Evaluation of dispersion models DIPCOT and RIMPUFF used in Decision Support Systems for nuclear and radiological emergency response

This paper presents evaluation of the atmospheric dispersion models DIPCOT and RIMPUFF which are incorporated for operational use in Decision Support Systems for nuclear emergencies. The evaluation is performed through comparisons of model results with real-scale measurements of gamma radiation dose rates in air obtained during the routine operation of the HIFAR Research Reactor located in Sydney, Australia. The area surrounding the reactor is characterized by moderately complicated topography and varying land cover. A total of 16 days have been computationally simulated, covering all atmospheric stability conditions. Qualitative and quantitative model evaluation is carried out, using comparisons of paired in space and time calculated and measured gamma dose rates, statistical indices, scatter plots, and contour plots. The models performance is satisfactory for a number of cases, while for others the performance is poor. This can be attributed to a number of factors, mainly uncertainties in the prediction of meteorological conditions

30-Day morbidity and mortality of bariatric metabolic surgery in adolescence during the COVID-19 pandemic – The GENEVA study

Background: Metabolic and bariatric surgery (MBS) is an effective treatment for adolescents with severe obesity. Objectives: This study examined the safety of MBS in adolescents during the coronavirus disease 2019 (COVID-19) pandemic. Methods: This was a global, multicentre and observational cohort study of MBS performed between May 01, 2020, and October 10,2020, in 68 centres from 24 countries. Data collection included in-hospital and 30-day COVID-19 and surgery-specific morbidity/mortality. Results: One hundred and seventy adolescent patients (mean age: 17.75 ± 1.30 years), mostly females (n = 122, 71.8%), underwent MBS during the study period. The mean pre-operative weight and body mass index were 122.16 ± 15.92 kg and 43.7 ± 7.11 kg/m2, respectively. Although majority of patients had pre-operative testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (n = 146; 85.9%), only 42.4% (n = 72) of the patients were asked to self-isolate pre-operatively. Two patients developed symptomatic SARS-CoV-2 infection post-operatively (1.2%). The overall complication rate was 5.3% (n = 9). There was no mortality in this cohort. Conclusions: MBS in adolescents with obesity is safe during the COVID-19 pandemic when performed within the context of local precautionary procedures (such as pre-operative testing). The 30-day morbidity rates were similar to those reported pre-pandemic. These data will help facilitate the safe re-introduction of MBS services for this group of patients

30-day morbidity and mortality of sleeve gastrectomy, Roux-en-Y gastric bypass and one anastomosis gastric bypass: a propensity score-matched analysis of the GENEVA data

Background: There is a paucity of data comparing 30-day morbidity and mortality of sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and one anastomosis gastric bypass (OAGB). This study aimed to compare the 30-day safety of SG, RYGB, and OAGB in propensity score-matched cohorts. Materials and methods: This analysis utilised data collected from the GENEVA study which was a multicentre observational cohort study of bariatric and metabolic surgery (BMS) in 185 centres across 42 countries between 01/05/2022 and 31/10/2020 during the Coronavirus Disease-2019 (COVID-19) pandemic. 30-day complications were categorised according to the Clavien–Dindo classification. Patients receiving SG, RYGB, or OAGB were propensity-matched according to baseline characteristics and 30-day complications were compared between groups. Results: In total, 6770 patients (SG 3983; OAGB 702; RYGB 2085) were included in this analysis. Prior to matching, RYGB was associated with highest 30-day complication rate (SG 5.8%; OAGB 7.5%; RYGB 8.0% (p = 0.006)). On multivariate regression modelling, Insulin-dependent type 2 diabetes mellitus and hypercholesterolaemia were associated with increased 30-day complications. Being a non-smoker was associated with reduced complication rates. When compared to SG as a reference category, RYGB, but not OAGB, was associated with an increased rate of 30-day complications. A total of 702 pairs of SG and OAGB were propensity score-matched. The complication rate in the SG group was 7.3% (n = 51) as compared to 7.5% (n = 53) in the OAGB group (p = 0.68). Similarly, 2085 pairs of SG and RYGB were propensity score-matched. The complication rate in the SG group was 6.1% (n = 127) as compared to 7.9% (n = 166) in the RYGB group (p = 0.09). And, 702 pairs of OAGB and RYGB were matched. The complication rate in both groups was the same at 7.5 % (n = 53; p = 0.07). Conclusions: This global study found no significant difference in the 30-day morbidity and mortality of SG, RYGB, and OAGB in propensity score-matched cohorts

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

Laparoscopic-assisted esophageal bypass for T4b esophageal tumor as a bridge to definitive therapy

Background/Aim: Esophagobronchial fistula is a common complication of advanced esophageal cancer, related to respiratory distress and mortality. Esophageal bypass has been successfully utilized for palliation, as bridging to definitive chemoradiotherapy. The aim of this study is to present an extremely difficult case of a mid-esophageal squamous cell carcinoma complicated with aerodigestive fistula that was treated using 3D laparoscopic-assisted esophageal bypass with curative intent. Case Report: A 49- year-old female patient presented with T4b esophagealsquamous cell carcinoma and esophagobronchial fistula. Laparoscopic-assisted V-shaped retrosternal esophageal bypass using a gastric conduit was started, which was converted to open surgery due to respiratory distress. The patient was able to undergo chemoradiotherapy treatment. Conclusion: 3D laparoscopic-assisted esophageal bypass can be a safe and feasible approach in patients with advanced midesophageal squamous cell carcinoma and esophagobroncial fistula. Additionally to the advantages of laparoscopic surgery, this operation permits oral feeding, and can be used with possible curative intent in patients with adequate response to chemoradiotherapy. © 2020 International Institute of Anticancer Research. All rights reserved

Intrathoracic hand-sewn esophagogastric anastomosis in prone position during totally minimally invasive two-stage esophagectomy for esophageal cancer

Utilization of totally minimally invasive esophagectomy for cancer is on the rise. Esophagogastric anastomosis is mechanically or robotically performed routinely; little report exists of hand-sewn esophagogastric anastomosis. This is the largest so far study with thoracoscopic hand-sewn esophagogastric anastomosis during fully minimally invasive two-stage esophagectomy for esophageal cancer in prone position. Consecutive two-stage totally minimally invasive esophagectomies for cancer were performed by one surgical team, from September 2016 to March 2019. All operations were technically identical in terms of patient positioning, surgical approach, extend of lymphadenectomy and type of anastomosis formed. Primary end points were anastomotic leak and anastomotic stricture rate, while secondary end points were 30-day and 90-day mortality rates. From the overall n = 80 patients, n = 67 were males, while n = 13 were females. Mean age was 64.6 years. Mean length of stay was n = 14 days. There were no conversions to open. Mean operating time was 420 minutes with no blood loss over 200 mL noted. Pulmonary and cardiac complication rate was 23.75% and 2.5%, respectively. Anastomotic leak rate was 2.5%. Anastomotic strictures were seen in 12.5% of cases. 30-day and 90-day mortality rate was 2.5% and 5%, respectively, with none accounted for ischemic conduit complications. Intrathoracic anastomosis in totally minimally invasive esophagectomy is challenging and accountable for most of the mortality associated with the procedure. In thoracoscopic two-stage esophagectomy, a mechanical anastomosis is usually preferred; this is believed to be due to the complexity of manual anastomosis associated with the thoracoscopic approach. We aim to present our series of completely hand-sewn intrathoracic anastomosis utilizing a totally minimally invasive approach with favorable outcomes. With this study, reproducibility of the anastomosis is shown that can potentially favor a change in the practice of esophageal surgeons worldwide. © 2020 The Author(s) 2020. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: [email protected]

RODOS meteorological pre-processor and atmospheric dispersion model DIPCOT: a model suite for radionuclides dispersion in complex terrain

The Meteorological Pre-Processor (MPP) of the Decision Support System RODOS acts as interface between the incoming meteorological data from stations and/or prognostic models and the Atmospheric Dispersion Models (ADMs) used for predicting the spread of the accidentally emitted radionuclides. The MPP includes a diagnostic Wind Field Model (WFM) to ensure mass conservation of the calculated wind field. Its output is usable by simple and complex ADMs and it is applicable for highly complex topography and from micro- to meso-scales. The MPP has been tested for both real and artificial flow fields and it has been optimized to function with very short execution times and to give the most reasonable results under all terrain complexity and atmospheric stability conditions. DIPCOT (DIsPersion over COmplex Terrain) is a Lagrangian Puff / Particle model that has been implemented in RODOS to simulate radionuclides atmospheric dispersion over complicated terrain. For this purpose, it uses a certain number of fictitious puffs/particles which are assumed to move with the mean wind flow plus a random velocity component to simulate turbulent diffusion. The calculation of the gamma radiation dose rates in air due to the radioactive plume is calculated by a very fast method that takes into account the inhomogeneous 3-dimensional cloud shape. DIPCOT has been evaluated by comparisons to widely used real-scale experimental data sets: Copenhagen, Prairie Grass, Indianapolis and Mol. The integration of the above models greatly enhances the applicability of the RODOS system