSA) is a risk factor for adverse postoperative outcome and perioperative professional societies recommend the use of regional anesthesia to minimize perioperative detriment. We studied the impact of OSA on postoperative complications in a high-volume orthopedic surgery practice, with a strong focus on regional anesthesia.

Methods

After Institutional Review Board approval, 41 766 cases of primary total hip and knee arthroplasties (THAs/TKAs) from 2005 to 2014 were extracted from institutional data of the Hospital for Special Surgery (approximately 5000 THAs and 5000 TKAs annually, of which around 90% under neuraxial anesthesia).

The main effect was OSA (identified by the International Classification of Diseases, ninth revision codes); outcomes of interest were cardiac, pulmonary, gastrointestinal, renal/genitourinary, thromboembolic complications, delirium, and prolonged length of stay (LOS). Multivariable logistic regression models provided ORs, corresponding 95% CIs, and p values.

Results

Overall, OSA was seen in 6.3% (n=1332) of patients with THA and 9.1% (n=1896) of patients with TKA. After adjustment for relevant covariates, OSA was significantly associated with 87% (OR 1.87, 95% CI 1.51 to 2.30), 52% (OR 1.52, 95% CI 1.13 to 2.04), and 44% (OR 1.44,95% CI 1.31 to 1.57) increased odds for pulmonary gastrointestinal complications, and prolonged LOS, respectively. The odds for other outcomes remained unaltered by OSA diagnosis.

Conclusion

We showed that, even in a setting with almost universal regional anesthesia use, OSA was associated with increased odds for prolonged LOS, and pulmonary and gastrointestinal complications. This puts forward the question of how effective regional anesthesia is in mitigating postoperative complications in patients with OSA.
Serum ropivacaine levels after local infiltration analgesia during total knee arthroplasty with and without adductor canal block
Authors: Koniuch Katherine L , Buys Michael Jay , Campbell Blake , Gililland Jeremy M , Pelt Christopher E , Pace Nathan L , Johnson Ken B
Published: January 2019

Background and objectives

A common analgesic technique for total knee arthroplasty (TKA) is to inject local anesthetic into the periarticular tissue during surgery, known as local infiltration analgesia (LIA). Since the solution used typically contains a large amount of local anesthetic, concerns arise about exceeding the maximum dosage when adding a peripheral nerve block. Little research exists that addresses serum ropivacaine concentrations following LIA combined with peripheral nerve block. We hypothesized that after combining LIA and adductor canal blockade (ACB), serum ropivacaine concentrations would remain below levels associated with local anesthetic toxicity.

Methods

This was a prospective observational study that included 14 subjects undergoing TKA with intraoperative LIA containing 270 mg ropivacaine with epinephrine. Patients weighing less than 80 kg were excluded due to standardized dosing by our pharmacy. Seven patients were assigned consecutively to receive LIA alone (Group LIA) and seven were assigned to receive LIA plus ACB with 100 mg ropivacaine with epinephrine (Group LIA+ACB). Venous serum ropivacaine concentrations were measured over 24 hours.

Results

Peak serum concentrations (Cmax) in Group LIA ranged from 0.23 to 0.75 µg/mL and occurred at times from 4 to 24 hours. Cmax in Group LIA+ACB ranged from 0.46 to 1.00 µg/mL and occurred at times from 4 to 8 hours. No participants demonstrated signs or symptoms of local anesthetic toxicity.

Conclusions

Total serum concentration of ropivacaine after LIA using 270 mg ropivacaine with and without an additional 100 mg perineural ropivacaine remained well below the toxicity threshold of 3.0 µg/mL at all time points. Additional studies are needed to ascertain the safety of combining LIA with peripheral nerve blockade.
Randomized comparison between interscalene and costoclavicular blocks for arthroscopic shoulder surgery
Authors: Aliste Julián , Bravo Daniela , Layera Sebastián , Fernández Diego , Jara Álvaro , Maccioni Cristóbal , Infante Carlos , Finlayson Roderick J , Tran De Q
Published: January 2019

Background

This randomized trial compared ultrasound-guided interscalene block (ISB) and costoclavicular brachial plexus block (CCB) for arthroscopic shoulder surgery. We hypothesized that CCB would provide equivalent analgesia to ISB 30 min after surgery without the risk of hemidiaphragmatic paralysis.

Methods

All 44 patients received an ultrasound-guided block of the intermediate cervical plexus. Subsequently, they were randomized to ISB or CCB. The local anesthetic agent (20 mL of levobupivacaine 0.5% and epinephrine 5 µg/mL) and pharmacological block adjunct (4 mg of intravenous dexamethasone) were identical for all study participants. After the block performance, a blinded investigator assessed ISBs and CCBs every 5 min until 30 min using a composite scale that encompassed the sensory function of the supraclavicular nerves, the sensorimotor function of the axillary nerve and the motor function of the suprascapular nerve. A complete block was defined as one displaying a minimal score of six points (out of a maximum of eight points) at 30 min. Onset time was defined as the time required to reach the six-point minimal composite score. The blinded investigator also assessed the presence of hemidiaphragmatic paralysis at 30 min with ultrasonography.

Subsequently, all patients underwent general anesthesia. Postoperatively, a blinded investigator recorded pain scores at rest at 0.5, 1, 2, 3, 6, 12, and 24 hours. Patient satisfaction at 24 hours, consumption of intraoperative and postoperative narcotics, and opioid-related side effects (eg, nausea/vomiting, pruritus) were also tabulated.

Results

Both groups displayed equivalent postoperative pain scores at 0.5, 1, 2, 3, 6, 12, and 24 hours. ISB resulted in a higher incidence of hemidiaphragmatic paralysis (100% vs 0%; P < 0.001) as well as a shorter onset time (14.0 (5.0) vs 21.6 (6.4) minutes; p<0.001). However, no intergroup differences were found in terms of proportion of patients with minimal composite scores of 6 points at 30 min, intraoperative/postoperative opioid consumption, side effects, and patient satisfaction at 24 hours.

Conclusion

Compared to ISB, CCB results in equivalent postoperative analgesia while circumventing the risk of hemidiaphragmatic paralysis. Further confirmatory trials are required. Future studies should also investigate if CCB can provide surgical anesthesia for arthroscopic shoulder surgery.

Clinical Trials Registration

NCT03411343.
Bilateral distribution of anterior cutaneous nerve entrapment syndrome (ACNES): are clinical features and outcomes comparable to unilateral ACNES?
Authors: Maatman Robbert C , Werner Mads U , Scheltinga Marc R M , Roumen Rudi M H
Published: January 2019

Background and objectives

Mirror-image pain may occur in the presence of a one-sided peripheral nerve lesion leading to a similar distribution of pain on the contralateral side of the body (“mirrored”). Anterior cutaneous nerve entrapment syndrome (ACNES) is a neuropathic pain syndrome due to entrapment of terminal branches of intercostal nerves T7–12 in the abdominal wall and sometimes presents bilaterally. This study aims to address specifics of bilateral ACNES and to determine potential differences in clinical presentation and treatment outcomes when compared with the unilateral form of ACNES.

Methods

Electronic patient files and questionnaires of a case series of patients who were evaluated for chronic abdominal wall pain in a single center were analyzed using standard statistical methods.

Results

Between June 1, 2011 and September 1, 2016, 1116 patients were diagnosed with ACNES, of which a total of 146 (13%) with bilateral ACNES were identified (female, n = 114, 78 %; median (range) age 36 (1181) years). Average NRS (Numeric Rating Scale; 0–10) scores were similar (median (range) NRS scores 6 (0–10) although peak NRS scores were significantly higher in the bilateral group (9 (5–10) vs 8 (2–10); p=0.02). After a median of 26 months (1–68), the proportion of patients with bilateral ACNES reporting treatment success was 61%.

Conclusions

One in eight patients with ACNES has bilateral abdominal wall pain. Characteristics are similar to unilateral ACNES cases. Further studies aimed at underlying mechanisms in mirror image pain pathogenesis could provide a more targeted approach in the management of this neuropathic pain.
RNA expression preoperatively and postoperatively following total knee replacement: a pilot study in patients with and without chronic postsurgical pain
Authors: Buvanendran Asokumar , Wang Dan , Kim Hyungsuk , Kroin Jeffrey S , McCarthy Robert J
Published: January 2019

Background and objective

Differences in gene expression may provide insight into the biological pathways involved in chronic postsurgical pain (CPSP). We compared blood RNA microarrays preoperatively and postoperatively following total knee arthroplasty (TKA) in patients with and without CPSP.

Methods

Patients scheduled for primary TKA had whole blood samples obtained preoperatively and at 48 hours and 6 months postsurgery. RNA expression (54 613 transcripts) were assayed using the “Affymetrix HG-U133 plus 2.0” microarray. Genes that met the threshold criteria of ±1.5-fold differential change in expression (CPSP vs non-CPSP), with p<0.0125, were considered for pathway analysis. WikiPathways was used to identify biological pathways that were affected (p<0.01) by differentially regulated genes.

Results

Four of 16 (25%) patients had CPSP at 6 months. Preoperatively, 325 (0.6%) genes met the criteria, with 292 (89.9%) having greater expression in the CPSP group. Twelve biological pathways were affected, with the mitogen-activated kinase, phosphatidylinositide 3-kinase–protein kinase B–mammalian target of rapamycin, and brain-derived neurotrophic factor signaling pathways having known association with pain. At 48 hours, 26 genes met the criteria; 7 pathways were affected, including transforming growth factor-β with known association with pain. At 6 months 55 genes met the criteria, with 49 increased in the CPSP group. Four biological pathways were affected, with only the chemokine signaling pathway having known association with pain.

Conclusions

Despite a lack of clinical differences, patients who develop CPSP have upregulated pain pathways preoperatively; however, only the chemokine pathway remained differentially upregulated at 6 months postsurgery.