bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical study of vortex-induced autorotation of an elliptic blade in lid-driven cavity flow
Authors: Hosseinjani Ali Akbar , Akbari Ghasem
Published: December 2022

Large-scale eddies in a lid-driven cavity are potential sources of angular momentum which can induce rotational effect in a free-to-rotate inertial body due to fluid–structure interaction. The novel objective of the present study is to investigate vortex-induced autorotation of an elliptic blade hinged at the centre of a lid-driven cavity. The governing equations are numerically solved using iterative direct forcing immersed boundary method. The impact of Reynolds number and blade length on dynamics characteristics of the blade are analysed. Considering left to right motion of horizontal top lid, four different vortex-induced modes are identified as the steady blade response, including stationary position, small-amplitude fluttering, clockwise autorotation and counter-clockwise autorotation. Long blades are mostly potential for steady clockwise autorotation, particularly in higher Reynolds numbers, due to dominance of principal near-wall cavity vortex compared to other vortices. In contrast, effective role of central counter-clockwise vortex in a short blade and weak interaction of such blade with the near-wall cavity vortex leads to a steady counter-clockwise rotation, particularly in high Reynolds numbers. In the case of low Reynolds numbers or blade with moderate length, vortex-induced blade motions in clockwise and counter-clockwise directions are fairly balanced, leading to stationary position or small-amplitude fluttering modes.
Broadband optical transmission through two-dimensional hole arrays
Authors: Cui Xiao-bin , Huang Cheng-ping
Published: December 2022

We suggest that a metal film perforated with two-dimensional (2D) hole arrays can support broadband optical transmission. This phenomenon is based on the impedance matching between the perforated metal film and incoming light waves at oblique incidence. Theoretical formulas for the effective impedance of the hole arrays and Brewster angle of broadband transmission have been derived in the infrared regime, taking account of the field penetration effect on the hole walls. With the numerical simulations, the predicted optical effect has also been demonstrated. Compared with the narrow transmission band due to surface-plasmon polariton resonance, our results present a non-resonant, broadband, and robust transmission channel for the 2D hole arrays.
Electrical tuning of moiré excitons in MoSe2 bilayers
Authors: Hagel Joakim , Brem Samuel , Malic Ermin
Published: December 2022

Recent advances in the field of vertically stacked 2D materials have revealed a rich exciton landscape. In particular, it has been demonstrated that out-of-plane electrical fields can be used to tune the spectral position of spatially separated interlayer excitons. Other studies have shown that there is a strong hybridization of exciton states, resulting from the mixing of electronic states in both layers. However, the connection between the twist-angle dependent hybridization and field-induced energy shifts has remained in the dark. Here, we investigate on a microscopic footing the interplay of electrical and twist-angle tuning of moiré excitons in MoSe2 homobilayers. We reveal distinct energy regions in PL spectra that are clearly dominated by either intralayer or interlayer excitons, or even dark excitons. Consequently, we predict twist-angle-dependent critical electrical fields at which the material is being transformed from a direct into an indirect semiconductor. Our work provides new microscopic insights into experimentally accessible knobs to significantly tune the moiré exciton physics in atomically thin nanomaterials.
Plasma etching and surface characteristics depending on the crystallinity of the BaTiO3 thin film
Authors: Lee Han Byeol , Joo Young-Hee , Patil Harshada , Kim Gwan-Ha , Kang Insu , Hou Bo , Kim Deok-kee , Um Doo-Seung , Kim Chang-Il
Published: December 2022

Due to its high dielectric constant (κ), the BaTiO3 (BTO) thin film has significant potential as a next-generation dielectric material for metal oxide semiconductor field-effect transistors (MOSFETs). Hence, the evaluation of the BTO thin film etching process is required for such nanoscale device applications. Herein, the etching characteristics and surface properties are examined according to the crystallinity of the BTO thin film. The results demonstrate that the etching rate is low in the high-crystallinity thin film, and the surface residues are much lower than in the low-crystallinity thin film. In particular, the accelerated Cl radicals in the plasma are shown to penetrate more easily into the low-crystallinity thin film than the high-crystallinity thin film. After the etching process, the surface roughness is significantly lower in the high-crystallinity thin film than in the low-crystallinity thin film. This result is expected to provide useful information for the process design of high-performance electronic devices.
Quantum error mitigation by hidden inverses protocol in superconducting quantum devices
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Authors: Leyton-Ortega V , Majumder S , Pooser R C
Published: December 2022

We present a method to improve the convergence of variational algorithms based on hidden inverses (HIs) to mitigate coherent errors. In the context of error mitigation, this means replacing the hardware implementation of certain Hermitian gates with their inverses. Doing so results in noise cancellation and a more resilient quantum circuit. This approach improves performance in a variety of two-qubit error models where the noise operator also inverts with the gate inversion. We apply the mitigation scheme on superconducting quantum processors running the variational quantum eigensolver (VQE) algorithm to find the H

2

ground-state energy. When implemented on superconducting hardware we find that the mitigation scheme effectively reduces the energy fluctuations in the parameter learning path in VQE, reducing the number of iterations for a converged value. We also provide a detailed numerical simulation of VQE performance under different noise models and explore how HIs and randomized compiling affect the underlying loss landscape of the learning problem. These simulations help explain our experimental hardware outcomes, helping to connect lower-level gate performance to application-specific behavior in contrast to metrics like fidelity which often do not provide an intuitive insight into observed high level performance.
People and infrastructure: multi-scale assessment of coastal and fluvial flood exposure in India
Authors: Zoraghein Hamidreza , Pinchoff Jessie , Balk Deborah , Montgomery Mark , Engin Hasim
Published: December 2022

India is one of the world’s most flood-prone countries, with present-day risks likely to be exacerbated by climate change in the coming decades. The type of risk varies by location, with the lives, homes, and livelihoods of residents of India’s coastal megacities threatened by coastal floods and storm surges while village-dwellers residing in rural flood plains may additionally lose both crops and livestock. Schools and health facilities throughout the country are also at risk. This multi-scale study employs several datasets, from multiple domains, to generate high-resolution estimates of potential exposure to fluvial and coastal floods for (1) urban and rural populations, (2) health facilities, and (3) educational facilities. Our results, presented at the state level, suggest high exposure to fluvial flooding with about 184 million or more than 1:7 of India’s population at risk. This proportion is somewhat higher for rural dwellers (15.8%) compared with urban residents (14.2%). Urban residents, however, are much more likely to be affected by coastal floods, likely due to the high population densities of India’s coastal megacities. In total, around 19,218 (15%) of health and 34,519 (18%) of educational facilities are exposed to either coastal or fluvial flood risks. A spatially detailed, locally refined, comprehensive flood risk assessment such as this is critical to inform and target public policy and guide disaster risk reduction plans. By improving infrastructure, increasing awareness, and developing proactive, targeted, and inclusive flood plans, communities can build resilience.
Comparisons of simulated radiation, surface wind stress and SST fields over tropical pacific by the GISS CMIP6 versions of global climate models with observations
Authors: Li J-L F , Cesana Gregory V , Xu Kuan-Man , Richardson Mark , Takahashi Hanii , Jiang J
Published: December 2022

This study compares the overall performance between versions 2.1 and 3 of National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies (GISS) global climate models (referred to as GISS-E2.1 and GISS-E3, respectively), in simulating the present-day Pacific climate using the CMIP6 protocol. Model physical representations and configurations are extensively changed from GISS-E2.1 to GISS-E3, which result in greatly reduced discrepancies, including ice water path (IWP), ice water content (IWC), radiative fluxes, surface wind stress (TAU), sea surface temperature (SST), precipitation (PR) and column water vapor (PRW), relative to satellite-based observational products over south Pacific oceans. Cloud only IWP (CIWP) shows the largest change, decreasing biases from ∼400 g kg−1in GISS-E2.1 to 10–20 g kg−1in GISS-E3. The combination of improved CIWP and the inclusion of snow in GISS-E3 may play roles on reducing overestimated outgoing longwave radiation, overestimated reflected shortwave at the top of atmosphere, and underestimated surface downward shortwave in GISS-E2.1. Both models’ intertropical convergence zones (ITCZs) are, however, located far too north of the equator, as found in radiative fluxes, PR and PRW but not in SST relative to observations. This introduces biases in TAU, PR and PRW over north flank of the equator and north Pacific. Over south Pacific, especially the trade wind regions, the improvements of radiation fluxes, SST, PR and PRW appear to be due to improved TAU associated with inclusion of snow-radiative effects. In particular, GISS-E3 reduces a longstanding too warm SST bias over trade-wind regions, from 4 K in GISS-E2.1 to within 0.5 K, and too cold SST bias over north Pacific Ocean. Although GISS-E3 shows improved geographic patterns of the simulated fields in particular over south Pacific oceans compared to GISS-E2.1, our results suggest that the location of ITCZ needs to be further improved.
Effect of Mn on microstructure, mechanical properties, and corrosion behaviour of Mg-Ni alloys
Authors: Patel Sonam M , Rao Vandana J
Published: December 2022

Previous research on Mg-Ni alloys focused on the mechanical characteristics and damping behaviour in the presence of Zn and rare Earth elements. There has not been much research on the Mg-Ni-Mn alloy’s microstructure, mechanical properties, and corrosion behaviour. The present research work fulfills this gap by concentrating on the microstructure, mechanical, and corrosion characteristics of Mg-Ni-Mn alloys. Here, different Mg-Ni-Mn alloys were developed by varying the nickel and manganese content. The microstructure of the developed alloys was studied using an optical microscope and scanning electron microscope. Ultimate tensile strength and microhardness of all alloys were performed on a tensometer (room temperature), and Vickers hardness tester respectively. The corrosion rate of Mg-Ni and Mg-Ni-Mn alloys was measured at 3.5 wt% NaCl solution by immersion test. The result shows that the nickel and manganese presence refine the grain size of magnesium. XRD analysis confirmed the presence of α-Mg and Mg2Ni phases in Mg-Ni alloys. Along with these phases, the Mn phase was observed in Mg-Ni-Mn alloys. Mechanical properties such as ultimate tensile strength and hardness of pure magnesium were increased in the presence of Ni and Mn. However, the presence of manganese in Mg-Ni alloy shows an adverse effect on corrosion behaviour. The corrosion rate of the Mg-Ni alloy was accelerated in the presence of manganese.
High-density analog image storage in an analog-valued non-volatile memory array
Authors: Zheng Xin , Zarcone Ryan V , Levy Akash , Khwa Win-San , Raina Priyanka , Olshausen Bruno A , Philip Wong H S
Published: December 2022

Data stored in the cloud or on mobile devices reside in physical memory systems with finite sizes. Today, huge amounts of analog data, e.g. images and videos, are first digitalized and then compression algorithms (e.g. the JPEG standard) are employed to minimize the amount of physical storage required. Emerging non-volatile-memory technologies (e.g. phase change memory (PCM), resistive RAM (RRAM)) provide the possibility to store the analog information in a compressed format directly into analog memory systems. Here, we demonstrate with hardware experiments an image storage and compression scheme (joint source-channel coding) with analog-valued PCM and RRAM arrays. This scheme stores information in a distributed fashion and shows resilience to the PCM and RRAM device technology non-idealities, including defective cells, device variability, resistance drift, and relaxation.
Anti–factor Xa vs aPTT for heparin monitoring in extracorporeal membrane oxygenation
Authors: Vo Tai , Bello Abdel , Ragan Monika , Flanagan James , Johnson Darriel
Published: December 2022

Purpose

The goal of this study was to evaluate the correlation of anti–factor Xa (anti-Xa) and activated partial thromboplastin time (aPTT) measures with heparin dosing in adult patients on extracorporeal membrane oxygenation (ECMO) support.

Methods

This was a retrospective cohort study evaluating adult patients managed on ECMO for at least 24 hours who received unfractionated heparin for systemic anticoagulation and were monitored per protocol using anti-Xa and/or aPTT coagulation assays. The primary outcome was the correlation between aPTT and anti-Xa measures. The secondary outcomes included, but were not limited to, the number of hemorrhagic and thrombotic events.

Results

Twenty-seven patients were included in this study. In the 227 events where both laboratory values were collected, a weak correlation was found between anti-Xa and aPTT (Spearman’s correlation coefficient = 0.4, P = 0). In the 12 hemorrhagic events that occurred, aPTT was collected for only 10 events. Fifty percent of those events were associated with supratherapeutic aPTT, while none of the hemorrhagic events were associated with a supratherapeutic anti-Xa level. Two thrombotic events occurred, one of which had subtherapeutic anti-Xa and aPTT and the other of which had neither an anti-Xa nor aPTT measure on the day the event occurred.

Conclusion

In a population of patients on ECMO, many of whom had coronavirus disease 2019 (COVID-19), there was a weak association between aPTT and anti-Xa measures. Hemorrhagic evens were more common than thrombotic events; however, a relationship between these events and aPTT or anti-Xa levels was not determined. The applicability of these findings to an ECMO population without COVID-19 is unknown and will require further study.
Productivity and Efficiency of a Department Resident Aesthetic Plastic Surgery Clinic
Authors: Nasr Hani Y , Boyd Carter J , Borab Zachary M , Vranis Neil M , Cassidy Michael F , Gursky Alexis K , Gober Rebecca , Zide Barry M , Ceradini Daniel J
Published: December 2022

Background

There has been increasing demand for aesthetic surgery procedures in the United States, highlighting the critical importance of the competence of plastic surgery residents and rigorous methods of aesthetic surgery training.

Objectives

The objective of this study was to review procedures and outcomes from our plastic surgery resident aesthetic clinic. Outcomes and costs were compared to national averages and reports from the literature.

Methods

A retrospective chart review identified all adult patients who presented to the Resident Aesthetic Surgery Clinic at NYU Langone Health in 2021. Patient demographics, comorbidities, procedural data, postoperative complications, revisions, and surgeon fees were compiled. A brief confidence survey was distributed to participating residents before and after their clinic rotation. Data were analyzed using IBM SPSS software (Armonk, NY).

Results

In 2021, 144/379 consultations led to an operation (38.0% conversion rate), resulting in 420 distinct surgical procedures. The majority (53.3%) of procedures involved the head and neck. Complication and revision rates were 5.5% and 1.0%, respectively, with surgeon fees consistently below the national average. Residents reported being significantly more confident performing face lifts, rhinoplasties, and aesthetic surgery in general following their clinic rotation.

Conclusions

These data represent the largest annual reported study of plastic surgery resident aesthetic procedures and outcomes, demonstrating the high volume and productivity of the NYU Resident Aesthetic Surgery Clinic. These results further support resident aesthetic clinics as a robust training modality.

Level of Evidence: 4
Gel Cohesivity and Breast Augmentation: Applications to Clinical Practice
Authors: Edwards Michael C , Gabriel Allen , Hammer Jason , Jewell Hillary L , Jewell Mark L
Published: December 2022

Matching breast implant gel cohesivity to the patient’s needs based on anatomical and soft tissue considerations and patient preferences is essential to optimizing aesthetic outcomes and patient satisfaction. Generally, gel cohesivity contributes to the feel and shape of the breast, which reflects volume distribution within the breast. Studies on the physical properties of silicone gel breast implants have established the relative cohesivity of implants from several manufacturers. Comprehensive patient education, tissue-based preoperative planning, and a thorough understanding of how implant properties may affect outcomes are recommended before breast augmentation. This review summarizes the literature on breast implant physical properties with a focus on gel cohesivity and translates gel cohesivity to practical considerations in choosing the right implant for the right patient in primary augmentation. Based on clinical experience, the authors generally recommend lower-cohesivity implants for patients who desire a tapered upper pole or a natural appearance/“anatomic shape” as well as for those with a high body mass index or a large amount of native breast tissue. Medium-cohesivity implants are most widely used and are appropriate for those with ptosis/augmentation mastopexy, patients with tight skin envelope, and for those seeking upper pole fullness. A high-cohesivity implant is recommended for patients desiring a round shape, those with constricted lower poles, and patients with a postpartum loose envelope, a thin, soft tissue envelope, or fibrous breast tissue.
DARTpaths, anin silicoplatform to investigate molecular mechanisms of compounds
Authors: Bhalla Diksha , Steijaert Marvin N , Poppelaars Eefje S , Teunis Marc , van der Voet Monique , Corradi Marie , Dévière Elisabeth , Noothout Luke , Tomassen Wilco , Rooseboom Martijn , Currie Richard A , Krul Cyrille , Pieters Raymond , van Noort Vera , Wildwater Marjolein
Published: December 2022

Xpaths is a collection of algorithms that allow for the prediction of compound-induced molecular mechanisms of action by integrating phenotypic endpoints of different species; and proposes follow-up tests for model organisms to validate these pathway predictions. The Xpaths algorithms are applied to predict developmental and reproductive toxicity (DART) and implemented into an in silico platform, called DARTpaths.

Availability and implementation

All code is available on GitHub https://github.com/Xpaths/dartpaths-app under Apache license 2.0, detailed overview with demo is available at https://www.vivaltes.com/dartpaths/.

Supplementary information

Supplementary data are available at Bioinformatics online.
Design of a treatment satisfaction measure for patients undergoing varicose vein treatment: Venous Treatment Satisfaction Questionnaire (VenousTSQ)
Authors: Gilbride Charlie J , Wilson Alison , Bradley-Gilbride Anita , Bayfield Janet , Gibson Kathleen , Gohel Manjit , Bradley Clare
Published: December 2022

Background

Established condition-specific patient-reported outcome measures for varicose veins are limited to the measurement of health status and function. A treatment satisfaction measure is needed to understand patient satisfaction with different treatment options. The aim of this study was to design a Venous Treatment Satisfaction Questionnaire (VenousTSQ) that would be ready for large-scale data collection and psychometric evaluation.

Methods

Relevant items were selected from the -TSQ Item Library and new items were designed where necessary. A draft VenousTSQ was prepared using the existing AneurysmTSQ as a template. Fifteen interviews were conducted from 4 days to 16 months after the procedure. The interviews were designed to elicit important sources of satisfaction or dissatisfaction before completion of draft questionnaires. The VenousTSQ drafts were modified between sets of interviews until no further changes were required.

Results

The final VenousTSQ consists of two questionnaires: VenousTSQ early (VenousTSQe) and VenousTSQ status (VenousTSQs). Items that need be asked only once are in the VenousTSQe, whereas those that can usefully be asked more than once are in the VenousTSQs. Of the 16 unique items forming the VenousTSQ, 12 were from the -TSQ Item Library. Only 1 of these 12 required significant modification.

Conclusions

The VenousTSQ represents a condition-specific psychological outcome measure for varicose veins, enabling patient satisfaction or dissatisfaction with such treatments to be measured. Large-scale data collection is under way to establish optimal scoring, quantitative validity, and reliability of the VenousTSQ.
HPB O03 Preclinical safety and feasibility of in situ Isolated Normothermic Liver Chemoperfusion (INLiC) for enhanced drug delivery
Authors: Clark Tamsyn , Ebeling Georg , Bau Luca , Voyce Daniel , Coussios Constantin , Friend Peter
Published: December 2022

Background

Up to 85% of patients with liver metastases have inoperable disease. Isolated liver chemoperfusion involves vascular isolation of the liver with regional delivery of chemotherapy, and aims to maximise the therapeutic response and limit extra-hepatic toxicity. Historically, the morbidity associated with drug leak from the liver circuit has limited its success. To improve the safety of this approach, we developed a surgical protocol for Isolated Normothermic Liver Chemoperfusion (INLiC) and assessed its short-term safety, and feasibility for enhancing drug delivery.

Methods

Laparotomy and complete, vascular isolation of the liver was performed on (n=9) 55–65 Kg pigs. The gastroduodenal artery, portal vein and inferior vena cava (IVC) were cannulated and normothermic machine perfusion of the liver established in situ. Systemic circulation was maintained with veno-venous bypass. High-dose, intra-arterial doxorubicin was delivered to the isolated liver, circulated for 1 hour and vascular reconnection performed. Biochemical and physiological parameters were assessed and doxorubicin quantified in blood, bile and tissue by high performance liquid chromatography.

Results

A standardised, surgical protocol was developed to enable INLiC. Physiological median liver outflows (1.1 L/min (0.9–1.1)), pH (7.35 (7.26–7.42)), lactate concentration (1.1 mM (0.33–2.3)) and an acceptable peak AST (805 U/L (308–1667)) were achieved. Population two-compartmental analysis of plasma doxorubicin decay demonstrated a distribution half-life of 1.3 minutes and a Cmax 8-times higher than tolerable by systemic delivery, due to cardiotoxicity. The resulting hepatic tissue concentration of doxorubicin was significantly higher than could be safely achieved with systemic delivery (p=0.019). Notably, there was no extra-hepatic leak of doxorubicin and it did not accumulate in cardiac or renal tissue.

Conclusions

INLiC is feasible, safe and enables high-dose drug delivery to the liver without extra-hepatic tissue accumulation.
HPB V09 Pringles manoeuvre- How we do it!
Authors: Karmarkar Rahi , Aroori Somaiah
Published: December 2022

Background

Minimally invasive liver resection (MILR) is a complex surgical procedure requiring extensive training and expertise. One of the critical challenges in MILR is the control of bleeding from the transection plane. Intraoperative blood loss and blood transfusion requirements are associated with increased operating time, postoperative morbidity, mortality, and reduced disease-free survival. Pringles manoeuvre is an established strategy to facilitate liver resection whilst maintaining haemostasis from the transection plane. Several techniques for performing the Pringle manoeuvre in MILR have been described. However, an optimal method has not been identified yet.

Methods

In our video presentation, we describe a novel technique for Pringle's manoeuvre in MILR using a deceptively simple Foley catheter device.

Results

A Foley catheter can provide uniform constriction of the hilar structures owing to its silastic properties. Its atraumatic tip allows its safe passage behind hilar structures without other instrument use. It does not require additional ports, is less traumatic, and is easy to apply. A foley catheter is also relatively inexpensive and readily available in operation theatres.

Conclusions

Pringle's manoeuvre using a Foley catheter is a simple, safe, easily reproducible, and cost-effective technique. We encourage this method of hepatic inflow occlusion in modern minimally invasive liver surgery.
OGC O07 Effect of Hyperthermic Intraperitoneal Chemotherapy (HIPEC) on survival and recurrence rates in advanced gastric cancer- systematic review and meta analysis
Authors: Patel Maitreyi , Arora Amandeep , Mukherjee Dipankar , Mukherjee Samrat
Published: December 2022

Background

Around 5–20% of patients who undergo surgery for advanced gastric cancer have peritoneal carcinomatosis and 10–54% have peritoneal recurrence after surgery, which is associated with poor prognosis. The role of hyperthermic intraperitoneal chemotherapy (HIPEC) in advanced gastric cancer (AGC) is not clearly defined. We performed a meta-analysis to assess the safety and survival benefit of HIPEC in AGC.

Methods

We conducted a meta-analysis, in accordance with the PRISMA guidelines, of the clinical trials and high-quality non-randomized studies evaluating the role of HIPEC in AGC over the last 10 years. The studies were searched in PubMed, EMBASE, MEDLINE and Cochrane databases between January 2011 to December 202. The PROSPERO registration number is CRD42022310556. Clinical data including overall survival (OS), recurrence-free survival, overall recurrence rate, peritoneal recurrence rate, and complications analyzed after data extraction using RevMan5.4.The primary endpoint was overall survival. The secondary end points were 5 year survival, disease-free survival, post operative complications: myelosuppression, liver dysfunction, intestinal obstruction, leak, and mortality. The impact of HIPEC on overall and peritoneal recurrence was also evaluated.

Results

Six randomized controlled trials and 10 nonrandomized studies met the inclusion criteria and were included in the meta-analysis, comprising a total of 1700 patients. While the use of HIPEC did not impact OS at one year, it was associated with significantly improved OS at 3 (OR 1.89, 95% CI 1.17–3.05) and at 5 years (OR 1.87, 95% CI 1.29–2.71). HIPEC was associated with reduced overall recurrence (OR 0.49, 95% CI 0.31–0.80) and peritoneal recurrence (OR 0.22, 95% 0.11–0.47). HIPEC was not associated with increased complications; however, the occurrence of postoperative renal dysfunction was significantly higher in the HIPEC group (OR 3.94, 95% CI 1.85–8.38). 3-year mortality was significantly favorable to HIPEC (OR 0.38, 95% CI 0.18–0.82).

Conclusions

The role of HIPEC in AGC has evolved over the past decade. These results suggest that HIPEC may improve survival rates and reduce recurrence rates in patients with AGC, without significant increase in complications. HIPEC may improve survival rates and reduce recurrence rates in patients with AGC, without any significant increase in complications with a favorable impact on 3 and 5-year survival. The prognosis is dependent on patient selection. High quality, multi-centre trials are needed to guide in patient selection and developing standardized protocols for the management for this cohort of patients.
OGBN P16 Pre-operative group and save, is there still a need in the elective and emergency laparoscopic cholecystectomy?
Authors: Hamid Mohammed , Kershaw Marie , Bhakthavalsalan Resya , Shivamurthy Rishika , Davies Sian , Ahmed Zuhair
Published: December 2022

Background

Laparoscopic cholecystectomy is associated with a high safety profile. This study aimed to quantify the rate of blood transfusion in the elective and emergency setting and explore patient outcome and selection for Group and Save (G&S) sampling.

Methods

A retrospective observational study investigating patients who underwent an elective or emergency laparoscopic cholecystectomy at a single Trust in the UK, between December 2019 and May 2021. Outcomes of interest were selected based on their clinical possibility of being influenced by the number of pre-operative G&S samples using multivariate logistic regression models.

Results

There were 959 patients; 631 (65.8%) elective and 328 (34.2%) emergency cholecystectomies. Median age was 48 (35–59) years, and 724 (75.5%) patients were female. Five patients (0.5%) needed blood transfusion post-operatively, with an average time of six hours. Three of these patients had haematological conditions. In adjusted models, male sex was associated with requiring a blood transfusion (OR 11.31, p=0.013); whilst having a pre-operative G&S sample had no impact on any patient outcome.

Conclusions

Blood loss requiring blood transfusion in laparoscopic surgery is very low. Male sex and haematological conditions may present as independent risk factors for blood loss in laparoscopic cholecystectomy. Pre-operative G&S sampling has no impact on patient outcome and could safely be omitted in both elective and emergency cases unless a personalised assessment suggests otherwise.
OGBN P21 A complex case of gallbladder and CBD stones treated with Laparoscopic Cholecystectomy and Trans-Cystic lithotripsy using SpyGlass™ Discover post failed ERCP
Authors: Abdelwahab Sameh , Shaalan Ramy , Kulli Christoph , Tait Ian , Patil Pradeep , Zino Samer , Kher Jan
Published: December 2022

Background

Laparoscopic Cholecystectomy and bile duct exploration remain the gold standard treatment for gallstone disease associated with bile duct stones. However, interval two session management with ERCP followed by Laparoscopic Cholecystectomy should be avoided. It exposes patients to preventable risk of perforation, bleeding, and pancreatitis, especially if the patient is fit and keen for surgery. Trans-Cystic bile duct exploration (TC BDE) appears to have less morbidity than Trans- Ductal bile duct exploration (TD BDE). However, large bile duct stones remain the main challenge for Trans-Cystic approach along with distorted anatomy.

Methods

We present a 48-year-old female with symptomatic gallstone disease and a complex past surgical history.

Results

Trial of ERCP failed despite Needle-knife papillotomy due to large mobile and hard papilla. Unfortunately, the patient suffered post ECRP pancreatitis that was complicated by an abdominal collection around the head of the pancreas. The collection required radiologic drainage through the anterior abdominal wall, 13 days post-pancreatitis. The patient recovered well and was listed for a Laparoscopic Cholecystectomy and bile duct exploration with high risk of conversion to open, 6 weeks after discharge. The operation was challenging due to presence of adhesions and shrunken gallbladder (Nassar grade IV). Trans-Cystic BDE was performed using basket inside catheter (BIC) technique. SpyGlass™ Discover choledochoscopy showed a clear distal CBD and a large 12mm stone in the common hepatic duct. The stone was hard and required a high setting of lithotripsy (30, Max). The stone was fragmented successfully, and all fragments extracted using baskets. The cystic duct was closed by suturing using 3.0 Vicryl and two Robinson abdominal drains were left in the abdomen; one in Morrison's pouch and one in the sub-diaphragmatic space. The patient had an uncomplicated post-operative recovery and was discharged home after 5 days. Follow-up 8 months later was satisfactory.

Conclusions

Trans-Cystic bile duct exploration has become increasingly safe and feasible even for large bile duct stones using new technology. ERCP should be avoided in young fit patients, especially females due to the higher risk of post-ERCP pancreatitis.
EGS P02 The long term impact of service re-organisation on outcomes for patients with complicated peptic ulcer disease
Authors: Couper Graeme , Hughes Michael , McKechnie Stuart , Paterson-Brown Simon
Published: December 2022

Background

20 years ago acute surgical services were re-organised in our region to deliver subspecialist care of upper-gastrointestinal emergencies. Improved outcomes were reported as a result. Currently the unit has 24-hour availability for interventional and diagnostic radiology, emergency endoscopy and a specialist oesophago-gastric consultant surgeon. The aims of this study are to determine if, a decade after a major service re-organisation, any further improvements have been achieved in short-term outcomes and to provide long-term survival figures for this group of patients.

Methods

All patients admitted during a 62-month period from January 2010-February 2015, corresponding in duration and exactly a decade later than the previous report following service re-organisation, were identified from a prospectively compiled database.

Results

287 patients were admitted during the study period. 235 patients were admitted with ulcer perforation and 52 patients underwent surgery for bleeding.

Perforation. 8 patients (8/235, 3.4%) received end of life care. 37 patients (37/235, 15.7%) had initial conservative management. 191 (191/235, 81.3%) patients underwent operation (includes 1 patient with failed conservative management). 18 patients (18/191, 9.4%) died post-operatively. No patients selected for conservative management died. Within 5 years following discharge a further 34 patients died. 50% (17/34) of these were due to cancer. Actual 5-year survival was 73.3% (165/225, 10 patients lost to follow up). Comparing with the period following subspecialisation, overall in-hospital mortality was 10.4% vs 11.1% (14/135 vs 26/235) p=0.84, in-hospital mortality following surgery 7.9% vs 9.4% (9/114 vs 18/191) p=0.65 and in-hospital mortality following conservative management 23.8% vs 0% (5/21 vs 0/36) p=0.005.

Bleeding. In-hospital mortality was 25% (13/52). This was not significantly different from the rate reported following service reorganisation, 23.5% (12/51) vs 25% (13/52) p=0.86. Within 5 years following discharge a further 12 patients died. 58% (7/12) of these were due to cancer. Actual 5-year survival was 51.9% (27/52 patients alive).

Conclusions

This study demonstrates that no improvement in surgical outcome in patients with complicated peptic ulcer disease has been achieved despite the delivery of what may be considered an optimal service. A significant improvement in outcome in patients selected as suitable for conservative management has been seen. 5-year survival figures for patients admitted with either perforation or bleeding are poor with cancer the most common cause of death within 5 years following discharge.
EGS P05 Surgical Same Day Emergency Care at a District General Hospital - Our Experience
Authors: Sultan Ahmed , Hussain Mohammad Iqbal , Sellahewa Chaminda , Bird Jonathan , Glover Gemma
Published: December 2022

Background

Surgical Same day emergency care (SDEC) is a new service started at a medium sized district general hospital (DGH) since November 2021. The surgical SDEC service is divided into Theatre (ambulatory theatres) and non-theatre (Hot Clinic) pathways aiming at improving patient experience, and reducing length of stay (LOS), by introducing a pathway through which patients are assessed, diagnosed, and initiated treatment and discharge on the same day for common emergency surgical conditions of gallstone disease, appendectomy, painful hernia, and abscesses. The service delivery planned with the existing facilities leading to structured fewer admissions, increased diagnostics, coordinating the patient flow with preop assessments, day case theatre utilisation and post-operative criteria led discharge. The Surgical SDEC is now established, and we continue to audit to benchmark success, recommend improvement and for quality assurance.

Methods

It's a prospective data collection of patients admitted under general surgery with the above common surgical emergency presentations over 6 months period since the start of the service in November 2021. The inclusion criteria were stable patients of ASA grade 1 and 2, BMI less than 40 kg/m2, and with social support. The unstable patients, ASA 3 or more and without social support were excluded. The postoperative follow up was arranged with virtual ward, clinics and in the event a post-surgery hot clinic review.

Results

From 15th November 2021 to 27th May 2022, 192 surgical operations were carried out. 130 Laparoscopic cholecystectomies, 22 hernia repairs, 13 diagnostic laparoscopies, and 27 abscesses incision and drainage. There were 77 male patients and 115 female patients with age ranging from 20 to 88 years old. About 70% of the patients were successfully discharged on the same day with a readmission rate of 3.6%. The cholecystectomy patients had a mean waiting time of 3.2 days and almost all cases were done within a week of admission. All the other cases including appendectomy were performed either the same day or the following day.

Conclusions

Surgical Same Day Emergency Care service proved to be a step forward for improving patient care. It allows the same day diagnostics and treatment, and reduces the length of stay, prevents readmissions, improves the quality of care, and helps recovery following the impacts of the pandemic. Finally, it has a significant financial benefit by decreasing readmissions, and it also utilisation of hospital beds more desired cases.
EGS P11 Ten year experience of treating Boerhaave syndrome: a single centre analysis
Authors: Hawkins Rosalyn , Phillips Benedict , Amalesh Thangadorai , Mukherjee Dipankar , Mukherjee Samrat
Published: December 2022

Background

Boerhaave syndrome is a rare condition characterised by spontaneous barogenic, transmural rupture of the oesophagus. We aimed to examine a ten-year experience of Boerhaave syndrome at our centre.

Methods

Cohort analysis of Boerhaave syndrome over a ten year period (2012–2022). Univariate analysis was employed to determine risk factors associated with inferior patient survival.

Results

During the study period, 40 patients presented with oesophageal perforation, of which 21 (52.5%) were spontaneous transmural rupture. Median age of patients with Boerhaave syndrome was 51 years, in predominantly male (15, 71.4%), non-smokers (13, 61.9%). The most common site of rupture was the lower oesophagus (12, 57.1%), although the exact site of rupture was unknown in 5 (23.8%) patients. 14 (66.7%) patients were treated conservatively with antibiotics. Three (14.3%) patients underwent endoscopic oesophageal stent insertion (either alone or in combination with surgical treatment). Five (23.0%) underwent thoracoscopic washout and drain insertion and 1 (4.8%) underwent open thoracotomy washout and drain insertion. Overall 10-year survival was 80.8%. There was no association between mortality and patient age, sex, smoking status, length of stay, location of perforation, coronavirus status or mode of nutrition on univariate analysis (p>0.05 throughout). Patient age was the greatest predictor of prolonged length of stay beyond 10 days (c-statistic 0.74). Modality of surgery also had no bearing on 1- and 10-year mortality (p=0.95).

Conclusions

Boerhaave syndrome is an uncommon condition which may be treated with an array of approaches, including non-operative measures, endoscopic and surgical intervention, depending on individual patient characteristics. The availability of multimodal treatment at a specialist oesophagogastric centre may have contributed to favourable patient outcomes. Given the rarity of Boerhaave syndrome, identification of risk factors for poor patient outcomes is difficult to determine, due to statistical underpowering.
EGS P29 Improving Quality of Operation Notes in General Surgery – A complete audit cycle
Authors: Mateen Mohammad , Kamran Zen , Mahmud Sajid , Khan Khurram
Published: December 2022

Background

Good quality of operation notes are essential for good post-operative care, patient safety and medico-legal issues. RCSEng have guidelines on items that should be included in all operation notes. RCSEng Guidelines state: Ensure that there are clear (preferably typed) operative notes for every procedure. The notes should accompany the patient into recovery and to the ward and should give sufficient detail to enable continuity of care by another doctor. We re-audited the quality of operation notes in general surgery.

Methods

We re-audited and compared the results with the first cycle. Four months (1st August to 30th November 2021) period of consecutive operation notes were reviewed. Operation notes for endoscopy were excluded. Operations notes were analysed for documentation of the items as per RCSEng guidelines. There were less operations post COVID-19, hence longer study period. After first cycle, departmental presentation given for education and posters displayed in theatres as reminder. Initial plan for 2nd cycle in 2020 but it was not possible due to COVID-19.

Problems/complications, extra procedures and prosthesis used were not included. Additional criteria reviewed was: type of anaesthetic, patient position, indication for procedure and ASA grade.

Results

A total of 239 operation notes were identified. 169 emergency and 70 elective cases. 193 were handwritten and 46 were typed.The results were compared to the first cycle:

Conclusions

Higher proportion was of emergency procedures during the 2nd cycle. Also, higher proportion of handwritten notes during 2nd cycle. There was improvement in documenting elective/emergency, time, type of anaesthesia, indication, position, operative findings/diagnosis, details of tissue removed/added/altered, blood loss, antibiotics, DVT prophylaxis. However, there was poorer documentation of date, name of assistant, incision, closure, signature remains.

Ongoing education of the surgeons is vital to improve the quality of the operation notes. We suggest addition of further headings on the current op-note as aid-memoire and introduction of digital operation notes.
EGS P30 Minimally Invasive Approach for the treatment of Boerhaaves
Authors: Sarkar Anik , Toh Simon
Published: December 2022

Background

Over the years the teaching has being a radical open approach to boerhaaves. Here at Queen Alexandra Hospital, we wanted to show a minimally invasive approach to boerhaaves and prove to be a feasible option, obviously in selected cases and under a specialist UGI unit.

Methods

A recording was obtained of the case and the endoscopy with permission.

Results

We were able to contain mediastinal contamination while at the same time, primarily repair the laceration transhiatally. Patient was extubated the same evening without any support. Patient was moving around day 1.

Conclusions

In selected patients, a minimally invasive approach to boerhaaves, wether it be thorascopically or laparoscopically should be considered. This should ultimately be performed under a UGI specialist unit.
EGS P32V Laparoscopic transcystic Antegrade Biliary Stenting
Authors: Taggarsi Meghana , Rate Anthony
Published: December 2022

Background

Laparoscopic cholecystectomy is the gold standard treatment for symptomatic cholelithiasis including pancreatitis. Symptomatic gall stones patients have up to 20% risk of having common bile duct (CBD) stones too. Although, guidelines have been laid down for management of suspected CBD stones, in practice there is a lot of variability and lack of standardisation. The waiting list for Magnetic resonance cholangiopancreatography (MRCP) is long, resulting in delayed treatment and increased length of hospital stay. Similarly, pre-operative endoscopic retrograde cholangiopancreatography (ERCP) can also increase the length of hospital stay due to long waiting lists, limited availability and overall risk of complications as high as 30%. Hence, the role of on-table cholangiogram (OTC) while performing laparoscopic cholecystectomy has been explored. The guidelines state that OTC should be performed in fit for surgery patients, without pre-operative investigations for diagnosing CBD stones. We have been practising early cholecystectomy with on-table cholangiogram (during the index admission), with selective insertion of antegrade biliary stent in patients with choledocholithiasis. We facilitate ERCP with stent removal and clearance of CBD stones after 4 weeks post-operatively.

We aim to present our technique of laparoscopic antegrade biliary stent insertion.

Methods

We follow the standard four-port technique for Laparoscopic cholecystectomy. Following dissection of Calot's triangle and visualisation of ‘critical view of safety’, an on-table cholangiogram is performed using a standard technique. If CBD stones are visualised, a transcystic antegrade stenting is done by Seldinger technique (without clearing the CBD of stones). The cholangiogram catheter is removed and flex-tip ureteric catheter is inserted transcystically. Through the ureteric catheter a flex-tip guidewire is inserted into CBD till its tip is visualised in the duodenum, under C-arm guidance. The ureteral catheter is then withdrawn carefully with guidewire placed satisfactorily. A double pig tail end biliary stent is rail-roaded over the guidewire, using a pushing catheter fashioned appropriately. As soon as the tip of the stent is visualised beyond the ampulla (in the X-ray), the guidewire and pushing catheter are withdrawn. The curling up of both ends of the stent is visualised and confirmed through C-arm guidance. Thereafter the procedure of cholecystectomy, as standard, is completed.

Results

The results of this procedure were analysed from 2014 to 2017, and subsequently published in 2018.

Conclusions

This technique does not involve skills required for CBD exploration. Hence, can be performed by general surgeons with expertise in minimal access surgeries, as it does not involve a steep learning curve. This technique is safe, reliable and cost-effective. It also decreases delays in biliary decompression, in-hospital stay and ensures timely treatment.