Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A pancreatite aguda (PA) Ã considerada uma situaÃÃo de emergÃncia abdominal, na forma grave da doenÃa os pacientes desenvolvem acentuada resposta inflamatÃria sistÃmica e SÃndrome de DisfunÃÃo de MÃltiplos ÃrgÃos (SDMO). Um terÃo das mortes relacionadas com PA acontecem antes da admissÃo hospitalar, e a maior parte dos casos estÃo relacionados com lesÃo pulmonar aguda (LPA) e sÃndrome do desconforto respiratÃrio agudo (SDRA). Objetivos: Avaliar as alteraÃÃes inflamatÃrias e funcionais do pulmÃo no curso da pancreatite aguda experimental induzida por ceruleÃna. MÃtodos: PA foi induzida em Ratos Wistar, machos pensando 100-150g, pela administraÃÃo de 4 doses de ceruleÃna (20Âg/kg) com intervalo de uma hora e os grupos controle receberam apenas soluÃÃo salina. ApÃs 24 horas, os animais foram sedados, analgesiados e traqueostomizados e anÃlise da funÃÃo pulmonar foi realizada atravÃs da espirometria, onde foram avaliados Fluxo, Volume Corrente (VC), FrequÃncia RespiratÃria (FR) e Volume Minuto (VM), e da mecÃnica pulmonar onde foram observados ElastÃncia DinÃmica (Edin), ComplacÃncia DinÃmica (Cdin), PressÃo de Pico, ResistÃncia (Res). Lavado bronco-alveolar (LBA) foi realizado para contagem total e diferencial de cÃlulas. Amostra de sangue arterial foi colhida para avaliaÃÃo dos parÃmetros gasomÃtricos. Em seguida os animais foram sacrificados e nÃveis sÃricos de amilase, lipase, EPO, TNF-α, GRO-KC, MIP-1, VEGF, IL-1β, IL-2, IL-6, IL-10, IL-12, IL-17, IL-18 e de malondialdeÃdo (MDA) foram medidos. Atividade de mieloperoxidase (MPO) e avaliaÃÃo histolÃgica de pÃncreas e pulmÃo foram determinadas. AlÃm disso, amostras de sangue venoso foram colhidas para avaliaÃÃo de translocaÃÃo bacteriana. Resultados: NÃveis sÃricos de amilase, lipase, citocinas, MDA e atividade de MPO pancreÃtica e pulmonar estavam aumentados nos animais com PA; houve danos ao tecido pancreÃtico e pulmonar, revelados na histologia, nos animais que receberam ceruleÃna, quando comparados ao grupo controle. O LBA dos animais tratados com ceruleÃna demonstrou maior quantidade de cÃlulas, sendo predominantemente macrÃfagos. Gasometria arterial nÃo apresentou diferenÃa significativa entre os grupos. Fluxo, VC e VM se mostraram diminuÃdos nos animais com PA; FR permaneceu inalterada. Edin e PressÃo de Pico estavam maiores e Cdin estava menor nos animais com PA e nÃo houve alteraÃÃes na Res. Estudo da bacteremia foi negativo em ambos grupos. ConclusÃo: CeruleÃna induz PA em ratos com elevaÃÃo dos nÃveis de amilase e lipase pancreÃtica, com alteraÃÃes histopatolÃgicas no pÃncreas e no pulmÃo dependente do infiltrado neutrofÃlico, radicais livres e citocinas inflamatÃrias. PA induz alteraÃÃes espiromÃtricas e na mecÃnica pulmonar que nÃo sÃo dependentes de processo infeccioso. / Acute pancreatitis (AP) is considered an emergency abdominal, the severe form of the disease patients develop intense systemic inflammatory response and Multiple Organ Dysfunction Syndrome (MODS). About one-third of all deaths from acute pancreatitis has been reported to occur prior to admission to hospital, and in most cases, is associated with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Objectives: To assess the inflammatory and functional lung alterations in the course of AP induced by cerulein. Methods: Male Wistar rats (100-150g) were treated four times with one hour interval, intraperitoneally with cerulein (20 μg / kg, suspended in saline) or saline. Twenty-four hours after the first injection of cerulein, the animals were anesthetized, tracheostomized and placed in a spirometer for small animals and with following parameters evaluated: Flow, Volume(VC), Respiratory Frequency(RF) and Minute Volume(MV), and lung mechanics were observed where Dynamic Elastance (Edyn), Dynamic Compliance (Cdyn), Peak Pressure, Resistance (Raw). Bronchoalveolar lavage (BAL) was performed to count and differential cell. Arterial blood sample was drawn for assessment of pulmonary gas exchange parameters. Then the animals were sacrificed and serum amylase, lipase, EPO, TNF-α, GRO-KC, MIP-1, VEGF, IL-1β, IL-2, IL-6, IL-10, IL-12, IL-17, IL-18 and malondialdehyde (MDA) were measured. Myeloperoxidase activity (MPO) and histological evaluation of pancreas and lung were determined. In addition, venous blood samples were collected for evaluation of bacterial translocation. Results: Serum levels of amylase, lipase, cytokines, MDA and MPO activity of pancreatic and lung were increased in animals with PA, there was damage to pancreatic tissue and lung histology revealed, in animals that received cerulein compared to the control group. There was an increase in the number of BAL cells, predominantly macrophages. Arterial blood gas analysis showed no significant difference between groups. Flow, and MV proved lower in animals with PA; FR remained unchanged. Edyn and pressure peak were larger and Cdyn was lower in animals with PA and no changes in Res. There was no translocation in any groups. Conclusion: Cerulein induced AP in rats with elevated serum amylase and pancreatic lipase, with histopathological changes in the pancreas and lung dependent neutrophilic infiltrate, free radicals and inflammatory cytokines. PA induces spirometric and lung mechanics alterations that are not dependent on bacterial translocation

<p>Evaluating respiratory mechanics during dynamic conditions without interrupting ongoing ventilation and flow, adds to the information obtained from the mechanics derived from static (= no flow) conditions, i.e., the flow signal has the potential to provide information on the properties of the respiratory system (including the tubing system). Hence monitoring the changes in the flow signal during ongoing mechanical ventilation would give information about the dynamic mechanics of the respiratory system. Any change in the mechanics of the respiratory system including the endotracheal tube (ETT) and the ventilatory circuit would affect the shape of the flow signal. </p><p>Knowledge of the airway pressure distal to the ETT at the carina level (= tracheal pressure) is required for calculating the extra resistive load exerted by the endotracheal tube in order to compensate for it. In a porcine model, the flow signal was used to non-invasively calculate tracheal pressure. There was good agreement between calculated and measured tracheal pressure with different modes of ventilation. However, calculation of tracheal pressure assumes that the inner diameter of the ETT is known, and this assumption is not met if the inner diameter is narrowed by secretions. Flow that passes a narrowed tube is decelerated and this is most pronounced with the high flow of early expiration, yielding a typical time constant over expiratory volume pattern that is easy to recognize during mechanical ventilation. This pattern reliably detected partial endotracheal obstruction during volume and pressure controlled mechanical ventilation. </p><p>A change in compliance of the respiratory system modifies the elastic recoil and this also affects the rate of the expiratory flow and the shape of its signal. In a porcine model, lung volume gains on the flow signal generated by the heartbeats (cardiogenic oscillations) provided information about the compliance of the respiratory system during ongoing mechanical ventilation</p><p>In conclusion analyzing the flow signal during ongoing ventilation can be a cheap, non-invasive and reliable tool to monitor the elastic and resistive properties of the respiratory system including the endotracheal tube.</p>

Evaluating respiratory mechanics during dynamic conditions without interrupting ongoing ventilation and flow, adds to the information obtained from the mechanics derived from static (= no flow) conditions, i.e., the flow signal has the potential to provide information on the properties of the respiratory system (including the tubing system). Hence monitoring the changes in the flow signal during ongoing mechanical ventilation would give information about the dynamic mechanics of the respiratory system. Any change in the mechanics of the respiratory system including the endotracheal tube (ETT) and the ventilatory circuit would affect the shape of the flow signal. Knowledge of the airway pressure distal to the ETT at the carina level (= tracheal pressure) is required for calculating the extra resistive load exerted by the endotracheal tube in order to compensate for it. In a porcine model, the flow signal was used to non-invasively calculate tracheal pressure. There was good agreement between calculated and measured tracheal pressure with different modes of ventilation. However, calculation of tracheal pressure assumes that the inner diameter of the ETT is known, and this assumption is not met if the inner diameter is narrowed by secretions. Flow that passes a narrowed tube is decelerated and this is most pronounced with the high flow of early expiration, yielding a typical time constant over expiratory volume pattern that is easy to recognize during mechanical ventilation. This pattern reliably detected partial endotracheal obstruction during volume and pressure controlled mechanical ventilation. A change in compliance of the respiratory system modifies the elastic recoil and this also affects the rate of the expiratory flow and the shape of its signal. In a porcine model, lung volume gains on the flow signal generated by the heartbeats (cardiogenic oscillations) provided information about the compliance of the respiratory system during ongoing mechanical ventilation In conclusion analyzing the flow signal during ongoing ventilation can be a cheap, non-invasive and reliable tool to monitor the elastic and resistive properties of the respiratory system including the endotracheal tube.

Mechanical ventilation (MV) is the primary form of therapeutic support for patients with acute respiratory failure (ARF) or acute respiratory distress syndrome (ARDS) until the underlying disease is resolved. However, as patient disease state and response to MV are highly variable, clinicians often rely on experience to set MV. The result is more variable care, as there are currently no standard approaches to MV settings. As a result of the common occurrence of MV and variability in care, MV is one of the most expensive treatments in critical care. Thus, an approach capable of guiding patient-specific MV is required and this approach could potentially save significant cost. This research focuses on developing models and model-based approaches to analyse and guide patient-specific MV care. Four models and metrics are developed, and each model is tested in experimental or clinical trials developed for the purpose. Each builds the understanding and methods necessary for an overall approach to guide MV in a wide range of patients. The first model, a minimal recruitment model, captures the recruitment of an injured lung and its response to positive end expiratory pressure (PEEP). However, the model was only previously validated in diagnosed ARDS patients, and was not proven to capture behaviours seen in healthy patients. This deficiency could potentially negate its ability to track disease state, which is crucial in providing rapid diagnosis and patient-specific MV in response to changes in patient condition. Hence, the lack of validation in disease state progression monitoring from ARDS to healthy, or vice-versa, severely limits its application in real-time monitoring and decision support. To address this issue, an experimental ARDS animal model is developed to validate the model across the transition between healthy and diseased states. The second model, a single compartment linear lung model, models the lung as a conducting airway connected to an elastic compartment. This model is used to estimate the respiratory mechanics (Elastance and Resistance) of an ARDS animal model during disease progression and recruitment manoeuvres. This model is later extended to capture high resolution, patient-specific time-varying respiratory mechanics during each breathing cycle. This extended model is tested in ARDS patients, and was used to titrate patient-specific PEEP using a minimum elastance metric that balances recruitment and the risk of lung overdistension and ventilation-induced injury. Studies have revealed that promoting patients to breathe spontaneously during MV can improve patient outcomes. Thus, there is significant clinical trend towards using partially assisted ventilation modes, rather than fully supported ventilation modes. In this study, the patient-ventilator interaction of a state of the art partially assisted ventilation mode, known as neurally adjusted ventilatory assist (NAVA), is investigated and compared with pressure support ventilation (PS). The matching of patient-specific inspiratory demand and ventilator supplied tidal volume for these two ventilation modes is assessed using a novel Range90 metric. NAVA consistently showed better matching than PS, indicating that NAVA has better ability to provide patient-specific ventilator tidal volume to match variable patient-specific demand. Hence, this new analysis highlights a critical benefit of partially assisted ventilation and thus the need to extend model-based methods to this patient group. NAVA ventilation has been shown to improve patient-ventilator interaction compared to conventional PS. However, the patient-specific, optimal NAVA level remains unknown, and the best described method to set NAVA is complicated and clinically impractical. The Range90 metric is thus extended to analyse the matching ability of different NAVA levels, where it is found that response to different NAVA levels is highly patient-specific. Similar to the fully sedated MV case, and thus requiring models and metrics to help titrate care. More importantly, Range90 is shown to provide an alternative metric to help titrate patient-specific optimal NAVA level and this analysis further highlights the need for extended model-based methods to better guide these emerging partially assisted MV modes. Traditionally, the respiratory mechanics of the spontaneously breathing (SB) patient cannot be estimated without significant additional invasive equipment and tests that interrupt normal care and are clinically intensive to carry out. Thus, respiratory mechanics and model-based methods are rarely used to guide partially assisted MV. Thus, there is significant clinical interest to use respiratory mechanics to guide MV in SB patients. The single compartment model is extended to effectively capture the trajectory of time-varying elastance for SB patients. Results show that without additional invasive equipment, the model was able estimate unique and clinically useful respiratory mechanics in SB patients. Hence, the extended single compartment model can be used as ‘a one model fits all’ means to guide patient-specific MV continuously and consistently, for all types of patient and ventilation modes, without interrupting care. Overall, the model-based approaches presented in this thesis are capable of capturing physiologically relevant patient-specific parameters, and thus, characterise patient disease state and response to MV. With additional, larger scale clinical trials to test the performance and the impact of model-based methods on clinical outcome, the models can aid clinicians to guide MV decision making in the heterogeneous ICU population. Hence, this thesis develops, extends and validates several fundamental model-based metrics, models and methods to enable standardized patient-specific MV to improve outcome and reduce the variability and cost of care.

Nas últimas décadas, considerável atenção foi direcionada para os dispositivos de mensuração não invasiva da configuração e coordenação toracoabdominal. Dentre os dispositivos mais empregados, destaca-se aquele que emprega a Pletismografia Respiratória por Indutância (PRI) que, apesar de ser considerado um dispositivo de avaliação reprodutível e acurado, apresenta divergências acerca do método de calibração para estimativa da participação dos compartimentos torácico e abdominal, principalmente quando utilizada em diferentes posturas corporais. O padrão-ouro da calibração da PRI é o método de calibração por isovolume (ISOCAL). Entretanto, a grande maioria dos estudos emprega somente a calibração qualitativa diagnóstica (QDC) devido ao fato desta não necessitar manobras respiratórias específicas. Em vista disso, o objetivo deste estudo foi comparar os dois métodos de calibração da PRI, em 3 diferentes posturas (decúbito dorsal, sedestação e ortostatismo). Foram avaliados 28 indivíduos saudáveis (18 mulheres/10 homens), com idade de 25,4±3,9 anos (média±DP). Todos os indivíduos foram submetidos aos dois métodos de calibração (ISOCAL e QDC) e avaliados nas 03 posturas. Foi verificado que os valores da constante de proporcionalidade dos sinais elétricos dos compartimentos (K) foram distintos em ambos os métodos de calibração nas 3 posturas avaliadas. Os valores de K avaliados com a calibração ISOCAL e QDC foram, respectivamente, 1,6±0,5 vs. 2,0±1,2 em decúbito dorsal, 2,5±0,8 vs. 0,6±0,3 em sedestação, e 2,0±0,8 vs. 0,6±0,3 em ortostatismo (p<0,05 para todas as comparações). Os nossos resultados sugerem que a QDC não deve ser considerada um método acurado para a calibração da PRI. Além disso, os valores da constante K do ISOCAL mostram ainda que a calibração do equipamento deve ocorrer para cada postura avaliada / In recent decades, considerable attention has been directed to devices for noninvasive measurement of thoracoabdominal configuration and coordination. Among the most commonly applied devices, there is one that employs the respiratory inductive plethysmography (PRI), which, despite being considered a device for reproducible and accurate assessment, shows variations on the calibration method to estimate the contribution of the thoracic and abdominal compartments especially when applied in different body postures. The gold standard in the calibration of PRI is the method of isovolume calibration (ISOCAL). However, most studies employ only the qualitative diagnostic calibration (QDC) due to the fact that this does not require specific respiratory maneuvers. This study aims to compare the two methods of calibration of the PRI in three different postures (supine, standing, and seated). A total of 28 healthy subjects (18 men mulheres/10), aged 25.4 ± 3.9 years (mean ± SD). All subjects underwent both methods of calibration (QDC and ISOCAL) and assessed at the 03 postures. It was found that the values of the constant of proportionality of the electrical signals of compartments (K) were different in both calibration methods evaluated in three postures. The values of K evaluated with calibration ISOCAL and QDC were respectively 1.6 ± 0.5 vs. 2.0 ± 1.2 supine position, 2.5 ± 0.8 vs. 0.6 ± 0.3 in seated position, and 2.0 ± 0.8 vs. 0.6 ± 0.3 in standing position (p <0.05 for all comparisons). Our results suggest that the QDC should not be considered an accurate method for calibration of the PRI. Moreover, the values of constant K ISOCAL also show that the calibration of equipment should occur for each position evaluated

A postura humana é um importante objeto de estudo na fisioterapia. Em especial, o estudo da postura sentada uma vez que este é o posicionamento corporal mais frequentemente adotado pelo homem. Sabe-se, ainda, que este é um posicionamento influenciado de forma significativa pelo mobiliário utilizado. Esta dissertação teve por objetivo analisar os efeitos na função pulmonar das posturas induzidas por dois sistemas cadeira-mesa diferentes, caracterizando a postura sentada e a função respiratória em cada mobiliário, correlacionando as posturas encontradas com o desempenho no teste de função pulmonar. Para atingir tal objetivo, inicialmente foram realizadas duas revisões sistemáticas sendo que a primeira abordou o tema A evolução do homem e a postura sentada: bases para o fisioterapeuta cujo objetivo era permitir a compreensão das sequelas mais comuns provocadas por diferentes posturas e entender as relações do indivíduo com seu meio ambiente, seu trabalho e com os aspectos sociais e culturais envolvidos nessa relação. A segunda revisão centrou-se no tema: Influência das variações da postura sentada na função respiratória revisão de literatura, por meio da qual foi realizada uma revisão bibliográfica para descrever o conhecimento produzido sobre as alterações da função respiratória em diferentes posturas corporais, em especial na postura sentada, observando-se que embora as alterações da função pulmonar sejam mais significativas em indivíduos com doenças pulmonares, cardíacas e do envelhecimento. Porém, mesmo em indivíduos saudáveis as alterações nos testes de função pulmonar podem ultrapassar a variação dos valores considerados normais para uma dada posição No decorrer deste estudo, considerando que a postura sentada é o posicionamento corporal mais freqüentemente adotado pelo homem e é influenciada pelo mobiliário utilizado, foram avaliadas quinze voluntárias utilizando-se 2 sistemas cadeira-mesa, um convencional (sistema A) e um experimental (sistema B). Foi realizada a avaliação postural por meio de fotogrametria em cada um dos mobiliários. Estas imagens foram analisadas, estimando-se a postura média dos indivíduos em cada mobiliário. A avaliação pulmonar consistiu da realização de espirometria. Os valores encontrados foram analisados verificando-se as médias obtidas em cada postura. Os dados posturais e respiratórios foram comparados, verificando-se se as diferentes posições adotadas pelas participantes resultaram em alterações nos valores espirométricos. Como resultado encontrou-se que a cadeira convencional induziu dois diferentes padrões posturais, sendo que um deles apresentou ângulos articulares similares aos do sistema B, com resultados espirométricos semelhantes. Já o segundo grupo apresentou ângulos corporais de acordo com o previsto e resultados espirométricos significativamente inferiores em VEF1, VEF1/CVF e FEFmáx. O sistema B diferiu da postura ortostática somente em FEFmáx, sugerindo similaridade de situação. Desta forma, pode-se concluir que o mobiliário utilizado na postura sentada influencia de forma significativa na função respiratória. Neste estudo o mobiliário experimental mostrou-se uma ferramenta capaz de beneficiar a função respiratória na postura sentada, além de suscitar a possibilidade de opções ao uso do mobiliário convencional para beneficiar pessoas em condições especiais como gestantes, obesos e pessoas com doenças pulmonares crônicas / Human posture is an important object of study in physiotherapy. Specially, the study of sitting posture considering that this is the most frequently body positioning adopted by man. It is known that this is a positioning influenced significantly by the furniture used. This dissertation had intended to examine the effects on pulmonary function of the postures induced by two different table-chair systems, featuring the seated posture and respiratory function in each furniture, correlating those postures found with performance on the pulmonary function test. To achieve this purpose, initially two systematic reviews were conducted: the first related to the theme \"The evolution of man and the sitting posture: bases for the physiotherapist\" whose goal was to enable understanding of the most common sequelae caused by different postures and understand the relationships of individuals with their environment, their work and with the social and cultural aspects involved in this relationship. The second review focused on the theme: \"Influence of sitting posture changes in respiratory function review of the literature\", through which it was carried out a literature review to describe the knowledge produced about respiratory function changes in different postures, especially in a sitting posture, noting that although the pulmonary function changes are most significant in individuals with lung and heart diseases, and the elderly, even in healthy individuals changes function tests may exceed the variation of values considered normal for a given position. Throughout this study, considering that the sitting posture is the body positioning most frequently adopted by man and is influenced by the furniture used, fifteen volunteers were assessed using two Chair-table systems, one considered as a conventional system (the system) and an experimental one (System B). Postural assessment was carried out by means of photogrammetry in each furniture. These images were analyzed, estimating the average position of individuals in each furniture. Pulmonary evaluation consisted of performing spirometry. The values found were analysed by checking the means obtained in each posture. Postural and respiratory data were compared by checking whether the various positions adopted by the participants resulted in changes in the spirometric values. As a result it was found that the conventional chair led two different postural patterns, being one of them presented joint angles similar to system B, with similar spirometric results. The second group had body angles in accordance with the expected ones and spirometric results significantly lower in Fev1, Fev1/FVC and FEFmáx. System B differed from orthostatic posture only in FEFmáx, suggesting a similarity of situation. In this way, it can be concluded that the furniture used in sitting posture influences significantly respiratory function. In this study the experimental furniture proved a tool capable of benefiting the respiratory function in sitting posture, and raise the possibility of options when using conventional furniture to benefit people in special conditions such as pregnant women, obese and people with chronic lung diseases

A postura humana é um importante objeto de estudo na fisioterapia. Em especial, o estudo da postura sentada uma vez que este é o posicionamento corporal mais frequentemente adotado pelo homem. Sabe-se, ainda, que este é um posicionamento influenciado de forma significativa pelo mobiliário utilizado. Esta dissertação teve por objetivo analisar os efeitos na função pulmonar das posturas induzidas por dois sistemas cadeira-mesa diferentes, caracterizando a postura sentada e a função respiratória em cada mobiliário, correlacionando as posturas encontradas com o desempenho no teste de função pulmonar. Para atingir tal objetivo, inicialmente foram realizadas duas revisões sistemáticas sendo que a primeira abordou o tema A evolução do homem e a postura sentada: bases para o fisioterapeuta cujo objetivo era permitir a compreensão das sequelas mais comuns provocadas por diferentes posturas e entender as relações do indivíduo com seu meio ambiente, seu trabalho e com os aspectos sociais e culturais envolvidos nessa relação. A segunda revisão centrou-se no tema: Influência das variações da postura sentada na função respiratória revisão de literatura, por meio da qual foi realizada uma revisão bibliográfica para descrever o conhecimento produzido sobre as alterações da função respiratória em diferentes posturas corporais, em especial na postura sentada, observando-se que embora as alterações da função pulmonar sejam mais significativas em indivíduos com doenças pulmonares, cardíacas e do envelhecimento. Porém, mesmo em indivíduos saudáveis as alterações nos testes de função pulmonar podem ultrapassar a variação dos valores considerados normais para uma dada posição No decorrer deste estudo, considerando que a postura sentada é o posicionamento corporal mais freqüentemente adotado pelo homem e é influenciada pelo mobiliário utilizado, foram avaliadas quinze voluntárias utilizando-se 2 sistemas cadeira-mesa, um convencional (sistema A) e um experimental (sistema B). Foi realizada a avaliação postural por meio de fotogrametria em cada um dos mobiliários. Estas imagens foram analisadas, estimando-se a postura média dos indivíduos em cada mobiliário. A avaliação pulmonar consistiu da realização de espirometria. Os valores encontrados foram analisados verificando-se as médias obtidas em cada postura. Os dados posturais e respiratórios foram comparados, verificando-se se as diferentes posições adotadas pelas participantes resultaram em alterações nos valores espirométricos. Como resultado encontrou-se que a cadeira convencional induziu dois diferentes padrões posturais, sendo que um deles apresentou ângulos articulares similares aos do sistema B, com resultados espirométricos semelhantes. Já o segundo grupo apresentou ângulos corporais de acordo com o previsto e resultados espirométricos significativamente inferiores em VEF1, VEF1/CVF e FEFmáx. O sistema B diferiu da postura ortostática somente em FEFmáx, sugerindo similaridade de situação. Desta forma, pode-se concluir que o mobiliário utilizado na postura sentada influencia de forma significativa na função respiratória. Neste estudo o mobiliário experimental mostrou-se uma ferramenta capaz de beneficiar a função respiratória na postura sentada, além de suscitar a possibilidade de opções ao uso do mobiliário convencional para beneficiar pessoas em condições especiais como gestantes, obesos e pessoas com doenças pulmonares crônicas / Human posture is an important object of study in physiotherapy. Specially, the study of sitting posture considering that this is the most frequently body positioning adopted by man. It is known that this is a positioning influenced significantly by the furniture used. This dissertation had intended to examine the effects on pulmonary function of the postures induced by two different table-chair systems, featuring the seated posture and respiratory function in each furniture, correlating those postures found with performance on the pulmonary function test. To achieve this purpose, initially two systematic reviews were conducted: the first related to the theme \"The evolution of man and the sitting posture: bases for the physiotherapist\" whose goal was to enable understanding of the most common sequelae caused by different postures and understand the relationships of individuals with their environment, their work and with the social and cultural aspects involved in this relationship. The second review focused on the theme: \"Influence of sitting posture changes in respiratory function review of the literature\", through which it was carried out a literature review to describe the knowledge produced about respiratory function changes in different postures, especially in a sitting posture, noting that although the pulmonary function changes are most significant in individuals with lung and heart diseases, and the elderly, even in healthy individuals changes function tests may exceed the variation of values considered normal for a given position. Throughout this study, considering that the sitting posture is the body positioning most frequently adopted by man and is influenced by the furniture used, fifteen volunteers were assessed using two Chair-table systems, one considered as a conventional system (the system) and an experimental one (System B). Postural assessment was carried out by means of photogrammetry in each furniture. These images were analyzed, estimating the average position of individuals in each furniture. Pulmonary evaluation consisted of performing spirometry. The values found were analysed by checking the means obtained in each posture. Postural and respiratory data were compared by checking whether the various positions adopted by the participants resulted in changes in the spirometric values. As a result it was found that the conventional chair led two different postural patterns, being one of them presented joint angles similar to system B, with similar spirometric results. The second group had body angles in accordance with the expected ones and spirometric results significantly lower in Fev1, Fev1/FVC and FEFmáx. System B differed from orthostatic posture only in FEFmáx, suggesting a similarity of situation. In this way, it can be concluded that the furniture used in sitting posture influences significantly respiratory function. In this study the experimental furniture proved a tool capable of benefiting the respiratory function in sitting posture, and raise the possibility of options when using conventional furniture to benefit people in special conditions such as pregnant women, obese and people with chronic lung diseases

The goal of lung-protective mechanical ventilation is to provide life-sustaining support of gas exchange while minimizing the risk of ventilator-induced lung injury. Multi-frequency oscillatory ventilation (MFOV) was proposed as an alternative lung-protective modality, in which multiple frequencies of pressure and flow oscillations are delivered simultaneously at the airway opening and allowed to distribute throughout the lung in accordance with regional mechanical properties. The distribution of oscillatory flow is frequency-dependent, such that regions overventilated at one frequency may be underventilated at another. Thus the central thesis of this work was that ventilation heterogeneity is frequency-dependent, and therefore ventilation with multiple simultaneous frequencies can be optimized to reduce the risk of ventilator-induced lung injury. Simulations in computational models of distributed oscillatory flow and gas transport demonstrated the sensitivity of regional ventilation heterogeneity to subject size, ventilation frequency, and injury severity. Although the risk of injury in the model associated with strain or strain rate individually was minimized by single-frequency ventilation, the risk of injury associated with mechanical power in lung parenchymal tissue was minimized by MFOV. In an experimental model of acute lung injury, MFOV was associated with reductions in the magnitude and spatial gradient of regional lung strain estimated by four-dimensional CT image registration, as well as increased rates of regional gas transport estimated by wash-in of xenon tracer gas. In conclusion, computational models demonstrated the potential for optimization of MFOV waveforms, and experimental trials demonstrated evidence of improved regional ventilation during MFOV.

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The increased work of breathing associated with intense cycling has been identified as a factor that may negatively affect cycling performance. The aerodynamic position, abnormal respiratory mechanics either at rest or during exercise, and the development of a tachypnoeic breathing pattern are factors known to increase the work of breathing. Breathing pattern retraining aims to decrease the work of breathing by delaying the onset of dynamic hyperinflation and the recruitment of accessory breathing muscles. To date no studies have investigated the performance, physiological and perceptual consequences of manipulating breathing pattern in trained cyclists. Purpose: The aim of the present study was to investigate the effect of breathing pattern retraining on 20-km time trial performance and respiratory and metabolic measures in competitive cyclists. Method: Twenty-four competitive male cyclists (age 37.7 ± 8.6 years, mean ± SD; peak 4.34 ± 0.47 L·min-1) were match paired on 20-km time trial performance and assigned at random to either an intervention group (breathing pattern retraining; N = 12) or control group (N = 12). 20-km time trial performance, pulmonary function and the physiological and perceptual response during a maximal incremental cycle step test were assessed pre- and post-intervention. The intervention group underwent four weeks of specific breathing pattern retraining using exercises designed to reduce dynamic hyperinflation and optimise respiratory mechanics. The control group attended the laboratory once a week during this period and performed a 10 minute sub-maximal ride wearing a biofeedback breathing harness. The control group was led to believe the purpose for their participation was to investigate the effect that maximal exercise had on breathing pattern, and to test the reliability of the breathing harness. There was no attempt to modify the breathing pattern of the control group. Data were analysed using an MS Excel spreadsheet designed for statistical analysis. The uncertainty in the effect was expressed as 90% confidence limits and a smallest worthwhile effect of 1.0% was assumed. Results: The intervention group showed substantial improvements in 20-km time trial performance (-1.5 ± 1.1%) and incremental power (3.2 ± 3%). Additionally, breathing frequency (-13.2 ± 8.9%; -9.5 ± 8.4%), tidal volume (10.6 ± 8.5%; 9.4 ± 7.6%), inspiratory time (10.1 ± 8%; 9.4 ± 7.7%), breathing RPE (-30 ± 33.9%; -24.7 ± 28.1%) and leg RPE (-27.9 ± 38.5%; -24.7 ± 28.2%) were all positively affected at lactate threshold and lactate turn point. No positive changes were observed in the control group for 20-km time trial performance (0.0 ± 1.0%), incremental power (-1.4 ± 3.5%), breathing frequency (-1.6 ± 8.0%; -2.0 ± 7.9%), tidal volume (0.9 ± 7.2%; 2.9 ± 9.4%), breathing RPE (16.1 ± 50.2%, 24.8 ± 43%) or leg RPE (13.4 ± 39.6%; 19.9 ± 43.2%) . Conclusion: These results provide evidence of the performance enhancing effect of four weeks of breathing pattern retraining in cyclists. Furthermore, they suggest breathing pattern can be retrained to exhibit a controlled pattern, without a tachypnoeic shift, during high intensity cycling. Additionally, these results indicate breathing pattern retraining attenuates the respiratory and peripheral perceived effort during incremental exercise. Key words: Breathing pattern disorders, retraining, blood stealing, cycling, performance, power output, respiratory mechanics, perceived exertion, 20km-TT