Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 4 uppsatser.

No description available.

Student Number : 0418382M - MSc(Eng) dissertation - School of Electrical Engineering and Information Technology - Faculty of Engineering and the Built Environment / Pulmonary embolism (PE) is a potentially fatal, yet potentially treatable condition. The problem of diagnosing PE with any degree of confidence arises from the nonspecific nature of the symptoms. In difficult cases, multiple tests will need to be performed on a patient before an accurate diagnosis can be made. These tests include Ventilation-Perfusion (V/Q) scanning, Spiral CT, leg ultrasound and d- Dimer testing. The aim of this research is to test the performance of using neural networks, namely Bayesian Neural Networks, to make a diagnosis based on available information. The information contains of a set of 12 V/Q scans which have been processed, and from which features have been extracted to provide inputs to the neural network. This system will act as a second opinion, and is not intended to replace an experienced clinician. The V/Q scans are analysed using image processing techniques in order to segment the lung from the background image and to determine if any abnormalities are present in the lung. The system must be able to discriminate between a genuine case of PE and of other diseases showing similar symptoms such as tuberculosis and parenchymal lung disease. Relevant features to be used in classification were then extracted from the images. The goal of this system is to make use of Bayesian neural networks. Using Bayesian networks, confidence levels can be calculated for each prediction the network makes. This makes them more informative than traditional multi layer perceptron (MLP) networks. The V/Q scans themselves are greyscale images of [256x256] size. In order to reduce redundancy and increase computational speed, Principal Component Analysis (PCA) is used to obtain the most significant information in each of the scans. Usually the Gold Standard for such a system would be pulmonary angiography, but in this case the Bayesian MLP (BMLP) is trained based on diagnosis by an experienced nuclear medicine physician. The system will be used to look at new cases for which the accuracy of the system can be established. Results showed good training performance, while validation performance was reasonable. Intermediate cases proved to be the most difficult to diagnose correctly.

Acknowledgements First and foremost, I am very grateful to my supervisor, Dr. Kerstin de Wit, for her mentorship and guidance throughout my time as a graduate student. It has been a pleasure to work with someone so innovative and passionate about clinical research. Her ability to bridge thrombosis and emergency medicine research to improve and change clinical practice is inspiring. I am grateful to my supervisory committee members, Dr. Teresa Chan, Dr. Lori-Ann Linkins, and Dr. Mathew Mercuri, for their continuous support throughout this process. Our scientific discussions were always insightful, and motivated me to push myself as a researcher. I am very thankful to the entire EMeRGE Research Group for creating such a helpful and friendly environment. Their diligence and commitment to conducting high-quality research motivated me to do the same, and greatly expanded my knowledge on clinical research. Working with this team made my experience as a graduate student very memorable. I would like to thank my family and friends for all of the support they gave me throughout this entire process. Their constant encouragement and emotional support helped me overcome challenges and persevere, for which I am infinitely grateful. / Background: There is an evidence-practice gap between guidelines for diagnosing pulmonary embolism (PE) and emergency physician practice. This is concerning because computed tomography (CT) scanning is being overused to exclude PE in the emergency department (ED). It is possible that the answer behind this lies within the physician-patient relationship. Past research on shared decision-making strategies have shown to decrease use of hospital resources, and improve patient outcomes. Objective: The aim of this three-part MSc thesis was to achieve a patient-centered approach to the testing of PE in the ED. Method: 1) A systematic review on existing shared decision-making models used for testing and/or treatment of medical decisions in the ED was conducted. 2) Qualitative interviews with ED patients being tested for PE identified patient-specific values and preferences which may present as barriers to patient-centered care in the ED. 3) Both the systematic review and patient interviews informed the development of a new shared information tool to be used in the ED. Results: The systematic review found that shared decision-making interventions in ED patients tested for acute coronary syndrome and clinically-important traumatic brain injuries can potentially reduce hospital admissions and increase discharge rates without negatively affecting health outcomes. The qualitative interviews highlighted four major themes: 1) patient satisfaction comes from addressing their primary concern; 2) preference for imaging over clinical examination; 3) patients expect 100% certainty when given a diagnosis; and 4) patients expect individualized care throughout their entire ED visit. This data led to the formation of a shared information sheet which ensures that testing decisions for low-risk PE patients align with patient-specific values. Conclusion: By placing the focus on patient-centered care, this study incorporates evidence-based medicine with patient priorities in order to improve patient outcomes in the ED. / Thesis / Master of Science (MSc) / Pulmonary embolism occurs when blood clots form in veins of the legs, and travel to the lungs, causing chest pain and shortness of breath. There are well-established, evidence-based guidelines on how to diagnose pulmonary embolism. Diagnostic tools such as the Wells score and D-dimer have been proven to be safe and effective in ruling out pulmonary embolism in low risk patients preventing the need for a CT scan. However, CT scans are still being overused to diagnose pulmonary embolism in low risk patients. Unnecessary testing in the emergency department (ED) exposes patients to the harms associated with CT scanning: such as increased risk of cancer, and diagnosing blood clots that are not actually there, resulting in unnecessary treatment. It is possible that the answer behind the over-testing of PE in the ED lies within the physician-patient relationship. This three-part study first reviewed all prior studies on shared decision-making strategies, which are techniques used to help physician align medical decisions with patient-specific values, in the ED. Second, we employed qualitative methods to identify patient-specific values and preferences on PE testing in the ED. Finally, both of these aims informed the development of a patient-centered shared information tool to overcome barriers to patient-centered care. Ultimately, the goal of this study is to achieve a patient-centered approach to the testing of pulmonary embolism in the ED.

by Cheung Ngai Man, Edmund. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 73-83). / Acknowledgments --- p.i / Abstract --- p.iii / List of Figures --- p.viii / List of Tables --- p.xi / Chapters / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Intramedullary nailing --- p.1 / Chapter 1.2 --- Reaming technique for intramedullary nailing --- p.3 / Chapter 1.3 --- The relationship between pulmonary fat embolism and reaming technique --- p.7 / Chapter 1.4 --- Objectives --- p.10 / Chapter 2 --- Methodology --- p.12 / Chapter 2.1 --- The measurement of the intramedullary pressure --- p.12 / Chapter 2.1.1 --- Animal model --- p.12 / Chapter 2.1.2 --- Intramedullary pressure measurement device --- p.12 / Chapter 2.1.3 --- Operative procedure --- p.14 / Chapter 2.1.4 --- Intramedullary pressure measurement --- p.16 / Chapter 2.2 --- The measurement of the plasma lipids and marrow lipids --- p.19 / Chapter 2.2.1 --- Samples collection --- p.19 / Chapter 2.2.2 --- Lipid extraction --- p.19 / Chapter 2.2.3 --- Thin layer chromatography --- p.20 / Chapter 2.2.4 --- Methylation --- p.24 / Chapter 2.2.5 --- Gas chromatographic analysis --- p.24 / Chapter 2.3 --- The measurement of the pulmonary lipids and fat emboli --- p.27 / Chapter 2.3.1 --- Pulmonary tissue collection --- p.27 / Chapter 2.3.2 --- Preparation for measurement of pulmonary lipids --- p.27 / Chapter 2.3.3 --- Fat emboli staining --- p.27 / Chapter 2.3.4 --- Image analysis --- p.28 / Chapter 2.4 --- Statistical analysis --- p.31 / Chapter 3 --- Results --- p.32 / Chapter 3.1 --- Intramedullary pressure measurement --- p.32 / Chapter 3.2 --- The analysis of bone marrow lipids --- p.34 / Chapter 3.3 --- The changes of the plasma lipids during reaming --- p.39 / Chapter 3.4 --- The measurement of the pulmonary fat emboli --- p.44 / Chapter 3.5 --- The relationship between the intramedullary pressure and plasma lipids and pulmonary fat intravasation --- p.52 / Chapter 4 --- Discuss --- p.55 / Chapter 4.1 --- The experimental design --- p.55 / Chapter 4.2 --- The change of the intramedullary pressures --- p.57 / Chapter 4.3 --- The application of the gas chromatography --- p.59 / Chapter 4.4 --- The composition of bone marrow lipids --- p.62 / Chapter 4.5 --- The changes of plasma lipids --- p.63 / Chapter 4.6 --- The pulmonary fat embolisation --- p.65 / Chapter 5 --- Conclusion --- p.69 / Chapter 6 --- Future direction on this study --- p.71 / References --- p.73 / Appendix --- p.84 / Chapter 1 --- The operation of the IM Press device --- p.84 / Chapter 2 --- The calibration of the IM Press --- p.85 / Chapter 3 --- The preparation of the internal standards for the lipid analysis --- p.89 / Chapter 4 --- The composition of the bone marrow lipids --- p.91 / Chapter 5 --- The composition of plasma lipids --- p.95 / Chapter 6 --- The composition of pulmonary lipids --- p.101 / Chapter 7 --- The measurement of the pulmonary fat emboli --- p.105

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.

No description available.

OBJECTIVES: Clot in transit represents a life-threatening manifestation of venous thromboembolism of which we have limited understanding. This study was designed to describe the risk factors, clinical characteristics and outcomes associated with the development of a clot in transit as well as death within clot in transit patients. METHODS: We enrolled 1,093 consecutive patients into our single-center Pulmonary Embolism Response Team Registry. We compared 76 patients who had a clot in transit to 589 pulmonary embolism patients who did not have a clot in transit. RESULTS: Clot in transit was present in 11.4% of patients who received an echocardiogram to look for it. Multivariate analysis showed congestive heart failure (OR 2.954, 95% CI 1.349 – 6.467, P = 0.0068), a pre-existing inferior vena cava filter (OR 2.777, 95% CI 1.204 – 6.407, P = 0.0167), and hemodynamic collapse (OR 3.495, 95% CI 1.129 – 10.823, P = 0.0300) to be independent predictors of clot in transit. All-cause mortality by 30 days was higher in clot in transit patients (24.3% vs 9.7%, P < 0.001). All-cause mortality by 7 days within clot in transit patients was associated with hemodynamic collapse (45.5% vs 12.3%, P = 0.018) and mental status change (63.6% vs 21.5%, P = 0.008). CONCLUSIONS: The presence of congestive heart failure, a pre-existing inferior vena cava filter, and hemodynamic collapse are independent predictors of clot in transit and should alert physicians to patients who may require an echocardiogram. The mortality for clot in transit is high even when compared to a more severe pulmonary embolism population. Clot in transit represents a high-risk finding that may require more aggressive interventions. / 2020-06-14T00:00:00Z

INTRODUCTION: Cirrhosis is a significant cause of mortality and morbidity worldwide. Recent studies suggested that cirrhosis is associated with an increased risk of venous thromboembolism (VTE), which disproves the old belief that chronic liver disease coagulopathy is considered protective against VTE. We conducted a retrospective study which is to our knowledge the first of its kind to assess clinical characteristics and outcomes of decompensated cirrhosis (DC) patients admitted with acute pulmonary embolism (APE). METHODOLOGY: We used the National Inpatient Sample database for the years 2016-2019. All adults admitted to the hospitals with a primary diagnosis of APE were included. Patients less than 18 years old, missing race, gender, or age were excluded. Patients were divided into two groups, either having DC or not. A multivariate logistic regression model was built by using only variables associated with the outcome of interest on univariable regression analysis at P < 0.05. RESULTS: 142 million discharges were included in the NIS database between the years 2016 and 2019, of which 1,294,039 met the study inclusion criteria, 6,200 patients (0.5%) had DC. For adult patients admitted to the hospitals with APE, odds of inpatient all-cause mortality were higher in the DC group than in patients without DC; OR of 1.996 (95% CI, 1.691-2.356, P-value < 0.000). Also, vasopressor use, mechanical ventilation, and cardiac arrest were more likely to occur in the DC group, OR of 1.506 (95% CI, 1.254-1.809, P-value < 0.000), OR of 1.479 (95% CI, 1.026-2.132, P-value 0.036), OR of 1.362 (95% CI, 1.050-1.767, P-value 0.020), respectively. In addition, DC patients tend to have higher total hospital charges and longer hospital length of stay, coefficient of 14521 (95% CI, 6752-22289, P-value < 0.000), and a coefficient of 1.399 (95% CI, 0.848-1.950, P-value < 0.000), respectively. CONCLUSION: This study demonstrates that DC is a powerful predictor of worse hospital outcomes in patients admitted with APE. An imbalance between clotting factors and natural anticoagulants produced by the liver is believed to be the primary etiology of thrombosis in patients with DC. The burden of APE can be much more catastrophic in cirrhotic than in non-cirrhotic patients; therefore, those patients require closer monitoring and more aggressive treatment.

Le but de notre travail a été d’évaluer l’effet de la réduction de la dose d’irradiation en TDM multibarrette quant à la performance diagnostique, la confiance de l’observateur dans le diagnostic proposé, la capacité à suggérer un diagnostic alternatif dans quelques pathologies courantes et/ou caractérisées par des situations de faibles contrastes entre les structures anatomiques normales ou pathologiques. Nous avons donc comparé ces paramètres entre des TDM à doses réduites et à doses standard telles que couramment rapportées dans la littérature dans les circonstances suivantes : • La suspicion clinique de colique néphrétique: le contraste naturel élevé du calcium avec les structures voisines suggère de pouvoir réduire fortement la dose, dans une pathologie potentiellement récidivante et qui intéresse des patients jeunes dont le pronostic est excellent. Notre étude a montré qu’une dose 10 fois inférieure à celle générée par des examens TDM courants permet des performances diagnostiques semblables à la TDM à dose conventionnelle. • La suspicion clinique de sinusite chronique: le contraste naturel élevé entre l’air des cavités sinusales, la muqueuse nasale et les os de la face permet de réduire fortement la dose, dans cette pathologie potentiellement récidivante et qui intéresse des patients jeunes dont le pronostic est excellent. Notre étude a montré qu’une dose 10 à 25 fois inférieure à celle générée par des examens TDM courants, et dès lors inférieure à celle générée par quatre incidences radiographiques, permet des performances diagnostiques semblables à la TDM à dose conventionnelle. • La suspicion clinique d’appendicite aiguë: L’appendice est situé dans une atmosphère anatomique caractérisée par un faible contraste entre les structures. Néanmoins, comme l’appendicite est une pathologie qui concerne l’adolescent et l’adulte jeune, nous avons tenté de réduire la dose des TDM dans ce contexte. Notre étude a montré qu’une dose 3 à 10 fois inférieure à celle générée par des examens TDM courants, et dès lors inférieure à celle générée par trois incidences radiographiques, permet des performances diagnostiques semblables à la TDM à dose conventionnelle. • La suspicion clinique de diverticulite aiguë du colon: la diverticulite aiguë du colon est également caractérisée par une atmosphère anatomique de faible contraste entre les structures. Néanmoins, comme cette pathologie peut concerner l’adulte jeune et récidiver, nous avons tenté de réduire la dose des TDM dans ce contexte. Notre étude a montré qu’une dose 3 à 10 fois inférieure à celle générée par des examens TDM courants, permet des performances diagnostiques semblables à la TDM à dose conventionnelle. • Le diagnostic d’embolie pulmonaire aiguë: la TDM spiralée occupe une position centrale dans le diagnostic d’embolie pulmonaire aiguë mais impose l’injection intraveineuse de produit de contraste iodé. La comparaison d’images obtenues à des doses variables d’irradiation a nécessité leur traitement à posteriori pour simuler la réduction de dose. Notre étude a montré qu’une dose 9 fois inférieure à celle générée par des examens TDM conventionnels permet des performances diagnostiques semblables. Ces investigations ont été complétées par l’investigation de l’influence du genre, de l’indice de masse corporelle et de l’âge sur la modulation automatique du courant au tube radiogène (6). Cette investigation a montré que la modulation automatique ne réduit la dose d’irradiation que d’au plus 20% avec peu ou pas de différence en fonction du genre, de l’âge ou de l’indice de masse corporel des patients ; indiquant ainsi qu’elle ne pouvait pas remplacer la réduction de la charge volontaire de l’opérateur.