Graduation date: 2005

published_or_final_version / abstract / toc / Community Medicine / Master / Master of Philosophy

Uma das aplicações básicas da engenharia biomédica se refere aos testes de equipamentos de uso clínico, a avaliação de sua natureza, acessibilidade e/ou suas características. No âmbito da avaliação do sistema respiratório, estão disponíveis diferentes parâmetros de referência (PR) para o teste de espirometria, um dos principais testes de função pulmonar, que permite medir: volumes, capacidades e fluxos pulmonares. Estes PR baseiam-se principalmente em dados étnicos, idade e gênero de indivíduos saudáveis, mas havendo diferenças entre populações avaliadas, como no Brasil com sua grande diversidade de raças e etnias, pode haver erro diagnóstico. Em razão disto, o objetivo deste estudo foi analisar três dos principais PR utilizados nesta população: PR-P (de Pereira e colaboradores de 2007), PR-K ( de Knudson e colaboradores de 1983) e PR-Q (de Quanjer e colaboradores de 2012). Procedeu-se um estudo exploratório descritivo com 683 indivíduos (180 homens e 503 mulheres) entre 24 e 59 anos, em boas condições de saúde, praticantes de exercícios físicos regulares com frequência mínima de duas vezes por semana. Foi aplicada anamnese, coletados dados de massa, estatura e realizada a espirometria forçada (espirômetro bidirecional - Care Fusion MicroLoop) e as variáveis respiratórias avaliadas foram VEF1, CVF, FEF75 e PFE. Como principais resultados verificou-se que a idade média foi de 42 anos (masculino: 40,6 anos; feminino: 44,4 anos); IMC médio de 26 Kg/m² (masculino: 26,26 Kg/m²; feminino: 26,44 Kg/m²); e tempo da prática de exercícios físicos médio de 52 meses (masculino: 66,9 meses; feminino: 37,9 meses). Ao se analisar a variação dos parâmetros de referência para classificação da função pulmonar entre os três protocolos testados, encontrou-se diferença estatisticamente significativa (p<0,05) entre CVF, VEF1, FEF75 e PFE para os valores previstos e atingidos em todos os PR, além de sinais restritivos e obstrutivos. Para o PR-P, mesmo com indivíduos com características assintomáticas e praticantes de exercícios físicos, 17,2% dos indivíduos foram classificados com algum grau de restrição e 17,3% com obstrução, distanciando-se do PR-K e PR-Q que, respectivamente apresentaram valores para restritivo de 7,0% e 12,8% e para obstrutivos de 7,1% e 4,8%. Conclui-se que os respectivos PR podem induzir a erros, levando a classificações diferentes, podendo um mesmo indivíduo ser considerado em estado de normalidade, restritivo ou obstrutivo, a depender do protocolo escolhido. O estado nutricional interferiu na função respiratória no gênero masculino ao se identificar associação significativa entre o estado nutricional e o teste de função pulmonar, x² = 9,80 (p = 0,04). Desta forma, homens acima do peso tiveram 1,9 vezes mais risco de apresentar o teste de função pulmonar insuficiente, mesmo praticando exercícios físicos regulares. Não houve associação significativa em nenhum dos gêneros entre o teste de função pulmonar e o tempo de prática de exercícios físicos. O teste de correlação de Pearson, confirmou a inexistência de correlação entre as variáveis VEF1, PFE e CVF com o tempo de prática para ambos os gêneros. / One of the basic applications of biomedical engineering refers to the testing of clinical use equipment, the assessment of its nature, accessibility and / or its features. In the evaluation of the respiratory system, are available different parameters of reference (PR) for the spirometry test, one of the main pulmonary function tests, which can measure: volumes, capacities and pulmonary flows. These PR based mainly on ethnic data, age and gender in healthy subjects, but with differences between populations studied, as in Brazil with its great diversity of races and ethnic groups, there may be misdiagnosis. Because of this, the objective of this study was to analyze in this population, three of the most used PR: PR-P (Pereira et al., 2007), PR-K (Knudson et al., 1983) and PR-Q (Quanjer et al., 2012). The procedure was a descriptive exploratory study with 683 subjects (180 men and 503 women) between 24 and 59 years, in good health, regular physical exercises practitioners with minimum frequency of twice a week. Anamnesis was applied, collected data of mass and height, performed forced spirometry (bidirectional spirometer - Care Fusion Microloop) and the following respiratory variables were measured, FEV1, FVC, PEF and FEF75. With the main results it was found that the average age was 42 years (male: 40.6 years; women: 44.4 years); BMI average of 26 kg / m² (male: 26.26 kg / m²; female: 26.44 kg / m²); and time the average physical exercises practice 52 months (male: 66.9 months; female: 37.9 months). When analyzing the variation of the reference parameters for pulmonary function classification between the three protocols tested, we found a statistically significant difference (p <0.05) between FVC, FEV1, PEF and FEF75 to the levels required and achieved in all PR, as well as restrictive and obstructive signs. For the PR-P, even with individuals with asymptomatic characteristics and practitioners of physical exercises, 17.2% of subjects were classified with some degree of restriction and 17.3% with obstruction, away from the PR-K and PR-Q which respectively had values for restrictive of 7.0% and 12.8% and for obstruction of 7.1% and 4.8%. We conclude that these PR may induce to errors, leading to different rating, where one individual can be considered in normal state, restrictive or obstructive, depending on the chosen protocol. It was identified that nutritional status interfere with respiratory function, demonstrating significant association between nutritional status and pulmonary function test for males, x² = 9.80 (p = 0.04). Thus, overweight men had 1.9 times more risk to have the insufficient lung function test, even practicing regular physical exercises. There was no significant association in any of the genres between the pulmonary function test and the time of physical activity. The Pearson correlation test confirmed the lack of correlation between the FEV1, FVC and PEF with practice time for both genders.

As infecções respiratórias agudas são uma importante causa de morbidade e mortalidade infantil em todo o mundo. Algumas dessas infecções podem resultar em Síndrome Respiratória Aguda Grave (SRAG). Os vírus respiratórios são os principais responsáveis por esta doença. O monitoramento e a vigilância das SRAG e dos vírus respiratórios são importantes para a gestão em saúde minimizando o impacto destas infecções respiratórias. O presente estudo buscou analisar a sazonalidade e impacto clínico das infecções causadas por vírus respiratórios em crianças internadas em hospital pediátrico do Paraná. Foram incluídos no estudo 229 pacientes de 0 até 15 anos de idade, de janeiro de 2012 a dezembro de 2015, com diagnóstico clínico de SRAG e amostra respiratória coletada e enviada ao Laboratório Central do Estado do Paraná para diagnóstico do agente etiológico. A busca dos casos de SRAG foi realizada utilizando o prontuário eletrônico GSUS (Gestão da Assistência de Saúde do SUS), arquivos do setor de fisioterapia e informações do Núcleo de Controle de Infecções hospitalares do hospital do estudo. Dos pacientes incluídos na pesquisa, foi preenchido um formulário de coleta de dados e posteriormente estes foram analisados de acordo com os objetivos da pesquisa. As análises estatísticas foram efetuadas com o pacote estatístico GRAPHPAD PRISM e foi considerado um nível de significância de 5%. A maioria dos pacientes da amostra pertencia à faixa etária de 0 a 6 meses de idade, não houve sexo predominante. No presente estudo as amostras positivas para pelo menos um agente etiológico contabilizaram 76,41%, e o vírus mais prevalente foi o Vírus Sincicial respiratório (VSR). Quanto à sazonalidade da detecção viral, houve predominância no final de outono e início do inverno, mais acentuada para o VSR. Quando analisada as três temperaturas ambientais da região, a incidência de SRAG foi significativamente maior no quartil descendente da temperatura média para mínima. Não foi observada diferença significativa entre os grupos etiológicos pesquisados com relação ao tempo desde o início dos sintomas até a internação. Houve predominância de internamentos em Unidade de Terapia Intensiva. O tempo de internamento foi significativamente maior naqueles pacientes com doença de base e não alterou conforme os agentes etiológicos identificados ou presença de codetecção. Os pacientes que apresentaram padrão misto na radiografia de tórax tiveram um tempo de internamento significativamente maior do que aqueles que apresentaram o padrão infiltrado intersticial. O tempo total foi significativamente menor no grupo Metapneumovírus em relação aos grupos Bordetella pertussis, Influenza, Rinovírus e grupo dos pacientes sem agentes infecciosos detectados. O tempo de ventilação mecânica não apresentou diferenças significativas entre os grupos etiológicos nem com relação à presença ou não de codetecção. A maior parte dos pacientes recebeu alta hospitalar, mas ocorreram três óbitos devido a SRAG, todos em pacientes com alguma doença de base ou condições de risco. / Acute respiratory infections are the most important cause of children morbidity and mortality worldwide. Some of these infections can result in Severe Acute Respiratory Syndrome (SARS). Respiratory viruses are primarily responsible for SARS. The monitoring and surveillance of SARS and respiratory viruses are important for health management, minimizing the impact of these respiratory infections. The present study was about the seasonality and clinical impact of respiratory viruses in children admitted to a pediatric reference hospital. The study included 229 children from 0 to 15 years old, from January 2012 to December 2015, with clinical diagnosis of SARS and respiratory sample collected and sent to the Central Laboratory of the State of Paraná for etiological agent analysis. The search for SARS cases was performed using the GSUS (Health Care Management of SUS) electronic filesystem, records of the center of physiotherapy and information of the Hospital Infection Control Center of the studied hospital. Of the patients included in the research, data collection forms were filled out and later analyzed according to the research objectives. Statistical analyzis were performed with the statistical package GRAPHPAD PRISM and a significance level of 5% was considered. The majority of patients in the sample belonged to the age group 0-6 months of age, and there was no predominant sex. Regarding the risk factors for viral infection, the presence of comorbidity or underlying disease was the most prevalent factor. In the present study, the positive samples for at least one etiological agent accounted for 76.41%, and the most prevalent virus was Respiratory Syncytial Virus (RSV). As for the seasonality of viral detection, there was a predominance in the late fall and early winter, which was more pronounced for RSV. When the environmental temperatures of the region were analyzed, the incidence of SARS was significantly higher in the descending quartile of the average minimum temperature. No significant difference was observed between the studied etiological groups in relation to the time from the beginning of the symptoms until the hospitalization. There was a predominance of hospitalizations in the Intensive Care Unit. The hospitalization time was significantly higher in patients with underlying disease or comorbidities and did not change according to the identified etiological agents or the presence of codetection. Patients who presented a mixed pattern on chest radiography had a significantly longer hospitalization time than those who had the interstitial infiltrate pattern. The total time was significantly lower in the Metapneumovirus group than in the Bordetella pertussis, Influenza, Rhinovirus and group of patients without detected infectious agents. Most patients were discharged from hospital, but there were three deaths due to SARS, all in patients with some underlying disease or risk conditions.

As infecções respiratórias agudas são uma importante causa de morbidade e mortalidade infantil em todo o mundo. Algumas dessas infecções podem resultar em Síndrome Respiratória Aguda Grave (SRAG). Os vírus respiratórios são os principais responsáveis por esta doença. O monitoramento e a vigilância das SRAG e dos vírus respiratórios são importantes para a gestão em saúde minimizando o impacto destas infecções respiratórias. O presente estudo buscou analisar a sazonalidade e impacto clínico das infecções causadas por vírus respiratórios em crianças internadas em hospital pediátrico do Paraná. Foram incluídos no estudo 229 pacientes de 0 até 15 anos de idade, de janeiro de 2012 a dezembro de 2015, com diagnóstico clínico de SRAG e amostra respiratória coletada e enviada ao Laboratório Central do Estado do Paraná para diagnóstico do agente etiológico. A busca dos casos de SRAG foi realizada utilizando o prontuário eletrônico GSUS (Gestão da Assistência de Saúde do SUS), arquivos do setor de fisioterapia e informações do Núcleo de Controle de Infecções hospitalares do hospital do estudo. Dos pacientes incluídos na pesquisa, foi preenchido um formulário de coleta de dados e posteriormente estes foram analisados de acordo com os objetivos da pesquisa. As análises estatísticas foram efetuadas com o pacote estatístico GRAPHPAD PRISM e foi considerado um nível de significância de 5%. A maioria dos pacientes da amostra pertencia à faixa etária de 0 a 6 meses de idade, não houve sexo predominante. No presente estudo as amostras positivas para pelo menos um agente etiológico contabilizaram 76,41%, e o vírus mais prevalente foi o Vírus Sincicial respiratório (VSR). Quanto à sazonalidade da detecção viral, houve predominância no final de outono e início do inverno, mais acentuada para o VSR. Quando analisada as três temperaturas ambientais da região, a incidência de SRAG foi significativamente maior no quartil descendente da temperatura média para mínima. Não foi observada diferença significativa entre os grupos etiológicos pesquisados com relação ao tempo desde o início dos sintomas até a internação. Houve predominância de internamentos em Unidade de Terapia Intensiva. O tempo de internamento foi significativamente maior naqueles pacientes com doença de base e não alterou conforme os agentes etiológicos identificados ou presença de codetecção. Os pacientes que apresentaram padrão misto na radiografia de tórax tiveram um tempo de internamento significativamente maior do que aqueles que apresentaram o padrão infiltrado intersticial. O tempo total foi significativamente menor no grupo Metapneumovírus em relação aos grupos Bordetella pertussis, Influenza, Rinovírus e grupo dos pacientes sem agentes infecciosos detectados. O tempo de ventilação mecânica não apresentou diferenças significativas entre os grupos etiológicos nem com relação à presença ou não de codetecção. A maior parte dos pacientes recebeu alta hospitalar, mas ocorreram três óbitos devido a SRAG, todos em pacientes com alguma doença de base ou condições de risco. / Acute respiratory infections are the most important cause of children morbidity and mortality worldwide. Some of these infections can result in Severe Acute Respiratory Syndrome (SARS). Respiratory viruses are primarily responsible for SARS. The monitoring and surveillance of SARS and respiratory viruses are important for health management, minimizing the impact of these respiratory infections. The present study was about the seasonality and clinical impact of respiratory viruses in children admitted to a pediatric reference hospital. The study included 229 children from 0 to 15 years old, from January 2012 to December 2015, with clinical diagnosis of SARS and respiratory sample collected and sent to the Central Laboratory of the State of Paraná for etiological agent analysis. The search for SARS cases was performed using the GSUS (Health Care Management of SUS) electronic filesystem, records of the center of physiotherapy and information of the Hospital Infection Control Center of the studied hospital. Of the patients included in the research, data collection forms were filled out and later analyzed according to the research objectives. Statistical analyzis were performed with the statistical package GRAPHPAD PRISM and a significance level of 5% was considered. The majority of patients in the sample belonged to the age group 0-6 months of age, and there was no predominant sex. Regarding the risk factors for viral infection, the presence of comorbidity or underlying disease was the most prevalent factor. In the present study, the positive samples for at least one etiological agent accounted for 76.41%, and the most prevalent virus was Respiratory Syncytial Virus (RSV). As for the seasonality of viral detection, there was a predominance in the late fall and early winter, which was more pronounced for RSV. When the environmental temperatures of the region were analyzed, the incidence of SARS was significantly higher in the descending quartile of the average minimum temperature. No significant difference was observed between the studied etiological groups in relation to the time from the beginning of the symptoms until the hospitalization. There was a predominance of hospitalizations in the Intensive Care Unit. The hospitalization time was significantly higher in patients with underlying disease or comorbidities and did not change according to the identified etiological agents or the presence of codetection. Patients who presented a mixed pattern on chest radiography had a significantly longer hospitalization time than those who had the interstitial infiltrate pattern. The total time was significantly lower in the Metapneumovirus group than in the Bordetella pertussis, Influenza, Rhinovirus and group of patients without detected infectious agents. Most patients were discharged from hospital, but there were three deaths due to SARS, all in patients with some underlying disease or risk conditions.

The original work presented in this thesis investigates some of the mechanisms that may be responsible for the aetiology of altitude-related cough. Particular attention is paid to its relationship to the long recognised, but poorly understood, changes in lung volumes that occur on ascent to altitude. The literature relevant to this thesis is reviewed in Chapter 1.<p><p>Widespread reports have long existed of a debilitating cough affecting visitors to high altitude that can incapacitate the sufferer and, on occasions, be severe enough to cause rib fractures (22, 34, 35). The prevalence of cough at altitude has been estimated to be between 22 and 42% at between 4200 and 4900 m in the Everest region of Nepal (10, 29). Traditionally the cough was attributed to the inspiration of the cold, dry air characteristic of the high altitude environment (37) but no attempts were made to confirm this aetiology. In the first formal study of cough at high altitude, nocturnal cough frequency was found to increase with increasing altitude during a trek to Everest Base Camp (5300 m) and massively so in 3 climbers on whom recordings were made up to 7000 m on Everest (8). After 9 days at 5300 m the citric acid cough threshold, a measure of the sensitivity of the cough reflex arc, was significantly reduced compared with both sea level and arrival at 5300 m.<p><p>During Operation Everest II, a simulated climb of Mount Everest in a hypobaric chamber, the majority of the subjects were troubled above 7000 m by pain and dryness in the throat and an irritating cough despite the chamber being maintained at a relative humidity of between 72 and 82% and a temperature of 23ºC (18). This argued against the widely held view that altitude-related cough was due to the inspiration of cold, dry air. <p><p>In the next major hypobaric chamber study, Operation Everest III, nocturnal cough frequency and citric acid cough threshold were measured on the 8 subjects in the study. The chamber temperature was maintained between 18 and 24ºC and relative humidity between 30 and 60% (24). This work is presented in Chapter 2 and, demonstrated an increase in nocturnal cough frequency with increasing altitude which immediately returned to control values on descent to sea level. Citric acid cough threshold was reduced at 8000 m compared to both sea level and 5000 m values. Changes in citric acid cough threshold at lower altitudes may not have been detected because of the constraints on subject numbers in the chamber. The study still however demonstrated an increase in clinical cough and a reduction in the citric acid cough threshold at extreme altitude, despite controlled environmental conditions, and thus refuted the long held belief that altitude-related cough is solely due to the inspiration of cold, dry air. <p><p>If altitude-related cough is not simply due to the inspiration of cold, dry air, other possible aetiologies are:<p>•\ / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished

In conclusion, the current air pollution levels in Hong Kong had a risk for school children's respiratory and cardiovascular health. In comparison between the highly- and least-polluted districts, a rise of 8 mug/m 3 annual mean for PM10 concentration was significantly associated with increased risks for some respiratory symptoms such as wheezing, cough, and phlegm, with decreased lung function in FEF25-75% and FEF75%, and with decreased cardiopulmonary fitness in predicted VO2max, after adjustment for confounding factors. An increase of 13 mug/m3 annual mean for NO2 in the moderately-polluted district did not individually cause adverse effects on children's respiratory and cardiopulmonary health. Physical activity appears to have no positive health effects on the children's VO2max in moderately- and highly-polluted districts. / In the past year preceding the study (May 2003 to April 2004), the annual means for PM10, NO2, SO2 and O3 were respectively 55.1 mug/m3, 51.4 mug/m3, 15.4 mug/m3, and 42.5 mug/m3 in the least-polluted district (LPD); 56.3 mug/m3, 64.7 mug/m3, 15.2 mug/m3, and 35.2 mug/m3 in the moderately-polluted district (MPD); and 63.8 mug/m3, 64.1 mug/m3, 22.2 mug/m3, and 31.7 mug/m3 in the highly-polluted district (HPD). The 99th percentiles were 178 mug/m3, 158 mug/m 3, 104 mug/m3, and 140 mug/m3 in the LPD; 169 mug/m3, 181 mug/m3, 106 mug/m 3, and 113 mug/m3 in the MPD; and 226 mug/m 3, 177 mug/m3, 140 mug/m3, and 137 mug/m 3 in the HPD. The average daily 1-h maximum O3 (peak O 3) was 83.7 mug/m3 in the LPD, 73.6 mug/m 3 in the MPD, and 64.8 mug/m3 in the HPD. / Lung function indices included FVC, FEV1, FEV 1/FVC, FEF25-75%, FEF25%, and FEF75%. Children in the HPD had lower FEV 1/FVC, FEF25-75%, and FEF25% than those in both the LPD and MPD, after controlling for their corresponding confounders. In comparison between the LPD and HPD, the adjusted mean differences for FEV1/FVC, FEF25-75%, and FEF25% were respectively 1.39%, 85 ml, and 113 ml in boys, and 1.60%, 86 ml, and 225 ml in girls. In addition, the decreased FEF75% of HPD was found in boys (62 ml) but not in girls. When comparing the MPD with LPD, the increased FEF25% was observed in girls in the LPD (158 ml), whereas boys in the LPD had lower FEF75% than those in the MPD (81 ml). There were no significant differences in children's FVC and FEV1 between districts. / The multistage fitness test (MFT) with the Matsuzaka's function was employed to predict cardiopulmonary fitness (VO2max) of children. After adjustment for the factors, girls in the LPD had significantly higher VO 2max than those in the MPD and HPD by 0.19 and 0.75 ml&middot;kg -1 &middot;min-1 respectively. The VO 2max among boys in the LPD was 0.48 ml&middot;kg-1 &middot;min -1 higher than those in the HPD. When we compared the VO 2max between students in MPD and HPD, higher VO2max in both boys and girls in the MPD were observed---by 0.49 and 0.56 ml&middot;kg -1 &middot;min-1 respectively. In LPD, significantly higher VO2max values were observed in both boys and girls who were physically active (children who took part in sports and/or vigorous free play at least three times a week for at least 30 minutes each time) compared with those who were not (0.71 and 0.65 ml&middot;kg-1 &middot;min -1 respectively), but those differences in VO2max among students in MPD and HPD were small and insignificant. / There were totally 2,641 (82.9%) children who participated in the study, and 2,203 participants were involved in analyses. After adjustment for confounding factors, girls living in the HPD had significantly increased odds ratios (ORs) for wheezing without cold (4.75), cough at night (1.71), phlegm without cold (3.61), compared with those in the LPD. Boys in the HPD had increased OR only for phlegm without cold (1.88). When comparing the MPD with LPD, the adjusted OR for cough at night achieved significance in girls (1.74) and marginal significance in boys (1.40). Sneeze with itchy-watery eyes and current/ever allergic rhinitis had negative associations with district. In comparison with LPD, the decreased OR for sneeze with itchy-watery eye in girls in HPD (0.65) reached statistical significance. Both boys and girls in MPD had significantly decreased ORs for current allergic rhinitis (0.72 and 0.50 respectively) and for ever allergic rhinitis (0.74 and 0.55 respectively). There were no significant differences in the prevalence rates of asthma and bronchitis between districts. / To explore associations between air pollution and respiratory and cardiovascular health of school children, a cross-sectional study was conducted among 3,186 primary school children in P3 and P4 from three districts with different air pollution levels in Hong Kong during March to June in 2004. / Gao Yang. / "August 2005." / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6339. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 137-154). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Submitted in fulfillment of the requirements for the Degree of Master of Technology Degree : Environmental Health, Durban University of Technology, Durban, South Africa, 2015. / Introduction Informal waste picking has both economic and environmental benefits, however there are many health risks associated with this activity. This cross sectional descriptive study assessed the respiratory health risks and dust (PM2.5) exposure among informal waste pickers operating at the New England landfill site in the Msunduzi Municipality. Data was collected from 102 informal waste pickers using a validated questionnaire adapted from the British Medical Research Council and American Thoracic Society. Our study population comprised of 66.4°/o women with a mean age of 36.7 years. Women reported greater use of safety shoes and gloves compared to men. Very few participants used dust masks or respirators. Results showed a high prevalence of chronic cough (57o/o), wheeze (51°/o) shortness of breath (31.6°/o) and cough with phlegm (29.0°/o) among all participants. Among those who reported having ever smoked, there was a significantly higher prevalence of cough with phlegm (45.2°/o p=0.02) and wheeze (73.1°/o, p= 0.05). Similarly, there was a bivariate association between current smoking and wheeze (p=0.02) and between ever smoked and wheeze {p< 0.05). A random sample of 28 waste pickers was chosen from the 102 participants for personal sampling. The levels and distribution of time weighted average to PM2.5 were calculated during an 8 hour working period. Average personal sampling levels of PM2.5 were very high compared to environmental levels. Personal sampling results showed a maximum exposure of 431 J.,Jg/m 3 and a mean of 187.4 J.,Jg/m 3 compared to a maximum level of 27.9 J.,Jg/m 3 and a mean of 16.5 J.,Jg/m 3 for environmental sampling. Mean personal sampling results significantly exceeded recommended eight hour time weighted average for South African National Standard for Occupational Exposure Limit (Republic of South Africa OHS ACT 85 of 1993), World Health Organisation and United State Environmental Protection Agency guidelines for PM2.5, while the environmental mean was within guidelines. This study showed that waste pickers are exposed to high levels of PM2.5 while working at the landfill site. Limited or no use of personal protective equipment increases risk of dust exposure and adverse respiratory effects. The relatively high prevalence of cough, shortness of breath and wheeze symptoms among these informal waste pickers may be linked to exposure to dust at the landfill site / PDF copy unavailable. please refer to hard copy for full text information / M

Le principal objectif de ce travail est l’étude de l’influence de la pesanteur sur la mécanique <p>respiratoire et le contrôle de la respiration, ainsi que sur les interactions cardio-respiratoires pendant les différents stades du sommeil. <p><p>Le chapitre introductif présente le contexte général et les objectifs de la thèse. Des sections abordant le sommeil, la respiration, et l’interaction cardio-respiratoire y sont présentées, résumant l’état actuel des connaissances sur les effets de la pesanteur sur chacun de ces systèmes. <p>Dans le deuxième chapitre, l’expérience “Sleep and Breathing in microgravity”, qui constitue la source des données à la base de ce travail, est présentée en détail. <p>L’étude des signaux de longue durée requiert avant tout de disposer d’outils performants <p>d’analyse des signaux. La première partie de la thèse présente en détail deux algorithmes :un <p>algorithme de détection automatique d’événements respiratoires (inspiration / expiration) <p>basé sur des réseaux neuronaux artificiels, et un algorithme de quantification de l’amplitude <p>et de la phase de l’arythmie sinusale pendant le sommeil, utilisant la méthode des ondelettes. <p>La validation de chaque algorithme est présentée, et leur performance évaluée. Cette partie <p>inclut aussi des courtes introductions théoriques aux réseaux de neurones artificiels ainsi <p>qu’aux méthodes d’analyse temps–fréquence (Fourier et ondelettes). <p>Une approche similaire à celle utilisée pour la détection automatique d’événements respiratoires a été appliquée à la détection d’événements dans des signaux de vitesse du sang <p>dans l’artère cérébrale moyenne, mesures obtenues par Doppler transcrânien. Ceci est le <p>sujet de la thèse annexe. <p>Ces deux algorithmes ont été appliqués aux données expérimentales pour extraire des <p>informations physiologiques quant à l’impact de la pesanteur sur la mécanique respiratoire et <p>l’interaction cardio-respiratoire. Ceci constitue la deuxième partie de la thèse. Un chapitre <p>est consacré aux effets de l’apesanteur sur la mécanique respiratoire pendant le sommeil. <p>Ce chapitre a mis en évidence, pour tous les stades de sommeil, une augmentation de la <p>contribution abdominale en microgravité, suivi d’un retour progressif vers des valeurs observées avant le vol. L’augmentation initiale était attendue, mais l’adaptation progressive <p>observée ne peut pas être expliquée par un effet purement mécanique, et nous suggère la <p>présence d’un mécanisme d’adaptation central. Un deuxième chapitre présente les résultats <p>comparant l’arythmie sinusale pendant le sommeil avant le vol, en apesanteur et après le retour sur terre. Le rythme cardiaque pendant le sommeil dans l’espace présente une moindre <p>variabilité. Les différences NREM–REM observées sur terre pour les influences vagales et sympathiques sont accentuées dans l’espace. Aucun changement significatif n’est présent pour <p>le gain et la différence de phase entre les les signaux cardiaque et respiratoire en comparant <p>le sommeil sur terre et en apesanteur. <p>La dissertation termine par une discussion générale du travail effectué, incluant les prin- <p>cipales conclusions ainsi que les perspectives qui en découlent. / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished

Ce travail a été consacré à l’étude non invasive de la circulation pulmonaire normale par mise en œuvre de l’échocardiographie Doppler. <p>En intégrant les mesures obtenues dans une approche physiopathologique, et en exploitant les nouvelles possibilités d’échocardiographes portables, techniquement performants, nous avons analysé les effets d’un inhibiteur de la phosphodiestérase-5 et d’une prostacycline, pour tenter d’en identifier d’éventuels effets introtropes intrinsèques, nous avons exploré le concept de réserve vasculaire pulmonaire comme facteur limitant de l’aptitude aérobie et indice potentiel d’une atteinte vasculaire pulmonaire précoce, et obtenu des résultats préliminaires permettant d’identifier une hypertension artérielle pulmonaire (HTAP) latente. Nos principaux résultats peuvent être résumés comme suit :<p>1. Chez le sujet sain, en normoxie ou dans un modèle expérimental d’HTAP induite par l’inhalation d’un mélange gazeux hypoxique, le sildenafil per os ou l’epoprostenol par voie intraveineuse, à des doses utilisées en clinique pour le traitement de l’HTAP, améliorent les indices de la fonction ventriculaire droite en proportion de leurs effets vasodilatatoires pulmonaires, sans effets inotropes intrinsèques détectables.<p>2. La consommation d’oxygène maximale du sujet sain augmente en raison directe de son volume capillaire pulmonaire (calculé à partir de sa capacité de diffusion pour l’oxyde nitrique et le monoxyde de carbone) et en raison inverse de sa résistance vasculaire pulmonaire, non seulement en altitude, mais aussi au niveau de la mer. Ce résultat suggère qu’une plus grande réserve vasculaire pulmonaire est propice aux efforts aérobiques intenses, probablement par moindre postcharge ventriculaire droite.<p>3. Des mesures réalisées chez un petit nombre de sujets suggèrent que la distensibilité vasculaire pulmonaire, calculée à partir d’une relation débit-pression vasculaire pulmonaire, est typiquement réduite chez des porteurs asymptomatiques de la mutation BMPR2, qui est actuellement le facteur de risque le plus élevé connu de l’HTAP. La mutation BMPR2 pourrait aussi être associée à une réactivité vasculaire pulmonaire accrue à l’hypoxie. <p>Nos résultats suggèrent indirectement que l’échocardiographie Doppler, de repos ou de stress, pourrait être davantage développée dans la mise au point de patients à risque d’HTAP./<p><p>Novel advances in echocardiography offer the opportunity to reliably characterize pulmonary circulation in terms of pressure-flow relationship, and to better understand the coupling of right ventricular (RV) function with normal and abnormal pulmonary hemodynamics. Moreover, when combined with the measurement of pulmonary capillary blood volume, this renewed methodological approach may help to understand the concept of pulmonary vascular reserve as a limiting factor of exercise capacity and potential sensitive marker of early vascular disease.<p><p>In the present work we used a model of hypoxic pulmonary vasoconstriction to analyse the effects of two targeted therapies of pulmonary arterial hypertension (PAH) on the RV function. We showed that the beneficial effects of these drugs are mainly driven by a decrease in RV afterload and not an enhanced myocardial inotropic state. Whether this is transposable to abnormal RV-arterial coupling in PAH patients remains to be investigated.<p><p>Echocardiography may be useful to explore the pulmonary vascular reserve as an important limiting factor of exercise capacity. We showed that a higher pulmonary vascular reserve, defined by a decreased PVR and increased lung diffusing capacity, allows for an improved aerobic exercise capacity (as assessed by a higher peak oxygen consumption), at a lower ventilatory cost, at sea level and at high altitude. <p><p>Stress echocardiography may detect an abnormal pulmonary vasoreactivity. We showed that asymptomatic relatives of patients suffering from idiopathic pulmonary arterial hypertension, and who carry a bone morphogenetic protein receptor type 2 mutation (BMPR2) present with a decreased pulmonary vascular distensibility and an enhanced pulmonary vasoreactivity to hypoxia, which are identifiable by echocardiography examination. However, the predictive value of these findings is not known. <p><p>Thus echocardiography may represent, in experienced and dedicated hands, a noninvasive, safe, widely available, applicable at the bed-side as well as in extreme environment (e.g. high altitudes), less expensive alternative for the evaluation of the pulmonary circulation, either by the interrogation of pressure-flow relationship (stress echocardiography), by the investigation of the right ventricle global and regional function in relation to its afterload (standard and Tissue Doppler Imaging), or by a combined approach with the measurement of lung diffusing capacity (DLNO / DLCO) to assess the pulmonary vascular reserve.<p><p>The present data are encouraging for further development and implementation of echocardiography for the detection, but also the diagnosis and follow-up of patients with pulmonary hypertension.<p><p> / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished