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Relationship between ozone, meteorological conditions, gas exchange and leaf injury in Nicotiana tabacum Bel-W3 in a sub-tropical region

Silva, Daiane T.; Meirelles, Sergio Tadeu; Moraes, Regina M.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD Publicador: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.12%
The city of Sao Paulo is located in a subtropical region whose climate exhibits few defined seasons as well as frequent oscillations in temperature and rainfall throughout the year. In addition to interfering with physiological processes, these peculiar climatic dynamics influence the formation of O-3 and its influx into leaves, causing species used as bioindicators in temperate climates to be ineffective here. This study evaluated gas exchange variations in CO2 and H2O and leaf injuries induced by O-3 in Nicotiana tabacum Bel-W3 in relation to oscillations in environmental conditions. Plants were exposed to an O-3-polluted environment for fifteen periods of fourteen days each throughout 2008. Gas exchange and O-3 were higher during the summer and winter but were highly variable in all seasons. Severe injuries occurred during the winter and spring, with significant variation in this parameter being observed throughout the year. An analysis of biotic and abiotic variables revealed complex relationships among them, with great importance of meteorological factors in plant responses. We conclude that under unstable climatic conditions, the relationship between O-3 flux and injury is weak, and the qualitative character of biomonitoring is further confirmed. (c) 2012 Elsevier Ltd. All rights reserved.

Estudo do comportamento hemodinâmico, da troca gasosa, da mecânica respiratória e da análise do muco brônquico na aplicação de técnicas de remoção de secreção brônquica em pacientes sob ventilação mecânica; Airway clearance techniques in patients submitted to mechanical ventilation: A hemodynamic, gas exchange, respiratory mechanics and bronquial sputum study

Rodrigues, Marcus Vinicius Herbst
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 11/12/2007 PT
Relevância na Pesquisa
66.17%
INTRODUÇÃO: A aspiração traqueal (ASP) é um procedimento de rotina em pacientes sob ventilação mecânica, porém em algumas situações pode não ser eficiente. Como adjuvante usa-se a técnica "Bag-Squeezing" (BS) que consiste na hiperinflação manual associada à compressão torácica manual expiratória seguida ASP. Embora efetiva esta técnica pode apresentar algumas limitações como a desconexão do ventilador mecânico, além do controle precário do pico de pressão inspiratória (PPI) e pico de fluxo inspiratório (PFI). Como opção, podemos substituir o ressuscitador manual pelo próprio ventilador mecânico, alterando seus parâmetros e evitando assim a desconexão. Propusemos padronizar esta técnica e denominá-la PEEP-ZEEP (PZ); realizando-se a inflação dos pulmões aumentando a PEEP em 10 cmH2O, por 5 ciclos respiratórios, seguido de rápida descompressão pulmonar pela redução abrupta da PEEP até 0 cmH20, simultâneo à compressão torácica manual. OBJETIVOS: Avaliar o comportamento hemodinâmico, da troca gasosa e da mecânica respiratória, na aplicação das técnicas ASP, BS e PZ e seus efeitos na remoção de secreções brônquicas em pacientes ventilados mecanicamente. MÉTODO: 1ª etapa - "Pacientes sem secreção brônquica" estudamos prospectivamente 45 pacientes...

Deficiência hídrica e aplicação de ABA sobre as trocas gasosas e o acúmulo de flavonóides em calêndula (Calendula officinalis L.); Water deficit and ABA application on leaf gas exchange and flavonoid content in marigold (Calendula officinalis L.)

Pacheco, Ana Cláudia
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/12/2007 PT
Relevância na Pesquisa
66.19%
Foram estudados os efeitos da deficiência hídrica e da aplicação de ácido abscísico (ABA) sobre alguns aspectos fisiológicos e a produção de flavonóides em plantas de calêndula. Testaramse quatro intervalos de suspensão da irrigação (controle - irrigação diária; 3; 6 e 9 dias sem irrigar) acompanhados por três doses de ABA (0, 10 e 100 µM), resultando em 12 tratamentos. O experimento foi instalado em condições de casa de vegetação com plantas envasadas. Os tratamentos foram aplicados no início do florescimento e seus efeitos foram avaliados pelo conteúdo relativo de água na folha (CRA) e trocas gasosas (A= fotossíntese líquida, gs= condutância estomática, E= transpiração, Ci= concentração intercelular de CO2 e TL= temperatura da folha); por meio de analisador portátil por infra-vermelho. A eficiência do uso da água (EUA) foi calculada como A/E. Aos 3 dias de suspensão da irrigação as plantas de calêndula não apresentaram alterações significativas nas variáveis de trocas gasosas avaliadas. Aos 6 dias de deficiência hídrica as variáveis Ci, CRA e EUA não apresentaram diferença em relação aos tratamentos com suprimento constante de água, acrescidos ou não de ABA. Porém, a imposição de estresse hídrico somada à aplicação de ABA nas plantas resultou em diminuição nos valores de E...

Comparative gas exchange performance during the wet season of three Brazilian Styrax species under habitat conditions of cerrado vegetation types differing in soil water availability and crown density

Habermann, Gustavo; Ellsworth, Patricia F. V.; Cazoto, Juliana L.; Simao, Edson; Bieras, Angela C.
Fonte: Elsevier Gmbh, Urban & Fischer Verlag Publicador: Elsevier Gmbh, Urban & Fischer Verlag
Tipo: Artigo de Revista Científica Formato: 351-359
ENG
Relevância na Pesquisa
66.04%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 06/01125-8; Processo FAPESP: 06/01180-9; We studied the influence of environmental conditions in different vegetation types of the Brazilian savanna (cerrado s.l.) on CO2 assimilation and water use efficiency of Styrax ferrugineus, S. camporum and S. pohlii, which are morphologically similar but have distinct distribution patterns. We measured leaf gas exchange and water relations in adult and young plants. Adult plants of S. ferrugineus were measured in the cerrado s. str.: plants of S. camporum at the edge of cerradao, a woodland vegetation; and in a riparian forest those of S. pohlii. Eight-month-old young plants were planted in the cerrado s. str., at the edge and in the understory of the cerradao, and in the understory of the riparian forest. For young plants, the high light availability in the cerrado s. str. resulted in a threefold greater CO2 assimilation rate (A) compared to the other sites. A of adult plants under full irradiation (1800 mu mol photons m(-2) s(-1)) was significantly lower in S. pohlii compared to S. ferrugineus and S. camporum. Although sufficient soil water was available at every site at the end of the wet season, the extreme high water content in the riparian forest soil led to increased stomatal conductance (gs) and transpiration rate (E) for young plants of S. camporum and S. pohlii...

Mecanismos que interferem no intercambio gasoso no tromboembolismo pulmonar experimental; Mechanisms underlying gas exchange alterations in an experimental model of pulmonary embolism

Juliana Heloisa Terra Ferreira
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 13/06/2006 PT
Relevância na Pesquisa
66.16%
A literatura aborda de forma muito ampla os mecanismos responsáveis pela gênese da hipoxemia no tromboembolismo pulmonar (TEP). O objetivo deste estudo foi analisar quais os mecanismos que contribuíram para a hipoxemia em um modelo de TEP agudo experimental. A embolização com coágulos autólogos foi realizada em sete porcos com peso de 24,00±0,6 kg, anestesiados e mecanicamente ventilados na modalidade controlada, com fração de oxigênio no ar inspirado (FiO2) de 0,21. A análise do intercâmbio gasoso foi realizada pela correlação entre a gasometria arterial e a capnografia volumétrica. Foi observada uma significativa redução das pressões parciais de oxigênio tanto no sangue arterial quanto no ar alveolar calculada pela equação do ar alveolar. A ventilação alveolar efetiva apresentou significativa redução, evidenciando a consistente queda do volume de gás alveolar que efetivamente participou das trocas gasosas (VAef). A relação entre a ventilação alveolar que efetivamente participou das trocas gasosas e o débito cardíaco (V?Aef/Q?), também apresentou uma redução significativa após a embolização. Embora a pressão parcial de dióxido de carbono (CO2) no sangue arterial aumente significativamente, a pressão parcial de CO2 no final da expiração (PetCO2) apresentou significativa redução...

Mechanisms underlying gas exchange alterations in an experimental model of pulmonary embolism

Ferreira,J.H.T.; Terzi,R.G.G.; Paschoal,I.A.; Silva,W.A.; Moraes,A.C.; Moreira,M.M.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2006 EN
Relevância na Pesquisa
66.14%
The aim of the present study was to determine the ventilation/perfusion ratio that contributes to hypoxemia in pulmonary embolism by analyzing blood gases and volumetric capnography in a model of experimental acute pulmonary embolism. Pulmonary embolization with autologous blood clots was induced in seven pigs weighing 24.00 ± 0.6 kg, anesthetized and mechanically ventilated. Significant changes occurred from baseline to 20 min after embolization, such as reduction in oxygen partial pressures in arterial blood (from 87.71 ± 8.64 to 39.14 ± 6.77 mmHg) and alveolar air (from 92.97 ± 2.14 to 63.91 ± 8.27 mmHg). The effective alveolar ventilation exhibited a significant reduction (from 199.62 ± 42.01 to 84.34 ± 44.13) consistent with the fall in alveolar gas volume that effectively participated in gas exchange. The relation between the alveolar ventilation that effectively participated in gas exchange and cardiac output (V Aeff/Q ratio) also presented a significant reduction after embolization (from 0.96 ± 0.34 to 0.33 ± 0.17 fraction). The carbon dioxide partial pressure increased significantly in arterial blood (from 37.51 ± 1.71 to 60.76 ± 6.62 mmHg), but decreased significantly in exhaled air at the end of the respiratory cycle (from 35.57 ± 1.22 to 23.15 ± 8.24 mmHg). Exhaled air at the end of the respiratory cycle returned to baseline values 40 min after embolism. The arterial to alveolar carbon dioxide gradient increased significantly (from 1.94 ± 1.36 to 37.61 ± 12.79 mmHg)...

Effect of saline infusion for the maintenance of blood volume on pulmonary gas exchange during temporary abdominal aortic occlusion

Amorim,F.F.; Pinheiro,B.V.P.; Beppu,O.S.; Romaldini,H.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2007 EN
Relevância na Pesquisa
66.17%
We analyzed the effects of saline infusion for the maintenance of blood volume on pulmonary gas exchange in ischemia-reperfusion syndrome during temporary abdominal aortic occlusion in dogs. We studied 20 adult mongrel dogs weighing 12 to 23 kg divided into two groups: ischemia-reperfusion group (IRG, N = 10) and IRG submitted to saline infusion for the maintenance of mean pulmonary arterial wedge pressure between 10 and 20 mmHg (IRG-SS, N = 10). All animals were anesthetized and maintained on spontaneous ventilation. After obtaining baseline measurements, occlusion of the supraceliac aorta was performed by the inflation of a Fogarty catheter. After 60 min of ischemia, the balloon was deflated and the animals were observed for another 60 min of reperfusion. The measurements were made at 10 and 45 min of ischemia, and 5, 30, and 60 min of reperfusion. Pulmonary gas exchange was impaired in the IRG-SS group as demonstrated by the increase of the alveolar-arterial oxygen difference (21 ± 14 in IRG-SS vs 11 ± 8 in IRG after 60 min of reperfusion, P = 0.004 in IRG-SS in relation to baseline values) and the decrease of oxygen partial pressure in arterial blood (58 ± 15 in IRG-SS vs 76 ± 15 in IRG after 60 min of reperfusion, P = 0.001 in IRG-SS in relation to baseline values)...

Effects of changes in the photosynthetic photon flux density on net gas exchange of Citrus limon and Nicotiana tabacum

Pimentel,Carlos; Ribeiro,Rafael Vasconcelos; Santos,Mauro Guida dos; Oliveira,Ricardo Ferraz de; Machado,Eduardo Caruso
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2004 EN
Relevância na Pesquisa
66.04%
The objective of this study was to evaluate the effects of changes in the photosynthetic photon flux density (PPFD) on net gas exchange of Citrus limon, a woody species, and Nicotiana tabacum, an herbaceous species. When PPFD was increased from 50 to 350 mumol.m-2.s-1 and returned to 50 mumol.m-2.s-1 after 60 min, the CO2 assimilation rate (A) increased and stabilized after 15 min in both species. Stomatal conductance (g s), however, continued to increase. After returning to low PPFD, A immediately diminished to a low value for both lemon and tobacco. Stomatal conductance of lemon diminished slowly over 60 min, whereas g s for tobacco took only 15 min to decrease. This difference in behavior is probably due to over-sensitivity of stomata of woody species, such as Citrus, when exposed to high light, retarding stomatal closure on return to low PPFD. Furthermore, when lemon, growing at a PPFD of 300 mumol.m-2.s-1, was submitted to a step increase of 600 mumol.m-2.s-1, there was an oscillatory behavior of A and g s requiring 150 min to stabilize. The causes of this behavior are discussed with respect to improved intrinsic water use efficiency by stomatal closure.

Combined Effects of Differential Irrigation and Feeding Injury by the Citrus Red Mite (Acari: Tetranychidae) on Gas Exchange of Orange Leaves

Hare, Daniel J.; Pehrson, John E.; Clemens, Tim; Youngman, Roger R.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
Relevância na Pesquisa
66.26%
Experiments were done to determine the combined and potentially interacting effects of differential irrigation and feeding damage by the citrus red mite, Panonychus citriMcGregor, on gas exchange of orange (Citrus sinensis (L.) Osbeck) leaves. Individual trees within a 40-yr-old grove were differentially irrigated at 80, 100, or 120% of their calculated evapotranspirational (ET) demand and differentially treated with acaricides in a factorial design. Gas exchange of orange leaves was measured at about 28-d intervals during the summer of 1987. Peak mite densities on acaricide-free trees were more than three times greater than the conventional treatment threshold, whereas peak densities on acaricide-treated trees just slightly exceeded this threshold. Gas exchange was significantly affected by irrigation and was generally highest in the 120% ET treatment. Gas exchange was generally independent of mite densities, and there was no interaction between irrigation and mite feeding on rates of gas exchange. Results suggest that for highest gas exchange rates, it may be more important to maintain irrigation levels close to or slightly above forecast ET levels than to suppress mite populations to their conventional, “visible-injury” treatment threshold.

Developmental energetics and gas exchange in amphibians and lungfish.

Mueller, Casey Anne
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011
Relevância na Pesquisa
66.24%
The development of amphibians and fishes is a complex process influenced by intrinsic and extrinsic factors. In this study I examine how energy use and gas exchange contribute to the success and rate of development in two Myobatrachid frogs, Pseudophryne bibronii and Crinia georgiana and the Australian lungfish, Neoceratodus forsteri. 1. Embryonic development of N. forsteri is affected by both temperature and oxygen level. Development time and the cost of development both decreased from 15 to 25°C. At 20°C survival and development rate were highest at oxygen partial pressures (PO₂) of 15 and 20.9 kPa. Hypoxia induced an early hatching age and stage and a decrease in hatchling mass. Breakdown of the vitelline membrane, which is stage-specific and unresponsive to PO₂ or temperature, allowed capsule conductance (GO₂) to increase, promoting oxygen uptake. The inherently low metabolic demand of N. forsteri results in an unusually low cost of development compared to other amphibians and fishes. 2. The partitioning and use of energy throughout development differs between P. bibronii and C. georgiana as modelled using dynamic energy budget theory. The aquatic C. georgiana reaches metamorphosis 1.7 times faster. The species switches energy partitioning at hatching to favour maturation over growth...

Allometric scaling of discontinuous gas exchange patterns in the locust Locusta migratoria throughout ontogeny

Snelling, E.; Matthews, P.; Seymour, R.
Fonte: Company of Biologists Ltd Publicador: Company of Biologists Ltd
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
66.12%
The discontinuous gas exchange cycle (DGC) is a three-phase breathing pattern displayed by many insects at rest. The pattern consists of an extended breath-hold period (closed phase), followed by a sequence of rapid gas exchange pulses (flutter phase), and then a period in which respiratory gases move freely between insect and environment (open phase). This study measured CO2 emission in resting locusts Locusta migratoria throughout ontogeny, in normoxia (21 kPa PO2), hypoxia (7 kPa PO2) and hyperoxia (40 kPa PO2), to determine whether body mass and ambient O2 affect DGC phase duration. In normoxia, mean CO2 production rate scales with body mass (Mb; g) according to the allometric power equation , closed phase duration (C; min) scales with body mass according to the equation C=8.0Mb0.38±0.29, closed+flutter period (C+F; min) scales with body mass according to the equation C+F=26.6M 0.20±0.25b and open phase duration (O; min) scales with body mass according to the equation O=13.3Mb 0.23±0.18. Hypoxia results in a shorter C phase and longer O phase across all life stages, whereas hyperoxia elicits shorter C, C+F and O phases across all life stages. The tendency for larger locusts to exhibit longer C and C+F phases might arise if the positive allometric scaling of locust tracheal volume prolongs the time taken to reach the minimum O2 and maximum CO2 set-points that determine the duration of these respective periods...

A test of the oxidative damage hypothesis for discontinuous gas exchange in the locust Locusta migratoria

Matthews, P.; Snelling, E.; Seymour, R.; White, C.
Fonte: The Royal Society Publicador: The Royal Society
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
66.04%
The discontinuous gas exchange cycle (DGC) is a breathing pattern displayed by many insects, characterized by periodic breath-holding and intermittently low tracheal O2 levels. It has been hypothesized that the adaptive value of DGCs is to reduce oxidative damage, with low tracheal O2 partial pressures (PO2 ∼2–5kPa) occurring to reduce the production of oxygen free radicals. If this is so, insects displayingDGCs should continue to actively defend a low tracheal PO2 even when breathing higher than atmospheric levels of oxygen (hyperoxia). This behaviour has been observed in moth pupae exposed to ambient PO2 up to 50 kPa. To test this observation in adult insects, we implanted fibre-optic oxygen optodes within the tracheal systems of adult migratory locusts Locusta migratoria exposed to normoxia, hypoxia and hyperoxia. In normoxic and hypoxic atmospheres, the minimum tracheal PO2 that occurred during DGCs varied between 3.4 and 1.2 kPa. In hyperoxia up to 40.5 kPa,the minimum tracheal PO2 achieved during a DGC exceeded 30 kPa, increasing with ambient levels. These results are consistent with a respiratory control mechanism that functions to satisfy O2 requirements by maintaining PO2 above a critical level, not defend against high levels of O2.; Philip G.D. Matthews...

Analysis of cutaneous and internal gill gas exchange morphology in early larval amphibians, Pseudophryne bibronii and Crinia georgiana

Mueller, C.; Seymour, R.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
66.12%
This study uses stereological techniques to examine body, internal gill and cardiovascular morphology of two larval amphibians, Pseudophryne bibronii and Crinia georgiana, to evaluate the roles of diffusive and convective gas exchange. Gosner stage 27 specimens were prepared for light microscopy and six parallel sections of equal distance taken through the body as well as a further six through the heart and internal gills. Body, internal gill and heart volume as well as body and internal gill surface areas were determined. The harmonic mean distance across the internal gills was also measured and used to estimate oxygen diffusive conductance, DO2. The species were of similar body size and surface area, but the heart and internal gills were larger in P. bibronii, which may represent precursors for greater growth of the species beyond stage 27. The much larger surface area of the skin compared to the internal gills in both species suggests it is the main site for gas exchange, with the gills supplementing oxygen uptake. The sparse cutaneous capillary network suggests diffusion is the main oxygen transport mechanism across the skin and directly into deeper tissues. A numerical model that simplifies larval shape, and has an internal (axial vessels) and external oxygen source...

The effect of palatal dysfunction on measures of ventilation and gas exchange in Thoroughbred racehorses during high intensity exercise

Allen, K.; Franklin, S.
Fonte: Equine Veterinary Journal Ltd Publicador: Equine Veterinary Journal Ltd
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
66.17%
REASON FOR PERFORMING STUDY: The effect of palatal instability (PI) on measures of ventilation and gas exchange is not well understood. OBJECTIVES: To assess to what degree different severities of naturally occurring palatal dysfunction affect ventilation and gas exchange during strenuous exercise. METHODS: A retrospective study was performed using data collected from 40 Thoroughbred racehorses diagnosed with naturally occurring dynamic palatal dysfunction during high speed treadmill exercise. Upper airway videoendoscopic recordings were made concurrently with measurements of ventilation and gas exchange. Three categories of soft palate dysfunction were formed: mild palatal instability; moderate to severe palatal instability; and dorsal displacement of the soft palate (DDSP). Minute ventilation, tidal volume, breathing frequency, end-tidal carbon dioxide and oxygen concentrations, oxygen consumption and carbon dioxide production were calculated during the last 10 s of the exercise test, when airway obstruction was at its worst. RESULTS: There was a trend for minute ventilation, tidal volume, oxygen consumption and carbon dioxide production to decrease with increasing degree of palatal dysfunction, although statistically significant differences were only seen with DDSP. End-tidal carbon dioxide increased and end-tidal oxygen decreased with increasing obstruction...

Efeitos da pressão positiva continua nas vias aereas aplicada durantes a circulação extracorporea na troca gasosa pulmonar no pos-operatorio de cirurgia de revascularização miocardica; Effects of continous positive airway pressure applied during cardiopulmonary bypass on pos-operative pulmonary gas exchange in coronary artery bypass grafting

Luciana Castilho de Figueiredo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 04/11/2008 PT
Relevância na Pesquisa
66.17%
Objetivo Comparar os índices de trocas gasosas no pós-operatório de pacientes submetidos à revascularização do miocárdio (RM) que receberam ou não pressão positiva contínua nas vias aéreas (CPAP) durante a circulação extracorpórea (CEC). Método: Trinta pacientes adultos submetidos à RM com CEC no período de março a setembro de 2005 foram alocados aleatoriamente em dois grupos: CPAP (n=15), pacientes que utilizaram CPAP a 10 cmH2O durante a CEC, e controle (n=15), pacientes que não utilizaram CPAP. Foram analisados a PaO2/FiO2 e o P(A-a)O2 em quatro momentos: Pré (logo antes da CEC, com FiO2 = 1,0); Pós (30min pós-CEC, com FiO2 = 1,0); PO imediato (12h após a cirurgia, com FiO2 = 0,4 utilizando máscara facial) e 1º PO (24 horas após a cirurgia, com FiO2 = 0,5 utilizando máscara facial). Resultados: A PaO2/FiO2 e o P(A-a)O2 mostraram uma piora significativa no decorrer do tempo dentro de cada grupo, porém sem diferenças significativas entre os grupos em nenhum momento. Quando a PaO2/FiO2 foi subdividida em três categorias, foi observada uma maior prevalência de pacientes do grupo CPAP com valores acima de 200mmHg (p=0,02) apenas no momento Pós (30min pós-CEC). Conclusão: O uso de CPAP de 10cmH2O durante a CEC...

CPAP at 10 cm H2O during cardiopulmonary bypass does not improve postoperative gas exchange

Figueiredo,Luciana Castilho de; Araújo,Sebastião; Abdala,Rosângela Cristina S.; Abdala,Abrão; Guedes,Cristina Aparecida Veloso
Fonte: Sociedade Brasileira de Cirurgia Cardiovascular Publicador: Sociedade Brasileira de Cirurgia Cardiovascular
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2008 EN
Relevância na Pesquisa
66.17%
OBJECTIVE: To compare postoperative (PO) pulmonary gas exchange indexes in patients submitted to myocardial revascularization (MR) with or without the application of continuous positive airway pressure (CPAP) during cardiopulmonary bypass (CPB). METHODS: Thirty adult patients submitted to MR with CPB between March and September 2005 were randomly allocated to two groups: CPAP (n=15), patients that received CPAP at 10 cmH2O during CPB, and control (n=15), patients that didn't receive CPAP. PaO²/FiO2 and P(A-a)O2 were analyzed at four moments: Pre (just before CPB, with FiO2=1.0 ); Post (30min post-CPB, with FiO2=1.0); immediate PO period (12h post-surgery, with FiO2=0.4 by using a Venturi® facial mask) and first PO day (24h post-surgery, with FiO2=0.5 by a facial mask). RESULTS: PaO2/FiO2 and P(A-a)O2 tend to get significantly worst as time elapsed during the postoperative period in both groups, but no differences were observed between them at any moment. When PaO2/FiO2 was subdivided into three categories, a greater prevalence of patients with values between 200 mmHg and 300mmHg were observed in CPAP group only at moment Post (30min post-CPB; p = 0.02). CONCLUSION: CPAP at 10cmH2O administered during CPB, although had lightly improved PaO2/FiO2 at 30 minutes post-CPB...

Neural regulation of discontinuous gas exchange in Periplaneta americana

Woodman, James; Cooper, Paul; Haritos, Victoria S
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.17%
Patterns of gas exchange among terrestrial arthropods are highly variable from continuous to discontinuous with discretely partitioned phases. The underlying initiation and co-ordination of these patterns is relatively poorly understood. Here we present a

Cyclic gas exchange in the giant burrowing cockroach, Macropanesthia rhinoceros : Effect of oxygen tension and temperature

Woodman, James; Cooper, Paul; Haritos, Victoria S
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.12%
The giant burrowing cockroach, Macropanesthia rhinoceros, is endemic to north-eastern Australia and excavates a permanent burrow up to 1 m deep into soil. Using flow-through respirometry, we investigated gas exchange and water loss at three different oxyg

Translational Imaging of Pulmonary Gas-Exchange Using Hyperpolarized 129Xe Magnetic Resonance Imaging

Kaushik, Suryanarayanan Sivaram
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2014
Relevância na Pesquisa
66.3%

The diagnosis and treatment of pulmonary diseases still rely on pulmonary function tests that offer archaic or insensitive biomarkers of lung structure and function. As a consequence, chronic obstructive pulmonary disease is the third leading cause of death in the US, and the hospitalization costs for asthma are on the order of $29 Billion. Pulmonary diseases have created a large and unsustainable economic burden, and hence there is still a dire need for biomarkers that can predict early changes in lung function. The work presented in this thesis looks to address this very issue, by taking advantage of the unique properties of hyperpolarized (HP) 129Xe in conjunction with magnetic resonance imaging (MRI), to probe the fundamental function of the lung - gas-exchange.

While a bulk of the inhaled HP 129Xe stays in the alveolar spaces, its moderate solubility in the pulmonary tissues causes a small fraction of this xenon in the alveolar spaces to diffuse into the pulmonary barrier tissue and plasma, and further into the red blood cells (RBC). Additionally, when in either of these compartments, xenon experiences a unique shift in its resonance frequency from the gas-phase (barrier - 198 ppm, RBC - 217 ppm). These unique resonances are collectively called the dissolved-phase of xenon. As the pathway taken by xenon to reach the RBCs is identical to that of oxygen...

The recommended care for critical patients with nursing diagnosis impaired gas exchange - Systematic Literature Review

Jeronymo, Ana Carolina de Oliveira; Universidade Federal Fluminense; Cruz, Isabel; Universidade Federal Fluminense
Fonte: Universidade Federal Fluminense Publicador: Universidade Federal Fluminense
Tipo: Peer-reviewed Article; Formato: text/html
Publicado em 13/05/2015 EN
Relevância na Pesquisa
66.12%
The nursing diagnosis impaired gas exchange is very common in intensive care units, and its resolution is used some nursing interventions, among them listen lungs and aspire airways. Objective: This research aimed to investigate what is the most efficient and current knowledge in making decisions about the care of the patient with this diagnosis. Method: Was used as a methodology to systematic review of the literature, using of scientific articles, as full text, published between 2009-2014, contained in LILACS and MEDLINE databases. Results: According to scientific evidence, endotracheal aspiration can be defined as an essential component of bronchial hygiene and mechanical. The main recommendations for suction are flights via: just suck when necessary; using a suction catheter with a diameter equal to less than half the tube diameter; should use the lowest possible vacuum pressure; should not remain more than 15 seconds performing the aspiration; should avoid washing with saline solution; should provide a hyperoxygenation process before aspiration; and lastly, it should be aseptic technique. Comparing the open and closed suction systems, there is little scientific evidence that supports the superiority of one system over the other. The aspiration procedure is associated with the complications and risks...