The effect of papaverine on the albumin permeability-surface area product (PS), reflection coefficient (σ), and capillary filtration coefficient (K(f)) was examined in isolated rabbit lungs. Because PS and K(f) are functions of vascular surface area and permeability, we also compared papaverine with two other means of maximizing lung surface area: isoproterenol (1 x 10-7 M) and a mild increase in vascular pressure. Only lungs perfused with 0.1 mg/ml papaverine were significantly different from control. PS increased from control (2.80 ± 0.16 to 5.53 ± 0.20 ml · min-1 · g dry lung-1 x 10-2), whereas σ decreased from control (0.92 ± 0.01 to 0.78 ± 0.03). K(f) after papaverine was significantly lower than baseline predrug K(f) (5.60 ± 0.78 to 4.56 ± 0.53 ml · s-1 · cmH2O-1 · g dry lung-1 x 10-3). However, this group's predrug K(f) was higher than that of any other group. Our results indicate that papaverine increases albumin permeability and decreases endothelial selectivity. The isolated perfused lung appears fully recruited, because K(f) and PS did not increase with isoproterenol or increased vascular pressure. Papaverine should be used with caution in the Ringer-perfused lung.

[pt] Esta dissertação apresenta um estudo numérico, utilizando o método dos elementos finitos, para simular o entupimento de rochas provocado pela injeção de água contendo partículas sólidas. Dentre os diferentes parâmetros que afetam o declínio de injetividade, quatro foram analisados, considerando-se a situação de fluxo unidimensional: fator de dano, concentração de partículas sólidas presentes no fluido de injeção, coeficiente de filtragem e taxa de injeção. Um estudo paramétrico ressaltando a influência destes fatores na perda de injetividade é também apresentado neste trabalho, concluindo-se que os resultados numéricos obtidos concordam satisfatoriamente com as observações experimentais disponíveis e soluções analíticas publicadas na literatura. O trabalho estuda também numericamente a simulação do entupimento dos poros da rocha considerando dois modelos de redução de permeabilidade e recupera valores do coeficiente de filtragem (Lambda ) e do fator de dano ( Beta ) através de análises inversa pelo método dos elementos finitos. / [en] This dissertation presents a numerical study, based on the finite element method, to simulate rock pore plugging caused by the injection of water containing solid particles in suspension. Amongst the parameters that affect rock injectivity decline, the following four were analyzed, considering undimensional flow: damage coefficient, solid particle concentration present in the injection fluid, filtration coefficient and injection rate. A parametric study standing out the influence of the these factors in the loss of injectivity is also presented in this work, concluding that the numerical results agree satisfactorily with the available experimental data and analytical solutions published in the literature. This work also numerically investigates the process of rock pore plugging considering two different permeability reduction models and recovers values of the filtration coefficient (Lambda ) and the damage factor ( Beta ) through inverse analyses carried outn by the finite element method.