Evaluation of International Contemporary Operative Outcomes and Management Trends Associated With Esophagectomy:A 4-Year Study of >6000 Patients Using ECCG Definitions and the Online Esodata Database

OBJECTIVE: This study aims to verify the utility of international online datasets to benchmark and monitor treatment and outcomes in major oncologic procedures. BACKGROUND: The Esophageal Complication Consensus Group (ECCG) has standardized the reporting of complications after esophagectomy within the web-based Esodata.org database. This study will utilize the Esodata dataset to update contemporary outcomes and to monitor trends in practice in an era of rapid technical change. METHODS: This observational study, based on a prospectively developed specific database, updates esophagectomy outcomes collected between 2015 and 2018. Evolution in patient and operative demographics, treatment, complications, and quality outcome measures were compared between patients undergoing surgery in 2015 to 2016 and 2017 to 2018. RESULTS: Between 2015 and 2018, 6022 esophagectomies from 39 centers were entered into Esodata. Most patients were male (78.3%) with median age 63. Patients having minimally invasive esophagectomy constituted 3177 (52.8%), a chest anastomosis 3838 (63.7%), neoadjuvant chemoradiotherapy 2834 (48.7%), and R0 resections 5441 (93.5%). For quality measures, 30- and 90-day mortality was 2.0% and 4.5%, readmissions 9.7%, transfusions 12%, escalation in care 22.1%, and discharge home 89.4%. Trends in quality measures between 2015 and 2016 (2407 patients) and 2017 and 2018 (3318 patients) demonstrated significant (P &lt; 0.05) improvements in readmissions 11.1% to 8.5%, blood transfusions 14.3% to 10.2%, and escalation in care from 24.5% to 20% A significantly (P &lt; 0.05) reduced incidence in pneumonia (15.3%-12.8%) and renal failure (1.0%-0.4%) was observed. Anastomotic leak rates increased from 11.7% to 13.1%, whereas leaks requiring surgery decreased 3.3% and 3.0%, respectively. CONCLUSIONS: The Esodata database provides a valuable resource for assessing contemporary international outcomes. This study highlights an increased application of minimally invasive approaches, a high percentage of complications, improvements in pneumonia and key quality metrics, but with anastomotic leak rates still &gt;10%.</p

CFD Simulation Of A Two Stage Twin Screw Compressor Including Leakage Flows And Comparison With Experimental Data

Computational Fluid Dynamics (CFD) is a common and validated simulation method in research and industry for the analysis of fluid systems. In the past years, it has proven to become more and more applicable for modeling the flow physics inside positive displacement (PD) machines. The working chamber and thus the discretized flow domain of PD machines is changing in time and characterized by complex thermodynamics. Compressible fluids, real-gas properties and leakage flows with trans- or supersonic characteristics are phenomena which have to be accounted for in order to properly model the behavior of the machine. As CFD methods evolve in general, but also for the application of PD machines in particular, the numerical model can replace a prototype during early stages of the product development. The desired simulation approach should be able to deliver sufficient accuracy at a feasible effort in terms of computational time and manpower to create the numerical model. This paper presents the methodology of creating the numerical model for the DS 160-250 Series screw compressor from Sullair. It is a dry running two stage twin screw compressor running with air at a rated power range between 160 and 250 kW. The two stages are gear driven by the main shaft at rotational speeds between 1180 and 2100 rev/min. Each stage features different rotor profiles, where the first stage has a 4-6, the second stage a 5-7 lobe combination. The total pressure ratio of the two stages combined is up to 10:1. To enhance the performance of the compressor, discharged air from the first stage is cooled down before entering the second stage. A specific meshing method is used to model the size-changing working chambers between rotors and casing, where only hexahedral cells and a constant mesh topology are used. The model accounts for radial and axial clearances between rotors and stator, where rotors and stator are connected with interfaces. The transient simulation results are compared to experimental measurements for torque, flow rate and volumetric efficiency. Also discharge pressure and temperature after first and second stage are compared to the experimental results. In addition, the possibilities of the simulation are exemplified by the gathering of time- and space-resolved monitor points like temperature or pressure at distinct points within the compressor. Apart from direct comparison to the experiment, also a sensitivity study regarding the change of housing clearances is presented, as leakage flow has severe impact on the compressor performance. These clearances and the resulting leakages are often not exactly known whereas they also vary because of manufacturing tolerances or deformations due to the load on rotors and stator. Here, the numerical simulation can serve as a helpful tool to estimate the sensitivity and change of machine characteristics, which is hard to determine in the scope of experiments

Cyclone: A close air support aircraft for tomorrow

To meet the threat of the battlefield of the future, the U.S. ground forces will require reliable air support. To provide this support, future aircrews demand a versatile close air support aircraft capable of delivering ordinance during the day, night, or in adverse weather with pin-point accuracy. The Cyclone aircraft meets these requirements, packing the 'punch' necessary to clear the way for effective ground operations. Possessing anti-armor, missile, and precision bombing capability, the Cyclone will counter the threat into the 21st Century. Here, it is shown that the Cyclone is a realistic, economical answer to the demand for a capable close air support aircraft

Prognostic implications of the extent of downstaging after neoadjuvant therapy for oesophageal adenocarcinoma and oesophageal squamous cell carcinoma

Background: There are few data evaluating the extent of downstaging in patients with oesophageal adenocarcinoma and oesophageal squamous cell carcinoma and the difference in outcomes for a similar pathological stage in neoadjuvant-naive patients. The aim of this study was to characterize the prognostic value of downstaging extent in patients receiving neoadjuvant therapy for oesophageal cancer.Methods: Oesophageal adenocarcinoma and oesophageal squamous cell carcinoma patients receiving either neoadjuvant chemotherapy or neoadjuvant chemoradiotherapy between 2004 and 2017 were identified from the National Cancer Database. The extent of downstaging was defined as the extent of migration between groups (for example stage IVa to IIIb = one stage). Cox multivariable regression was used to produce adjusted models for downstaging extent.Results: Of 13 594 patients, 11 355 with oesophageal adenocarcinoma and 2239 with oesophageal squamous cell carcinoma were included. In oesophageal adenocarcinoma, patients with downstaged disease by three or more stages (hazards ratio (HR) 0.40, 95 per cent c.i. 0.36 to 0.44, P &lt; 0.001), two stages (HR 0.43, 95 per cent c.i. 0.39 to 0.48, P &lt; 0.001), or one stage (HR 0.57, 95 per cent c.i. 0.52 to 0.62, P &lt; 0.001) had significantly longer survival than those with upstaged disease in adjusted analyses. In oesophageal squamous cell carcinoma, patients with downstaged disease by three or more stages had significantly longer survival than those with less downstaged disease, no change, or upstaged disease. Patients with downstaged disease by three or more stages (HR 0.55, 95 per cent c.i. 0.43 to 0.71, P &lt; 0.001), two stages (HR 0.58, 95 per cent c.i. 0.46 to 0.73, P &lt; 0.001), or one stage (HR 0.69, 95 per cent c.i. 0.55 to 0.86, P = 0.001) had significantly longer survival than those with upstaged disease in adjusted analyses.Conclusion: The extent of downstaging is an important prognosticator, whereas the optimal neoadjuvant therapy remains controversial. Identifying biomarkers associated with response to neoadjuvant regimens may permit individualized treatment

Antimicrobial Susceptibility Breakpoints and First-Step parC Mutations in Streptococcus pneumoniae: Redefining Fluoroquinolone Resistance

Clinical antimicrobial susceptibility breakpoints are used to predict the clinical outcome of antimicrobial treatment. In contrast, microbiologic breakpoints are used to identify isolates that may be categorized as susceptible when applying clinical breakpoints but harbor resistance mechanisms that result in their reduced susceptibility to the agent being tested. Currently, the National Committee for Clinical Laboratory Standards (NCCLS) guidelines utilize clinical breakpoints to characterize the activity of the fluoroquinolones against Streptococcus pneumoniae. To determine whether levofloxacin breakpoints can identify isolates that harbor recognized resistance mechanisms, we examined 115 S. pneumoniae isolates with a levofloxacin MIC of >2 μg/mL for first-step parC mutations. A total of 48 (59%) of 82 isolates with a levofloxacin MIC of 2 μg/mL, a level considered susceptible by NCCLS criteria, had a first-step mutation in parC. Whether surveillance programs that use levofloxacin data can effectively detect emerging resistance and whether fluoroquinolones can effectively treat infections caused by such isolates should be evaluated

Major Revamp And Retrofit Of Identical Process Compressor Trains.

LecturePg. 105-120Major uprates of process compressor train performance can be achieved utilizing the existing machinery. The following is a broad overview of a project to revamp two identical compressor trains to achieve levels well over original design flow. Significant internal modifications to an air compressor, a process compressor, and an expander have achieved most of our planned flow increase. The first train was modified in April 1986, and the second was modified in August 1986. An additional extensive uprate of our existing steam turbine driver to almost double the design power rating will push performance even beyond the envisioned maximum rate. This project was developed and managed by plant engineers. This paper documents the development, manufacturing, and startup phases of both the performance uprate as well as a seal system redesign for increased reliability. The mechanical redesign was primarily done by the original equipment manufacturers (OEMs). Contributions from corporate specialists, after market suppliers and independent consultants were also vital to the project's success. Measures taken to ensure the performance of the contractors and confidence in the reliability of the end products are described. The mechanical performance is up to company expectations now, but not without first overcoming a few obstacles. Actual operating rates are beyond expectations, primarily due to the effect of liquid carryover into the process compressor. Troubleshooting and performance testing techniques are described