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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Acetona exalada como novo biomarcador do diagnóstico de insuficiência cardíaca / Exhaled breath acetone as a new biomarker of heart failure diagnosis

Fabiana Goulart Marcondes Braga 19 March 2012 (has links)
A insuficiência cardíaca é uma síndrome clínica de alta morbimortalidade e por este motivo é crescente o interesse em se estudar novos biomarcadores da doença visando buscar caminhos para novas estratégias terapêuticas. Neste contexto, a análise do ar exalado pode ser promissora. Baseado nestes dados e na observação de que pacientes com insuficiência cardíaca grave exalam odor peculiar, ainda em estudo piloto, nós identificamos acetona no ar exalado de pacientes com insuficiência cardíaca. Assim, nosso estudo teve por objetivo primário avaliar o papel da acetona exalada como biomarcador do diagnóstico de insuficiência cardíaca e de insuficiência cardíaca descompensada. Como objetivo secundário, avaliar sua relação com a classe funcional segundo a classificação da New York Heart Assocation (NYHA) e sua correlação com o peptídeo natriurético do tipo B (BNP). Entre maio de 2009 e setembro de 2010, pacientes consecutivos com disfunção sistólica (grupo IC) admitidos na emergência (insuficiência cardíaca descompensada grupo ICDESCOMP) e pacientes estáveis nos últimos três meses encaminhados para o teste cardiopulmonar (insuficiência cardíaca compensada grupo ICCOMP) foram submetidos à coleta de ar exalado (extração em água) para posterior análise qualitativa por cromatografia gasosa acoplado à espectrometria de massas e quantificação por espectrofotometria de absorção, através da reação com salicilaldeído. Entre os 235 pacientes avaliados, 89 foram incluídos (59 com insuficiência cardíaca descompensada e 30 com insuficiência cardíaca compensada), 61% do sexo masculino e com mediana de idade de 52 anos. Vinte indivíduos saudáveis (grupo controle) pareados por idade participaram do estudo. O valor mediano (intervalo interquartil) de acetona exalada foi maior no grupo IC em relação ao controle [3,70 g/L (1,69-10,45 g/L) versus 0,39 g/L (0,30-0,79 g/L), p < 0,001]. O valor mediano de acetona em pacientes com insuficiência cardíaca descompensada foi maior do que no grupo com insuficiência cardíaca compensada [7,80 g/L (3,60-15,20 g/L) versus 1,22 g/L (0,682,19 g/L), p < 0,001]. A acurácia do método tanto para o diagnóstico de insuficiência cardíaca (acetona > 1,16 g/L; área sob a curva = 0,94) quanto para o diagnóstico de insuficiência cardíaca descompensada (acetona > 2,50 g/L; área sob a curva = 0,93) foi aproximadamente 85 %, semelhante à acurácia do BNP (BNP > 42 pg/mL; área sob a curva = 0,97 e BNP > 424 pg/mL; área sob a curva = 0,94, respectivamente). Houve correlação positiva entre acetona exalada e BNP (r = 0,772, p < 0,001). Observamos aumento progressivo nas concentrações de acetona exalada de acordo com a piora da classe funcional segundo NYHA (p < 0,001). Assim, podemos concluir que nosso estudo revelou a acetona exalada como um novo biomarcador do diagnóstico de insuficiência cardíaca e de insuficiência cardíaca descompensada, que está associado à maior gravidade da doença e que apresenta correlação positiva com BNP. Sua dosagem é um novo método de diagnóstico não invasivo que pode ser realizado à beira leito, cuja acurácia é semelhante à do BNP / Heart failure (HF) is a condition associated with high mortality and frequent hospital admissions. In this context, multiple biomarkers of heart failure severity have emerged recently. However, the usefulness of most of these biomarkers has not been fully established. Exhaled breath has been considered a suitable tool (biomarker) to evaluate different diseases. Based on the clinical observation that patients with acute decompensated heart failure (ADHF) exhale a distinct odor, in a pilot study we have identified acetone in exhaled breath of heart failure patients and this study aimed to evaluate the role of acetone as a new biomarker of heart failure and ADHF disease. As secondary aims, we intended to analyze the relation to New York Heart Association (NYHA) class and the correlation with B-Type Natriuretic Peptide (BNP). Patients with systolic dysfunction (HF group) admitted consecutively at the emergency room (ADHF group) and stable patients referred to the cardiopulmonary test (chronic HF CHF group) between May 2009 and September 2010 were submitted to exhaled breath collection (extraction into water). Acetone identification was done by gas chromatography-mass spectrometry (GC-MS) and its determination by absorption spectrophotometry after reaction with salicylaldehyde. Twenty healthy subjects matched for age were enrolled (control group). Among 235 patients with HF, 89 were included in the study (59 ADHF and 30 CHF), 61% male, with median age of 52 years. Median exhaled breath acetone value (interquartile range) was higher in the HF group when compared to control group [3.7 g/L (1.69-10.45 g/L) versus 0.39 g/L (0.30-0.79 g/L), p < 0.001] and also higher in ADHF when compared to CHF group [7.80 g/L (3.60-15.20 g/L) versus 1.22 g/L (0.682.19 g/L), p < 0,001]. The accuracy of the method to diagnose CHF (Acetone > 1.16 g/L; AUC = 0.94) and ADHF (Acetone > 2.5 g/L; AUC = 0.93) was similar to the accuracy of BNP (BNP > 42 pg/mL; AUC = 0.97 and BNP > 424 pg/mL; AUC = 0.94, respectively). There was a positive correlation between exhaled breath acetone and plasmatic BNP (r = 0.772, p < 0.001). Levels of exhaled breath acetone were different among the four different NYHA classes (p<0.001). In summary, we can conclude that our study showed exhaled breath acetone as a new biomarker of heart failure and ADHF. It is associated with heart failure severity and has a good correlation with BNP. This is a promising non-invasive diagnostic method of heart failure, whose accuracy is equivalent to BNP
12

Avaliação de estratégia ventilatória seqüencial em pacientes com lesão pulmonar aguda (LPA) / síndrome do desconforto respiratório agudo (SDRA) / Effects of open lung concept following ARDSNet ventilatory strategy in patients with early acute lung injury (ALI) / acute respiratory distress syndrome (ARDS)

Rotman, Vivian 19 September 2008 (has links)
A utilização de baixos volumes correntes na Injuria Pulmonar Aguda (LPA) / Síndrome do Desconforto Respiratório Agudo (SDRA) está comprovadamente associada à redução de mortalidade. No entanto, a aplicação de manobras de recrutamento e a utilização de níveis elevados de PEEP ainda são controversos. O objetivo do presente estudo foi comparar os efeitos da estratégia ARDSnet e de uma estratégia baseada no Open Lung Concept (OLC), aplicadas de forma seqüencial, com relação à função pulmonar, imagem tomográfica e atividade inflamatória, em pacientes com LPA / SDRA. Dez pacientes que preencheram os critérios de LPA / SDRA segundo a Conferência de Consenso de 1994 com tempo de evolução até 48 horas foram incluídos. Para seleção definitiva, gasometria arterial para cálculo da relação PaO2/FIO2 foi coletada após 30 minutos de ventilação com volume corrente (VT) = 10 mL/kg, PEEP=5 cmH2O e FIO2 = 100%. Nas primeiras 24 horas os pacientes foram ventilados segundo o protocolo ARDSnet. Após este período, caso PaO2/FIO2 350, adotava-se a estratégia de OLC, que consistia na realização de manobra de recrutamento e titulação de PEEP. A manobra de recrutamento foi realizada em PCV, com delta de pressão de 20 cmH2O, com incrementos seqüenciais de PEEP em 5 cmH2O, partindo-se de 20 cmH2O até 30 cmH2O. O objetivo durante a titulação de PEEP foi alcançar PaO2/FIO2 > 350, sendo três níveis testados (17, 19 e 21 cmH2O). Ventilação segundo OLC (com PEEP determinado durante a titulação e VT = 6 ml/kg) foi mantida por 24 h adicionais. Após 24 h de cada estratégia, TC de todo o pulmão (1,25 mm de espessura com 15 mm de espassamento) foi realizada após 24 h de cada estratégia. A instituição de OLC foi necessária em 9 dos 10 pacientes estudados. PEEP foi significativamente superior com OLC (17 [17 - 19] vs. 8 cmH2O [7,25 - 11]; p = 0,007) e resultou em melhora significativa de oxigenação, sustentada após 24 h de seguimento, sem diferença na pressão de platô, pressão de distensão, complacência estática, ventilação-minuto, PaCO2 e pH (p > 0,05). OLC determinou redução significativa na percentagem de volume pulmonar total (VPT) não aerado (13% [10,5 22,5] vs. 37% [31 40,5]; p = 0,008), sem aumento significativo na percentagem de VPT hiperinsuflado (5% [1 13,5] vs. 2% [0 6,5]; p = 0,079). A análise baseada em massa pulmonar total (MPT) evidenciou resultados semelhantes: a percentagem de MPT não aerada com OLC foi significativamente menor (30% [23 48,5] vs. 58% [51 60]; p=0,008), sem aumento significativo na percentagem de MPT hiperinsuflada (1% [0 2] vs. 0 % [0 1]; p=0,084). Não houve diferenças significativas nas doses infundidas de vasopressores, balanço hídrico ou pressão arterial. Observou-se, também, redução significativa nos níveis plasmáticos de IL-6 com OLC (3,32 [2,16 9,46] vs. 4,11 ng/mL [3,26 11,02]; p=0,018) Concluimos que, quando comparada à ARDSnet, OLC melhorou a oxigenação, reduzindo a fração de regiões pulmonares não aeradas, sem aumento significativo nas regiões hiperinsufladas, com níveis semelhantes de pressão arterial e balanço hídrico. / Low tidal volumes are associated with a reduction in mortality in ALI / ARDS. Nevertheless, the application of recruitment maneuvers and high levels of PEEP are still controversial. The aim of this study was to compare the ARDSnet protocol with a strategy based on Open Lung Concept (OLC), applied in a sequential way, in terms of pulmonary function, computed tomography images and inflammation, in patients with ALI / ARDS. Ten patients fulfilling criteria for ALI /ARDS, based on the American-European Consensus Conference, with less than 48 hours of evolution, were included. For definitive selection, blood gas collected after 30 min application of 5 cmH2O PEEP and VT = 10 mL/kg had to demonstrate a PaO2/FIO2 < 300 mmHg. The patients were initially ventilated for 24 hours according to the ARDSnet protocol. After this period, if the PaO2/FIO2 was 350, an OLC strategy was adopted, with recruitment maneuver and PEEP titration. The recruitment maneuver was applied in PCV, with sequential 5 cmH2O increments in PEEP, starting from 20 cmH2O until PEEP = 30 cmH2O, maintaining a delta pressure of 20 cmH2O. The aim of PEEP titration was to reach PaO2/FIO2 > 350 and three levels were tested: 17, 19 and 21 cmH2O. Ventilation according to OLC (VT = 6 mL/kg and PEEP´s level found during titration) was applied for the next 24 hours. Whole lung computed tomography images (1.25 mm thickness with 15mm gap) were acquired after 24 hours of each strategy. The institution of OLC was necessary in 9 of the 10 studied patients. The PEEP was significantly higher during OLC (17 [17-19] vs 8 cmH2O [8-11]; p=0,007) and resulted in a significant improvement on oxygenation sustained for 24 hours of follow-up, with no significant differences in plateau pressure, static compliance, minute-ventilation, PaCO2 and pH (p > 0.05). OLC resulted in a significant reduction of the fraction of total lung volume that was non-aerated, as compared to ARDSnet protocol (13% [10,5 22,5] vs. 37% [31 40,5]; p = 0,008), without a significant increase of the fraction of total lung volume that was hyperinsuflated (5% [1 13,5] vs. 2% [0 6,5]; p = 0,079). The results based on lung mass analysis were similar. OLC was associated with a reduction of the fraction of total lung mass that was non-aerated 30% [23 48,5] vs. 58% [51 60]; p=0,008), without a significant increase of the fraction of total lung mass that was hyperinsuflated (1% [0 2] vs. 0 % [0 1]; p=0,084). There was also a reduction in plasma levels of IL-6 with OLC (3,32 [2,16 9,46] vs. 4,11 ng/mL [3,26 11,02]; p=0,018). We concluded that, when compared with ARDSnet protocol, OLC improved oxygenation, reducing the fraction of non-aerated regions without significant increment in hyperinflated areas, with comparable levels of hemodynamics and fluid balance
13

Avaliação de estratégia ventilatória seqüencial em pacientes com lesão pulmonar aguda (LPA) / síndrome do desconforto respiratório agudo (SDRA) / Effects of open lung concept following ARDSNet ventilatory strategy in patients with early acute lung injury (ALI) / acute respiratory distress syndrome (ARDS)

Vivian Rotman 19 September 2008 (has links)
A utilização de baixos volumes correntes na Injuria Pulmonar Aguda (LPA) / Síndrome do Desconforto Respiratório Agudo (SDRA) está comprovadamente associada à redução de mortalidade. No entanto, a aplicação de manobras de recrutamento e a utilização de níveis elevados de PEEP ainda são controversos. O objetivo do presente estudo foi comparar os efeitos da estratégia ARDSnet e de uma estratégia baseada no Open Lung Concept (OLC), aplicadas de forma seqüencial, com relação à função pulmonar, imagem tomográfica e atividade inflamatória, em pacientes com LPA / SDRA. Dez pacientes que preencheram os critérios de LPA / SDRA segundo a Conferência de Consenso de 1994 com tempo de evolução até 48 horas foram incluídos. Para seleção definitiva, gasometria arterial para cálculo da relação PaO2/FIO2 foi coletada após 30 minutos de ventilação com volume corrente (VT) = 10 mL/kg, PEEP=5 cmH2O e FIO2 = 100%. Nas primeiras 24 horas os pacientes foram ventilados segundo o protocolo ARDSnet. Após este período, caso PaO2/FIO2 350, adotava-se a estratégia de OLC, que consistia na realização de manobra de recrutamento e titulação de PEEP. A manobra de recrutamento foi realizada em PCV, com delta de pressão de 20 cmH2O, com incrementos seqüenciais de PEEP em 5 cmH2O, partindo-se de 20 cmH2O até 30 cmH2O. O objetivo durante a titulação de PEEP foi alcançar PaO2/FIO2 > 350, sendo três níveis testados (17, 19 e 21 cmH2O). Ventilação segundo OLC (com PEEP determinado durante a titulação e VT = 6 ml/kg) foi mantida por 24 h adicionais. Após 24 h de cada estratégia, TC de todo o pulmão (1,25 mm de espessura com 15 mm de espassamento) foi realizada após 24 h de cada estratégia. A instituição de OLC foi necessária em 9 dos 10 pacientes estudados. PEEP foi significativamente superior com OLC (17 [17 - 19] vs. 8 cmH2O [7,25 - 11]; p = 0,007) e resultou em melhora significativa de oxigenação, sustentada após 24 h de seguimento, sem diferença na pressão de platô, pressão de distensão, complacência estática, ventilação-minuto, PaCO2 e pH (p > 0,05). OLC determinou redução significativa na percentagem de volume pulmonar total (VPT) não aerado (13% [10,5 22,5] vs. 37% [31 40,5]; p = 0,008), sem aumento significativo na percentagem de VPT hiperinsuflado (5% [1 13,5] vs. 2% [0 6,5]; p = 0,079). A análise baseada em massa pulmonar total (MPT) evidenciou resultados semelhantes: a percentagem de MPT não aerada com OLC foi significativamente menor (30% [23 48,5] vs. 58% [51 60]; p=0,008), sem aumento significativo na percentagem de MPT hiperinsuflada (1% [0 2] vs. 0 % [0 1]; p=0,084). Não houve diferenças significativas nas doses infundidas de vasopressores, balanço hídrico ou pressão arterial. Observou-se, também, redução significativa nos níveis plasmáticos de IL-6 com OLC (3,32 [2,16 9,46] vs. 4,11 ng/mL [3,26 11,02]; p=0,018) Concluimos que, quando comparada à ARDSnet, OLC melhorou a oxigenação, reduzindo a fração de regiões pulmonares não aeradas, sem aumento significativo nas regiões hiperinsufladas, com níveis semelhantes de pressão arterial e balanço hídrico. / Low tidal volumes are associated with a reduction in mortality in ALI / ARDS. Nevertheless, the application of recruitment maneuvers and high levels of PEEP are still controversial. The aim of this study was to compare the ARDSnet protocol with a strategy based on Open Lung Concept (OLC), applied in a sequential way, in terms of pulmonary function, computed tomography images and inflammation, in patients with ALI / ARDS. Ten patients fulfilling criteria for ALI /ARDS, based on the American-European Consensus Conference, with less than 48 hours of evolution, were included. For definitive selection, blood gas collected after 30 min application of 5 cmH2O PEEP and VT = 10 mL/kg had to demonstrate a PaO2/FIO2 < 300 mmHg. The patients were initially ventilated for 24 hours according to the ARDSnet protocol. After this period, if the PaO2/FIO2 was 350, an OLC strategy was adopted, with recruitment maneuver and PEEP titration. The recruitment maneuver was applied in PCV, with sequential 5 cmH2O increments in PEEP, starting from 20 cmH2O until PEEP = 30 cmH2O, maintaining a delta pressure of 20 cmH2O. The aim of PEEP titration was to reach PaO2/FIO2 > 350 and three levels were tested: 17, 19 and 21 cmH2O. Ventilation according to OLC (VT = 6 mL/kg and PEEP´s level found during titration) was applied for the next 24 hours. Whole lung computed tomography images (1.25 mm thickness with 15mm gap) were acquired after 24 hours of each strategy. The institution of OLC was necessary in 9 of the 10 studied patients. The PEEP was significantly higher during OLC (17 [17-19] vs 8 cmH2O [8-11]; p=0,007) and resulted in a significant improvement on oxygenation sustained for 24 hours of follow-up, with no significant differences in plateau pressure, static compliance, minute-ventilation, PaCO2 and pH (p > 0.05). OLC resulted in a significant reduction of the fraction of total lung volume that was non-aerated, as compared to ARDSnet protocol (13% [10,5 22,5] vs. 37% [31 40,5]; p = 0,008), without a significant increase of the fraction of total lung volume that was hyperinsuflated (5% [1 13,5] vs. 2% [0 6,5]; p = 0,079). The results based on lung mass analysis were similar. OLC was associated with a reduction of the fraction of total lung mass that was non-aerated 30% [23 48,5] vs. 58% [51 60]; p=0,008), without a significant increase of the fraction of total lung mass that was hyperinsuflated (1% [0 2] vs. 0 % [0 1]; p=0,084). There was also a reduction in plasma levels of IL-6 with OLC (3,32 [2,16 9,46] vs. 4,11 ng/mL [3,26 11,02]; p=0,018). We concluded that, when compared with ARDSnet protocol, OLC improved oxygenation, reducing the fraction of non-aerated regions without significant increment in hyperinflated areas, with comparable levels of hemodynamics and fluid balance
14

Radiological aspects of petroleum exploration and production in the sultanate of Oman

Al-Farsi, Afkar Nadhim January 2008 (has links)
This thesis is a study of naturally occurring radioactive materials (NORM) activity concentration, gamma dose rate and radon (222Rn) exhalation from the waste streams of large-scale onshore petroleum operations. Types of activities covered included; sludge recovery from separation tanks, sludge farming, NORM storage, scaling in oil tubulars, scaling in gas production and sedimentation in produced water evaporation ponds. Field work was conducted in the arid desert terrain of an operational oil exploration and production region in the Sultanate of Oman. The main radionuclides found were 226Ra and 210Pb (238U - series), 228Ra and 228Th (232Th - series), and 227Ac (235U - series), along with 40K. All activity concentrations were higher than the ambient soil level and varied over several orders of magnitude. The range of gamma dose rates at a 1 m height above ground for the farm treated sludge had a range of 0.06 0.43 µSv h 1, and an average close to the ambient soil mean of 0.086 ± 0.014 µSv h 1, whereas the untreated sludge gamma dose rates had a range of 0.07 1.78 µSv h 1, and a mean of 0.456 ± 0.303 µSv h 1. The geometric mean of ambient soil 222Rn exhalation rate for area surrounding the sludge was mBq m 2 s 1. Radon exhalation rates reported in oil waste products were all higher than the ambient soil value and varied over three orders of magnitude. This study resulted in some unique findings including: (i) detection of radiotoxic 227Ac in the oil scales and sludge, (ii) need of a new empirical relation between petroleum sludge activity concentrations and gamma dose rates, and (iii) assessment of exhalation of 222Rn from oil sludge. Additionally the study investigated a method to determine oil scale and sludge age by the use of inherent behaviour of radionuclides as 228Ra:226Ra and 228Th:228Ra activity ratios.
15

Measurement of 222Rn Exhalation Rates and 210Pb Deposition Rates in a Tropical Environment

Lawrence, Cameron Eoin January 2006 (has links)
This thesis provides the measurements of 222Rn exhalation rates, 210Pb deposition rates and excess 210Pb inventories for locations in and around Ranger Uranium Mine and Jabiru located within Kakadu National Park, Australia. Radon-222 is part of the natural 238U series decay chain and the only gas to be found in the series under normal conditions. Part of the natural redistribution of 222Rn in the environment is a portion exhales from the ground and disperses into the atmosphere. Here it decays via a series of short-lived progeny, that attach themselves to aerosol particles, to the long lived isotope 210Pb (T1/2 = 22.3 y). Attached and unattached 210Pb is removed from the atmosphere through wet and dry deposition and deposited on the surface of the earth, the fraction deposited on soils is gradually transported through the soil and can create a depth profile of 210Pb. Here it decays to the stable isotope 206Pb completing the 238U series. Measurements of 222Rn exhalation rates and 210Pb deposition rates were performed over complete seasonal cycles, August 2002 - July 2003 and May 2003 - May 2004 respectively. The area is categorised as wet and dry tropics and it experiences two distinct seasonal patterns, a dry season (May-October) with little or no precipitation events and a wet season (December-March) with almost daily precipitation and monsoonal troughs. November and April are regarded as transitional months. As the natural processes of 222Rn exhalation and 210Pb deposition are heavily influenced by soil moisture and precipitation respectively, seasonal variations in the exhalation and deposition rates were expected. It was observed that 222Rn exhalation rates decreased throughout the wet season when the increase in soil moisture retarded exhalation. Lead-210 deposition peaked throughout the wet season as precipitation is the major scavenging process of this isotope from the atmosphere. Radon-222 is influenced by other parameters such as 226Ra activity concentration and distribution, soil porosity and grain size. With the removal of the influence of soil moisture during the dry season it was possible to examine the effect of these other variables in a more comprehensive manner. This resulted in categorisation of geomorphic landscapes from which the 222Rn exhalation rate to 226Ra activity concentration ratios were similar during the dry season. These results can be extended to estimate dry season 222Rn exhalation rates from tropical locations from a measurement of 226Ra activity concentration. Through modelling the 210Pb budget on local and regional scales it was observed that there is a net loss of 210Pb from the region, the majority of which occurs during the dry season. This has been attributed to the fact that 210Pb attached to aerosols is transported great distance with the prevailing trade winds created by a Hadley Circulation cell predominant during the dry season (winter) months. By including the influence of factors such as water inundation and natural 210Pb redistribution in the soil wet season budgeting of 210Pb on local and regional scales gave very good results.

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