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Aluminum is a highly produced metal globally. In the built environments alone, aluminum is known for its light weight and anti-corrosive properties and is a common choice of material in window frames, curtain walls, and light fixtures. The metal is processed from its oxide, alumina, the production of which releases a caustic byproduct known as bauxite residue (BR). BR is stored in massive reservoirs, however, due to the sheer volume of production, industries handling the material are reaching their storage limits. It is of high importance to research methods to valorize BR. Researchers have proposed a multitude of valorization methods, which include metal recovery from the byproduct, and using BR as raw material in production of another material. However, it is counterproductive to expend considerable amounts of energy and use excessive raw materials to manage utilization of BR. This study compared a method of valorization of bauxite residue with clay bricks. The method of preparing alkali-activated materials (AAM) with bauxite residue as a precursor was semi-quantitatively analyzed to compare the raw materials in the AAM with clay bricks. The materials were analyzed for climate change, ozone depletion, human toxicity, and aquatic ecotoxicity using OpenLCA software and the ecoinvent version 3.4 database. While the alkali activators possessed high values of the environmental impact when measured by the kilogram, the impacts were greatly reduced due to their small percentage in weight contained in the AAM. This study is the first stage of analyzing the environmental costs of valorizing bauxite residue. The AAM showed low environmental impact in material use when impacts of toxicity are considered. However, it displayed a higher climate change impact than that of clay bricks. Transport of raw materials to the preparation site played a significant role in the analysis. The next step is to compare the energy used in preparing AAMs.

INTRODUCTION: As the population ages, so too does the age of those requiring surgery. People over the age of 100, centenarians, often have a greater degree of comorbidity and frailty than their younger counterparts but may also have a greater incidence of events requiring surgical intervention. There is, however, a dearth of literature describing the clinical course and practical considerations for this vulnerable population undergoing surgery. We aimed to describe the demographics of centenarians undergoing surgery, the procedures they receive, their intraoperative anaesthesia management, and their postoperative outcomes. PRESENTATION OF CASES: A retrospective cohort study was completed to understand key perioperative and intraoperative variables linked to improved outcomes. Of the 25 patients included in this study, 22 (88%) were female and the median age was 101 years. Emergency cases predominated (72%) and 44% of surgeries occurred after hours. 60% underwent an intermediate risk surgery, and no centenarians underwent high risk surgery in this study period. DISCUSSION: 64% of patients experienced at least one episode of intraoperative hypotension, with a median 3.5 epochs per patient. 68% of patients experienced postoperative complications and 20% of patients had a complication of Clavien-Dindo severity ≥ III. In centenarians, the risk of high severity postoperative complications was independent of the intrinsic procedural risk. CONCLUSION: Centenarian patients have an elevated burden of comorbidity, presenting often in the emergent setting. However, age alone should not preclude surgical intervention as expert multidisciplinary care can have acceptable outcomes.

Objectives: To compare agreement and variability of cardiac output measurement of 2-dimensional (2D) and 3D transesophageal echocardiography (TEE) with thermodilution before and after bypass. Design(s): Prospective observational study. Setting(s): Two tertiary hospitals. Intervention(s): Cardiac output (CO) was measured simultaneously with thermodilution and TEE by multiplying either the left ventricular outflow tract area (LVOTA) or aortic valve area (AVA), the velocity-time integral (VTI) of flow at the same site, and heart rate. The LVOTA was calculated using diameter for 2D TEE. Planimetry was used for 3D TEE. The AVA was measured using planimetry. Participant(s): The study comprised 82 adult patients undergoing coronary or valve surgery. Measurements and Main Results: One hundred fifty-four complete sets of measurements were obtained (82 prebypass and 72 postbypass). All TEE methods had acceptable correlation and absence of proportional or fixed bias except for the left ventricular outflow tract (LVOT) VTI modal trace method, which had poor correlation and proportional but not fixed bias (regression coefficient [95% confidence interval], bias [percentage of mean CO]): 2D LVOT VTI modal trace 0.67 (0.54-0.80), -36.4%; 2D LVOT VTI outer edge trace 0.96 (0.80-1.12), -15.3%; 2D AVA planimetry 0.96 (0.75-1.18), +4.9%; 3D LVOT area planimetry 1.18 (0.96-1.41), +0.8%; 3D AVA planimetry 1.20 (0.93-1.46), +0.4%. All TEE methods had wide levels of agreement compared with thermodilution (-3.94 to +0.23 L/min, -2.83 to +1.28 L/min, -2.23 to +2.73 L/min, -2.35 to +2.42 L/min, and -2.57 to +2.61 L/min, respectively). Measurement variability was superior for all TEE methods compared with thermodilution before but not after bypass. Conclusion(s): Although limits of agreement of CO measurement with 3D TEE and thermodilution are wide, 2D planimetry of the AVA and continuous wave Doppler may be substituted for thermodilution before and after bypass.Copyright © 2019 Elsevier Inc.

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Introduction. Transpulmonary thermodilution (TD) is the most used method for cardiac output (CO) monitoring during cardiac surgery. Although 2D transoesophageal (TOE) measurement of CO using spectral Doppler correlates with TD, 3D TOE more accurately measures left ventricular outflow tract (LVOT) and aortic valve (AV) area, which are used to calculate CO. The aim of this study is to compare the precision of CO measurement between 2D and 3D TOE against TD. Method. After ethics approval, 50 patients aged over 18 years scheduled for on-bypass cardiac surgery were recruited prospectively at two institutions. Exclusion criteria included more than mild valvular regurgitation, and atrial fibrillation. CO was measured simultaneously by TD and TOE before sternotomy and after cardiopulmonary bypass. CO was calculated using TOE by the product of either the LVOT or AV area, the velocity-time integral (VTI) of flow at the same site and heart rate. The LVOT area was assumed circular and calculated using the LVOT diameter for 2D but with planimetry using 3D TOE. The AV area was estimated with planimetry by both 2D and 3D TOE, and VTI with continuous wave Doppler. Both modal and outer edge traces of LVOT VTI were performed with the cursor 0.5 cm from the annulus. Measurements were averaged from 3 consecutive beats by 2 observers. Deming model II regression was used to assess fixed and proportional bias of agreement with TD. Bland-Altman technique was used to assess closeness of fit. Results. CO was measured at 94 time-points (50 before sternotomy, 44 after chest closure) in 50 patients. The 3D methods had better agreement than 2D with TD, with the best agreement with 3D planimetry of the AV (bias -0.04 Lmin-1, SD of difference between the mean 1.37 Lmin-1), followed by 3D LVOT area planimetry (0.14, 1.41), 2D AV area planimetry (0.28, 1.3) and 2D LVOT VTI outer edge trace (-0.59, 1.29). 3D LVOT area planimetry had the best correlation (slope 1.39, 95%CI 0.97-1.82), followed by 2D A

Purpose: Transpulmonary thermodilution (TD) is the gold standard for cardiac output (CO) monitoring during cardiac surgery but is feasible with TOE, but 2D TOE underestimates CO due to assumption of a circular LVOT, when 3D TOE demonstrates it is ovoid. The aim of this study is to determine if 3D TOE correlates better with TD than 2-D TOE. Methodology: After ethics approval, 50 adult patients without more than mild valvular regurgitation or A who were scheduled for bypass cardiac surgery were recruited prospectively at two institutions. CO was measured simultaneously by TD and TOE (2D/3D) before and after CPB. CO was calculated using the continuity method (product of VTI, area and heart rate) using the modal and outer-edge trace of the LVOT VTI. The aortic valve area was estimated with planimetry by both 2D and 3D TOE. Agreement analysis was performed using the Deming model II regression analysis and Bland-Altman technique (TD as the reference method). Results: Proportional but not fixed bias was present for the VTI modal method but not for any other method. Correlation for LVOT modal was poor (0.40) and CO was underestimated (mean bias = -1.59 L.min-1), but the limits of agreement were similar to other methods. Tracing the edge of the LVOT VTI rather than the modal line reduced the bias (-0.59 L.min-1), and improved correlation (0.92). 3D planimetry of the AV and continuous wave Doppler had the best agreement with TD. The mean bias approached zero for the 3D methods but with similar limits of agreement. Conclusion: For 2D measurements, tracing around the LVOT VTI rather than through the modal line improved precision. The other 2D and 3D measurements of CO showed absence of bias, and reasonable agreement with TD.