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Evidence-based medicine is at the heart of current medical practice where clinical decisions are driven by research data. However, most current therapy recommendations follow generalized protocols and guidelines that are based on epidemiological (population) studies and thus not suited for the individual patient's demands. Patient-tailored therapies are considered, hence, an unmet clinical need. We believe that mathematical models of the physiology can attend to such a clinical need, because they can be tuned to the individual patient. Such models provide a sound mathematical framework for personalized clinical decisions. In particular, physiological models in medicine can serve the following two purposes: 1) They can be an efficient tool to quantify cardiopulmonary dynamics, conduct virtual clinical/physiological experiments, and investigate the effects of specific treatments. 2) Model-based estimation techniques can assess physiological parameters or variables, which are otherwise impractical or dangerous to measure; they can effectively tune a generic model to become patient-specific, able to mimic the behavior of a particular patient. In this thesis, we propose a series of modifications to a previously developed cardiopulmonary model (CP Model) in order to better replicate heart-lung interaction phenomena that are typically observed under mechanical ventilation, hence allowing for a more accurate analysis of ventilation-induced changes in cardiac function. The response of this modified model is validated with experimental data collected during mechanical ventilation conditions. Further, as an industrial application of mathematical models, we present a patient emulator system that comprises the modified CP Model, a physical ventilator, and a piston-cylinder arrangement that serves as an electrical-to-hydraulic transducer. The modified CP Model then serves as the virtual patient that is being ventilated, where disease conditions can be instilled. Such a system is designed to offer a well-controlled experimental environment for ventilator manufacturers to efficaciously test and compare ventilation modalities and therapies, thereby enhancing their verification and validation manufacturing processes. Finally, we develop a model-based approach to estimate (noninvasively) the function of the cardiovascular system, in terms of cardiac performance (i.e., cardiac output) and the dynamics of the systemic arterial tree (i.e., time constant). With this technique, we envision to provide continuous and real-time bedside monitoring of changes in cardiovascular function, such as those induced by changes in ventilator settings.

published_or_final_version / Nursing Studies / Master / Master of Nursing

Thesis (M.D.)--University of Pennsylvania, 1808. / Microform version available in the Readex Early American Imprints series.

Thesis (M.A.)--Northern Kentucky University, 2007. / Made available through ProQuest. Publication number: AAT 1441241. ProQuest document ID: 1283973731. Includes bibliographical references (p. 30-33)

Made available in DSpace on 2014-06-11T19:25:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-26Bitstream added on 2014-06-13T20:14:18Z : No. of bitstreams: 1 lima_df_me_botfm.pdf: 419278 bytes, checksum: 677dde7aa062755eb6e9f71846ebfbc7 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Introdução: A fase avançada de pneumopatias, cardiopatias e doenças sistêmicas está associada com o desenvolvimento de insuficiência respiratória crônica (IRespC). O tratamento desta complicação inclui o uso de oxigenoterapia domiciliar prolongada. Na literatura nacional poucos estudos avaliaram a sobrevida em pacientes com doença pulmonar obstrutiva crônica (DPOC) ou com IRespC recebendo oxigenoterapia domiciliar prolongada (ODP). Objetivo: O objetivo deste estudo foi avaliar os fatores de predição de mortalidade em pacientes com IRespC tratados com ODP no período de um, dois e três anos. Pacientes e Métodos: Foram avaliados e acompanhados pelo período mínimo de três anos ou até o óbito, 142 pacientes cadastrados no ambulatório de oxigenoterapia da Faculdade de Medicina de Botucatu (FMB) até julho de 2005. Na avaliação inicial, foram coletados dados de identificação pessoal, história de tabagismo, o uso de medicação, composição corporal, força de preensão manual, função pulmonar, gases sanguíneos e hemograma. Também foram aplicados a escala de dispnéia de Borg, o índice de dispnéia basal (BDI) e o questionário de qualidade de vida na doença respiratória do Hospital Saint George (SGRQ). Resultados: Durante os três anos de estudo; 83 pacientes (58%) morreram: 37 (26%) durante o primeiro ano de acompanhamento, 23 (16%) no segundo ano e 23 (16%) no período de três anos. O grupo óbito apresentou valores de hematócrito e hemoglobina significativamente menores, maior sensação de dispnéia, avaliada pelo BDI e Borg, e apresentou maior 18 comprometimento do estado de saúde, avaliado pelos domínios, impacto, atividade e total do SGRQ. Os principais preditores de mortalidade, na avaliação que incluía todos os pacientes, no período de três anos foram: gênero masculino (HR=2,67, CI=1,15-6,18, p=0,02), menores valores de hemoglobina... / Introduction: The advanced stage of lung, heart and systemic diseases is associated with the development of chronic respiratory failure (CRF). The treatment of this complication includes the use of long term oxygen therapy (LTOT). In the national literature few studies have assessed the survival of patients with chronic obstructive pulmonary disease (COPD) or with chronic respiratory failure treated with LTOT. Aim: The aim of this study was to evaluate the predictors of mortality in patients with CRF treated with oxygen in the period of one, two and three years. Patients and Methods: One hundred forty two patients were evaluated and followed for the minimum period of three years or until death. The study group consisted of patients with CRF, clinically stable, seen at the Oxygen Therapy Outpatient Clinic of Botucatu School of Medicine Hospital. Information about the demographic characteristics, smoking history, comorbidity conditions and treatment were collected during the first visit; evaluation of body composition, handgrip strength, lung function and blood gases and blood counts were also undertaken at this time. In addition, the dyspnea sensation (basal dyspnea index - BDI - and Borg scale) and health related quality of life (Saint George Respiratory Questionnaire) scores were calculated. Results: During the follow-up, 83 (58%) patients died; 37 (26%) during the first year of follow-up, 23 (16%) in the second year and 23 (16%) considering in three years. The group of death showed significantly lower 20 hematocrit and hemoglobin, increased sensation of breathlessness, measured by BDI and Borg, and showed greater impairment of health status as measured by impact, activity and total score of SGRQ. The main predictors of mortality, after three years of follow-up were male gender (HR=2.67, CI=1.15-6.18, p=0.02), lower values of hemoglobin (HR=0.85, CI=0.74-0.98, p=0.02), and PaCO2... (Complete abstract click electronic access below)

Life-support treatment is regarded as the support of vital functions of respiration and circulation such as mechanical ventilation and inotropic support, and life-sustaining therapy which incorporate therapies such as artificial hydration, nutrition and haemodialysis. Life-support treatment is rendered to critically ill patients within the intensive care units. However, when treatment options are maximised, and the patient’s condition is unchanged, a decision is often made to withdraw treatment. Professional nurses are usually involved in the process of withdrawal of life-support treatment as they care for this population of patients. The study followed a qualitative, explorative, descriptive and contextual research paradigm in order to explore and describe the perceptions of professional nurses with regard to the process of withdrawing life-support treatment in a private intensive care unit. Data was collected by means of interviews, which were transcribed according to Tesch’s method of analysis. Field notes were used to supplement the data findings. Based on the data collected, it is clear that professional nurses experience difficulties when performing withdrawal of life-support treatment. There are a number of communication concerns which need to be addressed and suggestions were also made by the interview participants regarding these concerns. The study makes recommendations to assist professional nurses with the process of withdrawing life-support treatment in a private intensive care unit. The findings of the study will be disseminated to the relevant hospital and unit managers. Ethical principles were maintained throughout the study by adhering to the principles of privacy, confidentiality, anonymity and beneficence.

Critical care nursing is a speciality that continues to evolve and transform. Critical care nurses of the 21st century routinely care for the complex, critically ill patient, integrating sophisticated technology with the accompanying psychosocial challenges and the ethical conflicts associated with critical illness – while, at the same time, addressing the needs and concerns of the family. Providing nursing care in such a dynamic and fast-track unit can pose various challenges for the critical care nurse. Professional nurses are the backbone of any health-care system. The quality of nursing directly affects the patients’ outcomes, and nursing care must therefore be rendered meticulously. Mechanical ventilator support is routinely needed for critically ill adults in these care units and is also a common therapy in sub-acute and long-term care settings. The care of the mechanically ventilated patient is the core of a professional nurse`s practice in the critical care unit. The mechanically ventilated patient presents many challenges for the professional nurse, while the critical care unit poses as a stressful environment for the professional nurse as well as the patient. The objectives of this study therefore were to explore and describe the lived experiences of professional nurses while caring for mechanically ventilated patients, and to develop recommendations to support professional nurses while caring for mechanically ventilated patients. A qualitative, explorative, descriptive and contextual research design was utilised. Data was collected by means of semi-structured interviews and analysed according to the framework provided by Tesch. Purposive sampling was used to select a sample of professional nurses working in a critical care environment. Guba’s model was utilised to verify data and to ensure trustworthiness of the study. Ethical principles were adhered to throughout this research study. With the analysed data, recommendations were to support professional nurses while caring for mechanically ventilated.

This work takes us a step closer to realizing personalized medicine, complementing empirical and heuristic way in which clinicians typically work. This thesis presents mechanistic models of physiology. These models, given continuous signals from a patient, can be fine-tuned via parameter estimation methods so that the model's outputs match the patient's. We thus obtain a virtual patient mimicking the patient at hand. Therapeutic scenarios can then be applied and optimal diagnosis and therapy can thus be attained. As such, personalized medicine can then be achieved without resorting to costly genetics. In particular we have developed a novel comprehensive mathematical model of the cardiopulmonary system that includes cardiovascular circulation, respiratory mechanics, tissue and alveolar gas exchange, as well as short-term neural control. Validity of the model was proven by the excellent agreement with real patient data, under normo-physiological as well as hypercapnic and hypoxic conditions, taken from literature. As a concrete example, a submodel of the lung mechanics was fine-tuned using real patient data and personalized respiratory parameters (resistance, R_rs, and compliance, C_rs) were estimated continually. This allows us to compute the patient's effort (Work of Breathing), continuously and more importantly noninvasively. Finally, the use of Bayesian estimation techniques, which allow incorporation of population studies and prior information about model's parameters, was proposed in the contest of patient-specific physiological models. A Bayesian Maximum a Posteriori Probability (MAP) estimator was implemented and applied to a case-study of respiratory mechanics. Its superiority against the classical Least Squares method was proven in data-poor conditions using both simulated and real animal data. This thesis can serve as a platform for a plethora of applications for cardiopulmonary personalized medicine.

Orientador: Newton Nunes / Banca: Juliana Noda Bechara Belo / Banca: Paulo Sérgio Patto dos Santos / Banca: Carlos Augusto Araújo Valadão / Banca: José Antonio Marques / Resumo: Avaliaram-se os efeitos hemodinâmicos, ventilatórios e hemogasométricos decorrentes da utilização da ventilação controlada a volume ou a pressão, com diferentes valores de pressões positivas expiratórias finais (PEEPs) em cães submetidos ao cefalodeclive. Utilizaram-se 6 animais adultos, machos ou fêmeas, os quais foram induzidos à anestesia com propofol (8 mglkg por via IV), e mantidos sob anestesia total intravenosa com propofol (0,2 rnglkg/rnin) e sufentanil (0,1 f..L9/kg/min). Formaram-se dois grupos que se diferenciaram pela modalidade ventilatória utilizada, ou seja: GO-V ventilação controlada a volume e GO-P ventilação controlada a pressão. Os animais foram mantidos na posição de "Trendenlemburg" a 30° e submetidos a diferentes valores de PEEP (O, 5 e 10 cmH20). Os dados de cada grupo foram submetidos a uma análise de variância, seguido pelo pós teste de Tukey-Kramer. Para a comparação entre os dois grupos, utilizou-se do teste T pareado. Para todas as análises, considerou-se P<O,OS como estatisticamente significativo. Nos cães ventilados com pressão controlada foi observado variação no Vt, Ppico, Pplat, Vd alv , IS, PAPm, PCPm, 1002 e IV02 ao longo das PEEPs. No grupo dos ventilados com volume controlado houve alteração na Ppico, Pplat, Vd alv e FC. A comparação das diferentes ventilações foi caracterizada por 'variação no Vd alv, FC, PVC, PCPm, CV02, IV02 e Te02. Concluiu-se que os níveis progressivos de PEEP promoveram mínimas alterações hemodinâmicas, ventilatórias e hemogasométricas e ambas as modalidades são igualmente eficientes na manutenção da estabilidade respiratória e cardiovascular nas condições experimentais propostas. / Abstract: The hemodynamic, ventilatory, and btood gases parameters were evaluated in dogs undergoing either volume-controlled or pressure-controlled ventilatioo and varying PEEPs under head-down tilt. Six mature dogs of eifher sex were used. Anesthesia was induced with propofol (8 mglkg IV), and maintained with propofol (O.2mglkg/min) and sufentanil (0.1 f.1glkglmin). Two groups were constituted with differem ventilatory methods, namely: GD-V volume-controlled ventilation, and GD-P pressurecontrolled ventilation. The animais were maintained in "Trendelenburg" position at 3iJD aftd underwent increasing PEEP (O, 5 and 10 cmH20). Data from each group was analised statistically through an analysis of variance, which was followed by a post-hoc Tukey-Kramer test To compare groups a paired T test was used. For aD analises, p<O.05 was considered to be significant. In the dogs that underwent pressure-controlled ventilation, significant changes were documented for Vt, Ppico, Pplat, Vd alv, IS, PAPm, PCPm. 1002. and IVÜ2. as PEEPs changed. In the dogs that underwent volumecontrolled ventilation, changes were seen in Ppico, Pplat, Vd alv and FC. When groups were compared, significant differences were detected in Vd alv, FC, PVC, PCPm, CV02, IV02 . and T e02. Increasing PEEPs were concluded to cause minimal changes in the blood gases, and in the hemodynamic and ventilatory parameters. Also, both ventilatory methods were shown to be reliable in maintaining respiratory and cardiovascular stability under the proposed experimental conditions. / Doutor