<p> During exercise in a hot climate, it has been reported that children respond with a greater shift in blood volume from the central to the peripheral circulation, compared with adults. This can lead to inadequate central circulation, and early cessation of activity in children. No studies have considered if a transition in this hemodynamic response occurs during puberty in females. This study measured hemodynamic responses in pre/early (PEP), mid- (MP), and late- (LP) pubertal girls. Twenty-seven 9- to 16- year-old healthy girls (n=9, each group) cycled in a climatic chamber set at 35 ± 1°C and 50 ± 5% relative humidity for two 20-min bouts (10-min rest in between and a 10-min rest at the end). Cardiac output was measured upon chamber entry, in the middle and at the end of each exercise bout. Forearm blood flow (FBF) was measured upon chamber entry, 3 minutes after exercise bout 1 (E1) and bout 2 (E2) and at the end of rest 1 (R1) and rest 2 (R2). Overall, there was no significant group difference in the central hemodynamic (e.g. cardiac index, stroke volume index) responses to exercise in the heat. However, FBF among the three groups at R1 was almost significantly different (p=0.06), such that it was lower in LP than in PEP and MP. FBF in LP also tended to decrease from E1 to R1 (7.91±1.06 to 6.1±0.83 ml•100ml-1•min-1) and from E2 to R2 (9.47±1.47 to 8.26±1.20 ml•100ml-1•min-1). In contrast, PEP and MP showed little change in FBF at all time points. These findings strengthen the notion that there is a maturity-related decrease in forearm blood flow from pre- to late-puberty. In conclusion, under the conditions of the present study, there were very few differences in the hemodynamic responses of pre-, mid- and late- pubertal girls. It is possible that the transition to an adult-like hemodynamic response does not occur until later in a girl's physical development.</p> / Thesis / Master of Science (MSc)

Obstructive sleep apnea (OSA) is estimated to affect 2 to 4 percent of the adult population (Young T 1993, Skomro and Kryger 1999). However, an estimated 80 to 90 percent of adults with moderate to severe OSA may be clinically undiagnosed. Identification of those at risk and their subsequent diagnosis is, obviously, of great concern to clinicians. This investigation included three distinct research aims, which were the following: (1): In order to establish reliability of hemodynamic measures to be used during exercise testing, a study was conducted on the acetylene single-breath cardiac output (Qc) technique in 15 healthy subjects. This was completed in order to establish reliability of exercise Qc and total peripheral resistance (TPR), these responses could then be investigated acutely in the context of evaluating the relation of these measures to markers of disease in OSA patients. (2): The primary research aim was to describe the extent to which graded exercise testing may reveal abnormalities in hemodynamic function in obstructive sleep apnea (OSA) patients, particularly with respect to cardiac output (Qc), mean arterial pressure (MAP), and TPR that may be related to polysomnography (PSG) markers of OSA severity. Cardiorespiratory and hemodynamic responses that were evaluated included the following: peak oxygen consumption (VO2pk), end-tidal carbon dioxide production (PETCO2), end-tidal oxygen pressure (PETO2), heart rate (HR), blood pressure (systolic = SBP and diastolic = DBP), rate pressure product (RPP), TPR and its derivatives including MAP and Qc, in OSA patients. A global biochemical marker of vascular function, 24-hour urinary nitrite/ nitrate elimination was also determined for each patient. (3): The last aim was included in order to provide qualitative information concerning treatment, subjective sleep and daytime function, and physical activity levels of the OSA patients in this investigation as well as to give insights into the special challenges and potential for doing trials involving nCPAP and physical exercise training with OSA patients. Results from this study can be used to improve clinical evaluation procedures as well as to better understand underlying mechanisms relative to the link between cardiovascular disease and OSA / Ph. D.

The Banner University Medical Center's (BUMC) renal transplant program relies on the LifePort Kidney Transporter to optimize marginal kidney organs via hypothermic machine perfusion (HMP) prior to transplantation. Hemodynamic parameters produced by the device followed over the duration of support, combined with clinical experience, guide decisions in determining the acceptability of a donor kidney for implantation. Thus far, statistical evidence supporting ideal parameters remain undefined. The purpose of this study is to create a logistic model that will ascertain the post-implant sustainability of LifePort® supported kidneys and predict clinical outcomes. My hypothesis is that the statistical models constructed based on retrospective LifePort® parameters and clinical outcome data will successfully predict donor organ vascular health for transplantation and the optimal support duration. A successful model will contribute to increased efficiencies in the kidney transplant process as well as improved patient outcomes. An overview of the institution’s success was weighed using a survival analysis, with delayed graft function (DGF) as the endpoint. A logistic regression model and forecast model were built to predict the outcome for rejecting or accepting the organ for transplant, as well as to predict the hemodynamic parameters hours after the start of infusion. Results concluded a flow greater than 80 mL/min had a 90% probability of transplantation. The forecast model was capable of predicting flow for up to five hours. The calculated flow was in a 10 mL/min range of the actual flow, when up to one hour parameters were entered into the model. The study concluded practicality in the clinical setting, in kidney transplantation.

Orientador: Paulo Sérgio Patto dos Santos / Resumo: Objetivou-se avaliar os efeitos hemodinâmicos, hemogasométricos e sedativos da associação de xilazina e nalbufina em equinos hígidos. Foram utilizados 7 equinos adultos (385 ± 82kg), de ambos os sexos, com idade média de 7 ± 3 anos. Após a administração de bolus sequenciais de xilazina (0,8 mg/kg) e nalbufina (0,025 mg/kg), pela via intravenosa (IV), iniciou-se a infusão contínua de xilazina (0,7 mg/kg/hora) e nalbufina (0,03 mg/kg/hora). As variáveis FC, PAS, PAD, PAM, DC, PVC, PAPM, IS, IC, IRVS, FR, pH, PaO2, PaCO2, HCO3-, BE, temperatura corporal, sedação, ataxia e motilidade intestinal foram avaliadas antes do início da administração dos fármacos (Basal) e a cada vinte minutos após o início da infusão contínua até 80 minutos (T20, T40 e T60 e T80). Houve redução da FC, IC, FR e aumento do IRVS e da PaCO2 após o início da infusão contínua dos fármacos. Com os resultados obtidos é possível concluir que a associação de xilazina e nalbufina, nas doses empregadas neste estudo, promoveu sedação e manteve a motilidade reduzida, sem causar alterações clinicamente significativas nos parâmetros hemodinâmicos e hemogasométricos. / Abstract: The aim of this study was to evaluate the hemodynamic, hemogasometric and sedative effects of xylazine and nalbuphine in healthy horses. Seven adult horses (385 ± 82 kg), with a mean age of 7 ± 3 years, were used. Administration of sequential doses of xylazine (0.8 mg kg-1) and nalbuphine (0.025 mg kg-1), both intravenous (IV), continuous rate infusion of xylazine (0.7 mg kg-1 hour-1) and nalbuphine (0.03 mg kg-1 hour-1). The variables HR, RR SAP, DAP, MAP, CO, CVP, MPAP, SI, CI, SVRI RR pH, PaO2, PaCO2, HCO3-, BE, body temperature, sedation, ataxia and motility were taken immediately before the administration of the drugs (Basal) and then at 20-minute intervals during 80 minutes (T20, T40, T60 and T80). Reduction of HR, CI, respiratory rate (RR) and increase of ISVR and PaCO2 were observed after the administration of xylazine and nalburphine combination. The results allow us to conclude that the xylazine and nalbuphine association, at the doses used in this study, promoted sedation and maintenance of motility reduction without causing clinically significant changes in hemodynamic and hemogasometric parameters. / Mestre

O avanço da bioengenharia atual tem sido motivado pela crescente necessidade da humanidade em se buscar formas para amenizar o sofrimento, garantir tempo para um tratamento, melhorar a qualidade de vida ou sanar quadros clínicos de pacientes. Assim, a crescente necessidade de órgãos artificiais impulsiona a área de bioengenharia para que seja dado um suporte no desenvolvimento destes mecanismos. Neste contexto se encontra o presente trabalho. Aqui, apresenta-se uma metodologia numérica para que seja aplicada a desenvolvimento e testes de Dispositivos de Assistência Cardíaca, de forma a otimizar o processo de desenvolvimento e estimar os possíveis problemas inerentes ao seu funcionamento. Compondo a metodologia, uma ampla discussão de cada etapa numérica foi elaborada, contribuindo para uma metodologia flexível para uma ampla variedade de aplicações. A hemólise também foi investigada através dos principais modelos da literatura, bem como foram propostos modelos adaptados para tentar estimar a hemólise verificada experimentalmente. Além das metodologias para cada etapa, uma metodologia geral utilizando Sistemas de Referências Múltiplas (SRM) compõe os resultados, para uma sequência de passos numéricos que possa obter resultados satisfatórios em comparação com resultados de bancada por loop test. Outros resultados encontrados e devidamente discutidos foram inerentes a uma densidade de malha a ser utilizada para que ocorra simulações com independência de malha, na qual uma densidade a partir de 318,43 elementos/mm³ para referenciais não-inerciais é proposta. O mapeamento da turbulência por seis modelos que aplicam a média de Reynolds também é discutido, indicando os melhores modelos a serem empregados para um número de Reynolds relativo (Re*) que relaciona a influência dos contornos nos resultados numéricos obtidos. Além disso, uma nova abordagem por tensão fisiológica é proposta para o cálculo da hemólise, sendo comparada aos modelos clássicos adotados. Os resultados para hemólise indicam um bom ajuste para o novo modelo proposto, bem como indica o correto tratamento de unidades para os modelos tradicionais. Por fim, as análises recaem na melhoria do dispositivo e conclui a metodologia numérica a ser empregada, preenchendo lacunas em cada etapa e determinando uma maneira de análise numérica cujos resultados são confiáveis. / The advance of current bioengineering has been driven by the increasing need of humanity to seek ways to alleviate the suffering, ensure time to treatment, improve the quality of life or cure medical conditions of patients. Thus, the growing need for artificial organs boosts bioengineering area to be given a support in the development of these mechanisms. In this context is the present work. Here, we present a numerical methodology to be applied to development and Cardiac Assist Devices tests in order to optimize the development process and estimate the potential problems inherent in their operation. Compounding the methodology, a comprehensive discussion of each numerical step was developed, contributing to a flexible methodology for a wide variety of applications. Hemolysis was also investigated through the main models of literature, and have been proposed models adapted to try to estimate hemolysis verified experimentally. In addition to the methodologies for each step, a general methodology using Multiple Reference Systems (MRF) makes up the results for a sequence of numeric steps you can get satisfactory results compared to bench test results for loop. Other findings were discussed and properly attached to a mesh density being used for simulations occurring independently mesh in which a density from 318.43 elements/mm³ Non-inertial frames is proposed. The mapping of turbulence six models applying Reynolds medium is also discussed, indicating the best designs to be employed for a number of relative Reynolds (Re*) that relates the influence of the contours of numerical results obtained. In addition, a new approach by physiological stress is proposed for the calculation of hemolysis, being compared to classic models adopted. The results for hemolysis indicate agreement with the proposed new model, and indicates the correct treatment units to the traditional models. The final analyses fall into improved device and completes the numerical methodology to be used by filling gaps in each step and determining a way to numerical analysis results which are dependable.

Os agonistas alfa 2 adrenérgicos são sedativos empregados na rotina clínica de ruminantes, e têm, entre outras, a vantagem de possuir antagonistas específicos, que aumentam a segurança no uso destes medicamentos. Tendo em vista a escassez de estudos acerca dos parâmetros hemodinâmicos e respiratórios em ovinos em posição quadrupedal e submetidos à sedação com xilazina ou dexmedetomidina com posterior reversão pelo atipamezole, realizou-se o presente estudo. Para tanto, foram utilizados 12 ovinos, machos, com idade entre um e dois anos, peso médio de 37,7kg, distribuídos em dois grupos de seis animais que foram submetidos a dois tratamentos distintos com média de três semanas de intervalo, em estudo do tipo prospectivo, encoberto e aleatório, sendo designados como Grupo XILA (cloridrato de xilazina 0,2 mg/kg IM) e Grupo DEX (cloridrato de dexmedetomidina 15 &micro;g/kg IM). Para a instalação do cateter de artéria pulmonar os animais foram anestesiados com auxílio de máscara facial com isofluorano em oxigênio, e na sequência foram intubados e mantidos sob anestesia com o mesmo agente até o fim da instrumentação. Após a recuperação anestésica foram avaliados os parâmetros hemodinâmicos, hemogasométricos e respiratórios durante os primeiros 60 minutos com os animais em posição quadrupedal, para obtenção dos parâmetros basais. Finalizada esta avaliação, os animais foram submetidos aos protocolos de sedação segundo o seu grupo. Os parâmetros foram verificados e registrados aos cinco (S5), 15 (S15) e 30 minutos (S30) após sedação, e, após a aplicação de 30 &micro;g/kg IM de atipamezole aos cinco (R5) e 15 minutos (R15). Foram avaliados frequência e ritmo cardíaco, pressão arterial sistêmica, parâmetros hemodinâmicos, frequência respiratória, hemogasometria arterial e venosa mista, temperatura central, glicemia e grau de sedação. Os índices ventilatórios e hemodinâmicos foram calculados. O período de latência em XILA e DEX foram 3,9 e 5,2 minutos. A xilazina promoveu sedação mais intensa, com diferença significativa entre os grupos aos 5 e 15min após sedação (momentos S5 e S15). Após a sedação, observou-se redução significativa da frequência cardíaca nos dois grupos, que refletiu no débito cardíaco, índice cardíaco e pressão arterial média. Houve elevação não significativa da resistência vascular sistêmica em ambos os grupos, mas que após o atipamezole ficou significativamente mais baixa no grupo XILA. A xilazina causou taquipneia, que foi inibida após o atipamezole. Não houve alterações clinicamente importantes nos valores de PaCO2, PaO2, SaO2 e nem nos índices de ventilação, indicando que não ocorreu hipoxemia, hipercapnia ou hipoventilação durante a sedação. A glicemia elevou-se de maneira significativa nos dois grupos mantendo-se elevada mesmo após o antagonista. Após administração do atipamezole os animais levaram 10,0 e 11,7 minutos para ficarem em posição quadrupedal e 19,3 e 30 minutos para reversão dos efeitos da xilazina e da dexmedetomidina, respectivamente. Tanto a xilazina como a dexmedetomidina promoveram sedação segura, com poucos efeitos hemodinâmicos e cardiorrespiratórios, sugerindo que a administração pela via intramuscular seja adequada para sedação de ovinos com xilazina ou dexmedetomidina / Adrenergic alpha 2 agonists are sedatives used in ruminants clinical routine and have, among others, the advantage of specific antagonists which increase the safety of these drugs. Given the scarcity of studies on the hemodynamic and respiratory parameters in sheep in standing position and undergoing sedation with xylazine or dexmedetomidine with subsequent reversal by atipamezol, this study was performed. For this purpose were used 12 male sheep, aged between one and two years, average weight 37,7kg. Sheep were divided into two groups of six animals that were submitted to two different treatments with a mean interval of three weeks, in a study of prospective hidden and random type, being designated as XILA Group (xylazine hydrochloride 0.2 mg/kg) and DEX Group (dexmedetomidine hydrochloride 15 &micro;g/kg) given by intramuscular route. For the installation of pulmonary artery catheter, the animals were anesthetized with facial mask with isofluorane in oxygen, and were intubated and maintained under anesthesia with the same agent until the end of instrumentation. After recovery of anesthesia, we evaluated the hemodynamic, blood gas and respiratory parameters during the first 60 minutes with animals in standing position, to obtain the baseline parameters. Completed this evaluation, the animals were submitted to sedation protocols according to their group. The parameters were checked and registered to 5 (S5), 15 (S15) and 30 minutes (S30) after sedation, and after application of 30 &micro;g/kg atipamezole by intramuscular route to 5 (R5) and 15 minutes (R15). Frequency and heart rate, systemic blood pressure, hemodynamic parameters, respiratory rate, arterial and mixed venous blood gas analysis, core temperature, blood glucose and degree of sedation were evaluated. Ventilatory and hemodynamic indices were calculated. The onset period in XILA and DEX were 3.9 and 5.2 minutes. Xylazine promoted more intense sedation, with a significant difference between the groups at 5 and 15 minutes after alpha 2 administration (S5 and S15). After sedation, significant decrease in heart rate was observed in both groups, which reflected in cardiac output, cardiac index and mean arterial pressure. There was no significant increase in systemic vascular resistance in both groups, but after atipamezol was significantly lower in the XILA group. Xylazine caused tachypnea, which was inhibited after atipamezol. There were no clinically significant changes in PaCO2, PaO2, SaO2 nor in the ventilation indices, indicating that there was no hypoxemia, hypercapnia or hypoventilation during sedation period. Blood glucose rose significantly in both groups, remained higher even after antagonist. After administration of atipamezol sheep needed 10.0 and 11.7 minutes to remain in standing position and 19.3 and 30 minutes to reverse the effects of dexmedetomidine and xylazine, respectively. Xylazine and dexmedetomidine promoted safe sedation with few hemodynamic and cardiorespiratory effects, suggesting that the intramuscularly route is suitable for sedation of sheep with xylazine or dexmedetomidine

En IRMf, les conclusions de paradigmes expérimentaux restent encore sujettes à caution dans la mesure où elles supposent une connaissance a priori du couplage neuro-vasculaire, c’est-à- dire de la fonction de réponse hémodynamique qui modélise le lien entre la stimulation et le signal mesuré. Afin de mieux appréhender les changements neuronaux et vasculaires induits par la réalisation d’une tâche cognitive en IRMf, il apparaît donc indispensable d’étudier de manière approfondie les caractéristiques de la réponse hémodynamique. Cette thèse apporte un nouvel éclairage sur cette étude, en s’appuyant sur une méthode originale d’analyse intra-sujet des données d’IRMf : la Détection-Estimation Conjointe (« Joint Detection-Estimation » en anglais, ou JDE). L’approche JDE modélise de façon non paramétrique et multivariée la réponse hémodynamique, tout en détectant conjointement les aires cérébrales activées en réponse aux stimulations d’un paradigme expérimental. La première contribution de cette thèse a été centrée sur l’analyse approfondie de la variabilité hémodynamique, tant inter-individuelle qu’inter-régionale, au niveau d’un groupe de jeunes adultes sains. Ce travail a permis de valider la méthode JDE au niveau d’une population et de mettre en évidence la variabilité hémodynamique importante apparaissant dans certaines régions cérébrales : lobes pariétal, temporal, occipital, cortex moteur. Cette variabilité est d’autant plus importante que la région est impliquée dans des processus cognitifs plus complexes.Un deuxième axe de recherche a consisté à se focaliser sur l’étude de l’organisation hémodynamique d’une aire cérébrale particulièrement importante chez les êtres humains, la région du langage. Cette fonction étant liée à la capacité d’apprentissage de la lecture, deux groupes d’enfants sains, âgés respectivement de 6 et 9 ans, en cours d’apprentissage ou de consolidation de la lecture, ont été choisis pour mener cette étude. Deux apports méthodologiques importants ont été proposés. Tout d’abord, une extension multi-sessions de l’approche JDE (jusqu’alors limitée au traitement de données mono-session en IRMf) a été mise au point afin d’améliorer la robustesse et la reproductibilité des résultats. Cette extension a permis de mettre en évidence, au sein de la population d’enfants, l’évolution de la réponse hémodynamique avec l’âge, au sein de la région du sillon temporal supérieur. Ensuite, un nouveau cadre a été développé pour contourner l’une des limitations de l’approche JDE « standard », à savoir la parcellisation a priori des données en régions fonctionnellement homogènes. Cette parcellisation est déterminante pour la suite de l’analyse et a un impact sur les résultats hémodynamiques. Afin de s’affranchir d’un tel choix, l’alternative mise au point combine les résultats issus de différentes parcellisations aléatoires des données en utilisant des techniques de «consensus clustering». Enfin, une deuxième extension de l’approche JDE a été mise en place pour estimer la forme de la réponse hémodynamique au niveau d’un groupe de sujets. Ce modèle a pour l’instant été validé sur simulations, et nous prévoyons de l’appliquer sur les données d’enfant pour améliorer l’étude des caractéristiques temporelles de la réponse BOLD dans les réseaux du langage.Ce travail de thèse propose ainsi d’une part des contributions méthodologiques nouvelles pour caractériser la réponse hémodynamique en IRMf, et d’autre part une validation et une application des approches développées sous un éclairage neuroscientifique. / In fMRI, the conclusions of experimental paradigms remain unreliable as far as they supposesome a priori knowledge on the neuro-vascular coupling which is characterized by thehemodynamic response function modeling the link between the stimulus input and the fMRIsignal as output. To improve our understanding of the neuronal and vascular changes inducedby the realization of a cognitive task given in fMRI, it seems thus critical to study thecharacteristics of the hemodynamic response in depth.This thesis gives a new perspective on this topic, supported by an original method for intra-subjectanalysis of fMRI data : the Joint Detection-Estimation (or JDE). The JDE approachmodels the hemodynamic response in a not parametric and multivariate manner, while itjointly detects the cerebral areas which are activated in response to stimulations deliveredalong an experimental paradigm.The first contribution of this thesis is centered on the thorough analysis of the interindividualand inter-regiona hemodynamic variability from a population of young healthyadults. This work has allowed to validate the JDE method at the group level and to highlightthe striking hemodynamic variability in some cerebral regions : parietal, temporal, occipitallobes, motor cortex. This variability is much more important as the region is involved in morecomplex cognitive processes.The second research axis has consisted in focusing on the study of the hemodynamic orga-nizationof a particularly important cerebral area in Humans, the language system. Becausethis function embeds the reading learning ability, groups of healthy children of 6 and 9 yearsold respectively, who were in the process of learning or of strenghting reading, were chosen forthis study. Two important methodological contributions have been proposed. First, a multi-sessionsextension of the JDE approach (until now limited to the processing of mono-sessiondata in fMRI) was worked out in order to improve the robustness and the reproducibility ofthe results. Then, a new framework was developed to overcome the main shortcoming of theJDE approach. The latter indeed relies on a prior parcellation of the data in functionally ho-mogeneousregions, the choice of which is critical for the subsequent inference and impacts thehemodynamic results. In order to avoid this a priori choice, the finalized alternative combinesthe results from various random data fragmentations by using “consensus clustering”.Finally, a second extension of the JDE approach was developed in order to robustly estimatethe shape of the hemodynamic response at the group level. So far, this model was validatedon simulations, and we plan to apply it on children data to improve the study of the BOLDresponse temporal characteristics in the language areas. Thus, this PhD work proposes onone hand new methodological contributions to characterize the hemodynamic response infMRI, and on the other hand a validation and a neuroscientific application of the proposedapproaches.

Made available in DSpace on 2014-06-11T19:22:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2002Bitstream added on 2014-06-13T19:48:37Z : No. of bitstreams: 1 meletti_jfa_me_botfm.pdf: 304572 bytes, checksum: 2aa2c2ff89fef69f6ae6c470cdfdfd03 (MD5) / Diversos modelos experimentais têm sido utilizados para ilustrar as alterações hemodinâmicas e metabólicas que ocorrem durante o choque hemorrágico. O objetivo da pesquisa é observar os comportamentos hemodinâmicos e metabólicos que acontecem em um modelo seqüencial e progressivo de choque hemorrágico em cão, verificando quais índices alteram-se mais precocemente. Metodologia: O estudo foi realizado em 13 cães sob anestesia intravenosa total com pentobarbital sódico, em normoventilação e previamente esplenectomizado. Os animais não foram hidratados e a velocidade do sangramento foi ditada pela pressão arterial em que o animal se encontrava. Os atributos estudados foram divididos em hemodinâmicos (freqüência cardíaca – FC, pressão arterial média – PAM, índice de resistência vascular sistêmica – IRVS, índice sistólico – IS, índice cardíaco – IC, índice de choque – I. choque, índice de trabalho sistólico do ventrículo esquerdo – ITSVE, pressão capilar pulmonar – PCP, pressão venosa central – PVC) e metabólicos (saturação venosa mista – SvO2, pressão venosa de oxigênio – PvO2, transporte de oxigênio – DO2, consumo de oxigênio – VO2, Extração de oxigênio – TEO2, lactato sérico – Lactato). A coleta de dados e os atributos foram estudados em 6 momentos distintos: M1 – controle, M2 – sangramento de 10% da volemia calculada para o animal, M3 – sangramento de... / Many experimental models have been used to elucidate hemodynamic and metabolic alterations that occur during the hemorrhagic shock. The aim of this research is to observe hemodynamic and metabolic behaviours present in a sequential and progressive model of hemorrhagic shock in dogs, verifying which indexes change more precociously. Methods: This study was performed in 13 dogs under total intravenous anesthesia with sodic pentobarbital, with standart ventilation and formerly splenectomized. The animals were not hydrated and the bleeding velocity was according to the blood pressure of the animal. The studied parameters were divided into hemodynamics (heart rate – HR, mean arterial blood pressure – MAP, sistemic vascular resistance index – SVRI, sistolic index – SI, cardiac index – CI, shock index – S index, sistolic function of the left ventricle index – SFLVI, pulmonary capillary pressure – PCP, central venous pressure – CVP) and metabolics (mixed venous saturation – MVS, venous oxigen pressure – VOP, oxygen transport – OT, oxygen consumption – OC, oxygen extraction – OE and seric lactate). The results and parameters were evaluated in 6 different moments: M1 – control, M2 – bleeding of 10% of calculated volemic for the animal, M3 – increase of 10% in bleeding, M4 – increase of 10% in bleeding, M5 - increase... (Complete abstract, click electronic access below)

Coronary artery disease is a leading cause of death in the Western world. Symptoms present only late in the progression of the disease, limiting treatment options; moreover, the inability to biopsy arterial tissue in a living patient makes it difficult to study the pathology effectively. 89 patients were imaged twice at a one year interval using x-ray angiography (the traditional modality for assessment of arterial stenosis) and intravascular ultrasound (IVUS), which yields a detailed image of the structure of the vessel wall. 32 of these 89 patients were made available for analysis in this study. The Volcano Corp.~IVUS acquisition systems include software that provides a \textit{virtual histology} (VH) characterization of plaque composition that provides information otherwise only available by biopsy. Using a geometric reconstruction method described in previous work, a full working model of wall shear stresses (WSS) produced by blood flow and vessel wall composition is created. Using these, the morphologic structural information gleaned from the 3-D reconstruction, and some additional composite indices, combined with demographic information collected at enrollment and serum biomarkers collected from each patient during imaging, a detailed portrait of each patient's disease state is created, with the objective of predicting disease evolution over a 1 year timescale. We have, in the course of this study, accomplished the following 5 aims towards the goal of predicting localized changes in disease state on a 1 year timescale: Aim 1: Develop and validate a method of compensating for rotational motion of the catheter within the vessel and its effect upon the 3-D orientation of the reconstruction. Aim 2: Develop and validate a method of registering the reconstructed vessels that permits identification of a point-to-point correspondence on all quantitative indices. Aim 3: Successfully reconstruct, register, and analyze image sets for each of as many patients as possible for analysis. Aim 4: Identify statistically significant indices in the data suitable for use as features in a classifier. Aim 5: Construct and assess performance of a classification system that can draw useful conclusions about the 1-year progression of the arterial pathology in a patient not used in the training set. Aim 2 was a complete success. Branches were reliably present in the IVUS data in sufficient quantities to facilitate reliable identification of the overlap and the requisite spatial transformation required to map points from one pullback onto another. Aim 1 was much more problematic. While a method was developed which showed promise, the image acquisition protocol did not provide for orientation of the angiograms with an eye towards bifurcation identification. With neither an analytic model, nor reasonable fiducials, the method developed could only be tested on a small subset of the data, limiting both our confidence in its validation, as well as its usability in this study. It is hoped that the method can be refined and used in any subsequent study, given proper planning during the acquisition of the images, and that in turn the spatial reliability of the reconstructions can be improved beyond what is possible today. Regarding aim 3, 32 patients were ultimately processed completely. Aims 4 and 5 were completed successfully. Meaningful correlations were identified in the data, and the results illustrate that while we were by no means able to obtain perfect classification, we were able to handily beat a both a random, and a maximum likelihood classifier.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2007. / Härtill 4 uppsatser.